JP6943854B2 - Organic wastewater treatment methods and equipment - Google Patents

Organic wastewater treatment methods and equipment Download PDF

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JP6943854B2
JP6943854B2 JP2018529838A JP2018529838A JP6943854B2 JP 6943854 B2 JP6943854 B2 JP 6943854B2 JP 2018529838 A JP2018529838 A JP 2018529838A JP 2018529838 A JP2018529838 A JP 2018529838A JP 6943854 B2 JP6943854 B2 JP 6943854B2
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米山　豊
豊 米山
惇太 高橋
惇太 高橋
直明 片岡
直明 片岡
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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
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    • C02F3/00—Biological treatment of water, waste water, or sewage
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Description

本発明は、生活排水、下水等の低濃度有機性排水をメタン発酵処理し、その処理水を好気性生物処理する省エネルギー型生物学的処理プロセスを用いる有機性排水の処理方法および装置に関する。 The present invention relates to a method and apparatus for treating organic wastewater using an energy-saving biological treatment process in which low-concentration organic wastewater such as domestic wastewater and sewage is treated with methane fermentation and the treated water is treated with aerobic organisms.

有機性排水をメタン発酵処理する技術は、有機性排水を好気性生物処理する技術に比べて、（１）汚泥発生量が少ない、（２）ブロワなどの電気代が不要なためランニングコストがかからない、（３）発生したメタンガスを有効利用できる、等のメリットがあるため、近年、ＣＯＤＣｒ濃度２，０００〜３，０００ｍｇ／Ｌ以上の有機性排水を対象に普及している。メタン発酵処理としては、ＵＡＳＢ（Ｕｐ−ｆｌｏｗ Ａｎａｅｒｏｂｉｃ Ｓｌｕｄｇｅ Ｂｌａｎｋｅｔ（上向流嫌気性汚泥床）の略）法、固定床法、流動床法等がある。特に、ＵＡＳＢ法は、嫌気性微生物の自己造粒機能を利用して、沈降性の優れたグラニュール汚泥を反応槽内に高濃度に保持できるため、ＣＯＤＣｒ負荷１０〜３０ｋｇ／ｍ３／ｄなどの高負荷での処理が可能となるため、ＵＡＳＢ法は国内外の有機性排水をメタン発酵処理する方法として最も普及している。Compared to the technology for treating organic wastewater with methane fermentation, the technology for treating organic wastewater with aerobic organisms does not require running costs because (1) the amount of sludge generated is small and (2) electricity costs such as blowers are not required. , (3) Since the generated methane gas can be effectively used, etc., in recent years, it has become widespread for organic wastewater having a COD Cr concentration of 2,000 to 3,000 mg / L or more. Examples of the methane fermentation treatment include a UASB (Up-flow Anaerobic Sludge Blanket) method, a fixed bed method, and a fluidized bed method. In particular, the UASB method can maintain a high concentration of granule sludge with excellent sedimentation in the reaction vessel by utilizing the self-granulation function of anaerobic microorganisms, so that the COD Cr load is 10 to 30 kg / m 3 / d. The UASB method is the most popular method for methane fermentation treatment of organic wastewater in Japan and overseas because it enables treatment with a high load such as.

ブラジル、インド、東南アジア等の温暖化地域においては、下水等のＣＯＤＣｒ濃度４００〜１，０００ｍｇ／Ｌの有機性排水を対象とし、好気性生物処理（具体的には活性汚泥処理）の前処理としてＵＡＳＢ処理するケースが見られる。In warm regions such as Brazil, India, and Southeast Asia, pretreatment of aerobic biological treatment (specifically, activated sludge treatment) is targeted for organic wastewater with a COD Cr concentration of 400 to 1,000 mg / L such as sewage. In some cases, UASB processing is performed.

しかし、日本のように冬期の気温が０〜１０℃に下がる地域では、処理対象である下水の温度が５〜１５℃と低くなるため、ＵＡＳＢ槽内の温度も５〜１５℃と低温になり、下水をＵＡＳＢ処理する場合には、ＵＡＳＢ槽内の嫌気性菌の活動が抑制され，ＵＡＳＢ槽内に懸濁物質（Ｓｕｓｐｅｎｄｅｄ Ｓｏｌｉｄｓ、以下「ＳＳ」と略称する。）が溜まり、ＵＡＳＢ処理ができない状態となる。また、下水等のＣＯＤＣｒ濃度４００〜１０００ｍｇ／Ｌの有機性排水をＵＡＳＢ処理する場合、ＵＡＳＢ槽の加温に多量のエネルギーを必要とし、ＣＯＤＣｒ濃度１０００〜３０００ｍｇ／Ｌ以上の有機性排水をＵＡＳＢ処理する場合に比べ経済的ではない。こうした理由のため、寒冷地では、下水等のＣＯＤＣｒ濃度４００〜１，０００ｍｇ／Ｌの有機性排水にＵＡＳＢ法によるメタン発酵処理を適用することができなかった。However, in areas such as Japan where the temperature in winter drops to 0 to 10 ° C, the temperature of the sewage to be treated is as low as 5 to 15 ° C, so the temperature inside the UASB tank is also as low as 5 to 15 ° C. When the sewage is treated with UASB, the activity of anaerobic bacteria in the UASB tank is suppressed, suspended solids (Suspended Solids, hereinafter abbreviated as "SS") are accumulated in the UASB tank, and the UASB treatment cannot be performed. It becomes a state. In the case of UASB treating organic waste water of COD Cr concentration 400~1000mg / L of sewage or the like, require a large amount of energy to the heating of the UASB tank, the COD Cr concentration 1000~3000mg / L or more organic waste water It is not as economical as the case of UASB processing. For this reason, in cold regions, the methane fermentation treatment by the UASB method could not be applied to organic wastewater having a COD Cr concentration of 400 to 1,000 mg / L such as sewage.

この改良案として、本発明者らは、メタン発酵槽内の水温１８℃以上では、嫌気性生物を用いて被処理水をメタン発酵処理して、メタンガスを含む発生ガス、メタン発酵処理水及びメタン発酵処理汚泥を得るメタン発酵処理工程と、好気性生物を用いて前記メタン発酵処理水を生物学的酸化分解処理して好気性生物処理水及び好気性生物処理汚泥を得る好気性生物処理工程と、前記好気性生物処理汚泥の一部又は全部を酸発酵処理して酸発酵処理汚泥を得る酸発酵処理工程と、前記酸発酵処理汚泥を、混合脱ガス槽で発酵ガスを分離した後、前記メタン発酵処理工程の入り口側に、前記メタン発酵処理工程におけるスカムの発生を抑制するために供給する工程と、を備える有機性排水の処理方法を提案した（特許文献１）。特許文献１では、メタン発酵槽内の水温が１３℃以上１８℃未満では、前記メタン発酵処理汚泥の一部又は全部を、酸発酵処理工程の入り口側に供給すること、メタン発酵槽内の水温が１３℃未満では、最初沈殿池において被処理水（原水）を分離水と分離汚泥に分離し、分離汚泥或いは該分離汚泥を濃縮した濃縮分離汚泥を、好気性生物処理汚泥の一部とともに酸発酵処理して酸発酵処理汚泥を得、酸発酵処理汚泥を前記分離水と共にメタン発酵処理工程の入り口側に供給することも提案している（特許文献２）。 As an improvement plan, the present inventors methane-ferment the water to be treated with anaerobic organisms at a water temperature of 18 ° C. or higher in the methane fermentation tank, and generate gas containing methane gas, methane fermentation-treated water and methane. A methane fermentation treatment step for obtaining fermentation-treated sludge, and an aerobic biological treatment step for obtaining aerobic biologically treated water and aerobic biologically treated sludge by biologically oxidatively decomposing the methane fermentation treated water using aerobic organisms. The acid fermentation treatment step of obtaining the acid fermentation treatment sludge by acid fermentation treatment of a part or all of the aerobic biological treatment sludge, and the acid fermentation treatment sludge are separated from the fermentation gas in a mixed degassing tank, and then the above. We have proposed a method for treating organic wastewater, which comprises a step of supplying to the entrance side of the methane fermentation treatment step to suppress the generation of scum in the methane fermentation treatment step (Patent Document 1). According to Patent Document 1, when the water temperature in the methane fermentation tank is 13 ° C. or higher and lower than 18 ° C., a part or all of the methane fermentation treatment sludge is supplied to the entrance side of the acid fermentation treatment step, and the water temperature in the methane fermentation tank is supplied. When the temperature is lower than 13 ° C., the water to be treated (raw water) is first separated into separated water and separated sludge in the settling pond, and the separated sludge or concentrated separated sludge obtained by concentrating the separated sludge is acidified together with a part of aerobic biologically treated sludge. It is also proposed to ferment to obtain acid fermentation treated sludge and supply the acid fermentation treated sludge together with the separated water to the entrance side of the methane fermentation treatment step (Patent Document 2).

また、ＣＯＤＣｒ濃度１０００ｍｇ／Ｌ以下の低濃度有機性排水にＵＡＳＢ法を適用すると、ＵＡＳＢ処理水の溶存メタン量が多くなり、ＵＡＳＢ処理水を大気解放すると、溶存メタンは大気中にメタンガスとして放散されてしまう。メタンガスは強力な温室効果ガスの一つとして知られており、その温室効果は二酸化炭素の約２１倍であると言われている。溶存メタンの放散による地球温暖化に与える影響は大きい。この改良案として、本発明者らは、有機性排水をメタン発酵処理するメタン発酵処理槽と、前記メタン発酵処理槽で処理されたメタン発酵処理水を好気性生物処理する浸漬型の反応槽と、前記反応槽中の混合液を固液分離する固液分離装置とを備え、前記メタン発酵処理槽は、該メタン発酵処理槽中の前記メタン発酵処理水に溶存したメタンが大気中に放散するのを防止する蓋部と、前記溶存メタンが大気中に放散するのを防止した状態を保ちながら、前記メタン発酵処理水を前記反応槽に供給する供給部とを有し、前記反応槽は、脱窒処理をする無酸素槽と好気性生物処理する好気槽を有し、前記メタン発酵処理槽が有する供給部は、前記メタン発酵処理水を前記無酸素槽に供給し、前記メタン発酵処理槽の下流であって、前記反応槽の上流に設けられた溶存メタン回収槽を備え、前記溶存メタン回収槽は、該溶存メタン回収槽内の前記メタン発酵処理水に、二酸化炭素、窒素、空気、不活性ガスの内の１の気体または２以上の混合気体を吹き込む気体吹込装置と、前記気体の吹き込みにより回収されたメタンガスを前記無酸素槽に供給する供給部を有する有機性排水処理装置を提案している。Further, when the UASB method is applied to low-concentration organic wastewater having a COD Cr concentration of 1000 mg / L or less, the amount of dissolved methane in the UASB-treated water increases, and when the UASB-treated water is released to the atmosphere, the dissolved methane is released into the atmosphere as methane gas. Will be done. Methane gas is known as one of the powerful greenhouse gases, and its greenhouse effect is said to be about 21 times that of carbon dioxide. The effect of emission of dissolved methane on global warming is great. As an improvement plan, the present inventors include a methane fermentation treatment tank for methane fermentation treatment of organic wastewater and an immersion type reaction tank for aerobic biological treatment of methane fermentation treatment water treated in the methane fermentation treatment tank. The methane fermentation treatment tank is provided with a solid-liquid separation device for solid-liquid separation of the mixed liquid in the reaction tank, and the methane in the methane fermentation treatment water in the methane fermentation treatment tank dissipates into the atmosphere. The reaction tank has a lid portion for preventing methane fermentation and a supply unit for supplying the methane fermentation-treated water to the reaction tank while maintaining a state in which the dissolved methane is prevented from being released into the atmosphere. It has an anoxic tank for denitrification treatment and an aerobic tank for aerobic biological treatment, and the supply unit of the methane fermentation treatment tank supplies the methane fermentation treatment water to the anoxic tank to perform the methane fermentation treatment. A dissolved methane recovery tank provided downstream of the tank and upstream of the reaction tank is provided, and the dissolved methane recovery tank contains carbon dioxide, nitrogen, and air in the methane fermentation treated water in the dissolved methane recovery tank. , An organic wastewater treatment device having a gas blowing device for blowing one gas or a mixed gas of two or more of the inert gases and a supply unit for supplying the methane gas recovered by blowing the gas to the oxygen-free tank. is suggesting.

しかし、上記のように下水水温対策、溶存メタン対策を講じた場合でも、合流式下水道の雨天時、下水管渠が埋設していない開放系下水水路を有する地域、工場廃水の混入比率の高い地域等では流入下水性状の変化により、流入下水を直接、ＵＡＳＢメタン発酵処理すると処理成績が低下するケースが見られている。たとえば、合流式下水道の雨天時の場合、下水管渠が埋設していない開放系下水水路を有する地域の場合等、流入下水中に砂、シルト土等の無機物が多く含まれると、ＵＡＳＢ槽内に無機成分が多く堆積するため、ＵＡＳＢ槽内に嫌気性菌を含む有機性汚泥を保持する量が少なくなり、ＵＡＳＢ槽での有機物処理が低下し、ＵＡＳＢ処理後段の好気性生物処理の有機物負荷が過負荷となり、目標の放流水質が得られないことがあった。 However, even if measures against sewage temperature and dissolved methane are taken as described above, areas with open sewage canals where sewer pipes are not buried and areas with a high mixing ratio of factory wastewater during rainy weather of combined sewers. In some cases, the treatment results deteriorate when the inflow sewage is directly treated with UASB methane fermentation due to changes in the inflow sewage condition. For example, in the case of rainy weather of a combined sewer system, in the case of an area with an open sewerage channel where the sewer pipe is not buried, etc. Since a large amount of inorganic components are deposited in the UASB tank, the amount of organic sludge containing anaerobic bacteria is reduced in the UASB tank, the organic matter treatment in the UASB tank is reduced, and the organic matter load of the aerobic biological treatment after the UASB treatment is reduced. Was overloaded, and the target discharge water quality was sometimes not obtained.

特開2013-176746号公報Japanese Unexamined Patent Publication No. 2013-176746 特開2012-61435号公報Japanese Unexamined Patent Publication No. 2012-61435

本発明は、無機成分が多くＣＯＤＣｒ値が１，０００ｍｇ／Ｌ以下の低濃度有機性排水であっても、ＵＡＳＢ法による嫌気性処理及び好気性生物処理を用いて安定して処理する方法及び装置を提供することを目的とする。The present invention provides a method for stably treating low-concentration organic wastewater having a large amount of inorganic components and a COD Cr value of 1,000 mg / L or less by using anaerobic treatment and aerobic biological treatment by the UASB method. The purpose is to provide the device.

本発明によれば、ＣＯＤＣｒ値が１，０００ｍｇ／Ｌ以下の低濃度有機性排水を嫌気性処理し、嫌気性処理水を好気性生物処理する方法において、嫌気性処理に供される低濃度有機性排水のＶＳ／ＳＳの値が０．５以下になった場合、あるいは嫌気性処理でのガス発生量が、通常ガス発生量の１／２以下となる期間が２日以上連続した場合に、嫌気性処理の前段で固液分離することを特徴とする有機性排水の処理方法が提供される。ここで、「ＶＳ」は「強熱減量（volatile solids）」を意味し、「ＳＳ」は「懸濁物質（suspended solids）」を意味する。ＶＳ／ＳＳが０．５以下とは、懸濁物質中の有機物量が少なく、無機物量が多い状態である。嫌気性処理の前段で固液分離して、無機物を除去し、有機物の比率を高くすることによって、嫌気性処理及び好気性生物処理の効率を向上させる。 According to the present invention, in a method of anaerobic treating low-concentration organic wastewater having a COD Cr value of 1,000 mg / L or less and treating anaerobic treated water with aerobic organisms, the low concentration provided for anaerobic treatment. When the VS / SS value of organic wastewater becomes 0.5 or less, or when the amount of gas generated in anaerobic treatment is 1/2 or less of the amount of normal gas generated for two consecutive days or more. Provided is a method for treating organic wastewater, which comprises solid-liquid separation before the anaerobic treatment. Here, "VS" means "volatile solids" and "SS" means "suspended solids". When VS / SS is 0.5 or less, the amount of organic matter in the suspended solid is small and the amount of inorganic matter is large. The efficiency of anaerobic treatment and aerobic biological treatment is improved by solid-liquid separation before the anaerobic treatment to remove inorganic substances and increase the ratio of organic substances.

前記固液分離は、上向流固液分離装置を用いて行うことが好ましい。上向流固液分離装置は、掻き寄せ機を有する漏斗状底部を含む沈降部と、当該沈降部の上方に位置づけられている有機性排水導入管、及び当該有機性排水導入管の上方に設けられている緩速撹拌手段又はドラフトチューブを有する上向流分級部と、を有する構成であることが好ましく、粒径の大きな土砂は当該沈降部に沈降し、粒径の小さな無機粒子と有機性固形物は当該上向流分級部で分級され、前記嫌気性処理に送られる低濃度有機性排水から土砂及び無機粒子が除去される。 The solid-liquid separation is preferably performed using an upward flow solid-liquid separation device. The upward flow solid-liquid separator is provided above the settling portion including the funnel-shaped bottom having a scraper, the organic drainage introduction pipe located above the settling portion, and the organic drainage introduction pipe. It is preferable that the structure includes an upward flow classification portion having a slow-speed stirring means or a draft tube, and sediment having a large particle size settles in the sedimentation portion, and is organic with inorganic particles having a small particle size. The solid matter is classified in the upward flow classification section, and sediment and inorganic particles are removed from the low-concentration organic wastewater sent to the anaerobic treatment.

また、本発明によれば、有機性排水をメタン発酵処理するＵＡＳＢ槽、及びメタン発酵処理後の処理水を好気性生物処理する好気性生物処理槽を具備する有機性排水の処理装置であって、当該ＵＡＳＢ槽の前段に、固液分離装置と、切り換え弁と、切り換え流路とを設け、有機性排水のＶＳ／ＳＳの値が０．５以下になった場合に、あるいは嫌気性処理でのガス発生量が、通常ガス発生量の１／２以下となる期間が２日以上連続した場合に、切り換え弁で流路を切り換えて固液分離装置を経由してＵＡＳＢ槽に有機性排水を導入する、有機性排水の処理装置も提供される。 Further, according to the present invention, the organic wastewater treatment apparatus includes a UASB tank for methane fermentation treatment of organic wastewater and an aerobic biological treatment tank for aerobic biological treatment of treated water after methane fermentation treatment. , A solid-liquid separator, a switching valve, and a switching flow path are provided in front of the UASB tank, and when the VS / SS value of organic wastewater becomes 0.5 or less, or by anaerobic treatment. When the period in which the amount of gas generated is less than 1/2 of the amount of normal gas generated is continuous for two days or more, the flow path is switched by the switching valve and the organic wastewater is discharged to the UASB tank via the solid-liquid separator. Introduced organic wastewater treatment equipment is also provided.

流入下水のＶＳ／ＳＳ比が０．５以下になった場合、あるいは嫌気性処理でのガス発生量が、通常ガス発生量の１／２以下となる期間が２日以上連続した場合に、ＵＡＳＢ槽の前段で上向流固液分離装置を用いて、土砂などの無機物質を取り除くことにより、ＵＡＳＢ槽内の嫌気性菌を含む有機性汚泥の活性を維持できるため、安定したＵＡＳＢ処理が可能となり、後段の好気性生物処理後の放流水質も安定する。 UASB when the VS / SS ratio of the inflowing sewage is 0.5 or less, or when the gas generation amount in the anaerobic treatment is 1/2 or less of the normal gas generation amount for two consecutive days or more. By removing inorganic substances such as earth and sand using an upward flow solid-liquid separator in the front stage of the tank, the activity of organic sludge containing anaerobic bacteria in the UASB tank can be maintained, so stable UASB treatment is possible. Therefore, the quality of the discharged water after the treatment of aerobic organisms in the latter stage is also stable.

本発明の有機性排水の処理フローを示す説明図である。It is explanatory drawing which shows the treatment flow of the organic wastewater of this invention. 上向流固液分離槽の一例を示す概略説明図である。It is a schematic explanatory drawing which shows an example of the upward flow solid-liquid separation tank. 上向流固液分離槽の別の一例を示す概略説明図である。It is the schematic explanatory drawing which shows another example of the upward flow solid-liquid separation tank. 上向流固液分離槽のまた別の一例を示す概略説明図である。It is the schematic explanatory drawing which shows another example of the upward flow solid-liquid separation tank. 上向流固液分離槽の更に別の一例を示す概略説明図である。It is a schematic explanatory drawing which shows still another example of the upward flow solid-liquid separation tank. 上向流固液分離槽の更に別の一例を示す概略説明図である。It is a schematic explanatory drawing which shows still another example of the upward flow solid-liquid separation tank. 気固液分離部（ＧＳＳ）を有するＵＡＳＢ槽の一例を示す断面図である。It is sectional drawing which shows an example of the UASB tank which has the air-solid-liquid separation part (GSS). 気固液分離部（ＧＳＳ）を具備しないＵＡＳＢ槽の一例を示す断面図である。It is sectional drawing which shows an example of the UASB tank which does not have a gas-solid-liquid separation part (GSS). スカム捕集枠を具備するＵＡＳＢ槽の一例を示す断面図である。It is sectional drawing which shows an example of the UASB tank provided with the scum collection frame. 図９のスカム捕集枠を示す上面図である。It is a top view which shows the scum collection frame of FIG. 気液接触槽（槽タイプ）を示す説明図である。It is explanatory drawing which shows the gas-liquid contact tank (tank type). 気液接触槽（塔タイプ）を示す説明図である。It is explanatory drawing which shows the gas-liquid contact tank (tower type). 好気性生物処理装置（活性汚泥法）の一例を示す説明図である。It is explanatory drawing which shows an example of an aerobic biological treatment apparatus (activated sludge method). 好気性生物処理装置（活性汚泥法）の一例を示す説明図である。It is explanatory drawing which shows an example of an aerobic biological treatment apparatus (activated sludge method). 好気性生物処理装置（活性汚泥法）の一例を示す説明図である。It is explanatory drawing which shows an example of an aerobic biological treatment apparatus (activated sludge method). 好気性生物処理装置（散水ろ床法と砂ろ過との組み合わせ）の一例を示すフロー図である。It is a flow chart which shows an example of an aerobic biological treatment apparatus (combination of a sprinkling filter method and sand filtration). 好気性生物処理装置（散水ろ床と活性汚泥との組み合わせ）の一例を示すフロー図である。It is a flow chart which shows an example of an aerobic biological treatment apparatus (combination of a sprinkling filter and activated sludge). 好気性生物処理装置（散水ろ床と生物膜ろ過法との組み合わせ）の一例を示すフロー図である。It is a flow chart which shows an example of an aerobic biological treatment apparatus (combination of a sprinkling filter and a biofilm filtration method). 好気性生物処理装置（生物膜ろ過法（無酸素槽）と生物膜ろ過法（硝化槽）との組み合わせ）の一例を示すフロー図である。It is a flow chart which shows an example of an aerobic biological treatment apparatus (combination of a biofilm filtration method (anoxic tank) and a biofilm filtration method (nitrification tank)). 好気性生物処理装置（無酸素槽（生物膜ろ過法）と硝化槽（生物膜ろ過法）を一つの槽にしたもの）の一例を示すフロー図である。It is a flow chart which shows an example of an aerobic biological treatment apparatus (an oxygen-free tank (biofilm filtration method) and a nitrification tank (biofilm filtration method) are combined into one tank). 散水ろ床装置の一例を示す概略説明図である。It is a schematic explanatory drawing which shows an example of a sprinkler filter bed apparatus. 図２１に示す散水ろ床装置の一使用例を示す概略説明図である。It is the schematic explanatory drawing which shows one use example of the sprinkling filter | watering filter | drawing | FIG. 21. 図２１に示す散水ろ床装置の別の使用例を示す概略説明図である。It is the schematic explanatory drawing which shows the other use example of the sprinkler filter apparatus shown in FIG. 溶存メタン回収槽の好適例を示す説明図である。It is explanatory drawing which shows the preferable example of the dissolved methane recovery tank. 溶存メタン回収槽の好適例を示す説明図である。It is explanatory drawing which shows the preferable example of the dissolved methane recovery tank. 処理方法Ａのフロー図である。It is a flow chart of the processing method A. 処理方法Ｂのフロー図である。It is a flow chart of the processing method B. 処理方法Ｃのフロー図である。It is a flow chart of the processing method C. 処理方法Ｄのフロー図である。It is a flow chart of the processing method D. 実施例１で用いた処理フローを示す説明図である。It is explanatory drawing which shows the processing flow used in Example 1. FIG. 原水のＶＳ／ＳＳ比とＵＡＳＢ処理によるＣＯＤＣｒ除去率との関係を示すグラフである。It is a graph which shows the relationship between the VS / SS ratio of raw water, and the COD Cr removal rate by UASB treatment. 原水のＶＳ／ＳＳ比と好気性生物処理によるＢＯＤ濃度との関係を示すグラフである。It is a graph which shows the relationship between the VS / SS ratio of raw water, and the BOD concentration by aerobic biological treatment. 実施例２で測定したガス発生量及び強熱減量（ＶＳ）／懸濁物質（ＳＳ）の変動を示すグラフである。It is a graph which shows the fluctuation of the gas generation amount and the ignition loss (VS) / suspended solids (SS) measured in Example 2. FIG.

以下、添付図面を参照しながら本発明を詳細に説明する。 Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

図１は、本発明の有機性排水の処理フローを示す。本発明の有機性排水の処理方法は、好ましくはＵＡＳＢ処理による嫌気性処理水を好気性生物処理する方法であって、嫌気性処理工程の前段に固液分離工程を設け、嫌気性処理に供される有機性排水のＶＳ／ＳＳ比が０．５以下になった場合に、有機性排水を固液分離した後に嫌気性処理することを特徴とする。有機性排水のＶＳ／ＳＳ比が０．５を越える場合には、前段の固液分離工程を経由することなく、直接嫌気性処理工程に有機性排水を導入することができる。 FIG. 1 shows a treatment flow of organic wastewater of the present invention. The method for treating organic wastewater of the present invention is preferably a method for treating anaerobic treated water by UASB treatment with aerobic organisms, and a solid-liquid separation step is provided before the anaerobic treatment step to provide the anaerobic treatment. When the VS / SS ratio of the organic wastewater is 0.5 or less, the organic wastewater is solid-liquid separated and then anaerobically treated. When the VS / SS ratio of the organic wastewater exceeds 0.5, the organic wastewater can be directly introduced into the anaerobic treatment step without going through the solid-liquid separation step in the previous stage.

［ＶＳ／ＳＳ測定］
［ＳＳ（suspended solids：懸濁物質）］
懸濁物質量は、試料をろ過材を用いてろ過し、ろ過材上に残留した物質を１０５〜１１０℃で２時間乾燥して測定する。ろ過材にはガラス繊維ろ紙（ＧＦＢ）、有機性ろ過膜（ＭＦ）又は金属製ろ過板であって、いずれも孔径１μｍのものを使用する。
［ＶＳ（volatile solids：強熱減量）］
強熱減量は、懸濁物質量から強熱残留物量を差し引くことで算出できる。
［懸濁物質の強熱残留物］
強熱残留物量は、懸濁物質を白金るつぼ、磁性皿等にいれ、６００±２５℃で約１時間強熱して灰化し、残留物を測定する。
なお、ＳＳの測定方法及びＶＳの測定方法は、ＪＩＳ Ｋ ０１０２（工場排水試験方法２０１３年版）及び下水試験方法２０１２年版に準拠する。[VS / SS measurement]
[SS (suspended solids)]
The amount of suspended solids is measured by filtering the sample using a filter medium and drying the substance remaining on the filter medium at 105 to 110 ° C. for 2 hours. The filter material used is glass fiber filter paper (GFB), organic filtration membrane (MF), or metal filtration plate, all of which have a pore size of 1 μm.
[VS (volatile solids: ignition loss)]
Ignition loss can be calculated by subtracting the amount of ignition residue from the amount of suspended solids.
[Ignition residue of suspended solids]
The amount of ignition residue is measured by putting the suspended solid in a platinum crucible, a magnetic dish, etc. and igniting it at 600 ± 25 ° C. for about 1 hour to incinerate it.
The SS measurement method and VS measurement method conform to JIS K 0102 (factory wastewater test method 2013 version) and sewage test method 2012 version.

［前段固液分離］
ＵＡＳＢ処理工程の前段に固液分離工程を設けることにより、有機性排水中に含まれる固形物、特に後段のＵＡＳＢ処理の障害となる無機物粒子を除去することができる。ＵＡＳＢ工程の前段に設ける固液分離としては、自重による沈殿、ろ過、浮上分離、膜分離、遠心分離、上向流固液分離を用いることができる。有機性排水に含まれる無機物粒子が粒径の大きな土砂（粒径０．０７５ｍｍ〜２ｍｍ程度）の場合は沈降速度が大きいため沈殿、ろ過、浮上分離、膜分離、遠心分離などで良好に除去することができる。有機性排水に含まれる無機物粒子が粒径の小さなシルト土（粒径０．００５ｍｍ〜０．０７５ｍｍ程度）の場合は、沈殿処理だけでは分離が困難であり、上向流固液分離が適している。[Previous stage solid-liquid separation]
By providing a solid-liquid separation step before the UASB treatment step, it is possible to remove solid matter contained in the organic wastewater, particularly inorganic particles that hinder the UASB treatment in the subsequent step. As the solid-liquid separation provided in the first stage of the UASB step, precipitation by its own weight, filtration, levitation separation, membrane separation, centrifugation, and upward flow solid-liquid separation can be used. When the inorganic particles contained in the organic wastewater are earth and sand with a large particle size (particle size of about 0.075 mm to 2 mm), the sedimentation speed is high, so they are satisfactorily removed by precipitation, filtration, levitation separation, membrane separation, centrifugation, etc. be able to. When the inorganic particles contained in the organic wastewater are silt soil with a small particle size (particle size of about 0.005 mm to 0.075 mm), it is difficult to separate them only by precipitation treatment, and upward flow solid-liquid separation is suitable. There is.

図２に上向流固液分離槽の一例を示す。上向流固液分離槽１は、槽本体１１、槽底部に設けられている有機性排水導入管１２、槽上部に設けられている越流水排水口１３、槽下部に設けられている排泥管１４を具備する。上向流固液分離は、無機物粒子を含む有機性排水を上向流固液分離槽底部より上向流にて通水して、沈降速度の大きい無機物粒子を槽下部に堆積させ、沈降速度の小さい有機性汚泥を槽上部に流動させて、越流面からオーバーフローさせ、後段のＵＡＳＢメタン発酵槽に導入するものである。上向流固液分離槽下部に堆積した無機物粒子を含む汚泥は、槽底部に設けられている排泥管１４より排泥され、汚泥処理設備に導入される。上向流固液分離装置の分離速度は、１０ｍｍ／ｍｉｎ〜５０ｍｍ／ｍｉｎであり、好ましくは１５ｍｍ／ｍｉｎ〜２５ｍｍ／ｍｉｎである。この固液分離の際に、凝集剤（無機凝集剤及び／又は高分子凝集剤）を添加して、有機性汚泥を凝集汚泥として分離してもよい。凝集剤を添加した場合の上向流固液分離装置の分離速度は、５０ｍｍ／ｍｉｎ〜２００ｍｍ／ｍｉｎであり、好ましくは８０ｍｍ／ｍｉｎ〜１４０ｍｍ／ｍｉｎに向上する。凝集剤の添加及び混合方法としては、撹拌槽、管内注入及び管内混合（迂流管による混合、管内ミキサー混合など）のいずれも利用することができる。 FIG. 2 shows an example of an upward flow solid-liquid separation tank. The upward flow solid-liquid separation tank 1 includes a tank body 11, an organic drainage introduction pipe 12 provided at the bottom of the tank, an overflow water drainage port 13 provided at the upper part of the tank, and mud drainage provided at the lower part of the tank. A tube 14 is provided. In the upward flow solid-liquid separation, organic wastewater containing inorganic particles is passed by an upward flow from the bottom of the upward flow solid-liquid separation tank, and inorganic particles having a high sedimentation rate are deposited in the lower part of the tank, and the sedimentation rate is high. The small organic sludge is flowed to the upper part of the tank, overflows from the overflow surface, and introduced into the UASB methane fermentation tank in the subsequent stage. The sludge containing the inorganic particles accumulated in the lower part of the upward flow solid-liquid separation tank is discharged from the sludge pipe 14 provided at the bottom of the tank and introduced into the sludge treatment facility. The separation rate of the upward flow solid-liquid separator is 10 mm / min to 50 mm / min, preferably 15 mm / min to 25 mm / min. At the time of this solid-liquid separation, a coagulant (inorganic coagulant and / or polymer coagulant) may be added to separate the organic sludge as coagulated sludge. The separation rate of the upward flow solid-liquid separator when the flocculant is added is 50 mm / min to 200 mm / min, preferably 80 mm / min to 140 mm / min. As a method for adding and mixing the flocculant, any of a stirring tank, in-tube injection and in-tube mixing (mixing by a detour tube, in-pipe mixer mixing, etc.) can be used.

図３に、上向流固液分離槽の別の一例を示す。図３の上向流固液分離槽１ａは、槽の下部に沈殿部（図中「ｈ２」で示す）を有し、槽の上部に上向流分級部（図中「ｈ１」で示す）を有する。有機性排水導入管１２ａは槽の底部から高さＰ２の位置に接続され、有機性排水導入管１２ａの接続部から上方が上向流分級部ｈ１となる。上向流分級部の頂部には図２に示す装置と同様に、越流水排水口（図示せず）が設けられている。槽の底部は、漏斗状に形成されており、漏斗出口に排泥管１４ａが接続されている。有機性排水に含まれる無機物粒子が粒径の大きな土砂と粒径の小さなシルト土の混在物である場合、沈降性の良い粒径の大きな土砂は沈殿部ｈ２に沈降し、粒径の小さなシルト土（無機粒子）及び有機性固形物は上向流分級部ｈ１に上向流に随伴されて上昇するが、無機粒子と有機性固形物との上昇速度が相違するため、効率用良く分級することができる。 FIG. 3 shows another example of the upward flow solid-liquid separation tank. The upward flow solid-liquid separation tank 1a in FIG. 3 has a settling portion (indicated by “h2” in the figure) at the lower part of the tank, and an upward flow classification portion (indicated by “h1” in the figure) at the upper part of the tank. Has. The organic drainage introduction pipe 12a is connected to a position at a height P2 from the bottom of the tank, and the upward flow classification portion h1 is located above the connection portion of the organic drainage introduction pipe 12a. Similar to the device shown in FIG. 2, an overflow water drain port (not shown) is provided at the top of the upward flow classification unit. The bottom of the tank is formed in a funnel shape, and a mud drain pipe 14a is connected to the outlet of the funnel. When the inorganic particles contained in the organic wastewater are a mixture of soil having a large particle size and silt soil having a small particle size, the earth and sand having a good sedimentation property and having a large particle size settle in the settling portion h2, and the silt having a small particle size. Soil (inorganic particles) and organic solids rise in the upward flow classification part h1 along with the upward flow, but since the rising rates of the inorganic particles and the organic solids are different, they are efficiently classified for efficiency. be able to.

図４に、上向流固液分離槽のまた別の一例を示す。図４の上向流固液分離槽は、上向流分級部ｈ１が、底部から順番に小径部ａ１、拡径部ａ２及び大径部ａ３を有する点を除いて図３に示す上向流固液分離槽と同じ構造である。大径部ａ３の直径Ｄ２と小径部ａ１の直径Ｄ１の比、すなわちＤ２／Ｄ１は１．２２〜１．４１で、大径部ａ３の断面積Ｓ２と小径部ａ１の断面積Ｓ１の比、すなわちＳ２／Ｓ１は１．５〜２．０程度が適している。例えば、大径部ａ３の分離速度が１５ｍｍ／ｍｉｎ〜２５ｍｍ／ｍｉｎの時、Ｓ２／Ｓ１比２．０で小径部ａ１の分離速度は３０ｍｍ／ｍｉｎ〜５０ｍｍ／ｍｉｎとなる。このように上向流分級部の上方に拡径部及び大径部を設けて分離速度を変化させることで、粒径の小さなシルト土（無機粒子）と有機性固形物とを効率用良く分級することができる。 FIG. 4 shows another example of the upward flow solid-liquid separation tank. In the upward flow solid-liquid separation tank of FIG. 4, the upward flow as shown in FIG. 3 except that the upward flow classification portion h1 has a small diameter portion a1, a diameter expansion portion a2, and a large diameter portion a3 in order from the bottom. It has the same structure as the solid-liquid separation tank. The ratio of the diameter D2 of the large diameter portion a3 to the diameter D1 of the small diameter portion a1, that is, D2 / D1 is 1.22 to 1.41, and the ratio of the cross-sectional area S2 of the large diameter portion a3 to the cross-sectional area S1 of the small diameter portion a1. That is, S2 / S1 is preferably about 1.5 to 2.0. For example, when the separation speed of the large diameter portion a3 is 15 mm / min to 25 mm / min, the separation speed of the small diameter portion a1 is 30 mm / min to 50 mm / min at a ratio of S2 / S1 of 2.0. By providing an enlarged diameter portion and a large diameter portion above the upward flow classification portion in this way to change the separation rate, silt soil (inorganic particles) having a small particle size and organic solid matter can be efficiently classified. can do.

図５に、上向流固液分離槽の更に別の一例を示す。図５の上向流固液分離槽は、上向流分級部ｈ１に撹拌機１５を有し、下部沈降部ｈ２に汚泥かき寄せ機１６を有する点を除いて図３に示す上向流固液分離槽と同じ構造である。上向流分級部ｈ１の撹拌機１５の回転数は１〜６０ｒｐｍ、好ましくは５〜３０ｒｐｍであり、下部沈降部ｈ２の汚泥かき寄せ機１６の回転数は０．５〜５回転／Ｈｒ（時間）、好ましくは１〜３回転／Ｈｒ（時間）と非常に緩速である。撹拌機１５の撹拌翼は、プロペラ、パドル型等種々のタイプを使用できるが、低速型のパドルが適している。また撹拌翼は有機性排水導入管１２ｃの位置から鉛直方向上向きにｈ３の高さ位置の間に取り付けることが好ましい。ｈ３とｈ１は、ｈ１に対してｈ３が０．２〜０．７倍、好ましくは０．４〜０．６倍の寸法となるように構成することが望ましい。上向流分級部ｈ１での緩やかな撹拌を与えることにより、粒径の小さなシルト土（無機粒子）と有機性固形物を上向流分級部ｈ１で効率用良く分級することができる。 FIG. 5 shows yet another example of the upward flow solid-liquid separation tank. The upward flow solid-liquid separation tank of FIG. 5 has an upward flow solid-liquid liquid shown in FIG. 3 except that the upward flow classification portion h1 has a stirrer 15 and the lower sedimentation portion h2 has a sludge scraper 16. It has the same structure as the separation tank. The rotation speed of the stirrer 15 of the upward flow classification unit h1 is 1 to 60 rpm, preferably 5 to 30 rpm, and the rotation speed of the sludge scraper 16 of the lower sedimentation portion h2 is 0.5 to 5 rotations / Hr (hours). , Preferably 1 to 3 rotations / Hr (hours), which is very slow. As the stirring blade of the stirrer 15, various types such as a propeller and a paddle type can be used, but a low speed type paddle is suitable. Further, it is preferable that the stirring blade is attached between the position of the organic drainage introduction pipe 12c and the height position of h3 upward in the vertical direction. It is desirable that h3 and h1 are configured so that h3 has a size of 0.2 to 0.7 times, preferably 0.4 to 0.6 times, that of h1. By giving gentle stirring in the upward flow classification unit h1, silt soil (inorganic particles) having a small particle size and organic solids can be efficiently classified in the upward flow classification unit h1.

図６に、上向流固液分離槽の更に別の一例を示す。図６の上向流固液分離槽は、撹拌機１５の代わりにドラフトチューブ１７及び散気管１８を設けた点を除いて、図５に示す構造と同じある。有機性排水導入管１２ｄの上方近傍に散気管１８を設け、散気管１８からの気泡がドラフトチューブ１７の下端に供給されるように、ドラフトチューブ１７及び散気管１８が位置づけられている。ドラフトチューブ１７は有機性排水導入管１２ｄの位置から鉛直方向上向きにｈ４までの高さの間に取り付けることが好ましい。ｈ１に対してｈ４は０．４〜０．９倍、好ましくは０．６〜０．８倍の寸法となるように構成することが望ましい。散気管１８より空気を吹き込むことにより、ドラフトチューブ１７内において粒径の小さなシルト土（無機粒子）と有機性固形物を効率用良く分級することが可能となる。分級された粒径の小さなシルト土（無機粒子）はドラフトチューブ１７の外側より沈殿部ｈ２に下降し、有機性固形物は上向流分級部ｈ１の上部より越流される。空気吹込み量は０．１〜０．５ｍ３／ｍ２／ｍｉｎ、好ましくは０．２〜０．３５ｍ３／ｍ２／ｍｉｎである。FIG. 6 shows still another example of the upward flow solid-liquid separation tank. The upward flow solid-liquid separation tank of FIG. 6 has the same structure as that of FIG. 5 except that a draft tube 17 and an air diffuser tube 18 are provided instead of the stirrer 15. An air diffuser 18 is provided near the upper side of the organic drainage introduction pipe 12d, and the draft tube 17 and the air diffuser 18 are positioned so that air bubbles from the air diffuser 18 are supplied to the lower end of the draft tube 17. It is preferable that the draft tube 17 is attached between the position of the organic drainage introduction pipe 12d and the height up to h4 in the vertical direction. It is desirable that h4 has a size of 0.4 to 0.9 times, preferably 0.6 to 0.8 times that of h1. By blowing air from the air diffuser tube 18, it is possible to efficiently classify silt soil (inorganic particles) having a small particle size and organic solid matter in the draft tube 17. The classified silt soil (inorganic particles) having a small particle size descends from the outside of the draft tube 17 to the settling portion h2, and the organic solid matter overflows from the upper part of the upward flow classification portion h1. The amount of air blown is 0.1 to 0.5 m 3 / m 2 / min, preferably 0.2 to 0.35 m 3 / m 2 / min.

［嫌気性処理］
本発明の有機性排水処理方法において、嫌気性処理としてＵＡＳＢ処理を好適に用いることができる。ＵＡＳＢ処理は、嫌気性微生物の集塊作用を利用して活性の高い菌体をグラニュールとして反応槽内に大量に保持し、反応槽の底部から有機性排水を導入して、嫌気状態で有機性排水中の有機物を分解する方法である。図７〜９に本発明の有機性排水の処理方法において用いることができるＵＡＳＢ槽の好適例を示す。[Anaerobic treatment]
In the organic wastewater treatment method of the present invention, UASB treatment can be preferably used as the anaerobic treatment. In the UASB treatment, a large amount of highly active bacterial cells are retained in the reaction vessel as granules by utilizing the agglomeration action of anaerobic microorganisms, and organic wastewater is introduced from the bottom of the reaction vessel to be organic in an anaerobic state. It is a method of decomposing organic matter in anaerobic wastewater. FIGS. 7 to 9 show suitable examples of the UASB tank that can be used in the method for treating organic wastewater of the present invention.

図７のＵＡＳＢ槽（メタン発酵処理装置）２は、その内部に、汚泥床３２、気固液分離部（ＧＳＳ）３３及び嫌気性処理水を分離する越流堰３４を具備する。槽の頂部には覆蓋３５が設けられている。槽の上部には、気固液分離部（ＧＳＳ）３３に接続されている発生ガス排出管３７、及び越流堰３４に接続されている嫌気性処理水排出管３８が設けられている。槽の底部には有機性排水を導入する導入口と該導入口に接続されている導入管が設けられている。槽の下部には嫌気性処理後の汚泥を排泥する排泥口と該排泥口に接続されている排泥管３９が設けられている。 The UASB tank (methane fermentation treatment apparatus) 2 of FIG. 7 is provided with a sludge bed 32, a gas-solid-liquid separation unit (GSS) 33, and an overflow weir 34 for separating anaerobic treated water. A cover 35 is provided on the top of the tank. A generated gas discharge pipe 37 connected to the gas-solid-liquid separation unit (GSS) 33 and an anaerobic treated water discharge pipe 38 connected to the overflow weir 34 are provided in the upper part of the tank. At the bottom of the tank, an introduction port for introducing organic wastewater and an introduction pipe connected to the introduction port are provided. At the lower part of the tank, a mud drainage port for draining sludge after anaerobic treatment and a mud drainage pipe 39 connected to the mud drainage port are provided.

図７に示すＵＡＳＢ槽を用いる嫌気性処理において、有機性排水は、ＵＡＳＢ槽２の底部から導入され、汚泥床３２に拡散される。汚泥床３２の下部では、グラニュール汚泥が流動床を構成している。汚泥床３２に拡散された有機性排水中の溶解性有機物や有機酸（酢酸・プロピオン酸など）は、グラニュール汚泥に保持されている嫌気性菌によってメタンガスと二酸化炭素ガスに分解される。グラニュール汚泥及びメタンガスは処理水と共に浮上し、気固液分離部（ＧＳＳ）３３にて、メタンガス、グラニュール汚泥、嫌気性処理水に分離される。メタンガスは、発生ガス排出管３７を通して排出され、エネルギー源として利用することができる。嫌気性処理水は、嫌気性処理水排出管３８を通して後段の好気性生物処理に送られる。嫌気性処理汚後の汚泥は、排泥管３９を通して脱水処理又は酸発酵処理に送ることができる。本構成のＵＡＳＢ槽は、発生するメタンガス量が多い場合に適している。 In the anaerobic treatment using the UASB tank shown in FIG. 7, the organic wastewater is introduced from the bottom of the UASB tank 2 and diffused into the sludge bed 32. Below the sludge bed 32, granule sludge constitutes a fluidized bed. Soluble organic substances and organic acids (acetic acid, propionic acid, etc.) in the organic wastewater diffused in the sludge bed 32 are decomposed into methane gas and carbon dioxide gas by anaerobic bacteria held in the granule sludge. Granule sludge and methane gas float together with the treated water and are separated into methane gas, granule sludge and anaerobic treated water at the gas-solid-liquid separation unit (GSS) 33. Methane gas is discharged through the generated gas discharge pipe 37 and can be used as an energy source. The anaerobic treated water is sent to the subsequent aerobic organism treatment through the anaerobic treated water discharge pipe 38. The sludge after the anaerobic treatment is sent to the dehydration treatment or the acid fermentation treatment through the sludge pipe 39. The UASB tank having this configuration is suitable when the amount of methane gas generated is large.

図８のＵＡＳＢ槽（メタン発酵装置）は、気固液分離部を設けず、気体を透過しない材料からなる屋根材３６で槽の上部を密閉被覆し、屋根材３６にガス排気口及び発生ガス排出管３７を設けている点を除いて、図７に示すＵＡＳＢ槽と同様の構成を有する。図８に示す構成のＵＡＳＢ槽は、発生するメタンガス量が少ない場合に適している。 In the UASB tank (methane fermentation apparatus) of FIG. 8, the upper part of the tank is hermetically covered with a roofing material 36 made of a material that does not allow gas to permeate, and the roofing material 36 is provided with a gas exhaust port and generated gas. It has the same configuration as the UASB tank shown in FIG. 7, except that the discharge pipe 37 is provided. The UASB tank having the configuration shown in FIG. 8 is suitable when the amount of methane gas generated is small.

図９のＵＡＳＢ槽は、ＵＡＳＢ槽の内部の越流堰３４よりも中心寄りに、スカムを集めるスカム捕集枠５１を設けている点を除いて、図８に示すＵＡＳＢ槽と同じ構成を有する。スカム捕集枠５１は、図１０に示すように、越流堰３４と共にＵＡＳＢ槽本体５０の内壁の対向する位置の間に固定してもよいし、昇降手段により昇降自在に設けてもよい。 The UASB tank of FIG. 9 has the same configuration as the UASB tank shown in FIG. 8 except that a scum collecting frame 51 for collecting scum is provided closer to the center than the overflow weir 34 inside the UASB tank. .. As shown in FIG. 10, the scum collecting frame 51 may be fixed between the overflow weir 34 and the facing positions of the inner wall of the UASB tank main body 50, or may be provided so as to be able to be raised and lowered by an elevating means.

［バイオガス処理］
ＵＡＳＢ槽から発生するバイオガスは、メタン（６０〜８０ｖｏｌ％）及び二酸化炭素（２０〜４０ｖｏｌ％）の他に硫化水素（２００〜２０００ｐｐｍ）を含むため、必要に応じて脱硫して脱硫後バイオガスとして、エネルギー源として利用してもよいし、水性媒体と気液接触させてバイオガス中のメタンガスを溶解させて、溶存メタンを含む水素供与源として後述する好気性生物処理に供給してもよい。[Biogas treatment]
Since the biogas generated from the UASB tank contains hydrogen sulfide (200 to 2000 ppm) in addition to methane (60 to 80 vol%) and carbon dioxide (20 to 40 vol%), it is desulfurized as necessary and biogas after desulfurization. It may be used as an energy source, or it may be brought into gas-liquid contact with an aqueous medium to dissolve methane gas in biogas and supplied as a hydrogen donor source containing dissolved methane to an aerobic biological treatment described later. ..

脱硫後バイオガスと水性媒体とを接触させる気液接触槽は、槽タイプ（図１１）又は塔タイプ（図１２）のいずれでもよい。気液接触効率を高めるため、液面高さは４ｍ〜１０ｍが好ましく、塔タイプ（図１２）ではプラスチックろ材、繊維ろ材又は磁性ろ材などの充填材を充填することが好ましい。気液接触槽５８内には、散気板、散気塔、メンブレン膜等の気泡発生手段を水中に浸漬させ、水中に供給する脱硫後バイオガスの気泡径をできる限り微細にすることが好ましい。気液接触槽への脱硫後バイオガスの供給は、脱硫塔と気液接触槽とを密閉された配管で接続して行うことができる。また、水性媒体へのメタンガスの溶解度は水温に依存するため、水性媒体の温度を調節する。 The gas-liquid contact tank that brings the biogas into contact with the aqueous medium after desulfurization may be either a tank type (FIG. 11) or a tower type (FIG. 12). In order to improve the gas-liquid contact efficiency, the liquid level height is preferably 4 m to 10 m, and the tower type (FIG. 12) is preferably filled with a filler such as a plastic filter medium, a fiber filter medium, or a magnetic filter medium. In the gas-liquid contact tank 58, it is preferable to immerse a bubble generating means such as an air diffuser plate, an air diffuser tower, and a membrane film in water to make the bubble diameter of the desulfurized biogas supplied into the water as fine as possible. .. The biogas after desulfurization to the gas-liquid contact tank can be supplied by connecting the desulfurization tower and the gas-liquid contact tank with a closed pipe. Further, since the solubility of methane gas in the aqueous medium depends on the water temperature, the temperature of the aqueous medium is adjusted.

なお、ガス発生量の定量計測には、湿式流量計、乾式流量計、回転式流量計、差圧式流量計、面積式流量計、羽根車式流量計、超音波式流量計、渦式流量計などが適用できる。中でも、本発明には乾式流量計、回転式流量計、超音波式流量計を用いることができる。 For quantitative measurement of gas generation amount, wet flow meter, dry flow meter, rotary flow meter, differential pressure type flow meter, area type flow meter, impeller type flow meter, ultrasonic type flow meter, vortex type flow meter Etc. can be applied. Above all, a dry flow meter, a rotary flow meter, and an ultrasonic flow meter can be used in the present invention.

［好気性生物処理］
本発明の有機性排水処理方法において、嫌気性処理水及び必要に応じてバイオガスを処理した溶存メタンを含む水性媒体は好気性生物処理に供される。本発明の有機性排水処理方法において、ＵＡＳＢ処理による嫌気性処理水中の溶存メタンが大気中に放散することを防止しながら、有機物の分解により発生した溶存メタンを水素供与源として好気性生物処理する。硝化菌及び脱窒菌の作用により、嫌気性処理水中のＮＨ４−ＮをＮＯ２−Ｎ、ＮＯ３−Ｎに変換する硝化、及び脱窒菌の作用によりＮＯ２−Ｎ、ＮＯ３−Ｎを窒素（ガス）に変換させる脱窒の組合せからなる生物学的窒素処理工程である。硝化は好気槽で行われ、脱窒は無酸素槽で行われる。[Aerobic organism treatment]
In the organic wastewater treatment method of the present invention, an aqueous medium containing anaerobic treated water and, if necessary, dissolved methane treated with biogas is subjected to aerobic biological treatment. In the organic wastewater treatment method of the present invention, aerobic biological treatment is performed using the dissolved methane generated by the decomposition of organic matter as a hydrogen donor while preventing the dissolved methane in the anaerobic treated water by the UASB treatment from being released into the atmosphere. .. Nitrification that converts NH 4- N in anaerobic treated water to NO 2- N and NO 3- N by the action of nitrifying bacteria and denitrifying bacteria, and nitrogen conversion of NO 2- N and NO 3-N by the action of denitrifying bacteria It is a biological nitrogen treatment step consisting of a combination of denitrification to convert to (gas). Nitrification is performed in an aerobic tank and denitrification is performed in an oxygen-free tank.

本発明における好気性生物処理は、脱窒と硝化を交互に行う。嫌気性処理水中の溶存メタンは、溶存酸素の存在下でメタン酸化菌によりメタン酸化される。メタン酸化菌によるメタンの分解は下記式に示すように、中間生成物としてメタノール等の有機物を生成する。 The aerobic biological treatment in the present invention alternates between denitrification and nitrification. Dissolved methane in anaerobic treated water is methane-oxidized by methane-oxidizing bacteria in the presence of dissolved oxygen. Decomposition of methane by methane-oxidizing bacteria produces organic substances such as methanol as intermediate products, as shown in the following formula.

Figure 0006943854
Figure 0006943854

本発明における好気性生物処理においては、メタン負荷が高い場合や酸素供給が不十分な場合には、メタン酸化菌によってメタンが二酸化炭素と水までに分解されず、中間生成物（主にメタノール）が残存し、脱窒のための水素供与体として作用する。 In the aerobic biological treatment in the present invention, when the methane load is high or the oxygen supply is insufficient, methane is not decomposed into carbon dioxide and water by the methane-oxidizing bacteria, and an intermediate product (mainly methanol) is used. Remains and acts as a hydrogen donor for denitrification.

図１３〜１５に本発明の有機性排水の処理方法において用いることができる好気性生物処理装置の適用例を示す。ここでは、好気性生物処理装置は活性汚泥処理法を用いた例を示す。 FIGS. 13 to 15 show an application example of an aerobic biological treatment apparatus that can be used in the method for treating organic wastewater of the present invention. Here, an example of an aerobic biological treatment apparatus using an activated sludge treatment method is shown.

図１３の好気性生物処理装置は、無酸素槽と硝化槽で構成されている。後段の硝化槽で硝化を行い、硝化液を無酸素槽に循環させ、嫌気性処理水と混合することで脱窒処理される。図１３の反応槽は、仕切板４４で仕切られた３つの好気槽（硝化槽）２１ｂの前段に、仕切板で仕切られた無酸素槽（脱窒槽）４１を有する。無酸素槽４１は、槽上部に嫌気性処理水を導入する嫌気性処理水排出管３８が接続され、槽底部に水中撹拌機４２を有し、槽頂部に蓋部４３を有する。撹拌機４２により脱窒菌と溶存メタンとを十分に接触させ、蓋部４３により溶存メタンが大気中に放散されることを防止する。好気槽２１ｂは、仕切板で無酸素槽４１と仕切られているが、流体連通状態にある。好気槽２１ｂの底部には曝気ライン２２が設けられており、好気槽２１ｂ内に酸素を供給する。好気槽２１ｂは１槽でもよいが、硝化反応を良好に進行させるために複数槽を設けることが好ましい。最終段の好気槽２１ｂには、ポンプ４５を有する循環ラインが接続されており、循環ラインを介して硝化液を無酸素槽４１に戻して嫌気性処理水と混合して再び脱窒を行う。 The aerobic biological treatment apparatus of FIG. 13 is composed of an oxygen-free tank and a nitrification tank. Nitrification is performed in the subsequent nitrification tank, the nitrification liquid is circulated in the oxygen-free tank, and the nitrification treatment is performed by mixing with anaerobic treated water. The reaction tank of FIG. 13 has an oxygen-free tank (denitrification tank) 41 partitioned by a partition plate in front of three aerobic tanks (nitrification tanks) 21b partitioned by a partition plate 44. The oxygen-free tank 41 has an anaerobic treated water discharge pipe 38 for introducing anaerobic treated water connected to the upper part of the tank, a submersible agitator 42 at the bottom of the tank, and a lid 43 at the top of the tank. The stirrer 42 allows the denitrifying bacteria and the dissolved methane to be sufficiently brought into contact with each other, and the lid 43 prevents the dissolved methane from being released into the atmosphere. The aerobic tank 21b is separated from the oxygen-free tank 41 by a partition plate, but is in a fluid communication state. An aeration line 22 is provided at the bottom of the aerobic tank 21b to supply oxygen into the aerobic tank 21b. The aerobic tank 21b may be one tank, but it is preferable to provide a plurality of tanks in order to allow the nitrification reaction to proceed satisfactorily. A circulation line having a pump 45 is connected to the aerobic tank 21b in the final stage, and the nitrifying liquid is returned to the anoxic tank 41 via the circulation line, mixed with anaerobic treated water, and denitrified again. ..

図１４の好気性生物処理装置は、脱窒→硝化→脱窒→硝化の順に繰り返す反応槽である。図１４の反応槽は、仕切板４４でそれぞれが仕切られているが流体連通状態にある無酸素槽４１及び好気槽２１ｂを交互に有する。図中２個の無酸素槽４１には、それぞれ、嫌気性処理水を導入する嫌気性処理水排出管３８が接続され、槽底部には水中撹拌機４２が設けられ、槽頂部に蓋部４３が設けられている。嫌気性処理水は無酸素槽４１に導入され、脱窒された後、直後の好気槽２１ｂに送られて硝化される。好気槽２１ｂからの硝化液は、直後の無酸素槽４１に送られ、嫌気性処理水導入管８から導入される嫌気性処理水と混合されて、脱窒された後、直後の好気槽２１ｂに送られる。無酸素槽４１と好気槽２１ｂの槽数は各少なくとも２槽とすることが好ましく、好気性生物処理水のＴ−Ｎ（Total Nitrogen：総窒素）レベルに応じて設定することができる。図１３の反応槽と異なり、硝化液を無酸素槽４１に戻すためにポンプ及び循環路を必要としない。最初又は中間の好気槽２１ｂは、溶存メタンが大気中に放散しないように蓋部３２を有することが好ましい。最終段の好気槽２１ｂでは、残存有機物の仕上げ処理等を行う。 The aerobic biological treatment apparatus of FIG. 14 is a reaction vessel that repeats in the order of denitrification → nitrification → denitrification → nitrification. The reaction tank of FIG. 14 alternately has an oxygen-free tank 41 and an aerobic tank 21b, each of which is partitioned by a partition plate 44 but in a fluid communication state. Anaerobic treated water discharge pipes 38 for introducing anaerobic treated water are connected to each of the two oxygen-free tanks 41 in the figure, a submersible stirrer 42 is provided at the bottom of the tank, and a lid 43 is provided at the top of the tank. Is provided. The anaerobic treated water is introduced into the anoxic tank 41, denitrified, and then sent to the aerobic tank 21b immediately afterwards for nitrification. The nitrifying liquid from the aerobic tank 21b is sent to the anoxic tank 41 immediately after, mixed with the anaerobic treated water introduced from the anaerobic treated water introduction pipe 8, denitrified, and then immediately aerobic. It is sent to the tank 21b. The number of oxygen-free tanks 41 and aerobic tanks 21b is preferably at least two, and can be set according to the TN (Total Nitrogen) level of the aerobic biologically treated water. Unlike the reaction tank of FIG. 13, no pump or circulation path is required to return the nitrified liquid to the oxygen-free tank 41. The initial or intermediate aerobic tank 21b preferably has a lid 32 so that the dissolved methane does not dissipate into the atmosphere. In the final stage aerobic tank 21b, finishing treatment of residual organic matter and the like is performed.

図１５の好気性生物処理装置は、硝化→脱窒→硝化→脱窒の順に繰り返す反応槽である。図１５の反応槽は、仕切板４４でそれぞれが仕切られているが流体連通状態にある好気槽２１ｂ及び無酸素槽４１を交互に有する。図中２個の無酸素槽４１には、それぞれ、嫌気性処理水を導入する嫌気性処理水排出管３８が接続され、槽底部には水中撹拌機４２が設けられ、槽頂部に蓋部４３が設けられている。嫌気性処理水は無酸素槽４１に導入され、脱窒された後、直後の好気槽２１ｂに送られて硝化される。好気槽２１ｂからの硝化液は、直後の無酸素槽４１に送られ、嫌気性処理水導入管８から導入される嫌気性処理水と混合されて、脱窒された後、直後の好気槽２１ｂに送られる。図１４の反応槽と異なり、最初に好気槽２１ｂを設けることで、嫌気性処理水に硝化液を混合することができる。一方、図１４の反応槽と同様に硝化液を無酸素槽４１に戻すためにポンプ及び循環路を必要としない。 The aerobic biological treatment apparatus of FIG. 15 is a reaction vessel that repeats nitrification → denitrification → nitrification → denitrification in this order. The reaction tank of FIG. 15 alternately has an aerobic tank 21b and an oxygen-free tank 41, each of which is partitioned by a partition plate 44 but in a fluid communication state. Anaerobic treated water discharge pipes 38 for introducing anaerobic treated water are connected to each of the two oxygen-free tanks 41 in the figure, a submersible stirrer 42 is provided at the bottom of the tank, and a lid 43 is provided at the top of the tank. Is provided. The anaerobic treated water is introduced into the anoxic tank 41, denitrified, and then sent to the aerobic tank 21b immediately afterwards for nitrification. The nitrifying liquid from the aerobic tank 21b is sent to the anoxic tank 41 immediately after, mixed with the anaerobic treated water introduced from the anaerobic treated water introduction pipe 8, denitrified, and then immediately aerobic. It is sent to the tank 21b. Unlike the reaction tank of FIG. 14, by first providing the aerobic tank 21b, the nitrifying liquid can be mixed with the anaerobic treated water. On the other hand, as in the reaction tank of FIG. 14, a pump and a circulation path are not required to return the nitrifying liquid to the oxygen-free tank 41.

図１３〜１５に示す好気性生物処理装置の後段には沈殿池を設け、好気性生物処理後の余剰汚泥と処理水とに分離すると共に曝気槽への沈殿汚泥の返送を行い、曝気槽の汚泥濃度の調整を行う。 A settling pond is provided in the subsequent stage of the aerobic biological treatment apparatus shown in FIGS. Adjust the sludge concentration.

図１３〜１５に示す好気性生物処理装置は活性汚泥法以外の方法も適用できる。例えば、図１３の硝化液を無酸素槽に循環する方式について、活性汚泥処理法以外の例を図１６〜図２０に示す。 The aerobic biological treatment apparatus shown in FIGS. 13 to 15 can be applied to methods other than the activated sludge method. For example, FIGS. 16 to 20 show examples of the method of circulating the nitrifying solution of FIG. 13 in an oxygen-free tank, other than the activated sludge treatment method.

図１６は、散水ろ床法と砂ろ過との組み合わせを示す。前段散水ろ床（ＴＲ−１〜ＴＲ−３）と後段砂ろ過（ＳＦ）を設け、最終段の散水ろ床（ＴＲ−３）にて硝化された硝化液を前段の散水ろ床（ＴＲ−１）に循環する。ＴＲ−１では、ＵＡＳＢ処理水と硝化液が混合し、脱窒素処理される。散水ろ床法は槽内に充填材（プラスチック炉材等）を充填し、上部より排水を散布することで空気中の酸素を取り込みながら有機物処理を行う方式であり、曝気が不要なため、活性汚泥処理に比べて動力がかからない省エネルギー的な処理方法である。しかし、処理水ＳＳ濃度が高いため、散水ろ床の後段にろ過設備が必要となる。 FIG. 16 shows a combination of a sprinkling filter method and sand filtration. The first stage watering filter (TR-1 to TR-3) and the second stage sand filtration (SF) are provided, and the nitrified liquid nitrified in the final stage watering filter (TR-3) is applied to the front stage watering filter (TR-). Cycle to 1). In TR-1, the UASB treated water and the nitrifying liquid are mixed and denitrified. The watering filter method is a method in which a filler (plastic furnace material, etc.) is filled in the tank and wastewater is sprayed from above to treat organic substances while taking in oxygen in the air. It is an energy-saving treatment method that requires less power than sludge treatment. However, since the SS concentration of treated water is high, a filtration facility is required after the sprinkling filter bed.

図１７は、散水ろ床と活性汚泥との組み合わせを示す。前段散水ろ床（ＴＲ−１、ＴＲ−２）、後段活性汚泥法（ＡＴ）及び沈殿池（ＳＴ）としたものである。後段活性汚泥処理で硝化を行い、前段散水ろ床でＵＡＳＢ処理水と硝化液が混合し、脱窒素処理される。 FIG. 17 shows a combination of a sprinkler bed and activated sludge. The first stage sprinkler bed (TR-1, TR-2), the second stage activated sludge method (AT) and the settling basin (ST) are used. Nitrification is performed in the subsequent activated sludge treatment, and the UASB treated water and the nitrifying liquid are mixed in the first sprinkling filter and denitrified.

図１８は、散水ろ床と生物膜ろ過法との組み合わせを示す。前段散水ろ床（ＴＲ）、後段生物膜ろ過（ＢＡＦ）としたものである。後段生物膜ろ過で硝化を行い、前段散水ろ床でＵＡＳＢ処理水と硝化液が混合し、脱窒素処理される。生物膜ろ過法は槽内に３ｍｍ〜５ｍｍのろ材を充填し、排水と接触することで、ろ材表面に生物膜を形成され、ＢＯＤ処理、硝化が可能となると同時に、ＳＳを捕捉するため、散水ろ床のように後段にろ過設備を設ける必要がない。 図１９は、生物膜ろ過法（無酸素槽）と生物膜ろ過法（硝化槽）の組み合わせを示す。前段生物膜ろ過（無酸素槽）（ＢＡＦ）、後段生物膜ろ過（硝化槽）（ＢＡＦ）を組み合わせたものである。後段生物膜ろ過で硝化を行い、前段生物膜ろ過でＵＡＳＢ処理水と硝化液が混合し、脱窒素処理される。生物膜ろ過法（無酸素槽）と生物膜ろ過（硝化槽）を一つの槽にしてもよい（図２０）。 FIG. 18 shows a combination of a sprinkling filter and a biofilm filtration method. The first stage watering filter bed (TR) and the second stage biofilm filtration (BAF) are used. Nitrification is performed by post-stage biofilm filtration, and UASB-treated water and nitrifying liquid are mixed in the first-stage watering filter and denitrified. In the biofilm filtration method, the tank is filled with a filter medium of 3 mm to 5 mm, and when it comes into contact with wastewater, a biofilm is formed on the surface of the filter medium, which enables BOD treatment and nitrification, and at the same time, sprinkles water to capture SS. There is no need to install a filtration facility in the subsequent stage like a filter bed. FIG. 19 shows a combination of the biofilm filtration method (oxygen-free tank) and the biofilm filtration method (nitrification tank). It is a combination of first-stage biofilm filtration (anoxic tank) (BAF) and second-stage biofilm filtration (nitrification tank) (BAF). Nitrification is performed by the latter-stage biofilm filtration, and the UASB-treated water and the nitrifying liquid are mixed and denitrified by the first-stage biofilm filtration. The biofilm filtration method (oxygen-free tank) and the biofilm filtration (nitrification tank) may be combined into one tank (FIG. 20).

図２１〜２３は、図１６〜１８における散水ろ床を、散水ろ床式装置と浸漬ろ床式装置の機能を両立する反応槽を少なくとも２槽連結し、これらに供給する原水の流路を所定のタイミングで切り替えることで、水処理装置の運転を停止させることなく、効率良く悪臭及びろ床バエの発生を防止する構成とした例を示す。散水ろ床法は標準活性汚泥法に比べ、曝気が不要であり、消費電力が少なく、汚泥発生量が少なく、余剰汚泥の処分コストを削減できるが、散水ろ床のろ材上に付着した汚泥が腐敗することにより発生する悪臭やろ床バエと呼ばれるチョウバエの発生が問題となる。図２１〜２３に示す散水ろ床と浸漬ろ床の切り換えができる反応槽は、かかる問題を解決するものである。図２１〜２３に示す反応槽において「散水ろ床槽」とは、処理流体をろ床上部から散布して、ろ床を構成する担体の表面に生物膜を付着させた後、装置上部から下方へと流れる処理流体と生物膜とを接触させることにより、処理流体を生物処理する槽を意味する。また、「浸漬ろ床槽」とは、処理流体中に担体を浸漬させて、槽の上方もしくは下方から処理流体を接触させることにより、担体の表面に生物膜を付着させた後、生物膜と処理流体とを接触させることにより処理流体を生物処理する槽を意味する。 21 to 23 show that the sprinkling filter in FIGS. 16 to 18 is connected to at least two reaction tanks having both the functions of the sprinkling filter type device and the immersion filter type device, and the flow path of the raw water supplied to these is connected. An example is shown in which the water treatment apparatus is switched at a predetermined timing to efficiently prevent the generation of foul odors and filter bed flies without stopping the operation of the water treatment apparatus. Compared to the standard activated sludge method, the sprinkler filter method does not require aeration, consumes less power, generates less sludge, and can reduce the disposal cost of excess sludge. The problem is the foul odor generated by rotting and the generation of butterfly flies called sludge flies. The reaction vessel capable of switching between the sprinkling filter and the immersion filter shown in FIGS. 21 to 23 solves this problem. In the reaction tanks shown in FIGS. 21 to 23, the “watering filter tank” means that the treatment fluid is sprayed from the upper part of the filter bed to attach a biofilm to the surface of the carrier constituting the filter bed, and then downward from the upper part of the apparatus. It means a tank for biologically treating the processing fluid by bringing the processing fluid flowing into the biofilm into contact with the biological membrane. Further, the "immersion filter bed tank" means that the carrier is immersed in the treatment fluid and the treatment fluid is brought into contact with the treatment fluid from above or below the tank to attach the biofilm to the surface of the carrier and then the biofilm. It means a tank that bioprocesses a processing fluid by bringing it into contact with the processing fluid.

図２１に示すように、散水ろ床装置は、微生物を付着した第１の担体層１３１を備える第１槽１０３と、微生物を付着した第２の担体層１４１を備える第２槽１０４と、第1槽１０３又は第２槽１０４へ原水を供給可能な原水供給路１１２ａ、１１２ｂと、原水の供給を第1槽１０３と第２槽１０４との間で切り換える切換手段１０５とを備える。 As shown in FIG. 21, the watering filter has a first tank 103 having a first carrier layer 131 to which microorganisms are attached, a second tank 104 having a second carrier layer 141 to which microorganisms are attached, and a second tank 104. It is provided with raw water supply paths 112a and 112b capable of supplying raw water to the first tank 103 or the second tank 104, and a switching means 105 for switching the supply of raw water between the first tank 103 and the second tank 104.

図２２に示すように、第１槽１０３及び第２槽１０４は、一方の槽が「散水ろ床槽」として機能する場合には、他方の槽が「浸水ろ床槽」として機能する。原水の供給が、ポンプ１１１及び切替手段１０５及び原水供給路１１２ａを介して第１槽１０３に行われる場合には、第１槽１０３が、原水中に第１の担体層１３１を浸漬して生物処理する浸漬ろ床法により原水を処理する「浸漬ろ床槽」として機能し、第２槽１０４が、第１槽１０３で得られた処理水を第２の担体層１４１の上部から散布して生物処理する散水ろ床法により処理水を処理する「散水ろ床槽」として機能する。 As shown in FIG. 22, in the first tank 103 and the second tank 104, when one tank functions as a "sprinkling filter tank", the other tank functions as a "flooded filter tank". When the raw water is supplied to the first tank 103 via the pump 111, the switching means 105, and the raw water supply path 112a, the first tank 103 immerses the first carrier layer 131 in the raw water and organisms. It functions as an "immersion filter bed tank" that treats raw water by the immersion filter method, and the second tank 104 sprays the treated water obtained in the first tank 103 from the upper part of the second carrier layer 141. It functions as a "sprinkling filter tank" that treats treated water by the biological treatment sprinkling filter method.

一方、図２３に示すように、原水の供給が、ポンプ１１１、切替手段１０５及び原水供給路１１２ｂを介して第２槽１０４に行われる場合には、第２槽１０４が、原水中に第２の担体層１４１を浸漬して生物処理する浸漬ろ床法により原水を処理する「浸漬ろ床槽」として機能し、第１槽１０３が、第２槽１０４で得られた処理水を、第１の担体層１３１の上部から散布して生物処理する散水ろ床法により処理水を処理する「散水ろ床槽」として機能する。 On the other hand, as shown in FIG. 23, when the raw water is supplied to the second tank 104 via the pump 111, the switching means 105 and the raw water supply path 112b, the second tank 104 is second in the raw water. It functions as a "immersion filter bed tank" that treats raw water by the immersion filter method in which the carrier layer 141 of the above is immersed and biologically treated, and the first tank 103 uses the treated water obtained in the second tank 104 as the first It functions as a "sprinkling filter tank" for treating treated water by a sprinkling filter method in which the carrier layer 131 is sprayed from above and biologically treated.

装置の切り替えのタイミングは、（１）処理水出口にスクリーンを設け、スクリーンに補足されたろ床バエ、およびその幼虫を目視、監視カメラで確認し、ろ床バエの発生が確認されたタイミングで切り替えを行う方法、（２）３〜３０日のいずれかの期間で、一定期間ごとに切り替えを行う方法、（３）担体に付着した生物量を測定し、付着生物量が３０００〜６０００ｍｇ−ＳＳ／Ｌとなった場合にとなった場合に切り替えを行う方法、等が考えられる。 The timing of switching the device is as follows: (1) A screen is provided at the treated water outlet, and the filter bed flies captured on the screen and their larvae are visually confirmed with a surveillance camera, and the switching is performed at the timing when the occurrence of the filter bed flies is confirmed. (2) A method of switching at regular intervals in any period of 3 to 30 days, (3) The amount of biomass attached to the carrier is measured, and the amount of attached biomass is 3000 to 6000 mg-SS / A method of switching when it becomes L and the like can be considered.

上記のように、浸漬ろ床槽と散水ろ床槽を定期的に切り替えながら通水させることで、装置の運転を停止させることなく、効率良く悪臭及びろ床バエの発生を抑制することができる。 As described above, by passing water while periodically switching between the immersion filter bed tank and the sprinkler filter bed tank, it is possible to efficiently suppress the generation of foul odors and filter bed flies without stopping the operation of the device. ..

［メタン回収槽］
本発明の有機性排水処理方法において、ＵＡＳＢ処理による嫌気性処理水を好気性生物処理に供する前に、嫌気性処理水から溶存メタンを回収して、メタンガスとして脱窒処理に供給してもよい。この態様によれば、水素供与体としてのメタンガスの吹き込み量を調整することで、溶存メタンとして供給するよりも水素供与体の量を調整しやすい。[Methane recovery tank]
In the organic wastewater treatment method of the present invention, dissolved methane may be recovered from the anaerobic treated water and supplied as methane gas to the denitrification treatment before the anaerobic treated water by the UASB treatment is subjected to the aerobic biological treatment. .. According to this aspect, by adjusting the amount of methane gas blown as the hydrogen donor, it is easier to adjust the amount of the hydrogen donor than to supply it as dissolved methane.

図２４に、嫌気性処理水から溶存メタンを回収してメタンガスとして好気性生物処理に供するための溶存メタン回収槽の好適例を示す。溶存メタン回収槽７０は、気泡塔型の反応槽であり、底部に嫌気性処理水を導入する嫌気性処理水排出管３８が接続され、メタンガス以外の気体を吹き込むガス吹込ライン７１が設けられている。槽頂部には、メタンガスを含む混合ガスを無酸素槽４１に供給する配管７２が接続され、槽上部には、メタンガス回収後の嫌気性処理水を無酸素槽４１に送る配管が接続されている。溶存メタン回収槽７０内に嫌気性処理水を滞留させ、槽底部からメタンガス以外の気体を吹き込んで溶存メタンを追い出し、槽頂部からメタンガスを回収し、無酸素槽４１にメタンガスとして供給する。槽底部から吹き込むメタンガス以外の気体としては、二酸化炭素、窒素、空気、その他不活性ガス、及びこれらのすくなくとも１種以上の混合気体を挙げることができる。 FIG. 24 shows a preferable example of a dissolved methane recovery tank for recovering dissolved methane from anaerobic treated water and using it as methane gas for aerobic biological treatment. The dissolved methane recovery tank 70 is a bubble tower type reaction tank, and an anaerobic treated water discharge pipe 38 for introducing anaerobic treated water is connected to the bottom thereof, and a gas blowing line 71 for blowing a gas other than methane gas is provided. There is. A pipe 72 for supplying a mixed gas containing methane gas to the oxygen-free tank 41 is connected to the top of the tank, and a pipe for sending anaerobic treated water after recovery of methane gas to the oxygen-free tank 41 is connected to the upper part of the tank. .. Anaerobic treated water is retained in the dissolved methane recovery tank 70, and a gas other than methane gas is blown from the bottom of the tank to expel the dissolved methane, and the methane gas is recovered from the top of the tank and supplied to the oxygen-free tank 41 as methane gas. Examples of the gas other than the methane gas blown from the bottom of the tank include carbon dioxide, nitrogen, air, other inert gases, and at least one or more mixed gases thereof.

図２５に、溶存メタン回収槽８０の別の例を示す。溶存メタン回収槽８０は、一方の槽壁の上部に嫌気性処理水排出管３８が接続され、嫌気性処理水排出管３８とは反対側の槽壁の下部にメタンガス回収後の嫌気性処理水を無酸素槽４１に送る配管が接続され、槽内部には仕切板８１で流体連通状態に仕切った階段状の多段槽を設け、高低差を利用した自然流下により槽内に負圧を発生させ、溶存メタンを追い出す構成を具備する。最下段の槽の頂部にはメタンガスを含む混合ガスを無酸素槽４１に供給する配管８２が接続されている。 FIG. 25 shows another example of the dissolved methane recovery tank 80. In the dissolved methane recovery tank 80, an anaerobic treated water discharge pipe 38 is connected to the upper part of one tank wall, and the anaerobic treated water after methane gas recovery is connected to the lower part of the tank wall opposite to the anaerobic treated water discharge pipe 38. Is connected to the oxygen-free tank 41, and a stepped multi-stage tank is provided inside the tank, which is partitioned by a partition plate 81 in a fluid communication state, and a negative pressure is generated in the tank by natural flow using the height difference. , It has a structure to expel dissolved methane. A pipe 82 for supplying a mixed gas containing methane gas to the oxygen-free tank 41 is connected to the top of the lowermost tank.

メタン回収槽からメタンガスを含む混合ガスを無酸素槽４１へ送る配管７２及び８２にブロワを設けて、メタンガスを含む混合ガスをメタン回収槽から吸引してもよい。メタン回収槽内がより負圧となり、溶存メタンが大気中に放散することを防止することができる。 Blowers may be provided in the pipes 72 and 82 for sending the mixed gas containing methane gas from the methane recovery tank to the oxygen-free tank 41, and the mixed gas containing methane gas may be sucked from the methane recovery tank. The pressure inside the methane recovery tank becomes more negative, and it is possible to prevent dissolved methane from being released into the atmosphere.

［メタン酸化槽］
本発明の有機性排水処理方法において、ＵＡＳＢ処理による嫌気性処理水を好気性生物処理に供する前に、メタン酸化菌により処理してもよい。効率的なメタン酸化のために、担体に固定化されたメタン酸化菌を用いることが好ましく、ＵＡＳＢ処理槽（嫌気性処理）と無酸素槽（好気性生物処理）との間に、メタン酸化菌を固定化した担体を充填したメタン酸化槽を設けてもよい。メタン酸化槽の底部から導入された嫌気性処理水中の溶存メタンは、ガス吹き込みラインにより供給される酸素の存在下で、メタン酸化菌と接触させると、上記式（１）に示すようにメタノールなどの中間生成物を経て水と二酸化炭素に分解される。[Methane oxidation tank]
In the organic wastewater treatment method of the present invention, anaerobic treated water by UASB treatment may be treated with methane-oxidizing bacteria before being subjected to aerobic biological treatment. For efficient methane oxidation, it is preferable to use methane-oxidizing bacteria immobilized on a carrier, and between the UASB treatment tank (anaerobic treatment) and the anoxic tank (aerobic biological treatment), the methane-oxidizing bacteria A methane oxidation tank filled with a carrier on which the above is immobilized may be provided. When the dissolved methane in the anaerobic treated water introduced from the bottom of the methane oxidation tank is brought into contact with methane-oxidizing bacteria in the presence of oxygen supplied by the gas blowing line, methanol or the like is shown in the above formula (1). It is decomposed into water and carbon dioxide via the intermediate products of.

あるいは、メタン酸化槽の底部に、ＵＡＳＢ槽からの嫌気性処理水と、好気性生物処理の好気槽からの硝化液（溶存酸素４ｍｇ／Ｌ〜８ｍｇ／Ｌ）を供給して、空気を吹き込まない状態で、担体に固定化されたメタン酸化菌により溶存メタンを酸化し、硝化液中の亜硝酸、硝酸性窒素を脱窒菌により脱窒処理してもよい。 Alternatively, anaerobic treated water from the UASB tank and nitrification liquid (dissolved oxygen 4 mg / L to 8 mg / L) from the aerobic biological treatment aerobic tank are supplied to the bottom of the methane oxidation tank, and air is blown into the bottom. In the absence of this, dissolved methane may be oxidized by methane-oxidizing bacteria immobilized on a carrier, and nitrite and nitrate nitrogen in the nitrifying solution may be denitrified by denitrifying bacteria.

担体に固定化したメタン酸化菌を充填したメタン酸化槽を設ける場合には、槽の大きさをコンパクトにすることができる。 When a methane oxidation tank filled with methane-oxidizing bacteria immobilized on a carrier is provided, the size of the tank can be made compact.

担体としては、軽石、活性炭、プラスチックろ材等を好適に用いることができる。担体の表面にメタン酸化菌を固定するため、担体の表面はメタン酸化菌を担持することができる寸法の凹凸を有することが好ましい。担体は、粒径が５ｍｍ〜２０ｍｍ、好ましくは７ｍｍ〜１２ｍｍの球状又は楕円体状であることが好ましい。 As the carrier, pumice stone, activated carbon, plastic filter medium and the like can be preferably used. In order to fix the methane-oxidizing bacteria on the surface of the carrier, it is preferable that the surface of the carrier has irregularities having dimensions capable of carrying the methane-oxidizing bacteria. The carrier preferably has a spherical or ellipsoidal shape having a particle size of 5 mm to 20 mm, preferably 7 mm to 12 mm.

［好気性生物処理からの余剰汚泥の処理］
好気性生物処理により発生する余剰汚泥は、必要に応じて濃縮した後、濃縮余剰汚泥として再び好気性生物処理に戻してもよいし、さらに酸発酵処理をした後に嫌気性処理に供する有機性排水に添加してもよい。[Treatment of excess sludge from aerobic biological treatment]
Excess sludge generated by aerobic biological treatment may be concentrated as necessary and then returned to aerobic biological treatment as concentrated excess sludge, or organic wastewater to be subjected to anaerobic treatment after further acid fermentation treatment. May be added to.

［有機性排水］
本発明の処理方法によって処理する有機性排水は、ＣＯＤＣｒ値が１，０００ｍｇ／Ｌ以下、好ましくは６００ｍｇ／Ｌ以下、より好ましくは３００ｍｇ／Ｌ以下の低濃度有機性排水であり、生活排水や下水など有機物質を含む一般の排水である。嫌気性処理に供する有機性排水は、好気性生物処理からの余剰汚泥又は濃縮余剰汚泥を酸発酵処理した酸発酵汚泥、又は酸発酵汚泥を脱ガス処理した後に添加したものでもよい。[Organic wastewater]
The organic wastewater treated by the treatment method of the present invention is a low-concentration organic wastewater having a COD Cr value of 1,000 mg / L or less, preferably 600 mg / L or less, more preferably 300 mg / L or less, and includes domestic wastewater and domestic wastewater. It is general wastewater containing organic substances such as sewage. The organic wastewater to be subjected to the anaerobic treatment may be acid-fermented sludge obtained by acid-fermenting excess sludge from aerobic biological treatment or concentrated excess sludge, or acid-fermented sludge added after degassing.

酸発酵処理は、好気性生物処理からの余剰汚泥又は濃縮余剰汚泥中の有機物の一部を酢酸、プロピオン酸、乳酸等の有機酸に低分子化する。酸発酵処理において、酸生成に関与する微生物は通性嫌気菌であり、ＯＲＰ（酸化還元電位）が−２００ｍＶ〜５０ｍＶの範囲で生育させることが好ましい。酸発酵処理の際に、余剰汚泥又は濃縮余剰汚泥を２０〜３５℃、好ましくは２０〜２５℃に加温することが好ましく、熱源としてＵＡＳＢ槽から回収されたバイオガスを利用してもよい。酸発酵処理での酸発酵処理槽の最適なＨＲＴ（Hydraulic retention Time：水理学的滞留時間）は、溶解性有機物濃度（Soluble ＣＯＤＣｒ、以下「Ｓ−ＣＯＤＣｒ」と略す。）及び有機酸の生成量により決定することができ、固形性有機物が可溶化した割合である「ＣＯＤＣｒの可溶化比（Ｓ−ＣＯＤＣｒ／ＣＯＤＣｒ）」と、溶解性有機酸ＣＯＤＣｒ中の有機酸の割合である「有機酸（asＣＯＤＣｒ）／Ｓ−ＣＯＤＣｒ」が一定値を示すＨＲＴを最適ＨＲＴとすることが好ましい。The acid fermentation treatment reduces the molecular weight of some of the organic substances in the excess sludge from the aerobic biological treatment or the concentrated excess sludge to organic acids such as acetic acid, propionic acid, and lactic acid. In the acid fermentation treatment, the microorganism involved in acid production is a facultative anaerobic bacterium, and it is preferable to grow the ORP (oxidation-reduction potential) in the range of −200 mV to 50 mV. During the acid fermentation treatment, the excess sludge or concentrated excess sludge is preferably heated to 20 to 35 ° C., preferably 20 to 25 ° C., and biogas recovered from the UASB tank may be used as a heat source. The optimum HRT (Hydraulic retention Time) of the acid fermentation treatment tank in the acid fermentation treatment is the concentration of soluble organic matter (Soluble COD Cr , hereinafter abbreviated as "S-COD Cr ") and the organic acid. can be determined by the amount, the solid organic material is a percentage of solubilized "solubilization ratio of COD Cr (S-COD Cr / COD Cr) ", the proportion of the organic acid in soluble organic acid COD Cr It is preferable that the optimum HRT is an HRT in which the “organic acid (asCOD Cr ) / S-COD Cr” is a constant value.

酸発酵汚泥は、主として二酸化炭素、及び水素を含む発酵ガスを含む。発酵ガスは、嫌気性処理の際にＵＡＳＢ槽に流入すると、汚泥の浮上を促進し、汚泥と嫌気性菌との十分な接触を阻害し、ＵＡＳＢ槽内にスカムを発生させる原因となるため、有機性排水を嫌気性処理に供する前に脱ガスすることが好ましい。発酵汚泥の脱ガスは、発酵汚泥を有機性排水に添加した後、嫌気性処理に供する前に、一定時間滞留させて大気と接触させて発酵ガスを分離する、又は迂流、自然流下又は越流などで発酵ガスを分離する、などの方法で行うことができる。 Acid fermentation sludge mainly contains fermentation gas containing carbon dioxide and hydrogen. When the fermentation gas flows into the UASB tank during anaerobic treatment, it promotes the floating of sludge, inhibits sufficient contact between the sludge and anaerobic bacteria, and causes scum to be generated in the UASB tank. It is preferable to degas the organic wastewater before subjecting it to anaerobic treatment. Fermented sludge can be degassed by adding fermented sludge to organic wastewater and then allowing it to stay for a certain period of time to contact the atmosphere to separate the fermented gas, or by diversion, natural flow or excess before being subjected to anaerobic treatment. This can be done by separating the fermentation gas with a stream or the like.

以下、本発明の処理方法の態様を例示して説明する。以下の例示における各処理装置（槽）及び処理条件などは、特に断らない限り、上述したとおりである。 Hereinafter, aspects of the processing method of the present invention will be described as an example. Unless otherwise specified, each processing apparatus (tank) and processing conditions in the following examples are as described above.

［処理方法Ａ］
図２６は、好気性生物処理からの余剰汚泥を濃縮して酸発酵させた酸発酵汚泥を有機性排水に添加して脱ガスした後に、嫌気性処理を行う場合の本発明の処理方法のフローを示す。本処理フローは、嫌気性処理に供される有機性排水の温度が１８℃以上、特に２０℃〜２５℃である場合に有効である。[Processing method A]
FIG. 26 shows the flow of the treatment method of the present invention in the case of performing anaerobic treatment after adding acid-fermented sludge obtained by concentrating excess sludge from aerobic biological treatment and acid-fermenting it to organic wastewater and degassing it. Is shown. This treatment flow is effective when the temperature of the organic wastewater to be subjected to the anaerobic treatment is 18 ° C. or higher, particularly 20 ° C. to 25 ° C.

まず、有機性排水のＶＳ／ＳＳを測定して、ＶＳ／ＳＳが０．５以下の場合に上向流固液分離装置１にて有機性排水中の無機成分を除去し、上澄み液に酸発酵処理汚泥を混合した後、酸発酵処理汚泥を脱ガスして脱ガス混合水とする。有機性排水中のＶＳ／ＳＳが０．５を越える場合には、上向流固液分離装置を経由せずに、直接、有機性排水に酸発酵処理汚泥を混合して、脱ガスして脱ガス混合水とする。脱ガス混合水は、ＵＡＳＢ槽２に送られる。ＵＡＳＢ槽２にて嫌気性処理した後、嫌気性処理水を嫌気性処理水排出管３８を介して好気性生物処理装置３に送り、好気性生物処理する。ＵＡＳＢ槽２から発生するバイオガス（メタンガス）は発生ガス排出管３７を介してバイオガス処理装置１０に送られて脱硫後に酸発酵槽の加熱用熱源として利用してもよい。好気性生物処理装置３からの処理水は沈殿池５にて余剰汚泥と処理水に分離される。余剰汚泥の一部は、好気性生物処理装置３に戻される。余剰汚泥の残部は、必要に応じて濃縮装置１６にて濃縮汚泥とされ、酸発酵槽４に送られる。酸発酵槽４からの酸発酵処理汚泥は、脱ガス装置６に送られる。ＵＡＳＢ槽２からの嫌気性処理汚泥は脱水装置９にて脱水処理され、脱水ケーキを得る。 First, the VS / SS of the organic waste water is measured, and when the VS / SS is 0.5 or less, the inorganic component in the organic waste water is removed by the upward flow solid-liquid separation device 1, and the supernatant liquid is acidified. After mixing the fermentation-treated sludge, the acid-fermentation-treated sludge is degassed to obtain degassed mixed water. If the VS / SS in the organic wastewater exceeds 0.5, the organic wastewater is directly mixed with acid fermentation sludge and degassed without going through the upward flow solid-liquid separator. Use degassed mixed water. The degassed mixed water is sent to the UASB tank 2. After the anaerobic treatment in the UASB tank 2, the anaerobic treated water is sent to the aerobic biological treatment device 3 via the anaerobic treated water discharge pipe 38 to treat the aerobic organism. The biogas (methane gas) generated from the UASB tank 2 may be sent to the biogas treatment apparatus 10 via the generated gas discharge pipe 37 and used as a heat source for heating the acid fermentation tank after desulfurization. The treated water from the aerobic biological treatment device 3 is separated into excess sludge and treated water in the settling basin 5. A part of the excess sludge is returned to the aerobic biological treatment apparatus 3. The remaining portion of the surplus sludge is made into concentrated sludge by the concentrating device 16 as needed and sent to the acid fermenter 4. The acid fermentation-treated sludge from the acid fermentation tank 4 is sent to the degassing device 6. The anaerobic sludge from the UASB tank 2 is dehydrated by the dehydrating device 9 to obtain a dehydrated cake.

［処理方法Ｂ］
図２７に示す処理方法Ｂは、ＵＡＳＢ槽２からの嫌気性処理汚泥の一部又は全部を酸発酵処理槽４に送り、好気性生物処理装置３からの余剰汚泥又は濃縮余剰汚泥と混合して、酸発酵処理して形成される酸発酵処理汚泥を有機性排水に添加する点を除き、処理方法Ａと同様である。本処理方法は、嫌気性処理に供される有機性排水の温度が１３℃以上１８℃未満である場合に有効である。低温の有機性排水を嫌気性処理する場合には、嫌気性菌の活性が低下し、ＵＡＳＢ槽２内に懸濁物質（ＳＳ）が滞留し、メタン発酵が進行せず、ＵＡＳＢ槽２内の汚泥界面が上昇することがある。そこで、ＵＡＳＢ槽２から汚泥を引き抜き、酸発酵処理により低分子化して、再び脱ガス槽６経由でＵＡＳＢ槽２に戻すことにより、活性が低下した嫌気性菌であっても嫌気性処理が進行するようになる。酸発酵処理時の汚泥の加温には、バイオガス処理装置１０にて脱硫した後のバイオガスを利用してもよい。[Processing method B]
In the treatment method B shown in FIG. 27, a part or all of the anaerobic treated sludge from the UASB tank 2 is sent to the acid fermentation treatment tank 4 and mixed with the surplus sludge or the concentrated surplus sludge from the aerobic biological treatment apparatus 3. , The same as the treatment method A except that the acid fermentation sludge formed by the acid fermentation treatment is added to the organic wastewater. This treatment method is effective when the temperature of the organic wastewater to be subjected to the anaerobic treatment is 13 ° C. or higher and lower than 18 ° C. When low-temperature organic wastewater is anaerobically treated, the activity of anaerobic bacteria decreases, suspended solids (SS) stay in the UASB tank 2, methane fermentation does not proceed, and the UASB tank 2 contains. The sludge interface may rise. Therefore, sludge is extracted from the UASB tank 2, the molecular weight is reduced by acid fermentation treatment, and the sludge is returned to the UASB tank 2 via the degassing tank 6 again. Will come to do. Biogas after desulfurization by the biogas treatment apparatus 10 may be used for heating the sludge during the acid fermentation treatment.

［処理方法Ｃ］
図２８に示す処理方法Ｃは、まず有機性排水のＶＳ／ＳＳを測定して、ＶＳ／ＳＳが０．５以下の場合に上向流固液分離槽１にて固液分離して無機成分を除去した後の有機物の割合が比較的大きいＳＳを含む上澄み液を最初沈殿池６０に供給し、最初沈殿池６０にて濃縮して分離水と汚泥に分離し、汚泥を好気性生物処理装置３からの余剰汚泥又は濃縮余剰汚泥と混合して酸発酵処理し、酸発酵処理汚泥を分離水と混合して脱ガス処理して得られる脱ガス混合水をＵＡＳＢ槽２に送り、ＶＳ／ＳＳが０．５を越える場合には上向流固液分離槽１を経由せずに直接、最初沈殿池６０に送り分離水と汚泥に分離し、汚泥を好気性生物処理装置３からの余剰汚泥又は濃縮余剰汚泥と混合して酸発酵処理し、酸発酵処理汚泥を分離水と混合して脱ガス処理して得られる脱ガス混合水をＵＡＳＢ槽２に送る点を除いて、処理方法Ａと同様である。本処理方法は、嫌気性処理に供される有機性排水の温度が１３℃未満の場合に有効である。最初沈殿池６０にて有機性排水中の有機物成分を濃縮してから酸発酵処理することで、酸発酵処理槽４の温度の低下を防止することができる。酸発酵処理時の汚泥の加温には、バイオガス処理装置１０にて脱硫した後のバイオガスを利用することができる。[Processing method C]
In the treatment method C shown in FIG. 28, VS / SS of organic wastewater is first measured, and when VS / SS is 0.5 or less, solid-liquid separation is performed in the upward flow solid-liquid separation tank 1 to separate inorganic components. The supernatant liquid containing SS, which has a relatively large proportion of organic matter, is supplied to the first settling pond 60, concentrated in the first settling pond 60 and separated into separated water and sludge, and the sludge is separated into aerobic biological treatment equipment. The degassed mixed water obtained by mixing with the surplus sludge from 3 or the concentrated surplus sludge and performing acid fermentation treatment, mixing the acid fermentation treated sludge with the separated water and degassing treatment is sent to the UASB tank 2 and VS / SS. If it exceeds 0.5, it is first sent directly to the settling pond 60 without going through the upward flow solid-liquid separation tank 1 to separate it into separated water and sludge, and the sludge is separated from the aerobic biological treatment device 3 from the surplus sludge. Alternatively, the treatment method A and the treatment method A except that the degassing mixed water obtained by mixing with the concentrated excess sludge and performing acid fermentation treatment, mixing the acid fermentation treatment sludge with the separated water and degassing treatment is sent to the UASB tank 2. The same is true. This treatment method is effective when the temperature of the organic wastewater to be subjected to the anaerobic treatment is less than 13 ° C. By first concentrating the organic matter components in the organic wastewater in the settling basin 60 and then performing the acid fermentation treatment, it is possible to prevent the temperature of the acid fermentation treatment tank 4 from dropping. Biogas after desulfurization by the biogas treatment apparatus 10 can be used for heating the sludge during the acid fermentation treatment.

［処理方法Ｄ］
図２９は、ＵＡＳＢ嫌気性処理におけるガス発生量に基づいて、ＵＡＳＢ嫌気性処理前段での固液分離の有無（切り替え）を行う有機性排水の処理フローを示す。ここでは、ＵＡＳＢ槽２からのガス発生量と、有機性排水が上向流固液分離槽１を経由する流路と経由しない流路との切り換えについてのみ説明する。ＵＡＳＢ槽２の後段の好気性生物処理及び余剰汚泥の再利用、嫌気性処理汚泥の脱水などは、処理方法Ａ〜Ｃにおいて説明したいずれの態様でもよい。[Processing method D]
FIG. 29 shows a treatment flow of organic wastewater for performing solid-liquid separation (switching) in the first stage of the UASB anaerobic treatment based on the amount of gas generated in the UASB anaerobic treatment. Here, only the switching between the amount of gas generated from the UASB tank 2 and the flow path in which the organic wastewater passes through the upward flow solid-liquid separation tank 1 and the flow path that does not pass through will be described. The aerobic biological treatment in the latter stage of the UASB tank 2, the reuse of excess sludge, the dehydration of the anaerobic treated sludge, and the like may be any of the embodiments described in the treatment methods A to C.

まず、有機性排水は上向流固液分離槽１を経由せずにＵＡＳＢ槽２に送られ、嫌気性処理される。このときのＵＡＳＢ槽２からのガス発生量をモニタリングし、２日以上連続する同程度のガス発生量を通常ガス発生量とする。嫌気性処理が進行するにつれて、ＵＡＳＢ槽２内の有機性排水中の無機物は処理されずに蓄積されるため、有機物濃度が相対的に低下して、ガス発生量は低下する。ＵＡＳＢ槽２からのガス発生量が通常ガス発生量の１／２以下となる期間が２日以上続いた場合に、有機性排水の流路を切り換えて上向流固液分離槽１を経由してＵＡＳＢ槽２に有機性排水を導入する。上向流固液分離槽１を経由することにより、有機性排水中の無機物は除去され、ＵＡＳＢ槽２内の有機物濃度が相対的に上昇し、ＵＡＳＢ槽２からのガス発生量が増加する。ＵＡＳＢ槽２からのガス発生量が通常ガス発生量に戻った時点で、有機性排水の流路を切り換えて上向流固液分離槽１をバイパスさせ、直接ＵＡＳＢ槽２に送る。ＵＡＳＢ槽２からのガス発生量のモニタリング値が再び通常ガス発生量の１／２以下となる期間が２日以上続いた時点で、有機性排水の流路を切り換えて上向流固液分離槽１を経由してＵＡＳＢ槽２に有機性排水を導入する。以後、ガス発生量に基づいて流路切換えを行う。 First, the organic wastewater is sent to the UASB tank 2 without passing through the upward flow solid-liquid separation tank 1 and is anaerobically treated. The amount of gas generated from the UASB tank 2 at this time is monitored, and the same amount of gas generated for two consecutive days or more is defined as the normal amount of gas generated. As the anaerobic treatment progresses, the inorganic substances in the organic wastewater in the UASB tank 2 are accumulated without being treated, so that the organic matter concentration is relatively lowered and the amount of gas generated is lowered. When the period in which the amount of gas generated from the UASB tank 2 is 1/2 or less of the normal amount of gas generated continues for 2 days or more, the flow path of the organic wastewater is switched and the gas is passed through the upward flow solid-liquid separation tank 1. Introduce organic wastewater into the UASB tank 2. By passing through the upward flow solid-liquid separation tank 1, the inorganic substances in the organic wastewater are removed, the concentration of the organic substances in the UASB tank 2 is relatively increased, and the amount of gas generated from the UASB tank 2 is increased. When the amount of gas generated from the UASB tank 2 returns to the normal amount of gas generated, the flow path of the organic wastewater is switched to bypass the upward flow solid-liquid separation tank 1 and directly sent to the UASB tank 2. When the monitoring value of the gas generation amount from the UASB tank 2 continues to be 1/2 or less of the normal gas generation amount again for 2 days or more, the flow path of the organic wastewater is switched to the upward flow solid-liquid separation tank. Organic wastewater is introduced into the UASB tank 2 via 1. After that, the flow path is switched based on the amount of gas generated.

以下、実施例を用いて本発明を具体的に説明するが、本発明はこれらに限定されるものではない。 Hereinafter, the present invention will be specifically described with reference to Examples, but the present invention is not limited thereto.

［実施例１］
表１に示す性状の有機性排水（原水）を用い、図３０に示す装置にて処理した。[Example 1]
Organic wastewater (raw water) having the properties shown in Table 1 was used and treated with the apparatus shown in FIG.

Figure 0006943854
Figure 0006943854

図３０において、上向流固液分離槽１は有効容量３０Ｌ（直径２０ｃｍ×高さ１．５ｍ）、ＵＡＳＢ槽２は有効容量１０Ｌ、好気性生物処理装置３は有効総容量２０Ｌ、無酸素槽（脱窒槽ＤＮ）−好気槽（硝化槽ＡＴ）−無酸素槽（脱窒槽ＤＮ）−好気槽（硝化槽ＡＴ）の構成を具備する。原水（有機性排水）のＶＳ／ＳＳが０．５以下の場合に、原水（有機性排水）を上向流固液分離槽１に供給し、越流水をＵＡＳＢ槽２の底部から導入し、嫌気性処理した後、ＵＡＳＢ槽２からの越流水を好気性生物処理装置３の無酸素槽ＤＮ２槽にそれぞれ導入し、各無酸素槽ＤＮの直後の好気槽ＡＴに流入させ、好気性生物処理した。最終段からの好気性生物処理水を沈殿池５にて固液分離し、余剰汚泥を好気性生物処理装置３の初段の無酸素槽ＤＮに戻し、上澄液を活性汚泥処理水槽に供給し、処理水を放流した。 In FIG. 30, the upward flow solid-liquid separation tank 1 has an effective capacity of 30 L (diameter 20 cm × height 1.5 m), the UASB tank 2 has an effective capacity of 10 L, and the aerobic biological treatment device 3 has an effective total capacity of 20 L, an oxygen-free tank. (Denitrification tank DN) -Aerobic tank (nitrification tank AT) -Anoxic tank (denitrification tank DN) -Aerobic tank (nitrification tank AT). When the VS / SS of the raw water (organic wastewater) is 0.5 or less, the raw water (organic wastewater) is supplied to the upward flow solid-liquid separation tank 1, and the overflow water is introduced from the bottom of the UASB tank 2. After the anaerobic treatment, the overflow water from the UASB tank 2 is introduced into the anoxic tank DN2 tank of the aerobic organism treatment apparatus 3, respectively, and flows into the aerobic tank AT immediately after each anoxic tank DN to be aerobic organisms. Processed. The aerobic biological treatment water from the final stage is solid-liquid separated in the settling pond 5, the excess sludge is returned to the anoxic tank DN of the first stage of the aerobic biological treatment device 3, and the supernatant is supplied to the activated sludge treatment water tank. , The treated water was discharged.

上向流固液分離槽１の通水速度は０．４ｍ／ｈ〜１．０ｍ／ｈに調整し、ＵＡＳＢ槽２の通水条件はＨＲＴ８時間、線速度（ＬＶ）０．７ｍ／ｈとした。好気性生物処理のＢＯＤ容積負荷は１．０ｋｇ／ｍ３／ｄ、ＨＲＴ８時間〜１２時間の範囲とした。有機性排水の温度は１５℃〜２５℃の範囲であった。The water flow rate of the upward flow solid-liquid separation tank 1 is adjusted to 0.4 m / h to 1.0 m / h, and the water flow conditions of the UASB tank 2 are HRT 8 hours and linear velocity (LV) 0.7 m / h. bottom. The BOD volume loading for aerobic biotreatment was 1.0 kg / m 3 / d and the HRT ranged from 8 hours to 12 hours. The temperature of the organic wastewater was in the range of 15 ° C to 25 ° C.

表２及び図３１に、原水のＶＳ／ＳＳ比とＵＡＳＢ処理によるＣＯＤＣｒ除去率を示す。Table 2 and FIG. 31 show the VS / SS ratio of raw water and the COD Cr removal rate by UASB treatment.

Figure 0006943854
Figure 0006943854

Ａ系列（前処理なし：比較例）は原水ＶＳ／ＳＳ比０．８でＣＯＤＣｒ除去率６０％、原水ＶＳ／ＳＳ比０．５でＣＯＤＣｒ除去率３０％、原水ＶＳ／ＳＳ比０．３でＣＯＤＣｒ除去率２０％、原水ＶＳ／ＳＳ比０．１５でＣＯＤＣｒ除去率１０％であり、原水ＶＳ／ＳＳ比が低下するとともにＵＡＳＢ処理のＣＯＤＣｒ除去率は低下する傾向にあり、特に原水ＶＳ／ＳＳ比０．５以下の範囲で顕著であった。A sequence (without pretreatment: Comparative example) COD Cr removal rate of 60% raw water VS / SS ratio 0.8, COD Cr removal rate of 30% raw water VS / SS ratio of 0.5, the raw water VS / SS ratio 0. The COD Cr removal rate is 20% at 3, and the COD Cr removal rate is 10% at a raw water VS / SS ratio of 0.15. The raw water VS / SS ratio tends to decrease and the COD Cr removal rate of the UASB treatment tends to decrease. It was particularly remarkable in the range of raw water VS / SS ratio of 0.5 or less.

一方、Ｂ系列（前処理有：実施例）は原水ＶＳ／ＳＳ比０．８でＣＯＤＣｒ除去率６０％、原水ＶＳ／ＳＳ比０．５でＣＯＤＣｒ除去率６０％、０．３でＣＯＤＣｒ除去率５８％、原水ＶＳ／ＳＳ比０．１５でＣＯＤＣｒ除去率５５％であり、原水ＶＳ／ＳＳ比が低下してもＵＡＳＢ処理のＣＯＤＣｒ除去率は安定していた。On the other hand, B-series (pretreatment Conditioning: example) COD Cr removal rate of 60% raw water VS / SS ratio 0.8, COD Cr removal rate of 60% raw water VS / SS ratio 0.5, COD 0.3 The Cr removal rate was 58%, the raw water VS / SS ratio was 0.15, and the COD Cr removal rate was 55%. Even if the raw water VS / SS ratio decreased, the COD Cr removal rate in the UASB treatment was stable.

ＶＳ／ＳＳが０．５以下の場合に、ＵＡＳＢ処理前に固液分離による前処理を行うことで、ＵＡＳＢ処理の安定性を確保することができることが確認できた。 It was confirmed that the stability of the UASB treatment can be ensured by performing the pretreatment by solid-liquid separation before the UASB treatment when the VS / SS is 0.5 or less.

表３及び図３２に、原水のＶＳ／ＳＳ比と好気性生物処理によるＢＯＤ濃度を示す。 Table 3 and FIG. 32 show the VS / SS ratio of raw water and the BOD concentration by aerobic biological treatment.

Figure 0006943854
Figure 0006943854

Ａ系列（前処理なし：比較例）は原水ＶＳ／ＳＳ比０．８で活性汚泥処理水ＢＯＤ濃度２ｍｇ／Ｌ、原水ＶＳ／ＳＳ比０．５で活性汚泥処理水ＢＯＤ濃度５ｍｇ／Ｌ、原水ＶＳ／ＳＳ比０．３で活性汚泥処理水ＢＯＤ濃度１０ｍｇ／Ｌ、原水ＶＳ／ＳＳ比０．１５で活性汚泥処理水ＢＯＤ濃度２０ｍｇ／Ｌであり、原水ＶＳ／ＳＳ比が低下するとともに活性汚泥処理水ＢＯＤ濃度は増加する傾向にあり、特に原水ＶＳ／ＳＳ比０．５以下の範囲で顕著であった。 Series A (no pretreatment: comparative example) has an activated sludge treated water BOD concentration of 2 mg / L at a raw water VS / SS ratio of 0.8, and an activated sludge treated water BOD concentration of 5 mg / L at a raw water VS / SS ratio of 0.5. The VS / SS ratio is 0.3 and the activated sludge treated water BOD concentration is 10 mg / L, and the raw water VS / SS ratio is 0.15 and the activated sludge treated water BOD concentration is 20 mg / L. The BOD concentration of the treated water tended to increase, and was particularly remarkable in the range of the raw water VS / SS ratio of 0.5 or less.

一方、Ｂ系列（前処理有：実施例）は原水ＶＳ／ＳＳ比０．８で活性汚泥処理水ＢＯＤ濃度２ｍｇ／Ｌ、原水ＶＳ／ＳＳ比０．５で活性汚泥処理水ＢＯＤ濃度２ｍｇ／Ｌ、原水ＶＳ／ＳＳ比０．３で活性汚泥処理水ＢＯＤ濃度２ｍｇ／Ｌ、原水ＶＳ／ＳＳ比０．１５で活性汚泥処理水ＢＯＤ濃度２ｍｇ／Ｌであり、原水ＶＳ／ＳＳ比が低下しても活性汚泥処理水ＢＯＤ濃度は一定値を示していた。 On the other hand, in the B series (with pretreatment: Example), the activated sludge treated water BOD concentration was 2 mg / L at a raw water VS / SS ratio of 0.8, and the activated sludge treated water BOD concentration was 2 mg / L at a raw water VS / SS ratio of 0.5. The activated sludge treated water BOD concentration is 2 mg / L at a raw water VS / SS ratio of 0.3, and the activated sludge treated water BOD concentration is 2 mg / L at a raw water VS / SS ratio of 0.15. However, the BOD concentration of activated sludge treated water showed a constant value.

ＶＳ／ＳＳが０．５以下の場合に、ＵＡＳＢ処理前に固液分離による前処理を行うことで、ＵＡＳＢ後段の好気性生物処理（活性汚泥処理）の安定性を確保できることが確認できた。 When VS / SS was 0.5 or less, it was confirmed that the stability of the aerobic biological treatment (activated sludge treatment) in the subsequent stage of UASB can be ensured by performing the pretreatment by solid-liquid separation before the UASB treatment.

［実施例２］
表４に示す性状の有機性排水（原水）を用い、図２９に示す処理方法Ｄを行った。有機物の比率の高い期間として原水性状ＶＳ／ＳＳ比０．８を用い、有機物の比率が低い期間として原水性状ＶＳ／ＳＳ比０．３を用いた。[Example 2]
Using the organic wastewater (raw water) having the properties shown in Table 4, the treatment method D shown in FIG. 29 was performed. A raw water VS / SS ratio of 0.8 was used as a period of high organic matter ratio, and a raw water VS / SS ratio of 0.3 was used as a period of low organic matter ratio.

Figure 0006943854
Figure 0006943854

図２９において、上向流固液分離槽１は有効容量６．９Ｌ（直径９．４ｃｍ×高さ１ｍ）、ＵＡＳＢ槽２は有効容量１５Ｌ（直径６．２ｃｍ、高さ５ｍ）とした。実験（ガス発生量測定結果に基づいて有機性排水の流路を切り換えた）、対照（有機性排水の流路を切り換えず常に上向流固液分離槽１をバイパスした）の２系列の実験を行った。 In FIG. 29, the upward flow solid-liquid separation tank 1 has an effective capacity of 6.9 L (diameter 9.4 cm × height 1 m), and the UASB tank 2 has an effective capacity of 15 L (diameter 6.2 cm, height 5 m). Two series of experiments, an experiment (the flow path of organic wastewater was switched based on the measurement result of gas generation) and a control (the flow path of organic wastewater was not switched and the upward flow solid-liquid separation tank 1 was always bypassed). Was done.

まず、有機性排水は上向流固液分離槽１を経由せずにＵＡＳＢ槽２に送られ、嫌気性処理される。このときのＵＡＳＢ槽２からのガス発生量をモニタリングし、５．２〜７．０Ｌ／ｄの範囲を通常ガス発生量とした。ＵＡＳＢ槽２からのガス発生量をモニタリングし続け、通常ガス発生量の１／２以下となる期間が２日以上続いた時点で、有機性排水の流路を切り換えて上向流固液分離槽１を経由してＵＡＳＢ槽２に有機性排水を導入した。ＵＡＳＢ槽２からのガス発生量が通常ガス発生量に戻った時点で、有機性排水の流路を切り換えて上向流固液分離槽１をバイパスさせ、直接ＵＡＳＢ槽２に送った。ＵＡＳＢ槽２からのガス発生量のモニタリング値が再び通常ガス発生量の１／２以下となる期間が2日以上続いた時点で、有機性排水の流路を切り換えて上向流固液分離槽１を経由してＵＡＳＢ槽２に有機性排水を導入するＵＡＳＢ槽２のガス発生量が２日以上の期間、通常ガス量の１／２以下になった場合、ＵＡＳＢの前段で固液分離した後にＵＡＳＢ処理した。対照として、有機性排水の流路を切り換えずに、常時、有機性排水を直接ＵＡＳＢ槽２に通水して、ＵＳＡＢ槽２からのガス発生量をモニタリングした。 First, the organic wastewater is sent to the UASB tank 2 without passing through the upward flow solid-liquid separation tank 1 and is anaerobically treated. The amount of gas generated from the UASB tank 2 at this time was monitored, and the range of 5.2 to 7.0 L / d was set as the normal amount of gas generated. Continue to monitor the amount of gas generated from the UASB tank 2, and when the period of less than 1/2 of the normal amount of gas generated continues for 2 days or more, the flow path of the organic wastewater is switched to the upward flow solid-liquid separation tank. Organic wastewater was introduced into the UASB tank 2 via 1. When the amount of gas generated from the UASB tank 2 returned to the normal amount of gas generated, the flow path of the organic wastewater was switched to bypass the upward flow solid-liquid separation tank 1 and sent directly to the UASB tank 2. When the monitoring value of the gas generation amount from the UASB tank 2 continues to be 1/2 or less of the normal gas generation amount again for 2 days or more, the flow path of the organic wastewater is switched to the upward flow solid-liquid separation tank. When the amount of gas generated in the UASB tank 2 that introduces organic wastewater into the UASB tank 2 via 1 is less than 1/2 of the normal gas amount for a period of 2 days or more, solid-liquid separation was performed in the previous stage of the UASB. It was later treated with UASB. As a control, the amount of gas generated from the USAB tank 2 was monitored by passing the organic wastewater directly to the UASB tank 2 at all times without switching the flow path of the organic wastewater.

実験系列及び対照系列共に、上向流固液分離槽１の通水速度は０．４ｍ／ｈ〜１．０ｍ／ｈに調整し、ＵＡＳＢ槽２の通水条件はＨＲＴ８時間、線速度（ＬＶ）０．７ｍ／ｈとした。表５にガス発生量の経日変動と、流路切り換えを行った時点をあわせて示す。 In both the experimental series and the control series, the water flow rate of the upward flow solid-liquid separation tank 1 was adjusted to 0.4 m / h to 1.0 m / h, and the water flow conditions of the UASB tank 2 were HRT 8 hours and linear velocity (LV). ) 0.7 m / h. Table 5 also shows the daily fluctuation of the amount of gas generated and the time when the flow path was switched.

Figure 0006943854
Figure 0006943854

実験経過日数０〜２５日目、実験経過日数７５〜１１６日目、実験経過日数１５５〜２００日目の期間は有機物の比率の高い期間として原水性状ＶＳ／ＳＳ比０．８を用いた。一方、実験経過後２７〜７０日目、実験経過後１２１〜１４８日目の期間は有機物の比率が低い期間として原水性状ＶＳ／ＳＳ比０．３を用いた。 During the period of 0 to 25 days of the experiment, 75 to 116 days of the experiment, and 155 to 200 days of the experiment, a raw water VS / SS ratio of 0.8 was used as a period with a high ratio of organic matter. On the other hand, in the period of 27 to 70 days after the experiment and 121 to 148 days after the experiment, the raw water VS / SS ratio of 0.3 was used as the period in which the ratio of organic matter was low.

実験系列及び対照系列共に、実験開始後２０日目まで６．６〜７．１Ｌ／ｄと約６．８ｄ／Ｌ程度で安定していたため、約６．８ｄ／Ｌを通常ガス発生量とした。実験系列では、実験開始後２７日目でガス発生量５．２Ｌ／ｄ、実験開始後２９日目でガス発生量２．６Ｌ／ｄ、実験開始後３０日目でガス発生量２．５Ｌ／ｄとなり、通常ガス発生量６．８Ｌ／ｄの１／２以下となる期間が２日以上連続したので、有機性排水の流路を切り換えて、上向流固液分離装置１を経由した後にＵＡＳＢ槽２に通水させた。その結果、実験開始後４４日目でガス発生量３Ｌ／ｄ、実験開始後７０日目でガス発生量２．５Ｌ／ｄと通常ガス発生量の１／２以下で安定していた。その後、ガス発生量は微増し、実験開始後８８日目でガス発生量は４．６Ｌ／ｄ、実験開始後８９日目でガス発生量４．７Ｌ／ｄとなり、２日間連続して通常ガス発生量の１／２を超えるようになったので、有機性排水の流路を切り換えて、上向流固液分離装置１をバイパスして、ＵＡＳＢ槽２に直接通水させた。その結果、実験開始後９５日目にガス発生量６．３Ｌ／ｄとなり、実験開始後１１０日目までガス発生量７Ｌ／ｄ前後で安定していた。その後、ガス発生量は減少し、実験開始後１２７日目で３．１Ｌ／ｄ、実験開始後１２８日目で２．９Ｌ／ｄと通常ガス発生量６．８Ｌ／ｄの１／２以下に２日間連続で低下したので、有機性排水の流路を切り換えて上向流固液分離装置１を経由してＵＡＳＢ槽２に通水させた。その結果、ガス発生量は微増し、実験開始後１５５日目で３．９Ｌ／ｄ、実験開始後１５６日目で４Ｌ／ｄと通常ガス発生量の１／２を超える期間が２日間連続したため、再び有機性排水の流路を切り換えて、上向流固液分離装置１をバイパスして、ＵＡＳＢ槽２に直接通水させた。ガス発生量は増加し続け、実験開始後２００日目まで５〜６．５Ｌ／ｄで安定していた。 Since both the experimental series and the control series were stable at about 6.8 d / L, which was 6.6 to 7.1 L / d until the 20th day after the start of the experiment, about 6.8 d / L was set as the normal gas generation amount. .. In the experimental series, the gas generation amount was 5.2 L / d on the 27th day after the start of the experiment, the gas generation amount was 2.6 L / d on the 29th day after the start of the experiment, and the gas generation amount was 2.5 L / d on the 30th day after the start of the experiment. Since the period of d, which is 1/2 or less of the normal gas generation amount of 6.8 L / d, has continued for 2 days or more, after switching the flow path of the organic drainage and passing through the upward flow solid-liquid separator 1. Water was passed through the UASB tank 2. As a result, the gas generation amount was stable at 3 L / d 44 days after the start of the experiment and 2.5 L / d gas generation 70 days after the start of the experiment, which was less than 1/2 of the normal gas generation amount. After that, the amount of gas generated increased slightly, reaching 4.6 L / d on the 88th day after the start of the experiment and 4.7 L / d on the 89th day after the start of the experiment. Since it became more than 1/2 of the generated amount, the flow path of the organic wastewater was switched, the upward flow solid-liquid separation device 1 was bypassed, and water was directly passed through the UASB tank 2. As a result, the gas generation amount was 6.3 L / d on the 95th day after the start of the experiment, and the gas generation amount was stable at around 7 L / d until the 110th day after the start of the experiment. After that, the amount of gas generated decreased to 3.1 L / d on the 127th day after the start of the experiment and 2.9 L / d on the 128th day after the start of the experiment, which is less than half of the normal gas generation amount of 6.8 L / d. Since it decreased for two consecutive days, the flow path of the organic wastewater was switched and water was passed through the UASB tank 2 via the upward flow solid-liquid separator 1. As a result, the amount of gas generated increased slightly, 3.9 L / d on the 155th day after the start of the experiment and 4 L / d on the 156th day after the start of the experiment, which was a period exceeding 1/2 of the normal gas generation for two consecutive days. The flow path of the organic drainage was switched again to bypass the upward flow solid-liquid separation device 1 and allow water to flow directly to the UASB tank 2. The amount of gas generated continued to increase and was stable at 5 to 6.5 L / d until the 200th day after the start of the experiment.

一方、対照系列では、実験開始後２７日目でガス発生量５Ｌ／ｄ、実験開始後２９日目でガス発生量２Ｌ／ｄ、実験開始後３０日目でガス発生量１．９Ｌ／ｄとなり、ガス発生量が急激に低下したが、有機性排水の流路を切り換えることなく、そのままＵＡＳＢ槽２に直接通水させ続けた。その結果、ＵＡＳＢ槽２からのガス発生量は低下し続け、実験開始後５５日目ではガス発生量０ Ｌ／ｄとなり、実験開始後６３日までガス発生量０ Ｌ／ｄが連続したため、実験を中止した。ＵＡＳＢ槽２内の汚泥を採取するとシルト土が大半を占めていたことがわかった。 On the other hand, in the control series, the gas generation amount was 5 L / d on the 27th day after the start of the experiment, the gas generation amount was 2 L / d on the 29th day after the start of the experiment, and the gas generation amount was 1.9 L / d on the 30th day after the start of the experiment. Although the amount of gas generated decreased sharply, the water flow was continued directly to the UASB tank 2 without switching the flow path of the organic drainage. As a result, the amount of gas generated from the UASB tank 2 continued to decrease, and the amount of gas generated was 0 L / d 55 days after the start of the experiment, and the amount of gas generated was 0 L / d continuously until 63 days after the start of the experiment. Was canceled. When the sludge in the UASB tank 2 was collected, it was found that the silt soil accounted for the majority.

また、実験系列において、ＵＡＳＢ槽２に供給する有機性排水の強熱減量（ＶＳ）／懸濁物質（ＳＳ）も測定した。図３３に、ガス発生量及び強熱減量（ＶＳ）／懸濁物質（ＳＳ）の変動を合わせて示す。ＵＡＳＢ槽２からのガス発生量が低下した時点での流路切り換えのタイミングは、強熱減量（ＶＳ）／懸濁物質（ＳＳ）が０．５以下になった時点での流路切り替えのタイミングとよく一致していることがわかる。実験開始後８９日目のＵＡＳＢ槽２からのガス発生量に基づく流路切り替えは、通常ガス発生量の１／２を超えた３．８Ｌ／ｄを検出した実験開始後８０日目で行うべきであったことがわかる。 In the experimental series, the ignition loss (VS) / suspended solids (SS) of the organic wastewater supplied to the UASB tank 2 was also measured. FIG. 33 also shows the fluctuations in the amount of gas generated and the ignition loss (VS) / suspended solids (SS). The timing of flow path switching when the amount of gas generated from the UASB tank 2 decreases is the timing of flow path switching when the ignition loss (VS) / suspended solids (SS) becomes 0.5 or less. It can be seen that it matches well with. The flow path switching based on the amount of gas generated from the UASB tank 2 on the 89th day after the start of the experiment should be performed 80 days after the start of the experiment when 3.8 L / d, which exceeds 1/2 of the normal amount of gas generated, is detected. It turns out that it was.

以上、嫌気性処理からのガス発生量が、通常ガス量の１／２以下になる期間が２日以上連続した時点あるいは嫌気性処理に供される低濃度有機性排水の強熱減量（ＶＳ）／懸濁物質（ＳＳ）の値が０．５以下になった時点で、有機性排水を直接嫌気性処理する流路から、有機性排水を固液分離してから嫌気性処理する流路に切り換え、嫌気性処理からのガス発生量が、通常ガス発生量の１／２を超える期間が２日以上連続した時点あるいは嫌気性処理に供される低濃度有機性排水の強熱減量（ＶＳ）／懸濁物質（ＳＳ）の値が０．５をこえるようになった時点で、有機性排水を固液分離してから嫌気性処理する流路から有機性排水を直接嫌気性処理する流路に切り換えることで、ガス発生量が極端に低下することなく、安定したガス発生量が得られ、安定した嫌気性処理を行うことができることが確認できた。 As described above, when the amount of gas generated from the anaerobic treatment is 1/2 or less of the normal amount of gas for two consecutive days or more, or when the low-concentration organic wastewater subjected to the anaerobic treatment is subjected to strong heat reduction (VS). / When the value of Suspended Substance (SS) becomes 0.5 or less, from the channel for direct anaerobic treatment of organic wastewater to the channel for anaerobic treatment after solid-liquid separation of organic wastewater. Strong heat loss (VS) of low-concentration organic wastewater that is subjected to anaerobic treatment or when the amount of gas generated from switching and anaerobic treatment exceeds 1/2 of the normal amount of gas generated for two consecutive days or more. / When the value of suspended substance (SS) exceeds 0.5, the flow path for anaerobic treatment of organic wastewater directly from the flow path for solid-liquid separation of organic wastewater. It was confirmed that by switching to, a stable gas generation amount can be obtained without an extremely decrease in the gas generation amount, and a stable anaerobic treatment can be performed.

１：上向流固液分離槽
１１：槽本体
１２、１２ａ、１２ｂ、１２ｃ、１２ｄ：有機性排水導入管
１３：越流水排水口
１４：排泥管
１５：撹拌機
１６：掻き寄せ機
１７：ドラフトチューブ
１８：散気管
ｈ１：上向流分級部
ｈ２：下部沈降部
ａ１：小径部
ａ２：拡径部
ａ３：大径部
２：ＵＡＳＢ槽（メタン発酵処理装置）
３２：汚泥床
３３：気固液分離部（ＧＳＳ）
３４：越流堰
３５：覆蓋
３６：屋根材
３７：発生ガス排出管
３８：嫌気性処理水排出管
３９：排泥管
５０：ＵＡＳＢ槽本体
５１：スカム捕集枠
３：好気性生物処理装置
２１ｂ：好気槽
２２：曝気ライン
４１：無酸素槽（脱窒槽）
４２：水中撹拌機
４３：蓋部
４４：仕切板
４５：ポンプ
４：酸発酵槽
５：沈殿池
６：脱ガス装置
９：脱水装置
１０：バイオガス処理装置
１６：濃縮装置
５８：気液接触槽
６０：最初沈殿池
７０：溶存メタン回収槽
７１：ガス吹込ライン
７２：配管
８０：溶存メタン回収槽
８１：仕切板
８２：配管
１０３：第1槽（散水ろ床槽又は浸水ろ床槽）
１０４：第２槽（散水ろ床槽又は浸水ろ床槽）
１０５：切換手段
１１２ａ、１１２ｂ：原水供給路
１３１：第１の担体層
１４１：第２の担体層1: Upward flow solid-liquid separation tank 11: Tank body 12, 12a, 12b, 12c, 12d: Organic drainage introduction pipe 13: Overflow water drainage port 14: Mud drainage pipe 15: Stirrer 16: Scraper 17: Draft tube 18: Air diffuser h1: Upward flow classification part h2: Lower sedimentation part a1: Small diameter part a2: Expanded diameter part a3: Large diameter part 2: UASB tank (methane fermentation treatment equipment)
32: Sludge bed 33: Air-solid-liquid separation part (GSS)
34: Overflow dam 35: Cover 36: Roofing material 37: Generated gas discharge pipe 38: Anaerobic treated water discharge pipe 39: Mud drain pipe 50: UASB tank body 51: Scum collection frame 3: Aerobic biological treatment device 21b : Aerobic tank 22: Aeration line 41: Anoxic tank (denitrification tank)
42: Submersible stirrer 43: Lid 44: Partition plate 45: Pump 4: Acid fermentation tank 5: Sedimentation pond 6: Degassing device 9: Degassing device 10: Biogas processing device 16: Concentrating device 58: Gas-liquid contact tank 60: First settling pond 70: Dissolved methane recovery tank 71: Gas blowing line 72: Pipe 80: Dissolved methane recovery tank 81: Partition plate 82: Pipe 103: First tank (watering filter tank or flooded filter tank)
104: Second tank (sprinkling filter bed tank or flooded filter bed tank)
105: Switching means 112a, 112b: Raw water supply path 131: First carrier layer 141: Second carrier layer

Claims (8)

ＣＯＤＣｒ値が１，０００ｍｇ／Ｌ以下の低濃度有機性排水を嫌気性処理し、嫌気性処理水を好気性生物処理する方法において、嫌気性処理に供される低濃度有機性排水の強熱減量（ＶＳ）／懸濁物質（ＳＳ）の値が０．５以下になった場合に、嫌気性処理の前段で当該低濃度有機性排水を固液分離して無機物粒子を除去し、嫌気性処理に供される低濃度有機性排水の強熱減量を（ＶＳ）／懸濁物質（ＳＳ）の値が０．５を越える場合には固液分離せずに嫌気性処理することを特徴とする有機性排水の処理方法。 In a method of anaerobic treating low-concentration organic wastewater having a COD Cr value of 1,000 mg / L or less and treating anaerobic treated water with aerobic organisms, the ignition of low-concentration organic wastewater subjected to anaerobic treatment When the value of loss on ignition (VS) / suspended solids (SS) becomes 0.5 or less, the low-concentration organic wastewater is solid-liquid separated to remove inorganic particles before the anaerobic treatment, resulting in anaerobic conditions. The characteristic is that the ignition loss of low-concentration organic wastewater used for treatment is anaerobically treated without solid-liquid separation when the value of (VS) / suspended solids (SS) exceeds 0.5. How to treat organic wastewater. ＣＯＤＣｒ値が１，０００ｍｇ／Ｌ以下の低濃度有機性排水を嫌気性処理し、嫌気性処理水を好気性生物処理する方法において、嫌気性処理でのガス発生量が、通常ガス発生量の１／２以下となる期間が２日以上連続した場合に、嫌気性処理の前段で当該低濃度有機性排水を固液分離して無機物粒子を除去し、嫌気性処理でのガス発生量が、通常ガス発生量に戻った場合には固液分離せずに嫌気性処理することを特徴とする有機性排水の処理方法。 In a method in which low-concentration organic wastewater having a COD Cr value of 1,000 mg / L or less is anaerobically treated and anaerobic treated water is treated with aerobic organisms, the amount of gas generated in the anaerobic treatment is the amount of normal gas generated. When the period of 1/2 or less is continuous for 2 days or more, the low-concentration organic wastewater is solid-liquid separated to remove inorganic particles in the first stage of the anaerobic treatment, and the amount of gas generated in the anaerobic treatment is increased. A method for treating organic wastewater, which comprises anaerobic treatment without solid-liquid separation when the amount of gas generated returns to normal. 前記固液分離は、上向流固液分離装置を用いて行うことを特徴とする請求項１又は２に記載の有機性排水の処理方法。 The method for treating organic wastewater according to claim 1 or 2, wherein the solid-liquid separation is performed using an upward flow solid-liquid separation device. 前記上向流固液分離装置は、掻き寄せ機を有する漏斗状底部を含む沈降部と、当該沈降部の上方に位置づけられている有機性排水導入管、及び当該有機性排水導入管の上方に設けられている緩速撹拌手段、又はドラフトチューブ及び散気管を有する上向流分級部と、を有し、粒径の大きな土砂は当該沈降部に沈降し、粒径の小さな無機粒子と有機性固形物は当該上向流分級部で分級され、前記嫌気性処理に送られる低濃度有機性排水から土砂及び無機粒子が除去される、請求項３に記載の有機性排水の処理方法。 The upward flow solid-liquid separator is provided above a settling portion including a funnel-shaped bottom having a scraper, an organic drainage introduction pipe located above the settling portion, and an organic drainage introduction pipe. It has a slow-speed stirring means provided , or an upward flow classification part having a draft tube and an air diffuser, and sediment with a large particle size settles in the sedimentation part, and inorganic particles with a small particle size and organic matter. The method for treating organic wastewater according to claim 3, wherein the solid matter is classified in the upward flow classification section, and sediment and inorganic particles are removed from the low-concentration organic wastewater sent to the anaerobic treatment. 有機性排水をメタン発酵処理するＵＡＳＢ槽、及びメタン発酵処理後の処理水を好気性生物処理する好気性生物処理槽を具備する有機性排水の処理装置であって、
当該ＵＡＳＢ槽の前段に、有機性排水をＵＡＳＢ槽に導入する流路と、固液分離装置と、切り換え弁と、有機性排水を前記固液分離装置に導入する切り換え流路とを設け、
前記切り換え弁は、前記固液分離装置の上流で前記有機性排水をＵＡＳＢ槽に導入する流路と前記切り換え流路との接続部に設けられており、有機性排水のＶＳ／ＳＳの値が０．５以下になった場合に、有機性排水を導入する流路から切り換え流路に切り換えて固液分離装置を経由してＵＡＳＢ槽に有機性排水を導入する切り換え弁である、有機性排水の処理装置。 An organic wastewater treatment apparatus including a UASB tank for methane fermentation treatment of organic wastewater and an aerobic biological treatment tank for aerobic biological treatment of treated water after methane fermentation treatment.
A flow path for introducing organic wastewater into the UASB tank, a solid-liquid separation device, a switching valve, and a switching flow path for introducing organic wastewater into the solid-liquid separation device are provided in front of the UASB tank.
The switching valve is provided at a connection portion between the flow path for introducing the organic waste water into the UASB tank and the switching flow path upstream of the solid-liquid separation device, and the VS / SS value of the organic waste water is measured. if it becomes 0.5 or less, a switching valve for introducing the organic waste water in UASB tank via the solid-liquid separation device is switched to the switching flow path from the flow path for introducing the organic waste water, the organic waste water Processing equipment. 有機性排水をメタン発酵処理するＵＡＳＢ槽、及びメタン発酵処理後の処理水を好気性生物処理する好気性生物処理槽を具備する有機性排水の処理装置であって、
当該ＵＡＳＢ槽の前段に、有機性排水をＵＡＳＢ槽に導入する流路と、固液分離装置と、切り換え弁と、有機性排水を前記固液分離装置に導入する切り換え流路とを設け、
前記切り換え弁は、前記固液分離装置の上流で前記有機性排水をＵＡＳＢ槽に導入する流路と前記切り換え流路との接続部に設けられており、嫌気性処理でのガス発生量が通常ガス発生量の１／２以下となる期間が２日以上連続した場合に、有機性排水を導入する流路から切り換え流路に切り換えて、固液分離装置を経由してＵＡＳＢ槽に有機性排水を導入する切り換え弁である、有機性排水の処理装置。 An organic wastewater treatment apparatus including a UASB tank for methane fermentation treatment of organic wastewater and an aerobic biological treatment tank for aerobic biological treatment of treated water after methane fermentation treatment.
A flow path for introducing organic wastewater into the UASB tank, a solid-liquid separation device, a switching valve, and a switching flow path for introducing organic wastewater into the solid-liquid separation device are provided in front of the UASB tank.
The switching valve is provided at a connection portion between the flow path for introducing the organic wastewater into the UASB tank and the switching flow path upstream of the solid-liquid separation device, and the amount of gas generated in the anaerobic treatment is usually large. If the period is 1/2 or less of the amount of generated gas was continuous over two days, by switching the switching flow path from the flow path for introducing the organic waste water, the organic waste water in UASB tank via the solid-liquid separator An organic wastewater treatment device that is a switching valve that introduces. 前記固液分離装置は、上向流固液分離装置である、請求項５又は６に記載の処理装置。 The processing device according to claim 5 or 6, wherein the solid-liquid separation device is an upward flow solid-liquid separation device. 前記上向流固液分離装置は、掻き寄せ機を有する漏斗状底部を含む沈降部と、当該沈降部の上方に位置づけられている有機性排水導入管、及び当該有機性排水導入管の上方に設けられている緩速撹拌手段、又はドラフトチューブ及び散気管を有する上向流分級部と、を有する、請求項７に記載の処理装置。 The upward flow solid-liquid separator is provided above a settling portion including a funnel-shaped bottom having a scraper, an organic drainage introduction pipe located above the settling portion, and an organic drainage introduction pipe. The processing apparatus according to claim 7, further comprising a slow-speed stirring means provided , or an upward flow classification unit having a draft tube and an air diffuser tube.
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