JP4862361B2

JP4862361B2 - Waste water treatment apparatus and waste water treatment method

Info

Publication number: JP4862361B2
Application number: JP2005323791A
Authority: JP
Inventors: 聡山田; 求小泉; 倫明田中
Original assignee: Kurita Water Industries Ltd
Current assignee: Kurita Water Industries Ltd
Priority date: 2005-11-08
Filing date: 2005-11-08
Publication date: 2012-01-25
Anticipated expiration: 2025-11-08
Also published as: TW200823153A; KR101335186B1; TWI379810B; SG132606A1; KR20070049560A; CN1962493A; JP2007130526A

Description

本発明は排水処理装置及び排水処理方法に係り、特に、被処理水を生物処理した後、生物処理水中の菌体や生物代謝物を含む溶解性物質や懸濁性物質を除去するために凝集剤を添加して凝集処理を行うに当たり、凝集剤の添加量を低減した上で良好な処理水を得る排水処理装置及び排水処理方法に関する。 The present invention relates to a wastewater treatment apparatus and a wastewater treatment method, and in particular, after biologically treating water to be treated, agglomeration is performed to remove soluble substances and suspended substances including cells and biological metabolites in biologically treated water. The present invention relates to a wastewater treatment apparatus and a wastewater treatment method for obtaining good treated water after reducing the amount of the flocculant added in performing the agglomeration treatment.

有機性排水の処理方法として、生物処理法が広く採用されている。そして、生物処理水中の懸濁物質や溶解性物質等の汚染物質を除去するために、或いは排水量が多い場合には水回収のために、生物処理水を凝集処理すること、更には、凝集処理後に膜処理することも行われている。 Biological treatment methods are widely adopted as a method for treating organic wastewater. In order to remove contaminants such as suspended substances and soluble substances in biologically treated water, or to collect water when there is a large amount of wastewater, the biologically treated water is agglomerated, A film treatment is also performed later.

例えば、特開２００５−２３８１５２号公報には、有機物含有水を生物処理し、生物処理水に凝集剤を添加して凝集処理し、凝集処理水を固液分離し、分離水を濾過装置で濾過し、濾過水を更に逆浸透膜分離装置で膜分離処理する方法が記載されている。また、この方法において、固液分離手段として浮上分離装置も記載されている。固液分離手段としての加圧浮上分離装置は沈殿槽に比べて設置スペースが小さくて足りる利点がある。 For example, in Japanese Patent Application Laid-Open No. 2005-238152, organic substance-containing water is biologically treated, and a flocculant is added to the biologically treated water for agglomeration treatment, the agglomerated treated water is separated into solid and liquid, and the separated water is filtered by a filtration device. In addition, a method is described in which the filtrate is further subjected to a membrane separation treatment with a reverse osmosis membrane separation device. In this method, a floating separation device is also described as a solid-liquid separation means. The pressurized flotation separation device as the solid-liquid separation means has an advantage that a small installation space is sufficient as compared with the settling tank.

生物処理水を凝集処理する際に、凝集作用促進のために添加する凝集剤（無機凝集剤）は、ランニングコストに直結する要素であるために、その添加量の低減が望まれているが、生物処理水の凝集処理では、溶存有機物（Ｓ−ＴＯＣ）、特に、生物代謝物の凝集処理が困難であり、通常、大量の凝集剤が必要とされている。 The flocculant (inorganic flocculant) that is added to promote the flocculation action when the biologically treated water is flocculated is a factor that directly affects the running cost. In the agglomeration treatment of biologically treated water, it is difficult to agglomerate dissolved organic matter (S-TOC), particularly biological metabolites, and a large amount of aggregating agent is usually required.

特に近年、水資源のリサイクルが重要視されるようになり、排水の回収が行われるようになってきているが、排水として排出された水を生物処理後に再利用可能な水準に高度に浄化するためには、大量の凝集剤を必要とする。このため、生物処理水の凝集処理における凝集剤の添加量低減は大きな課題となってきている。 In recent years, in particular, the recycling of water resources has become more important, and wastewater is being collected, but the water discharged as wastewater is highly purified to a level that can be reused after biological treatment. This requires a large amount of flocculant. For this reason, reduction of the addition amount of the coagulant | flocculant in the coagulation process of biologically treated water has become a big subject.

なお、凝集剤の添加量低減方法として、高分子凝集助剤を併用する等の方法も提案されているが、助剤添加のためのコストがかかることから、より平易で安価な方法が求められているのが現状である。
特開２００５−２３８１５２号公報 As a method for reducing the amount of flocculant added, a method such as using a polymer flocculant aid has been proposed. However, since the cost for adding the adjunct is high, a simpler and cheaper method is required. This is the current situation.
JP-A-2005-238152

本発明は、上記従来の問題点を解決し、被処理水を生物処理した後、生物処理水中の菌体や生物代謝物を含む溶解性物質や懸濁性物質を除去するために凝集剤を添加して凝集処理するに当たり、凝集剤の添加量を低減した上で良好な処理水を得ることができる排水処理装置及び排水処理方法を提供することを目的とする。 The present invention solves the above-mentioned conventional problems, and after biologically treating the water to be treated, a flocculant is added to remove soluble substances and suspended substances including bacterial cells and biological metabolites in the biologically treated water. An object of the present invention is to provide a wastewater treatment apparatus and a wastewater treatment method capable of obtaining good treated water after reducing the addition amount of a flocculant in addition and coagulation treatment.

本発明者らは、上記課題に対し鋭意検討した結果、生物処理後の菌体及び生物代謝物等を凝集処理するに当たり、凝集反応槽における撹拌の際に空気曝気を実施し、次いで凝集処理水を加圧浮上分離することにより、凝集剤の添加量を低減することができることを見出した。また、凝集反応系内の水を更に最適なｐＨ領域に調整し、酸化剤を併用することで処理水質は更に向上することを見出した。 As a result of intensive studies on the above-mentioned problems, the present inventors conducted air aeration at the time of agitation in an agglomeration reaction tank, and then agglomerated treated water when agglomerating the cells and biological metabolites after biological treatment. It was found that the amount of the flocculant added can be reduced by separating the particles with pressure. Further, it has been found that the quality of treated water is further improved by adjusting the water in the agglomeration reaction system to an optimum pH range and using an oxidizing agent in combination.

本発明はこのような知見に基いて達成されたものであり、以下を要旨とするものである。
［１］被処理水を生物的に処理する生物反応槽と、該生物反応槽から流出する生物処理水に凝集剤を添加して凝集反応を行う凝集反応槽と、該凝集反応槽から流出する凝集処理水を固液分離する加圧浮上分離装置とを備えた排水処理装置において、前記凝集反応槽に曝気手段を設けたことを特徴とする排水処理装置。
［２］［１］において、前記凝集反応槽内の水のｐＨを３〜６に調整するためのｐＨ調整剤添加手段を有することを特徴とする排水処理装置。
［３］［１］又は［２］において、前記凝集反応槽に酸化剤を添加する酸化剤添加手段を有することを特徴とする排水処理装置。
［４］［１］〜［３］のいずれか１項において、前記加圧浮上分離装置から流出する加圧浮上分離水を固液分離する濾過装置を有することを特徴とする排水処理装置。
［５］［１］〜［４］のいずれか１項において、前記凝集反応槽が２槽以上の多段に設けられ、前段の凝集反応槽が空気曝気槽であり、後段の凝集反応槽が機械攪拌槽であることを特徴とする排水処理装置。
［６］被処理水を生物的に処理する生物反応工程と、該生物反応工程から流出する生物処理水に凝集剤を添加して凝集反応を行う凝集反応工程と、該凝集反応工程から流出する凝集処理水を固液分離する加圧浮上分離工程とを備えた排水処理方法において、前記凝集反応工程における凝集反応を曝気下に行うことを特徴とする排水処理方法。
［７］［６］において、前記凝集反応工程の水にｐＨ調整剤を添加して、該水のｐＨを３〜６に調整することを特徴とする排水処理方法。
［８］［６］又は［７］において、前記凝集反応工程の水に酸化剤を添加することを特徴とする排水処理方法。
［９］［６］〜［８］のいずれか１項において、前記加圧浮上分離工程から流出する加圧浮上分離水を固液分離する濾過工程を有することを特徴とする排水処理方法。
［１０］［６］〜［９］のいずれか１項において、前記凝集反応工程は、２槽以上の多段に設けられた凝集反応槽で行われ、前段の凝集反応槽で空気曝気下に凝集反応が行われ、後段の凝集反応槽で機械攪拌下に凝集反応が行われることを特徴とする排水処理方法。 The present invention has been achieved on the basis of such findings and has the following gist.
[1] A biological reaction tank that biologically treats water to be treated, an agglomeration reaction tank that performs an agglutination reaction by adding a flocculant to the biologically treated water that flows out from the biological reaction tank, and an outflow from the aggregation reaction tank A wastewater treatment apparatus provided with a pressurized flotation separation apparatus for solid-liquid separation of agglomerated treated water, wherein the agglomeration reaction tank is provided with aeration means.
[2] The wastewater treatment apparatus according to [1], further comprising a pH adjuster addition unit for adjusting the pH of water in the aggregation reaction tank to 3 to 6.
[3] The wastewater treatment apparatus according to [1] or [2], further comprising an oxidant addition unit that adds an oxidant to the aggregation reaction tank.
[4] The wastewater treatment apparatus according to any one of [1] to [3], further comprising a filtration device that performs solid-liquid separation of the pressurized flotation separated water flowing out from the pressurized flotation separation device.
[5] In any one of [1] to [4], the agglomeration reaction tank is provided in multiple stages of two or more, the agglomeration reaction tank in the front stage is an air aeration tank, and the agglomeration reaction tank in the rear stage is a machine. A wastewater treatment apparatus characterized by being a stirring tank.
[ 6 ] A biological reaction step for biologically treating the water to be treated, an agglutination reaction step for adding a flocculant to the biologically treated water flowing out from the biological reaction step to perform an agglutination reaction, and an outflow from the agglutination reaction step A wastewater treatment method comprising a pressurized flotation separation step for solid-liquid separation of flocculated water, wherein the flocculation reaction in the agglomeration reaction step is performed under aeration.
[ 7 ] The wastewater treatment method according to [ 6 ], wherein a pH adjuster is added to the water in the aggregation reaction step to adjust the pH of the water to 3-6.
[ 8 ] The wastewater treatment method according to [ 6 ] or [ 7 ], wherein an oxidizing agent is added to the water in the aggregation reaction step.
[ 9 ] The wastewater treatment method according to any one of [ 6 ] to [ 8 ], further including a filtration step for solid-liquid separation of the pressurized floating separation water flowing out from the pressurized floating separation step.
[10] In any one of [6] to [9], the agglutination reaction step is performed in an agglomeration reaction tank provided in multiple stages of two or more tanks, and agglomeration is performed under air aeration in the agglomeration reaction tank in the previous stage. A wastewater treatment method, wherein a reaction is carried out and agglomeration reaction is carried out in a subsequent agglomeration reaction tank with mechanical stirring.

生物処理水中の菌体や生物代謝物を含む溶解性物質や懸濁性物質、特に生物代謝物の凝集処理は困難であり、従来においては多量の凝集剤を必要としていたが、本発明によれば、生物処理水を凝集処理するに当たり、凝集処理時の撹拌を曝気（通常、空気）によって行うことと凝集フロックの分離を加圧浮上分離で行うこととを組合わせて処理することにより、凝集性及び固液分離性を改善することができ、これにより、凝集剤添加量の削減を図った上で、良好な処理水を得ることができる。 It is difficult to agglomerate soluble substances and suspended substances containing microbial cells and biological metabolites in biologically treated water, especially biological metabolites, and a large amount of flocculant has been conventionally required. For example, in aggregating biologically treated water, agglomeration is performed by combining agitation (usually air) with agitation (usually air) and separation of agglomerated flocs by pressurized flotation. And solid-liquid separation properties can be improved. As a result, the amount of flocculant added can be reduced and good treated water can be obtained.

本発明によるこのような効果の作用機構の詳細は明らかになっていないが、以下のように考察される。 Although the details of the working mechanism of such an effect according to the present invention are not clarified, it is considered as follows.

生物処理後の水には、水中に分散して存在する菌体や溶存する高分子有機物（例えばタンパク質等）が存在するが、特に凝集処理と濾過を組み合わせた装置において、その濾過水質に大きな影響を及ぼすのはタンパク質であると考えられる。生物処理槽で見られる発泡のように、タンパク質の一部には空気との親和性を有するものが存在する。本発明においては、無機凝集剤によりタンパクが荷電中和され粗大化したような状態で空気曝気されると、粗大化したタンパクが気泡と絡まったような状態になると考えられる。その結果、凝集反応槽の後段で加圧浮上法により固液分離すると、さらに微細気泡がからまることにより、分離性が向上すると考えられる。 In biologically treated water, there are cells that are dispersed in the water and dissolved high-molecular organic substances (such as proteins), but this has a significant effect on the quality of filtered water, especially in devices that combine flocculation and filtration. It is thought that it is protein that exerts. Some of the proteins have affinity with air, such as foaming seen in biological treatment tanks. In the present invention, when the protein is neutralized by charge neutralization with an inorganic flocculant and aerated, it is considered that the coarsened protein becomes entangled with bubbles. As a result, it is considered that when the solid-liquid separation is performed by the pressure flotation method at the latter stage of the agglomeration reaction tank, the fine bubbles are further entangled to improve the separability.

また、特に鉄系凝集剤においては、ｐＨが弱酸性〜弱アルカリ性域においては三価の鉄が凝集に有効であるが、例えば塩化第二鉄（三価鉄）系凝集剤を用いた場合でも凝集剤中に若干の割合で二価鉄が存在する。そこで、凝集反応槽で曝気を行うと、このような二価の鉄は酸化され凝集に有効な三価鉄となる。また、凝集反応槽に次亜塩素酸などの酸化剤を添加するとさらに酸化効果が増大する（請求項３，７）。また、タンパク質の多くは弱酸性域に等電点を有するため、ｐＨが酸性領域（例えばｐＨ３〜６）ほど水への解離がなくなり凝集効果が高まると考えられる（請求項２，６）。 Particularly in the case of iron-based flocculants, trivalent iron is effective for agglomeration when the pH is weakly acidic to weakly alkaline. For example, even when a ferric chloride (trivalent iron) -based flocculant is used. There is a small proportion of divalent iron in the flocculant. Therefore, when aeration is performed in the aggregation reaction tank, such divalent iron is oxidized and becomes trivalent iron effective for aggregation. Further, when an oxidizing agent such as hypochlorous acid is added to the agglomeration reaction tank, the oxidation effect is further increased (claims 3 and 7). In addition, since many proteins have an isoelectric point in a weakly acidic region, it is considered that the dissociation into water disappears in the acidic region (for example, pH 3 to 6), and the aggregation effect is enhanced (claims 2 and 6).

このような作用機構により、本発明によれば、少ない凝集剤添加量で高水質の処理水が得られ、
(1) 凝集剤添加量の低減による凝集剤コストの低減、更には中和剤コスト及び汚泥処理費の削減が図れる。
(2) 凝集フロックの加圧浮上分離性の向上、それによる加圧浮上分離装置の通水速度の向上による設置スペースの削減が図れる。
(3) 凝集剤添加量の低減と加圧浮上分離による分離水の水質向上による、後段処理効率の改善、即ち、後段に濾過装置を設けた場合に、その濾過装置の逆洗頻度の低減、更にその後段に逆浸透（ＲＯ）膜分離装置を設けた場合に、そのＲＯ膜のファウリング防止を図ることができる。
といった効果のもとに、効率的な水回収、再利用を行える。 By such an action mechanism, according to the present invention, high-quality treated water can be obtained with a small amount of flocculant added,
(1) The coagulant cost can be reduced by reducing the amount of coagulant added, and the neutralizer cost and sludge treatment cost can be reduced.
(2) The installation space can be reduced by improving the pressure floating separation performance of the coagulation floc and thereby improving the water flow rate of the pressure floating separation apparatus.
(3) Reduction of the flocculant addition amount and improvement of the quality of the separated water by pressurized flotation separation, improving the post-treatment efficiency, that is, when a post-stage filter is provided, reducing the backwash frequency of the filter Further, when a reverse osmosis (RO) membrane separation device is provided at the subsequent stage, fouling of the RO membrane can be prevented.
Based on these effects, efficient water recovery and reuse can be achieved.

以下に本発明の排水処理装置及び排水処理方法の実施の形態を詳細に説明する。 Hereinafter, embodiments of the wastewater treatment apparatus and the wastewater treatment method of the present invention will be described in detail.

［排水］
本発明において、処理対象となる排水は、通常生物処理される有機物含有排水であれば良く、特に限定されるものではないが、例えば、電子産業排水、化学工場排水、食品工場排水などが挙げられる。例えば、電子部品製造プロセスでは、現像工程、剥離工程、エッチング工程、洗浄工程などから各種の有機性排水が多量に発生し、しかも排水を回収して純水レベルに浄化して再使用することが望まれているので、これらの排水は本発明の処理対象排水として適している。 [Drainage]
In the present invention, the wastewater to be treated is not particularly limited as long as it is an organic matter-containing wastewater that is usually biologically treated. Examples thereof include electronic industrial wastewater, chemical factory wastewater, and food factory wastewater. . For example, in the electronic component manufacturing process, a large amount of various organic wastewater is generated from the development process, peeling process, etching process, cleaning process, etc., and the wastewater can be collected and purified to a pure water level for reuse. As desired, these wastewaters are suitable as the wastewater to be treated of the present invention.

このような有機性排水としては例えば、イソプロピルアルコール、エチルアルコールなどを含有する有機性排水、モノエタノールアミン（ＭＥＡ）、テトラメチルアンモニウムハイドロオキサイド（ＴＭＡＨ）などの有機態窒素、アンモニア態窒素を含有する有機性排水、ジメチルスルホキシド（ＤＭＳＯ）などの有機硫黄化合物を含有する有機性排水が挙げられる。 Examples of such organic wastewater include organic wastewater containing isopropyl alcohol, ethyl alcohol, and the like, organic nitrogen such as monoethanolamine (MEA) and tetramethylammonium hydroxide (TMAH), and ammonia nitrogen. Organic waste water and organic waste water containing organic sulfur compounds such as dimethyl sulfoxide (DMSO) can be mentioned.

［生物処理］
排水を生物処理するための生物反応槽としては、有機物の分解効率に優れるものであれば良く、既知の好気性又は嫌気性生物処理方式の生物反応槽が使用できる。例えば、活性汚泥を槽内に浮遊状態で保持する浮遊方式、活性汚泥を担体に付着させて保持する生物膜方式などを採用することができる。また、生物膜方式では固定床式、流動床式、展開床式など任意の微生物床方式でよく、更に担体として、活性炭、種々のプラスチック担体、スポンジ担体などがいずれも使用できる。 [Biological treatment]
Any biological reaction tank for biologically treating the wastewater may be used as long as it has an excellent organic substance decomposition efficiency, and a known aerobic or anaerobic biological treatment system biological reaction tank can be used. For example, a floating method for holding activated sludge in a suspended state in a tank, a biofilm method for holding activated sludge attached to a carrier, and the like can be employed. The biofilm method may be any microbial bed method such as a fixed bed method, a fluidized bed method, and a developed bed method, and as the carrier, any of activated carbon, various plastic carriers, sponge carriers, and the like can be used.

浮遊方式では、処理水から活性汚泥を分離する固液分離手段が必要であり、生物処理反応槽の後段に沈殿槽、膜分離装置などの固液分離手段を設ける。他の方式では生物処理反応槽内に活性汚泥を維持することから、このような固液分離手段を省略することができる。 In the floating system, solid-liquid separation means for separating activated sludge from treated water is required, and solid-liquid separation means such as a precipitation tank and a membrane separation apparatus are provided after the biological treatment reaction tank. In other systems, activated sludge is maintained in the biological treatment reaction tank, so that such solid-liquid separation means can be omitted.

担体としてはスポンジ担体が好ましく、スポンジ担体であれば微生物を高濃度に維持することができる。スポンジ素材としても特に限定されないが、エステル系ポリウレタンが好適である。担体の投入量としても特に制限はないが、通常、生物反応槽の槽容量に対する担体の見掛け容量で１０〜５０％程度とすることが好ましい。 A sponge carrier is preferable as the carrier, and microorganisms can be maintained at a high concentration if the sponge carrier is used. The sponge material is not particularly limited, but ester polyurethane is preferable. Although there is no restriction | limiting in particular as the input amount of a support | carrier, Usually, it is preferable to set it as about 10 to 50% by the apparent capacity | capacitance of the support | carrier with respect to the tank capacity of a biological reaction tank.

好気性状態で微生物的に有機物を分解する好気性生物反応槽としては、槽内に酸素（空気）を供給するための散気管、曝気機などの酸素ガス供給手段が設けられた曝気槽を用いることができる。 As an aerobic biological reaction tank that microbially decomposes organic matter in an aerobic state, an aeration tank provided with oxygen gas supply means such as an air diffuser for supplying oxygen (air) into the tank and an aerator is used. be able to.

一方、嫌気性状態で微生物的に有機物を分解する嫌気性生物反応槽としては、担体や粒状汚泥を保持した嫌気槽を用いることができる。 On the other hand, as an anaerobic biological reaction tank that microbially decomposes organic matter in an anaerobic state, an anaerobic tank holding a carrier and granular sludge can be used.

生物反応槽は、好気性生物反応槽又は嫌気性生物反応槽の１槽式でも、好気性生物反応槽及び／又は嫌気性生物反応槽の多槽式でもよく、また、１槽式で槽内に仕切り壁を設けてもよい。 The biological reaction tank may be an aerobic biological reaction tank or an anaerobic biological reaction tank, or an aerobic biological reaction tank and / or a multi-tank type anaerobic biological reaction tank. A partition wall may be provided.

［凝集処理］
本発明においては、排水を生物反応槽で生物処理して得られる生物処理水の凝集処理に当たり、生物処理水に凝集剤を添加すると共に、曝気による撹拌を行う。 [Aggregation treatment]
In the present invention, in coagulation treatment of biologically treated water obtained by biological treatment of wastewater in a biological reaction tank, a flocculant is added to the biologically treated water, and stirring by aeration is performed.

＜凝集槽＞
凝集処理に用いる凝集反応槽（以下「凝集槽」と称す。）は１槽のみでも良く、２槽以上の凝集槽を多段に設けたものであっても良い。 <Coagulation tank>
The agglomeration reaction tank (hereinafter referred to as “aggregation tank”) used for the agglomeration treatment may be only one tank or may be provided with two or more agglomeration tanks in multiple stages.

凝集処理設備は一般に凝集剤を被処理水に十分に接触させるための急速撹拌槽と凝集フロックを成長させる緩速撹拌槽で構成される。本発明に係る曝気による撹拌は急速撹拌槽で行い、次の緩速撹拌槽では曝気を用いない撹拌によりフロックの安定成長化を図ることが望ましい。従って、２槽以上の凝集槽を多段に設ける場合、前段の凝集槽を空気曝気槽とし、後段の凝集槽を機械撹拌槽とすることが好ましい。 The agglomeration treatment facility is generally composed of a rapid agitation tank for sufficiently bringing the aggregating agent into contact with the water to be treated and a slow agitation tank for growing the agglomeration floc. It is desirable that stirring by aeration according to the present invention is performed in a rapid stirring tank, and in the next slow stirring tank, stable growth of flocs is achieved by stirring without using aeration. Therefore, when two or more flocculation tanks are provided in multiple stages, it is preferable that the preceding flocculation tank be an air aeration tank and the latter flocculation tank be a mechanical stirring tank.

空気曝気槽における空気曝気量には特に制限はなく、凝集剤が十分に撹拌される程度以上であれば良い。この空気曝気槽は機械撹拌を併用したものであっても良い。 There is no restriction | limiting in particular in the amount of air aeration in an air aeration tank, What is necessary is just more than the grade in which a coagulant | flocculant is fully stirred. This air aeration tank may be a combination of mechanical stirring.

＜凝集剤＞
凝集処理に用いる凝集剤としては、塩化第二鉄、ポリ硫酸鉄などの鉄系凝集剤、硫酸アルミニウム、塩化アルミニウム、ポリ塩化アルミニウム等のアルミニウム系凝集剤が例示できるが、凝集効果の面からは鉄系凝集剤が好ましい。これらの無機凝集剤は、１種を単独で用いても良く、２種以上を併用しても良い。 <Flocculant>
Examples of the aggregating agent used in the aggregating treatment include iron-based aggregating agents such as ferric chloride and polyiron sulfate, and aluminum-based aggregating agents such as aluminum sulfate, aluminum chloride, and polyaluminum chloride. Iron-based flocculants are preferred. These inorganic flocculants may be used individually by 1 type, and may use 2 or more types together.

無機凝集剤の添加量は、生物処理水の性状や水質にもよるが、通常５０〜３００ｍｇ／Ｌ程度とすることが好ましい。 The amount of the inorganic flocculant added is usually about 50 to 300 mg / L, although it depends on the properties and water quality of the biologically treated water.

また、排水の性状に応じて有機凝集剤、浮上助剤を併用することでさらに凝集処理水の水質向上や加圧浮上分離性の向上効果が得られることがある。この場合、有機凝集剤は無機凝集剤添加工程の前段で添加しても良く、後段で添加しても良く、また無機凝集剤の添加工程に添加しても良い。 Further, the combined use of an organic flocculant and a flotation aid depending on the properties of the wastewater may further improve the water quality of the agglomerated treated water and improve the pressure flotation separation property. In this case, the organic flocculant may be added before the inorganic flocculant addition step, may be added after the step, or may be added to the inorganic flocculant addition step.

有機凝集剤の添加量は、生物処理水の水質や有機凝集剤の使用形態によっても異なるが、通常の場合、１〜１０ｍｇ／Ｌ程度とすることが好ましい。 The amount of the organic flocculant to be added varies depending on the quality of the biologically treated water and the usage form of the organic flocculant, but is usually preferably about 1 to 10 mg / L.

＜ｐＨ調整＞
凝集処理時のｐＨは、曝気撹拌を行う凝集槽において、ｐＨ３〜６であることが好ましく、このようにｐＨ酸性領域に調整することにより凝集処理効果を高めることができる。特に鉄系凝集剤を用いた場合は、ｐＨ５．５以下での曝気撹拌による混合が効果的であり、アルミニウム系凝集剤を用いた場合はｐＨ５．５以下に曝気撹拌により混合させた後、再度ｐＨ６．０以上に調整すると効果的である。 <PH adjustment>
The pH during the coagulation treatment is preferably pH 3 to 6 in the coagulation tank in which aeration and agitation are performed, and the coagulation treatment effect can be enhanced by adjusting to the pH acidic region in this way. In particular, when an iron-based flocculant is used, mixing by aeration stirring at pH 5.5 or lower is effective. When an aluminum-based flocculant is used, mixing is performed by aeration stirring at pH 5.5 or lower, and then again. It is effective to adjust the pH to 6.0 or higher.

凝集処理設備が２槽以上の凝集槽で構成される場合、曝気撹拌を実施する凝集槽の少なくとも一つの凝集槽でｐＨ３〜６に調整し、他の凝集槽は排水性状と適用凝集剤種に合わせてｐＨ３〜６以外のｐＨに調整するようにしても良い。 When the agglomeration treatment equipment is composed of two or more agglomeration tanks, the pH is adjusted to 3 to 6 in at least one agglomeration tank of the agglomeration tank for carrying out aeration and stirring, and the other agglomeration tanks have drainage properties and applicable flocculant species. In addition, it may be adjusted to a pH other than pH 3-6.

ｐＨ調整には塩酸（ＨＣｌ）、硫酸（Ｈ_２ＳＯ_４）等の酸や、水酸化ナトリウム（ＮａＯＨ）等のアルカリが適宜用いられる。 For pH adjustment, an acid such as hydrochloric acid (HCl) or sulfuric acid (H ₂ SO ₄ ) or an alkali such as sodium hydroxide (NaOH) is appropriately used.

＜酸化剤＞
前述の如く凝集処理工程においては酸化剤を添加することが好ましく、これにより、より一層良好な凝集処理結果を得ることができる。 <Oxidizing agent>
As described above, it is preferable to add an oxidizing agent in the coagulation treatment step, and thereby, a better coagulation treatment result can be obtained.

酸化剤としては、次亜塩素酸ナトリウム（ＮａＣｌＯ）、過硫酸ナトリウム等の１種又は２種以上を用いることができ、その添加量は生物処理水の水質や凝集処理条件によっても異なるが、通常１〜１０ｍｇ／Ｌ程度とすることが好ましい。 As the oxidizing agent, one or more of sodium hypochlorite (NaClO), sodium persulfate and the like can be used, and the amount of addition varies depending on the quality of the biological treatment water and the coagulation treatment conditions. It is preferable to set it as about 1-10 mg / L.

［加圧浮上分離］
凝集処理水は次いで加圧浮上分離を行って、生成した凝集フロックを固液分離する。 [Pressure floating separation]
The agglomerated water is then subjected to pressure levitation separation to solid-liquid separate the produced agglomerated floc.

この加圧浮上分離には通常の加圧浮上分離装置を用いることができる。 A normal pressure levitation separation apparatus can be used for this pressure levitation separation.

本発明では凝集処理において曝気を行うことにより凝集処理水の加圧浮上分離性が改善されることにより、加圧浮上分離時の通水ＬＶを通常の加圧浮上分離処理における通水ＬＶである４〜７ｈｒ^−１から１０〜２０ｈｒ^−１に高めることができ、処理効率の向上、装置の小型化による設置スペースの削減を図ることができる。 In the present invention, by performing aeration in the agglomeration treatment, the pressure floating separation performance of the coagulated treated water is improved, so that the water flow LV at the time of pressure floating separation is the water flow LV in the normal pressure floating separation process. It can be increased from 4 to 7 hr ⁻¹ to 10 to 20 hr ⁻¹ , thereby improving the processing efficiency and reducing the installation space by downsizing the apparatus.

［濾過］
加圧浮上分離で得られた分離水は更に濾過装置で濾過することが好ましい。この濾過装置としては、砂、アンスラサイト等の濾材を充填した充填層型濾過器、精密濾過（ＭＦ）膜、限外濾過（ＵＦ）膜などの膜を用いた膜濾過器等を用いることができる。 [filtration]
It is preferable that the separated water obtained by pressure flotation separation is further filtered by a filtration device. As this filtration device, it is possible to use a packed bed type filter filled with a filter medium such as sand or anthracite, a membrane filter using a membrane such as a microfiltration (MF) membrane, an ultrafiltration (UF) membrane, or the like. it can.

本発明によれば、凝集処理時に曝気を行うことによる加圧浮上分離性の改善で、良好な水質の加圧浮上分離水が得られることから、この濾過装置の目詰まりを防止して濾過装置の逆洗頻度を低減し、処理効率の向上を図ることができる。 According to the present invention, the pressure floating separation water having a good water quality can be obtained by improving the pressure floating separation performance by aeration during the agglomeration treatment, so that the filtration device is prevented from being clogged. The frequency of backwashing can be reduced, and the processing efficiency can be improved.

［ＲＯ膜処理］
加圧浮上分離水、又はこれを濾過して得られる濾過処理水は、更にＲＯ膜分離装置に通水してＲＯ膜処理しても良く、ＲＯ膜処理による脱イオン処理で高純度水を得ることができる。 [RO membrane treatment]
Pressurized floating separation water or filtered water obtained by filtering this may be further passed through an RO membrane separation device and subjected to RO membrane treatment, and high-purity water is obtained by deionization treatment by RO membrane treatment. be able to.

この場合、ＲＯ膜処理に先立ち、加圧浮上分離水中の残留ＳＳを除去するために加圧浮上分離水を前述の濾過装置に通し、濾過処理するのが好ましい。ただし、加圧浮上分離水を直接ＲＯ膜処理しても良い。 In this case, prior to the RO membrane treatment, in order to remove residual SS in the pressurized flotation separated water, it is preferable to pass the pressurized flotation separation water through the above-described filtration device and perform the filtration treatment. However, the pressurized floating separation water may be directly subjected to the RO membrane treatment.

ＲＯ膜分離装置としては、既存の任意の装置を使用することができる。 As the RO membrane separation apparatus, any existing apparatus can be used.

本発明では、少ない無機凝集剤添加量で良好な加圧浮上分離水を得ることができ、又、その濾過処理水はＦＩ値が低く、これをＲＯ膜分離装置に給水することができるので、ＲＯ膜分離装置のファウリングによる膜フラックスの低下を抑制して、長期間安定して処理水（透過水）を得ることができる。 In the present invention, it is possible to obtain good pressurized flotation separated water with a small amount of inorganic flocculant added, and since the filtered water has a low FI value, it can be supplied to the RO membrane separator. Treatment water (permeated water) can be obtained stably for a long period of time by suppressing a decrease in membrane flux due to fouling of the RO membrane separator.

なお、ＦＩ値とは、水をＲＯ膜分離装置に通水して脱イオン処理する際のＲＯ膜分離装置への給水の水質がＲＯ膜処理に適しているか否かを判断する指標として用いられるものである。水中の溶存有機物やＳＳの量は概ね同等であっても、これをＲＯ膜処理すると膜フラックスが早期に低下するときとそうでないときがあり、そのような場合、ＲＯ給水のＦＩ値では差が生じている。 The FI value is used as an index for determining whether or not the quality of water supplied to the RO membrane separation device when water is passed through the RO membrane separation device for deionization is suitable for the RO membrane treatment. Is. Even if the amount of dissolved organic matter and SS in the water is approximately the same, when the RO membrane treatment is performed, the membrane flux may or may not decrease early. In such a case, there is a difference in the FI value of the RO water supply. Has occurred.

ＦＩ値は、後述の実施例における水質評価で記載するように所定の孔径を有するメンブレンフィルタに試料水を通水して所定量を濾過するに要する時間を計測する操作を行って、初期の所要時間と、所定時間通水後の所要時間とから求めることができ、膜汚染、膜目詰まりを起こし易いか又は起こし難い水質かを判定するのに用いられる。一般に、ＦＩ値５以下の水質でもＲＯ給水として許容されることがあるが、通常、ＦＩ値４以下の水質であることが望まれている。従って、本発明では、生物処理水を凝集処理及び加圧浮上分離処理し、好ましくは更に濾過処理してＦＩ値４以下の水を得、これをＲＯ膜処理することが好ましい。 As described in the water quality evaluation in the examples described later, the FI value is obtained by performing an operation of passing the sample water through a membrane filter having a predetermined pore diameter and measuring a time required for filtering the predetermined amount. It can be determined from the time and the required time after passing water for a predetermined time, and is used to determine whether the water quality is likely to cause membrane contamination and membrane clogging. In general, water quality with an FI value of 5 or less may be allowed as RO water supply, but it is usually desired that the water quality has an FI value of 4 or less. Therefore, in the present invention, it is preferable that the biologically treated water is subjected to a flocculation treatment and a pressure levitation separation treatment, preferably further subjected to a filtration treatment to obtain water having an FI value of 4 or less, and this is subjected to RO membrane treatment.

［その他の処理］
更に、本発明では、加圧浮上分離装置の後段で、上記以外のその他の処理を併用しても良い。例えば、残留溶解性有機物を除去するために、活性炭塔を設けて活性炭による吸着処理を行っても良い。 [Other processing]
Furthermore, in this invention, you may use together other processes other than the above in the back | latter stage of a pressurization floating separator. For example, in order to remove residual soluble organic matter, an activated carbon tower may be provided to perform adsorption treatment with activated carbon.

この場合、活性炭塔は濾過装置の後段であって、ＲＯ膜分離装置の前段に設けることが好ましい。 In this case, the activated carbon tower is preferably provided in the subsequent stage of the filtration apparatus and in the previous stage of the RO membrane separation apparatus.

［処理装置］
以下に図面を参照して本発明の排水処理装置の一例を説明する。 [Processing equipment]
An example of the waste water treatment apparatus of the present invention will be described below with reference to the drawings.

図１〜５は、本発明の排水処理装置の一例を示す系統図であり、１は生物反応槽、２，２Ａ，２Ｂ，２Ｃは凝集槽、３は加圧浮上分離槽、４は濾過装置、５はＲＯ膜分離装置、６は活性炭塔を示す。 1 to 5 are system diagrams showing an example of the waste water treatment apparatus of the present invention, wherein 1 is a biological reaction tank, 2, 2A, 2B, and 2C are coagulation tanks, 3 is a pressurized flotation separation tank, and 4 is a filtration device. Reference numeral 5 denotes an RO membrane separator, and 6 denotes an activated carbon tower.

図１の排水処理装置においては、排水は生物反応槽１で生物処理された後、曝気手段を設けた第１凝集槽２Ａにおいて、無機凝集剤（例えば鉄系凝集剤）、酸化剤及び酸が添加されて急速撹拌下にｐＨ３〜６の条件で凝集処理された後、撹拌機が設けられた第２凝集槽２Ｂに導入されて有機凝集剤とアルカリが添加されてｐＨ５〜８の条件で緩速撹拌下に凝集処理され、凝集処理水は次いで加圧浮上分離槽３で加圧浮上分離され、分離水は更に濾過装置４で濾過され濾過水が処理水として取り出される。 In the wastewater treatment apparatus of FIG. 1, after the wastewater is biologically treated in the biological reaction tank 1, an inorganic flocculant (for example, an iron-based flocculant), an oxidizing agent, and an acid are contained in the first flocculant tank 2 </ b> A provided with aeration means. After being added and subjected to agglomeration treatment under conditions of pH 3 to 6 under rapid stirring, the mixture is introduced into the second agglomeration tank 2B provided with a stirrer, and an organic flocculant and an alkali are added thereto, and the mixture is relaxed under conditions of pH 5 to 8. The agglomeration treatment is carried out with rapid stirring, and the agglomerated water is then separated by pressurized flotation in the pressurized flotation separation tank 3, and the separated water is further filtered by the filtration device 4 and the filtered water is taken out as treated water.

図２に示す装置は、図１において、濾過装置４の後段に更にＲＯ膜分離装置５を設けたものであり、図１の装置と同様にして得られた濾過処理水が更にＲＯ膜分離装置５で脱イオン処理された後処理水として取り出される。 The apparatus shown in FIG. 2 is one in which an RO membrane separation device 5 is further provided in the subsequent stage of the filtration device 4 in FIG. 1, and the filtered water obtained in the same manner as the device of FIG. 5 is de-ionized and removed as treated water.

図３の装置は、図２の装置において、濾過装置４とＲＯ膜分離装置５との間に活性炭塔６を設け、また、第１凝集槽２Ａで無機凝集剤（例えばアルミニウム系凝集剤）及び酸化剤と、酸又はアルカリを添加し、第２凝集槽２Ｂで酸又はアルカリのみを添加するようにしたものであり、図１の場合と同様に凝集処理、加圧浮上分離処理、濾過処理された水が、活性炭塔６で残留溶解性有機物が除去された後、更にＲＯ膜分離装置５で脱イオン処理され、処理水として取り出される。 The apparatus of FIG. 3 includes an activated carbon tower 6 between the filtration apparatus 4 and the RO membrane separation apparatus 5 in the apparatus of FIG. 2, and an inorganic flocculant (for example, an aluminum flocculant) and a first flocculant 2A. An oxidant and an acid or alkali are added, and only the acid or alkali is added in the second flocculation tank 2B. The flocculation process, the pressure levitation separation process, and the filtration process are performed as in the case of FIG. After the residual soluble organic substances are removed by the activated carbon tower 6, the water is further deionized by the RO membrane separator 5 and taken out as treated water.

図４に示す装置は、図２の装置において、凝集槽を１槽のみとし、曝気手段を設けた凝集槽２において、無機凝集剤と、酸化剤と、酸又はアルカリを添加してｐＨ弱酸性条件下に凝集処理した後、加圧浮上分離槽３で加圧浮上分離処理した後、濾過処理、ＲＯ膜分離処理を行って処理水が取り出される。 The apparatus shown in FIG. 4 has a weak cohesive pH in the apparatus shown in FIG. 2 by adding an inorganic flocculant, an oxidizer, and an acid or alkali to the flocculant tank 2 provided with aeration means. After flocculation treatment under the conditions, the pressure levitation separation tank 3 is subjected to pressure levitation separation treatment, followed by filtration and RO membrane separation treatment, and treated water is taken out.

図５に示す装置は図１の装置において、凝集槽を３槽としたものであり、生物処理水は機械撹拌手段を設けた第１凝集槽２Ａで有機凝集剤と酸又はアルカリが添加されてｐＨ５〜７の条件下に凝集処理され、次いで第２凝集槽２Ｂにて曝気撹拌下に無機凝集剤、及び酸化剤と、酸又はアルカリが添加されてｐＨ３〜６条件下に凝集処理され、更に第３凝集槽２Ｃにおいて機械撹拌下に酸又はアルカリが添加されてｐＨ６〜８の条件下に凝集処理され、凝集処理水は加圧浮上分離処理、次いで濾過処理されて処理水が取り出される。 The apparatus shown in FIG. 5 has three coagulation tanks in the apparatus of FIG. 1, and the biologically treated water is obtained by adding an organic coagulant and acid or alkali in the first coagulation tank 2A provided with mechanical stirring means. Coagulation treatment is performed under the conditions of pH 5 to 7, and then the inorganic coagulant, the oxidizing agent, and the acid or alkali are added under aeration and stirring in the second coagulation tank 2B, and the coagulation treatment is performed under the conditions of pH 3 to 6. In the third flocculation tank 2C, acid or alkali is added under mechanical agitation and flocculation treatment is performed under conditions of pH 6 to 8, and the flocculation water is subjected to a pressure levitation separation treatment and then a filtration treatment, and the treated water is taken out.

なお、図１〜５に示す装置は、本発明の排水処理装置の一例であって、本発明は何ら図示の方法に限定されるものではなく、前述の如く凝集槽や後段の処理装置において、他の様々な態様を採用することができる。 The apparatus shown in FIGS. 1 to 5 is an example of the waste water treatment apparatus of the present invention, and the present invention is not limited to the illustrated method. In the coagulation tank and the subsequent treatment apparatus as described above, Various other aspects can be employed.

以下に実施例及び比較例を挙げて本発明をより具体的に説明する。 Hereinafter, the present invention will be described more specifically with reference to Examples and Comparative Examples.

実施例１〜４
図１に示す装置により、本発明に従って有機性排水の処理を行った。処理した有機性排水の水質、用いた生物反応槽及び凝集槽等の仕様及び運転条件は下記の通りであり、２４００Ｌ／日の処理量で処理を行った。 Examples 1-4
With the apparatus shown in FIG. 1, the organic waste water was treated according to the present invention. The water quality of the treated organic waste water, the specifications and operating conditions of the used biological reaction tank and coagulation tank, etc. were as follows, and the treatment was performed at a throughput of 2400 L / day.

このときの処理水の水質評価を、加圧浮上分離槽の分離水を採取して、０．４５μｍフィルターに２．１ｋｇ／ｃｍ^２の加圧条件で濾過したときの濾過時間から以下のようにして算出されるＦＩ値と、濾過装置の濾過継続時間（濾過装置が閉塞に到り逆洗を必要とするまでの濾過継続可能時間）で評価し、結果を表１に示した。 The quality of the treated water at this time is as follows from the filtration time when the separated water in the pressurized flotation separation tank is collected and filtered under a pressure condition of 2.1 kg / cm ² through a 0.45 μm filter. The FI value calculated in this way and the filtration duration time of the filtration device (the filtration continuation time until the filtration device reaches clogging and requires backwashing) were evaluated, and the results are shown in Table 1.

なお、前述の如く、ＲＯ膜分離装置への通水基準はＦＩ値４以下であり、ＦＩ値４以下の処理水が得られることが望ましい。
ＦＩ＝｛（１−Ｔ_０／Ｔ_１５）／Ｔ_１５｝１００
Ｔ_０：初期５００ｃｃの濾過に要する時間（ｓｅｃ）
Ｔ_１５：濾過継続１５ｍｉｎ後の５００ｃｃの濾過に要する時間（ｓｅｃ） In addition, as mentioned above, the water flow standard to the RO membrane separation apparatus has an FI value of 4 or less, and it is desirable to obtain treated water having an FI value of 4 or less.
FI = {(1−T ₀ / T ₁₅ ) / T ₁₅ } 100
T ₀ : Time required for initial 500 cc filtration (sec)
T ₁₅ : Time required for filtration of 500 cc after ₁₅ minutes of filtration (sec)

［有機性排水水質］
ＢＯＤ：１０００ｍｇ／Ｌ [Organic wastewater quality]
BOD: 1000mg / L

［生物反応槽］
槽容量：２４００Ｌ
曝気量：２００Ｌ／ｍｉｎ
担体：３ｍｍ角のスポンジを見掛け容量で槽容量の５０％添加 [Bioreaction tank]
Tank capacity: 2400L
Aeration amount: 200 L / min
Carrier: Appearance of 3mm square sponge and 50% addition of tank capacity

［第１凝集槽］
槽容量：５０Ｌ
無機凝集剤：３８重量％塩化第二鉄水溶液を２００ｍｇ／Ｌ（ＦｅＣｌ_３換算量）添加
酸化剤：次亜塩素酸ナトリウムを表１に示す量添加
槽内ｐＨ：表１に示す通り（ＨＣｌ又はＮａＣｌ添加により調整）
空気曝気量：２０Ｌ／ｍｉｎ [First aggregation tank]
Tank capacity: 50L
Inorganic flocculant: 38 wt% ferric chloride aqueous solution added at 200 mg / L (FeCl ₃ equivalent amount) Oxidizing agent: Sodium hypochlorite added in the amount shown in Table 1 pH in the tank: As shown in Table 1 (HCl or Adjust by adding NaCl)
Air aeration amount: 20L / min

［第２凝集槽］
槽容量：５０Ｌ
有機凝集剤：ポリアクリルアミド部分加水分解物を０．５ｍｇ／Ｌ添加
槽内ｐＨ：表１に示す通り（ＨＣｌ又はＮａＯＨ添加により調整）
撹拌機：平羽４０ｍｍ×２００ｍｍ，６０ｒｐｍのパドル撹拌 [Second aggregation tank]
Tank capacity: 50L
Organic flocculant: 0.5 mg / L of polyacrylamide partial hydrolysate pH in the tank: As shown in Table 1 (adjusted by adding HCl or NaOH)
Stirrer: Flat blade 40mm x 200mm, 60rpm paddle stirring

［加圧浮上分離槽］
槽：直径１３０ｍｍの円筒形浮上分離槽
加圧水比：３０％
通水ＬＶ：１０ｍ／ｈｒ [Pressure levitation separation tank]
Tank: 130mm diameter cylindrical floating separation tank Pressurized water ratio: 30%
Water flow LV: 10m / hr

［濾過装置］
濾過方式：重力式２層濾過
濾過ＬＶ：５．６ｍ／ｈｒ [Filtering equipment]
Filtration method: Gravity type two-layer filtration Filtration LV: 5.6 m / hr

比較例１
実施例１において、第１凝集槽の撹拌手段を空気曝気ではなく、第２凝集槽と同様のパドル撹拌としたこと以外は同様にして処理を行い、処理結果を表１に示した。 Comparative Example 1
In Example 1, treatment was performed in the same manner except that the stirring means of the first flocculation tank was not air aeration but paddle stirring similar to that of the second flocculation tank, and the treatment results are shown in Table 1.

比較例２
比較例１において、第１凝集槽における無機凝集剤添加量を表１に示すように増量したこと以外は同様にして処理を行い、処理結果を表１に示した。 Comparative Example 2
In Comparative Example 1, the treatment was performed in the same manner except that the amount of the inorganic flocculant added in the first flocculation tank was increased as shown in Table 1, and the treatment results are shown in Table 1.

表１より次のことが明らかである。 From Table 1, the following is clear.

即ち、第１凝集槽で機械撹拌を行った比較例１では処理水のＦＩ値が高く、処理水の水質が劣る。また濾過継続時間も実施例１〜４に比べて短い。無機凝集剤添加量を多くした比較例２では、ＦＩ値は改善されるものの十分ではなく、また、凝集フロックの形成及びそのフロックの泡との親和性の両方が不十分のために加圧浮上分離性が悪いことから、濾過継続時間は非常に短いものとなる。 That is, in Comparative Example 1 in which mechanical stirring was performed in the first flocculation tank, the FI value of the treated water was high, and the quality of the treated water was inferior. Moreover, the filtration continuation time is also short compared with Examples 1-4. In Comparative Example 2 in which the amount of the inorganic flocculant added was increased, the FI value was improved but not sufficient, and the pressure flotation occurred because both the formation of the floc floc and the affinity of the floc with the foam were insufficient. Due to poor separation, the filtration duration is very short.

これに対して、第１凝集槽で空気曝気を行った実施例１〜４ではいずれも良好な結果が得られており、特に、酸化剤を添加した場合（実施例３）、更に、第１凝集槽のｐＨを酸性領域とした場合（実施例１，２）では、良好な結果が得られている。 In contrast, in Examples 1 to 4 in which air aeration was performed in the first coagulation tank, good results were obtained. In particular, when an oxidizing agent was added (Example 3), the first When the pH of the coagulation tank is in the acidic region (Examples 1 and 2), good results are obtained.

実施例５
実施例１において、第１凝集槽に添加する無機凝集剤としてＰＡＣ（ポリ塩化アルミニウム）を用い、その添加量を２５０ｍｇ／Ｌとすると共に、第１凝集槽及び第２凝集槽のｐＨを表１に示す値としたこと以外は同様にして処理を行い、処理結果を表２に示した。 Example 5
In Example 1, PAC (polyaluminum chloride) was used as an inorganic flocculant to be added to the first flocculation tank, the amount added was 250 mg / L, and the pH values of the first flocculation tank and the second flocculation tank were as shown in Table 1. The processing was performed in the same manner except that the values shown in Table 2 were obtained, and the processing results are shown in Table 2.

比較例３
実施例５において、第１凝集槽の撹拌手段を空気曝気ではなく、第２凝集槽と同様のパドル撹拌としたこと以外は同様にして処理を行い、処理結果を表２に示した。 Comparative Example 3
In Example 5, treatment was performed in the same manner except that the stirring means of the first coagulation tank was not air aeration but paddle stirring similar to that of the second coagulation tank, and the processing results are shown in Table 2.

表２より、無機凝集剤としてＰＡＣを用いた場合にも、空気曝気による本発明の効果が得られることが分かる。なお、実施例５と比較例３との対比において、実施例５はＦＩ値においては比較例３よりも良好であり、濾過継続時間も比較例３の場合よりも長い。 Table 2 shows that the effect of the present invention by air aeration can be obtained even when PAC is used as the inorganic flocculant. In comparison between Example 5 and Comparative Example 3, Example 5 is better in FI value than Comparative Example 3, and the filtration duration is longer than that in Comparative Example 3.

本発明の排水処理装置の実施の形態を示す系統図である。It is a systematic diagram which shows embodiment of the waste water treatment equipment of this invention. 本発明の排水処理装置の他の実施の形態を示す系統図である。It is a systematic diagram which shows other embodiment of the waste water treatment equipment of this invention. 本発明の排水処理装置の別の実施の形態を示す系統図である。It is a systematic diagram which shows another embodiment of the waste water treatment equipment of this invention. 本発明の排水処理装置の別の実施の形態を示す系統図である。It is a systematic diagram which shows another embodiment of the waste water treatment equipment of this invention. 本発明の排水処理装置の別の実施の形態を示す系統図である。It is a systematic diagram which shows another embodiment of the waste water treatment equipment of this invention.

符号の説明Explanation of symbols

１生物反応槽
２凝集槽
２Ａ第１凝集槽
２Ｂ第２凝集槽
２Ｃ第３凝集槽
３加圧浮上分離槽
４濾過装置
５ＲＯ膜分離装置
６活性炭塔 DESCRIPTION OF SYMBOLS 1 Biological reaction tank 2 Coagulation tank 2A 1st coagulation tank 2B 2nd coagulation tank 2C 3rd coagulation tank 3 Pressurization floating separation tank 4 Filtration apparatus 5 RO membrane separation apparatus 6 Activated carbon tower

Claims

被処理水を生物的に処理する生物反応槽と、
該生物反応槽から流出する生物処理水に凝集剤を添加して凝集反応を行う凝集反応槽と、
該凝集反応槽から流出する凝集処理水を固液分離する加圧浮上分離装置と
を備えた排水処理装置において、
前記凝集反応槽に曝気手段を設けたことを特徴とする排水処理装置。 A biological reaction tank for biologically treating the water to be treated;
An agglomeration reaction tank for performing an agglutination reaction by adding a flocculant to the biologically treated water flowing out of the biological reaction tank;
In a wastewater treatment apparatus provided with a pressurized flotation separation device for solid-liquid separation of the agglomerated treated water flowing out of the agglomeration reaction tank,
A wastewater treatment apparatus characterized in that aeration means is provided in the agglomeration reaction tank.

請求項１において、前記凝集反応槽内の水のｐＨを３〜６に調整するためのｐＨ調整剤添加手段を有することを特徴とする排水処理装置。 The wastewater treatment apparatus according to claim 1, further comprising a pH adjuster addition unit for adjusting the pH of the water in the aggregation reaction tank to 3 to 6.

請求項１又は２において、前記凝集反応槽に酸化剤を添加する酸化剤添加手段を有することを特徴とする排水処理装置。 The wastewater treatment apparatus according to claim 1, further comprising an oxidant addition unit that adds an oxidant to the aggregation reaction tank.

請求項１ないし３のいずれか１項において、前記加圧浮上分離装置から流出する加圧浮上分離水を固液分離する濾過装置を有することを特徴とする排水処理装置。 The wastewater treatment apparatus according to any one of claims 1 to 3, further comprising a filtration device for solid-liquid separation of the pressurized floating separation water flowing out from the pressurized floating separation device.

請求項１ないし４のいずれか１項において、前記凝集反応槽が２槽以上の多段に設けられ、前段の凝集反応槽が空気曝気槽であり、後段の凝集反応槽が機械攪拌槽であることを特徴とする排水処理装置。5. The aggregation reaction tank according to claim 1, wherein the aggregation reaction tank is provided in multiple stages of two or more tanks, the preceding aggregation reaction tank is an air aeration tank, and the latter aggregation reaction tank is a mechanical stirring tank. Wastewater treatment equipment characterized by.

被処理水を生物的に処理する生物反応工程と、
該生物反応工程から流出する生物処理水に凝集剤を添加して凝集反応を行う凝集反応工程と、
該凝集反応工程から流出する凝集処理水を固液分離する加圧浮上分離工程と
を備えた排水処理方法において、
前記凝集反応工程における凝集反応を曝気下に行うことを特徴とする排水処理方法。 A biological reaction process for biologically treating the water to be treated;
An agglutination reaction step in which an aggregating agent is added to the biologically treated water flowing out of the biological reaction step to perform an agglutination reaction;
In a wastewater treatment method comprising a pressurized flotation separation step for solid-liquid separation of the agglomerated treated water flowing out of the agglomeration reaction step,
A wastewater treatment method, wherein the aggregation reaction in the aggregation reaction step is performed under aeration.

請求項６において、前記凝集反応工程の水にｐＨ調整剤を添加して、該水のｐＨを３〜６に調整することを特徴とする排水処理方法。 The wastewater treatment method according to claim 6 , wherein a pH adjuster is added to the water in the aggregation reaction step to adjust the pH of the water to 3-6.

請求項６又は７において、前記凝集反応工程の水に酸化剤を添加することを特徴とする排水処理方法。 The wastewater treatment method according to claim 6 or 7 , wherein an oxidizing agent is added to the water in the aggregation reaction step.

請求項６ないし８のいずれか１項において、前記加圧浮上分離工程から流出する加圧浮上分離水を固液分離する濾過工程を有することを特徴とする排水処理方法。 The wastewater treatment method according to any one of claims 6 to 8 , further comprising a filtration step of solid-liquid separation of the pressurized floating separation water flowing out from the pressurized floating separation step.

請求項６ないし９のいずれか１項において、前記凝集反応工程は、２槽以上の多段に設けられた凝集反応槽で行われ、前段の凝集反応槽で空気曝気下に凝集反応が行われ、後段の凝集反応槽で機械攪拌下に凝集反応が行われることを特徴とする排水処理方法。In any one of Claims 6 thru | or 9, the said agglutination reaction process is performed in the agglutination reaction tank provided in the multistage of 2 or more tanks, and the agglutination reaction is performed under air aeration in the agglutination reaction tank of the front | former stage, A wastewater treatment method, wherein agglomeration reaction is performed with mechanical stirring in a subsequent agglomeration reaction tank.