JPS5861900A - Treatment of sludge - Google Patents

Abstract

PURPOSE:To reduce equipment costs and to control the temp. of heat treated sludge securely by mixing compressed steam with excess sludge prior to the heat treatment, recovering the heat thereof, and flashing the heat treated sludge having atmospheric pressure into a vacuum cooler. CONSTITUTION:The sludge which is finished of a heat treatment flows into a vacuum evaporator 21 and is released roughly to atmospheric pressure, then steam is generated by flashing, but the generated steam is pressurized and recovered by an ejector 23 and is mixed with the sludge. The heat treated sludge from the evaporator 21 is flashed into a vacuum cooler 22 of which the degree of vacuum is automatically controlled by a vacuum ejector 24 to the temp. corresponding to the degree of vacuum. The heat treated sludge from the cooler 22 flows into a digesting tank 7, where anaerobic digestion (methane fermentation) is induced by methane bacteria and acid forming bacteria and the gases contg. generated methane are fed intoa gas tank 8a.

Description

【発明の詳細な説明】 本発明は、有機質汚泥を好気性菌の存在下で曝気分解す
る工程で生成する実質的に好気性菌体からなる余剰汚泥
を、熱処理した後、メタン発酵させ゛る工程を含んだ汚
泥処理方法の設備費、運転費を下げる方法に関するもの
である。DETAILED DESCRIPTION OF THE INVENTION The present invention heat-treats excess sludge, which is substantially composed of aerobic bacterial cells and is generated in a step of aerobically decomposing organic sludge in the presence of aerobic bacteria, and then performs methane fermentation. The present invention relates to a method for reducing equipment costs and operating costs of a sludge treatment method including processes.

第１図は、従来使用されていた汚泥処理方法の１例を示
す概略工程図である。FIG. 1 is a schematic process diagram showing one example of a conventionally used sludge treatment method.

汚水は最初沈殿池（１）に専かれ生汚泥を分離した後、
後述する最終沈殿池（３）で分離された汚泥（フィード
バック汚泥）と混合してエアレーションタ殴池（３）に
おいて、処理水と、はぼ菌体の集合である汚泥とに分離
されるが、その１部ｔよエアレーションクンク１ｔ＋に
フィードバックされ、残部は余剰汚泥として、汚泥濃縮
槽（４）に投入、デカントされる。汚泥濃縮槽（４）で
上澄水を除かれ、いく分りｌ縮された汚泥線、汚泥ポン
プ１ｌｉ）により昇圧され、陽に重管式間接熱交換器（
以下ＨＸ　１ｍ　１のように記載する。磁２以下につい
ても同じ。）に入り、後述する廃熱温水ボイラ掲で加熱
され九温水により加熱され、ＨＸ％２に入り、後述する
ＥＸ＆３で加熱せられた熱媒により間接加熱され、反応
器（６）Ｋ入る。反応器（６）で、きらに外熱ボイラー
用で発生した蒸気または池設備からのＸｇＬを、吹込ま
れ弁理して、例えは、１７５℃、ゲージ圧８．１１＠、
となり、約３０分の熱処理を受けた熱処理汚泥はメタン
発酵し易い性質に変性しており、ＨＸＮｎ３で熱媒に熱
を与えることにより冷却され、さらにＩ（ＸＮＩ１４で
水冷されて消化槽ｆ７）をで投入される。消化４１１１
７１では、メタン菌と酸生成菌により＃気性消化（メタ
ン発酵）が起こり、発生したメタン含有ガスはガスタン
ク（８ａ）に送られ、消化後の汚泥（消化汚Ｎ）ｔ−１
、汚泥貯槽（８）に送られ、この貯槽で最初沈殿池（１
）からの生汚泥と混合して、高分子凝集剤を加えられた
後、圧枦器１Ｇ１でか過され、脱水クーキとなり、竪型
多段焼却炉−に投入され焼却される。焼却炉＋１（１の
鉱焼ガス＃ｉ廃熱ボイクｌｌＩ］に送られ、発生した蒸
気は、反応器（６）の加熱に使用される。The sewage is first sent to a sedimentation tank (1) and after separating raw sludge,
It is mixed with sludge (feedback sludge) separated in the final settling tank (3), which will be described later, and separated into treated water and sludge, which is a collection of bacteria, in the aeration tank (3). One part t is fed back to the aeration tank 1t+, and the remaining part is fed into the sludge thickening tank (4) and decanted as surplus sludge. The supernatant water is removed in the sludge thickening tank (4), the sludge line is compressed to some extent, the pressure is increased by the sludge pump 1li), and the pressure is increased by the sludge pump 1li).
Hereinafter, it will be described as HX 1m 1. The same goes for magnetic 2 and below. ), heated by the waste heat hot water boiler (described later) and heated by hot water, enters HX%2, is indirectly heated by the heating medium heated by EX&3, which will be described later, and enters the reactor (6)K. In the reactor (6), steam generated for the external heat boiler or XgL from the pond equipment is blown into the reactor (6), and the temperature is 175°C and the gauge pressure is 8.11@, for example.
The heat-treated sludge that has been heat-treated for about 30 minutes has been modified to be more susceptible to methane fermentation, and is cooled by applying heat to the heating medium with HXNn3, and then water-cooled with I (XNI14 and digested tank f7). It will be put in. Digestion 4111
At 71, pneumatic digestion (methane fermentation) occurs by methane bacteria and acid-producing bacteria, and the generated methane-containing gas is sent to the gas tank (8a), and the sludge after digestion (digested sludge N) t-1
, the sludge is sent to the sludge storage tank (8), and in this storage tank it is first settled in the sedimentation tank (1).
), a polymer flocculant is added thereto, the mixture is filtered through a pressurizer 1G1 to form a dehydrated cookie, and the resulting product is placed in a vertical multi-stage incinerator for incineration. The steam generated is sent to the incinerator +1 (mineral gas #i waste heat boiler llI of 1) and is used to heat the reactor (6).

ガスエンジンＯｓの燃料に使用され、ガスエンジン０１
の排ガスは廃熱温水ボイラ（１１に送られ、温水ボイラ
帽の温水はＨＸ　ｋ　ｌの加熱用に用いられる。Used as fuel for gas engine Os, gas engine 01
The exhaust gas is sent to the waste heat hot water boiler (11), and the hot water in the hot water boiler cap is used for heating HX k l.

なお、この従来法の例で１よ、最初沈殿池１．）で分離
した生汚泥を、メタン発酵しないで、汚泥貯槽（８）に
投入しているが、生汚泥中に土砂などの不純物が少ない
場合には、調温して消化槽（７）に投入すると、さらに
メタンガス発生量か増加するので有利である。In addition, in this example of the conventional method, the first settling tank is 1. ) is charged into the sludge storage tank (8) without methane fermentation, but if there are few impurities such as earth and sand in the raw sludge, the temperature is controlled and the raw sludge is charged into the digestion tank (7). This is advantageous because the amount of methane gas generated further increases.

Ｌ記従来法社、メタン発酵を起こし轍い余剰汚泥を熱処
理して、発酵し易い基質に変える点に特徴があり、その
結果メタン含有ガス（低位発熱量的５５００ｋｃａｌ−
一）発生量が、熱処理をしない場合に比べて１．５〜！
、０倍に増大するので、エネルギー回収の見地から極め
て優れた方′法と考えられている。L Conventional method is characterized by methane fermentation and heat treatment of surplus sludge from ruts to convert it into a substrate that is easy to ferment.As a result, methane-containing gas (lower calorific value 5500 kcal
1) The amount generated is 1.5~ compared to the case without heat treatment!
, it is considered to be an extremely excellent method from the standpoint of energy recovery.

しかしながら、一方においては、間接熱交換器を使用し
ているため、上記実施例の二重管式のものに限らず、シ
ェル、チューブ式のものを用いても、設備費が格段に高
くなる。However, on the other hand, since an indirect heat exchanger is used, the equipment cost is significantly increased even if a shell and tube type is used instead of the double pipe type of the above embodiment.

まえ、周知のとおり、メタン発酵の適温は中温消化の場
合、３５十２℃、高温消化の場合５３十０．５℃と非常
に巾が狭く、この温度範囲を外れると、発酵速度が激減
するが、間接熱交換器の場合、運転時間の経過と共に不
可避的に、伝熱面のよごれが起こって伝熱が悪くなり、
し友がって、消化槽（７）の入口における熱処理汚泥、
ひいては消化槽（１）自身の温度調整が困難に寿る。As is well known, the optimum temperature for methane fermentation is very narrow, ranging from 35-20 degrees Celsius for medium-temperature digestion to 530-0.5 degrees Celsius for high-temperature digestion, and outside of this temperature range, the fermentation rate will decrease dramatically. However, in the case of an indirect heat exchanger, as the operating time passes, the heat transfer surface inevitably gets dirty and heat transfer deteriorates.
Accordingly, the heat-treated sludge at the inlet of the digestion tank (7),
As a result, it becomes difficult to adjust the temperature of the digestion tank (1) itself.

本発明者らは上記間！ｌ！点を解決するため、種種研究
を行ったが、特に１反応器（６）で、汚泥の熱処理を、
曝気しながら行うことによ抄、処理条件を、１００〜１
２０℃（ゲージ圧０〜ｌ’ｌ＊）Ｋ下げ得ることをみい
だした。The inventors mentioned above! l! In order to solve this problem, various studies were conducted, and in particular, in one reactor (6), heat treatment of sludge was
The papermaking and processing conditions were adjusted to 100 to 1 by performing the process with aeration.
It has been found that the temperature can be lowered by 20°C (gauge pressure 0 to l'l*).

この結果、ＩＩ！１ｌｆｉに示したＨ　Ｘ　＆　２およ
びＨＸ隘３の存在価値が減り、省隼しても大した影響が
ないことになる。As a result, II! The existence value of HX & 2 and HX 3 shown in 1lfi will decrease, and even if they are saved, it will not have much effect.

また、′ＨｘＮｎ４は間接熱交換器の宿命であるよごれ
による伝熱ｔの減少があるが、フツツシ蒸発の原理を用
いれば、減圧する仁とにより、冷却が可能で、応答の速
い圧調整により容易に、より有利に湿度調節ができる。In addition, 'HxNn4 has a decrease in heat transfer t due to contamination, which is the fate of indirect heat exchangers, but if the principle of evaporation is used, cooling is possible by reducing the pressure, and it is easy to adjust the pressure with quick response. This makes it possible to control humidity more effectively.

さらに、反応器（６）を出た高鮪の齢・処理汚泥は大気
圧にフ２ツシすれば、蒸気を発生するが、スチームエジ
ェクターを用いれば、反応器１６）に供給すべき、蒸気
で、前記７ラツシにより発生した蒸気を回収利用できる
。また圧縮機を用いて圧縮しても大した費用にな−らな
い。Furthermore, if the aged and treated sludge of high-quality tuna that comes out of the reactor (6) is exposed to atmospheric pressure, it will generate steam, but if a steam ejector is used, the steam that should be supplied to the reactor 16) will be generated. , the steam generated by the above-mentioned 7 lashes can be recovered and used. Moreover, even if it is compressed using a compressor, it does not cost much.

本発明は、上記の知見と考察を基にして完成されたもの
で、そのｌｌ旨とするところは、次のとおシである。The present invention was completed based on the above knowledge and consideration, and its main purpose is as follows.

−ｔなわら先づ、最初沈殿池で汚水から生汚泥を分＊除
太し、次にエアレーションタンクで、曝気の下で、好気
性菌により汚水の含有する有機物を分解し、さらに最終
沈殿池で、処理水と余剰汚泥とを分離し、こめ余剰汚泥
を、反応器において、１００℃を超える温度、大気圧を
超える圧で熱処理し良後、ＩＩ！Ｉｌｌ＆理汚泥に前記
最初沈殿池から分離し九生汚結を加えて、または加えな
いで、消化槽でメタン発酵させ、メタン含有ガスを回収
する工程を含む汚泥処理方法において；前記反応器を出
走熱処理汚泥をほぼ大気圧にフラッジした際に発生する
蒸気を、圧縮して、熱処理前の余−ｊ汚泥に混合するこ
とによシ熱回収することと、前記７ツクシによりほぼ大
気圧になった熱処理汚泥に、１記最初沈殿池で分・離し
た生汚泥を加えまたは加えないで、真空度を調節した真
空冷却器に７ツツ、シすることによ抄調温することを特
徴とする汚泥処理方法に存する。First, the raw sludge is removed from the wastewater in the first settling tank, then in the aeration tank, the organic matter contained in the wastewater is decomposed by aerobic bacteria under aeration, and then in the final settling tank. Then, the treated water and surplus sludge are separated, and the collected surplus sludge is heat-treated in a reactor at a temperature exceeding 100°C and a pressure exceeding atmospheric pressure. In a sludge treatment method comprising a step of separating the sludge from the first settling tank and adding or not adding Kusei contamination to the sludge, fermenting methane in a digestion tank and recovering methane-containing gas; Heat is recovered by compressing the steam generated when heat-treated sludge is flooded to almost atmospheric pressure and mixing it with the residual sludge before heat treatment, and the pressure is brought to almost atmospheric pressure by the above-mentioned 7 pumps. A sludge characterized in that the temperature of the sludge is adjusted by adding or not adding the raw sludge separated and separated in the first settling tank to the heat-treated sludge, and placing it in a vacuum cooler whose degree of vacuum is adjusted for 7 times. It depends on the processing method.

次に、本発明の実施態様の１例を第２図に示して具体的
に説明する。図中一点鎖線で囲った範囲以外は第１図に
示した従来法の１例と同じである。Next, an example of an embodiment of the present invention will be specifically described with reference to FIG. 2. The area other than the area surrounded by the dashed line in the figure is the same as the example of the conventional method shown in FIG.

汚泥ポンプ（６）Ｋよシ加圧され、ＨＸ陳１で廃熱温水
ボイラ（Ｉｌｌで加熱された温水（９０Ｑ−９５℃）に
より予熱された汚泥は、スチームエジェクタ（２）Ｋよ
り、後述する減圧蒸発器（！葛で発生した蒸気を加圧回
収した蒸気と混合して昇温し、さらに反応器の入口また
は反応器内（またはその両者）に吹込まれる蒸気で加熱
されて、１００℃を超える温度になり、熱処理が行われ
る。このＩＩｌ！！Ｉ処理温度は、前述のとおり、曝気
の下に行うき、１００〜１２０℃で充分で、望ましい作
業条件であるが、曝気を行わない場合においても、なる
べく低い温度、例えば１５０℃前後で行うと、本発明の
効果は充分認められるので、曝気の有無にこだわらない
。The sludge, which is pressurized by the sludge pump (6) K and preheated by hot water (90Q-95°C) heated by the waste heat hot water boiler (Ill) in the HX 1, is transferred from the steam ejector (2) K as described below. The steam generated in a vacuum evaporator (!Kudzu) is mixed with the steam recovered under pressure and raised in temperature, and further heated by the steam blown into the reactor inlet or inside the reactor (or both) to reach 100℃. The temperature exceeds 100°C, and heat treatment is performed. As mentioned above, the temperature of this IIl!!I treatment is 100 to 120°C, which is sufficient and desirable working conditions when performed under aeration, but without aeration. Even in this case, the effect of the present invention is fully recognized when the temperature is as low as possible, for example around 150°C, so whether or not aeration is used is not a concern.

熱処理を終った汚泥（熱処理汚泥）は減圧蒸発器１！Ｉ
Ｋ至シはぼ大気圧に放圧され、フラッジ現象で蒸気を発
生するが、発生水蒸気は、前述のようにエジェクター−
により加圧回収されて汚泥に混合される。The sludge that has undergone heat treatment (heat treated sludge) is transferred to vacuum evaporator 1! I
The water vapor is depressurized to near atmospheric pressure and generates steam due to the flooding phenomenon.
is recovered under pressure and mixed into sludge.

減圧蒸発器−を出た熱処理汚泥は、真空エジェクターＩ
ＮＫより真空度が自動調節される真空冷却器ｍｌ　Ｋ　
７９　ツシｘされ、真空度（０，０５〜０．０７　Ｖ　
）に応じ九温度になる。電気式および空気式の真空度調
節機構の例を電気式の場合第３図、空気式の場合４Ｍ４
図に示す。The heat-treated sludge leaving the vacuum evaporator is transferred to the vacuum ejector I.
Vacuum cooler ML K that automatically adjusts the degree of vacuum from NK
79 Tensioned and vacuum degree (0.05 to 0.07 V
) depending on the nine temperatures. Examples of electric and pneumatic vacuum level adjustment mechanisms are shown in Figure 3 for the electric type and 4M4 for the pneumatic type.
As shown in the figure.

真空冷却ｓｗを出走Ｓ＋魁理汚泥は、消化槽（７）Ｋ至
り、以下第１図に示し九従来法と同一の処理を受ける。The S+Kari sludge leaving the vacuum cooling SW reaches the digestion tank (7)K, and undergoes the same treatment as in the nine conventional methods shown in FIG. 1 below.

１１１図に示した従来法の説明の際にも述べたが、上記
実施例において、最初沈殿池１１）で分離し良化汚泥を
汚泥貯槽（８）に投入するかわり、生汚泥の土砂含有量
が少ない場合は、消化槽（１）に投入してメタン発酵の
原料に使用することが有利であるが、この際、真空冷却
器（２）Ｋ役人調温するか、他の調温設備を用いるかに
ついて本発明はこだわらない。As mentioned in the explanation of the conventional method shown in Fig. 111, in the above embodiment, instead of separating the improved sludge in the initial settling tank 11) and putting it into the sludge storage tank (8), the sediment content of the raw sludge is If the amount is low, it is advantageous to put it into the digestion tank (1) and use it as a raw material for methane fermentation, but in this case, use the vacuum cooler (2) K to adjust the temperature, or use other temperature control equipment. The present invention is not particular about the use.

なおスチームエジェクタ（２）、真空エジェクターおよ
び反応器（６）加熱用に使用する高圧蒸気は廃熱ボイラ
ｉｌｌで生産せられるが、蒸気が不足する場合は他設備
例えば他のボイラ（図示せず）から供給され、過剰の場
合は他設備に供給するか、廃熱ボイ１１の温水加熱に用
いるか、場合によっては廃棄される。Note that high-pressure steam used for heating the steam ejector (2), vacuum ejector, and reactor (6) is produced in the waste heat boiler ill, but if steam is insufficient, other equipment such as another boiler (not shown) is produced. If there is an excess, it is either supplied to other equipment, used for heating hot water in the waste heat boiler 11, or discarded as the case may be.

また、汚泥ポンプの位置はＩＩ２図のようにＩＩＩＸ？
＆Ｌ１の上流に位置していても、ＨＸｌｉｌとスチーム
エジェクタ吹込口との闇に位置していても、スチームエ
ジェクタ吹込口と反応器（６）の闇に位置していても大
差なく、これらにこだわらない〇さらに、スチームエジ
ェクタ（２）の代わりにコンプレッサを使用しでも、真
空エジェクタおよびこれに後続する冷却器のかわりに、
真空ポンプを用いても、本発明の技術的意味を損うもの
でなく、これらにこだわらない。Also, the position of the sludge pump is IIIX as shown in Figure II2?
There is no big difference whether it is located upstream of &L1, between HXlil and the steam ejector inlet, or between the steam ejector inlet and the reactor (6), No〇Furthermore, even if a compressor is used instead of the steam ejector (2), instead of the vacuum ejector and the cooler following it,
Even if a vacuum pump is used, the technical meaning of the present invention is not impaired, and the present invention is not limited thereto.

上記説明で明らかなように、本発明の汚泥処理方法は、
余剰汚泥の熱処理の際の熱回収方法として、伝熱面を通
して熱のみを移動させるのではなく、物質移動と相変化
を利用しているので、伝熱面のよごれに基づく、熱移動
の経時変化はＦｉＸ１４１１以外、まったく無く、接熱
交轡器を殆んど省いたので設備費は安価になシ、東た真
空冷却器を用いるととによシ熱魁理汚泥の温度調節が正
確に行える。As is clear from the above explanation, the sludge treatment method of the present invention includes:
As a heat recovery method during heat treatment of surplus sludge, mass transfer and phase change are used instead of transferring only heat through the heat transfer surface, so changes in heat transfer over time based on dirt on the heat transfer surface can be observed. Except for the FiX1411, there is no other equipment, and since most of the indirect heat exchangers are omitted, the equipment cost is low, and the temperature of the heated sludge can be precisely controlled using the vacuum cooler. .

【図面の簡単な説明】[Brief explanation of drawings]

第１図は従来の汚泥処理方法の１例を示す工程図、第２
図は本発明の汚泥処理方法の１例を示す工程図、第３図
と第４図はそれぞれ真空冷却器の電気式と空気式調節方
法を示す図面である＝出願人　株式会社田熊総合研究所 代理人　弁理士　中　村　！ｌ−！７４′Ｔ：〒；ｊバ
１第３図 第４図 手続補正書 昭和５７年ｌθ月２３日 特許庁長官　若　杉　和　犬　殿 事件の表示　　特願昭５６−１５９６ｆｓ２号発明の名
称　　汚泥処理方法 補正をする者 事＃よ、）ＩＳｌｌ、　　　　特許出願人住所（居所）
大阪市を区堂島−派１丁目３番２３号氏名（名称）ｌＩ
Ａ式会社田熊総合研究所代　　理　　人 ’ａ　０６　（９３２）　０６６１〜２番日付　昭和　
　年　　月　　日 補正の対象　明細書、発明の詳細な説明の欄補正の内容
　明細書ｊＩ２頁第２行目「有機質汚泥」とあるを「有
機質汚水」と補正します。Figure 1 is a process diagram showing an example of a conventional sludge treatment method;
The figure is a process diagram showing one example of the sludge treatment method of the present invention, and Figures 3 and 4 are drawings showing electric and air control methods for a vacuum cooler, respectively. = Applicant: Takuma Research Institute Co., Ltd. Agent Patent Attorney Nakamura! l-! 74'T:〒;j BA1 Figure 3 Figure 4 Procedural amendment dated 23rd lθ, 1980, Commissioner of the Japan Patent Office Kazu Inu Wakasugi Incident Patent Application No. 1596 fs2 Title of invention Sludge treatment method amendment ISll, Patent Applicant Address (Residence)
Dojima-Ha 1-3-23, Osaka City Name: I
Type A Company Takuma General Research Institute Representative Rin'a 06 (932) 0661-2 Date Showa
Year Month Date Target of amendment Contents of amendment in the detailed description of the invention column In the second line of page 2 of the specification, "organic sludge" is amended to read "organic sewage."

Claims (1)

【特許請求の範囲】[Claims] 最初沈殿池で汚水から生汚泥を分離除去し、次にエアレ
ーションタンクで、曝気の下で、好気性菌により汚水の
含有する有機物を分解し、最終沈殿池で、処理水と余剰
汚泥とを分離し、この余≠１汚泥を、反応器において１
００℃を超える温度、大気圧を超える圧で熱処理した後
、熱処理汚泥に前記最初沈殿池で分離した生汚泥を加え
て、または加えないで、消化槽でメタン発酵させ、メタ
ン含有ガスを回収する工程を含む汚泥処理方法において
ｉ前記反ｆ３ｖ！Ａを出た熱処理汚泥をほぼ大気圧にフ
ラッジした際に発生する蒸気を圧縮して、熱処理前の余
剰汚泥に混合することにより、熱回収するコトと、前記
フラッジにより＃１ぼ大気圧になった熱処理汚泥、に、
前記最初沈殿池で分離した生汚泥を加えまたは加えない
で、真空度を調節した真空冷却器にフラッジすることＫ
より調温することを特徴とする汚泥処理方法。The raw sludge is separated and removed from the wastewater in the first settling tank, then the organic matter contained in the wastewater is decomposed by aerobic bacteria under aeration in the aeration tank, and the treated water and excess sludge are separated in the final settling tank. Then, this remaining ≠ 1 sludge is
After heat treatment at a temperature exceeding 00°C and a pressure exceeding atmospheric pressure, the heat-treated sludge is subjected to methane fermentation in a digestion tank with or without adding the raw sludge separated in the first settling tank, and methane-containing gas is recovered. In the sludge treatment method including the step i said anti-f3v! Heat is recovered by compressing the steam generated when the heat-treated sludge from A is flooded to almost atmospheric pressure and mixing it with the surplus sludge before heat treatment, and the flooding brings the pressure to about #1 atmospheric pressure. heat treated sludge,
Flooding into a vacuum cooler with a controlled vacuum degree, with or without adding the raw sludge separated in the first settling tank.
A sludge treatment method characterized by better temperature control.