JP2008086848A - Apparatus and method for treating organic liquid waste - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an apparatus and a method for treating organic liquid waste by which the deterioration of the degree of see-through of the treated water is prevented by a simple constitution while solving the problem that the degree of see-through of the treated water is deteriorated since a minute turbid medium to be produced at a modification step leaks in the treated water in a method and an apparatus for treating organic waste water, in each of which the sludge withdrawn from a biological treatment tank is modified by ozone or the like and the modified sludge is returned to a biological treatment step to volume-reduce the returned sludge. <P>SOLUTION: In the apparatus and the method for treating organic liquid waste, the sludge withdrawn from the biological treatment tank is modified by ozone or the like and the modified sludge is returned to the biological treatment step to volume-reduce the returned sludge, are characterized in that a polymer flocculant is added to a liquid mixture from the biological treatment tank and the flocculant-added liquid mixture is subjected to solid-liquid separation. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a treatment apparatus and treatment method for biologically treating organic wastewater with microorganisms, and in particular, treatment of organic wastewater in which sludge generated by biological treatment is modified to be readily biodegradable for treatment. The present invention relates to a method and a processing apparatus.

  Biological treatment of organic effluent using microorganisms, such as activated sludge treatment, is cheaper than other treatment methods and has superior treatment performance, but it is difficult to dehydrate. A large amount of excess sludge is generated. In such a treatment method, in order to reduce the volume of sludge, the sludge extracted from the biological treatment process is treated with an oxidizing agent such as ozone, a physical means such as an acid / alkali, a mill, or a high heat bacterium. An organic drainage treatment method has been proposed in which sludge is modified to be readily biodegradable and then the modified sludge is returned to the biological treatment process for biological treatment (for example, Patent Document 1).

In such a treatment method, the amount of sludge generated can be reduced, and the amount of sludge discharged outside the system can be made almost zero by adjusting the amount of reformed sludge. However, as the sludge stabilized in biological treatment is modified to be readily biodegradable and returned to the biological treatment process, the soluble COD incorporated in the sludge is solubilized and flows into the biological treatment process. Solubility COD increases. For this reason, when biological treatment is insufficient, soluble COD may flow out into the treated water, and hydroxides such as iron and aluminum are added to the biological treatment tank in order to prevent outflow of COD components in the treated water. Has been proposed (Patent Document 2).
Japanese Patent Laid-Open No. 6-206088 JP 2004-25093 A

  In organic wastewater treatment methods and treatment equipment, sludge extracted from the biological treatment process is reformed with ozone, etc., and sludge is reduced by returning the modified sludge to the biological treatment process. Since cell walls are destroyed, fine turbidity is likely to occur. Therefore, even if soluble COD, BOD, and the like are sufficiently removed, the fine turbidity may leak in the treated water and the transparency of the treated water may deteriorate. Further, when iron or aluminum is added, there is a problem that even if there is a COD removal effect, the fine turbidity removal effect is not sufficient, and a large amount of inorganic sludge is generated.

The present invention provides the following organic drainage treatment apparatus and organic drainage treatment method.
(1) A biological treatment tank for treating organic drainage with microorganisms, a polymer flocculant addition means for adding a polymer flocculant to a liquid mixture from the biological treatment tank, and a liquid mixture to which the polymer flocculant is added Solid-liquid separation means for separating the sludge and the treatment liquid, and at least a part of the sludge separated by the solid-liquid separation means and / or reforming means for modifying the drawn sludge from the biological treatment tank to be easily biodegradable And a modified sludge returning means for returning the modified sludge to the biological treatment tank.
(2) In the above (1), the polymer flocculant is a copolymer of 20 to 50 mol% of a cationic monomer represented by the following formula [1] and 50 to 80 mol% of a nonionic monomer. An organic drainage treatment apparatus characterized by the above.

（式［１］中、Ｒ^１は水素原子またはメチル基、Ｒ^２およびＲ^３はそれぞれ独立にメチル基またはエチル基、Ｒ^４は水素原子、メチル基、エチル基またはベンジル基、Ｘは酸素原子またはＮＨ、Ｙは炭素数２〜４のアルキレン基またはヒドロキシアルキレン基、Ｚは対アニオンである。）
（３） 有機性排液を微生物で処理する生物処理工程と、生物処理工程からの混合液に高分子凝集剤を添加する高分子凝集剤添加工程と、高分子凝集剤が添加された混合液を汚泥と処理液とに分離する固液分離工程と、固液分離された汚泥の少なくとも一部および／または生物処理工程からの引抜き汚泥を易生物分解性に改質する改質工程と、改質汚泥を生物処理工程に返送する改質汚泥返送工程とを有することを特徴とする有機性排液の処理方法。
（４） 上記（３）において、高分子凝集剤は、下記式［１］で表されるカチオン性単量体２０〜５０ｍｏｌ％と、非イオン性単量体５０〜８０ｍｏｌ％との共重合物であることを特徴とする有機性排液の処理方法。

(In the formula [1], R ¹ is a hydrogen atom or a methyl group, R ² and R ³ are each independently a methyl group or an ethyl group, R ⁴ is a hydrogen atom, a methyl group, an ethyl group or a benzyl group, and X is an oxygen atom. NH or Y is an alkylene group or hydroxyalkylene group having 2 to 4 carbon atoms, and Z is a counter anion.)
(3) A biological treatment process for treating organic drainage with microorganisms, a polymer flocculant addition process for adding a polymer flocculant to a mixed liquid from the biological treatment process, and a mixed liquid in which the polymer flocculant is added A solid-liquid separation process that separates the sludge into a sludge and a treatment liquid; a reforming process that modifies at least a part of the solid-liquid separated sludge and / or a sludge extracted from the biological treatment process to be easily biodegradable; An organic wastewater treatment method comprising: a modified sludge return step for returning quality sludge to a biological treatment step.
(4) In the above (3), the polymer flocculant is a copolymer of 20 to 50 mol% of a cationic monomer represented by the following formula [1] and 50 to 80 mol% of a nonionic monomer. A method for treating organic drainage, wherein

（式［１］中、Ｒ^１は水素原子またはメチル基、Ｒ^２およびＲ^３はそれぞれ独立にメチル基またはエチル基、Ｒ^４は水素原子、メチル基、エチル基またはベンジル基、Ｘは酸素原子またはＮＨ、Ｙは炭素数２〜４のアルキレン基またはヒドロキシアルキレン基、Ｚは対アニオンである。）
本発明において処理の対象となる有機性排液は、生物処理によって処理される有機物、アンモニア性窒素化合物、有機性窒素化合物、硝酸性窒素、亜硝酸性窒素などを含有する排液であるが、難生物分解性の有機物または無機物が含有されていてもよい。このような有機性排液としては下水、し尿、埋立浸出水、食品工場排水、化学工場排水、その他の産業排液などがあげられる。

(In the formula [1], R ¹ is a hydrogen atom or a methyl group, R ² and R ³ are each independently a methyl group or an ethyl group, R ⁴ is a hydrogen atom, a methyl group, an ethyl group or a benzyl group, and X is an oxygen atom. NH or Y is an alkylene group or hydroxyalkylene group having 2 to 4 carbon atoms, and Z is a counter anion.)
The organic drainage to be treated in the present invention is a drainage containing organic matter, ammoniacal nitrogen compound, organic nitrogen compound, nitrate nitrogen, nitrite nitrogen, etc. that are treated by biological treatment. A non-biodegradable organic substance or inorganic substance may be contained. Such organic effluents include sewage, human waste, landfill leachate, food factory effluent, chemical factory effluent, and other industrial effluents.

  The biological treatment employed in the present invention is an aerobic biological treatment, an anaerobic biological treatment, or a biological treatment combining these. Examples of the aerobic biological treatment include an activated sludge method and a biofilm method. The activated sludge method is an aerobic biological treatment method for treating organic wastewater in the presence of activated sludge. Organic wastewater is mixed with activated sludge in a biological treatment tank (aeration tank) and aerated. A standard activated sludge method is generally used in which solid-liquid separation is performed with a solid-liquid separator and a part of the separated sludge is returned to the aeration tank. However, other treatment methods obtained by modifying this method may be used. The biofilm method is a treatment in which a biofilm is formed on a carrier and contacted with drainage under aerobic conditions. Examples of the anaerobic treatment include an anaerobic digestion method and a high-load anaerobic treatment method. Furthermore, in addition to a general aerobic treatment and / or anaerobic treatment, a nitrification step of nitrifying (oxidizing) ammoniacal nitrogen to nitric acid or nitrite nitrogen under aerobic conditions with nitrifying bacteria, and nitric acid or nitrous acid Biological treatment including a denitrification step of reducing anaerobic nitrogen under anaerobic conditions by denitrifying bacteria.

  In the present invention, a polymer flocculant is added to the mixed solution from the biological treatment apparatus. As the polymer flocculant used in the present invention, those generally used for coagulation sedimentation, sludge dehydration and the like can be used, and cationic ones are preferable, but nonionic or anionic ones may also be used. Cationic ones include homopolymers of (meth) acrylate cationic monomers or copolymers with nonionic monomers, Mannich modified products of polyacrylamide, poly (dimethyldiallylammonium chloride), dialkyl Cationic polymer flocculants such as amine-epichlorohydrin condensate, alkylene dichloride-polyalkylene polyamine condensate, polyethyleneimine, dicyandiamide-formalin condensate, polyvinylamidine and chitosan can be used. In particular, a copolymer of (meth) acrylic cationic monomer 20 to 50 mol% represented by the following formula [1] and nonionic monomer 50 to 80 mol% can be suitably used. Examples of the nonionic monomer include acrylamide and methacrylamide.

（式［１］中、Ｒ^１は水素原子またはメチル基、Ｒ^２およびＲ^３はそれぞれ独立にメチル基またはエチル基、Ｒ^４は水素原子、メチル基、エチル基またはベンジル基、Ｘは酸素原子またはＮＨ、Ｙは炭素数２〜４のアルキレン基またはヒドロキシアルキレン基、Ｚは対アニオンである。）
（メタ）アクリル系カチオン性単量体との含有量がこの範囲をはずれると凝集汚泥の沈降速度を充分に高めることができず、また、微細な濁質を十分に除去することができない。

(In the formula [1], R ¹ is a hydrogen atom or a methyl group, R ² and R ³ are each independently a methyl group or an ethyl group, R ⁴ is a hydrogen atom, a methyl group, an ethyl group or a benzyl group, and X is an oxygen atom. NH or Y is an alkylene group or hydroxyalkylene group having 2 to 4 carbon atoms, and Z is a counter anion.)
If the content of the (meth) acrylic cationic monomer is outside this range, the sedimentation rate of the coagulated sludge cannot be sufficiently increased, and the fine turbidity cannot be sufficiently removed.

   A particularly preferred cationic polymer flocculant that can be used in the present invention is a copolymer of 20 to 50 mol% of a (meth) acrylic cationic monomer represented by the following formula [2] and 50 to 80 mol% of acrylamide. It is.

本発明で使用される高分子凝集剤は固有粘度（１Ｎ ＮａＮＯ_３水溶液の３０℃での測定値）が１〜１５ｄＬ／ｇ、好ましくは３〜１０ｄＬ／ｇ、より好ましくは５〜８ｄＬ／ｇのものを好適に用いることができる。固有粘度が低すぎると凝集汚泥の沈降速度が十分に速くならなく、また、固有粘度が高すぎると微細な濁質を十分に除去する事が出来ず、十分に透視度を改善することができなくなる。

The polymer flocculant used in the present invention has an intrinsic viscosity (measured value of a 1N NaNO ₃ aqueous solution at 30 ° C.) of 1 to 15 dL / g, preferably 3 to 10 dL / g, more preferably 5 to 8 dL / g. A thing can be used suitably. If the intrinsic viscosity is too low, the sedimentation rate of the coagulated sludge will not be sufficiently high, and if the intrinsic viscosity is too high, the fine turbidity cannot be removed sufficiently and the transparency can be improved sufficiently. Disappear.

  The amount of the polymer flocculant added varies depending on the operating conditions such as sludge concentration, amount of treated water and sludge residence time in the mixed solution in the biological treatment tank, but is usually 0.1 to 20 mg based on the mixed solution to be added. / L, preferably about 1 to 10 mg / L.

  The polymer flocculant is usually added in the form of an aqueous solution, and the concentration of the polymer in the aqueous solution is usually 0.02 to 2% by weight, preferably 0.1 to 0.6% by weight. When the polymer flocculant is an aqueous suspension or a W / O emulsion, it can be added directly to the mixed solution in the state of an aqueous suspension or a W / O emulsion.

  The addition position of the polymer flocculant is not particularly limited as long as it is a route from the biological treatment tank to the solid-liquid separation means. For example, a biological treatment tank; a communication path from the biological treatment tank to the solid-liquid separation means; It can be added within the means. Moreover, a coagulation tank can be provided and added between the biological treatment tank and the solid-liquid separation means. For example, the coagulation tank can be formed by partitioning the outlet of the biological treatment tank with a partition wall or the like.

  The addition of the polymer flocculant can be performed continuously or intermittently. Moreover, it can add when the separability of turbidity deteriorates (when a transparency degree deteriorates), or when deterioration is anticipated.

  In the present invention, the mixed liquid to which the polymer flocculant has been added is separated into a separation liquid as a treatment liquid and separated sludge by a solid-liquid separation means. As such solid-liquid separation means, for example, a solid-liquid separation device such as a sedimentation tank, a flotation separation tank, a centrifugal separator or a membrane separator can be used. In the case of using a membrane separator, a conventionally known membrane separator can be used, and the mixed liquid is circulated at a high flow rate on one side of the membrane surface using a liquid feeding means such as a pump, and the filtrate is supplied from the other side. Take out the circulating water flow caused by aeration caused by the pump circulation type cross-flow filtration type aeration device and the membrane surface, and perform filtration while preventing the concentration of suspended substances on the membrane surface. An immersion membrane separator can be used.

  In the present invention, a part of the biological sludge is extracted from the treatment system in such a biological treatment, and a reforming process is performed for reforming the extracted sludge to be easily biodegradable in the reforming treatment tank. The sludge subjected to the reforming treatment is preferably drawn out of at least a part of the separated sludge separated by the solid-liquid separation means described above, but may be sludge drawn out in a mixed liquid state from the biological treatment tank. These drawn sludges may be introduced directly into the reforming treatment step, or may be introduced into the reforming treatment step after being concentrated by a separately prepared concentration means. As the concentration means, a concentration means used for concentration of sludge such as centrifugal concentration, gravity concentration, flotation concentration and membrane separation can be appropriately used.

  When extracting from separated sludge, part or all of the part discharged as excess sludge can be extracted as extracted sludge, but in addition to the discharged excess sludge, sludge returned to the biological treatment process as return sludge. It is also possible to carry out a reforming treatment by drawing a part of the excess, whereby the generation amount of excess sludge can be further reduced. In this case, if the amount corresponding to the apparent amount of growth in the biological treatment process is extracted and reformed, the amount of excess sludge generated can be reduced to zero.

  Any method can be adopted as a reforming treatment method for reforming the extracted sludge so as to be easily decomposed by organisms. For example, modification treatment by ozone treatment, modification treatment by acid treatment, modification treatment by alkali treatment, modification treatment by high-heat bacteria, modification treatment by physical treatment such as mill, disk, ultrasonic, etc., modification by heat treatment Quality treatment, reforming treatment combining these, and the like can be employed. Among these, the modification treatment by ozone treatment is preferable because the treatment operation is simple and the treatment efficiency is high.

  Among such reforming processes, the ozone process will be described first. In the ozone treatment as the reforming treatment, the sludge extracted from the biological treatment system may be introduced into the ozone treatment tank and brought into contact with ozone, and the sludge is easily biodegradable by the oxidizing action of ozone. When the ozone treatment is performed in an acidic region having a pH of 5 or less, the oxidative decomposition efficiency is increased. The pH adjustment at this time is preferably performed by adding an inorganic acid such as sulfuric acid, hydrochloric acid or nitric acid to the biological sludge as a pH adjusting agent, adjusting the biological sludge by an acid fermentation treatment, or a combination thereof. . When adding a pH adjuster, it is preferable to adjust pH to 3-4, and when performing an acid fermentation process, it is preferable to carry out so that pH may become 4-5.

   The ozone treatment can be performed by adjusting the drawn sludge or the acid fermentation treatment solution as it is, or if necessary by concentrating it with a centrifuge, etc., and then adjusting the pH to 5 or less and bringing it into contact with ozone. As a contact method, a method of introducing sludge into an ozone treatment tank and blowing ozone, a method of mechanical stirring, a method of using a packed bed, or the like can be employed. In addition to ozone gas, ozone-containing gas such as ozone-containing air or ozonized air can be used as ozone. The amount of ozone used is 0.002 to 0.05 g-O3 / g-VSS, preferably 0.005 to 0.03 g-O3 / g-VSS. Biological sludge is oxidized and decomposed by ozone treatment and converted into BOD components.

  Next, the acid treatment as another method for modifying the extracted sludge to be easily biodegradable will be described. In the acid treatment, the extracted sludge extracted from the biological treatment system is guided to the reforming tank, and mineral acids such as hydrochloric acid and sulfuric acid are introduced. And is retained for a predetermined time under acidic conditions of pH 2.5 or less, preferably pH 1-2. The residence time is, for example, 5 to 24 hours. At this time, it is preferable to heat the sludge, for example, to 50 to 100 ° C., because the reforming is promoted. By treatment with such an acid, the sludge becomes readily biodegradable and can be easily decomposed and removed by returning it to the biological treatment system.

  Further, the alkali treatment as the sludge reforming treatment will be described. In the alkali treatment, the extracted sludge drawn from the biological treatment system is guided to the reforming tank, and the alkali such as sodium hydroxide and potassium hydroxide is reduced to 0. .1 to 1% by weight may be added and retained for a predetermined time. The residence time is about 0.5 to 2 hours, and the sludge is easily biodegradable. At this time, it is preferable to heat the sludge, for example, to 50 to 100 ° C., because the reforming is promoted.

  The heat treatment as the reforming treatment can be performed by heat treatment alone, but is preferably performed in combination with acid treatment or alkali treatment. In the case of performing the heat treatment alone, for example, the temperature can be set to 70 to 100 ° C. and the residence time can be set to 2 to 3 hours.

  The sludge that has become biodegradable by the reforming treatment by introducing the modified sludge thus modified to be easily biodegradable into the biological treatment tank is used as the BOD component in the biological treatment tank. It is decomposed by the microorganisms inside and the amount of sludge generated is reduced.

  In the sludge reforming treatment, the cell walls of microorganisms constituting the sludge are destroyed and fine turbidity is generated. In addition, microorganisms (bacteria) used in biological treatment have a sticky substance made of polysaccharides or the like on the outside of the cells, so that the bacteria adhere to each other to form a large flock and are easily separated into solid and liquid. Sludge is formed. On the other hand, in the sludge volume reduction method in which the reformed sludge is introduced into the biological treatment tank, the operation is such that excessive or little excess sludge is not extracted outside the system, and the average sludge residence time (SRT) becomes long. In this case, the above-mentioned adhesive is reduced by the self-decomposition of microorganisms, it becomes difficult to form a large floc, and it tends to flow out as a pin floc by solid-liquid separation.

  In the present invention, as described above, in order to perform solid-liquid separation by adding a polymer flocculant to the mixed liquid in the biological treatment process, it compensates for the reduction of the sticky substance, flocks the bacterial cells, and solid-liquid separation of the biological sludge. Facilitate. Furthermore, fine turbidity can be taken in by the flocculating action of the polymer flocculant and the sludge can be flocked. When a sedimentation tank or centrifuge is used as the solid-liquid separation means, the fine suspended substance in the treated water When the treated water transparency is improved by preventing the outflow and a filter or a membrane separator is employed as the solid-liquid separation means, clogging of these solid-liquid separation means can be suppressed.

  According to the present invention, in an organic wastewater treatment method and treatment apparatus for reducing sludge by reforming sludge extracted from a biological treatment process with ozone or the like and returning the modified sludge to the biological treatment process, Even when the water transparency deteriorates, the treated water transparency can be improved with a simple device and method.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a system diagram showing a method for treating organic effluent according to one embodiment, and adopts a standard activated sludge method as a biological treatment and an ozone method as a reforming treatment. In FIG. 1, 1 is an aeration tank, 2 is a precipitation tank, and 3 is a reforming tank.

  In the treatment method, the organic waste liquid as the treatment liquid is introduced into the aeration tank 1 from the treatment liquid passage 5 and the return sludge and the modified sludge are introduced from the sludge return passage 12 and the modified sludge return passage 14, respectively. Then, aeration is performed by aeration of air from the aeration device 7, and aerobic treatment is performed in the presence of aerobic microorganisms. Specific processing conditions such as aeration conditions are the same as those for normal aerobic processing.

  The liquid mixture in the aeration tank 1 is introduced into the sedimentation tank 2 via the transfer path 8, and the polymer flocculant 4 is continuously added along the transfer path 8. The mixed liquid to which the polymer flocculant has been added is agglomerated by the polymer flocculant while being transferred through the transfer path 8, and is solid-liquid separated into the separated sludge and the separated liquid in the precipitation tank 2. Is discharged from the processing liquid passage 9 as a processing liquid. The separated sludge is taken out from the sludge take-out path 10, a part is introduced into the reforming tank 3 from the sludge extraction path 11, and the remaining part is returned from the sludge return path 12 to the aeration tank 1. In the reforming tank 3, ozone is diffused from the air diffuser 13 to perform reforming treatment by ozone treatment, and a part of the biological sludge is reformed to be easily biodegradable. The modified sludge is returned to the aeration tank 1 from the modified sludge return path 14.

  In the above embodiment, a part of the separated sludge separated in the sedimentation tank 2 is introduced into the reforming tank 3, but is introduced into the reforming tank 3 from the aeration tank 1 via the mixed liquid extraction path 15. You may do it.

  Moreover, in the said embodiment, although the polymer flocculent 4 is added to the liquid mixture by the transfer path 8 which connects the aeration tank 1 and the precipitation tank 2, the coagulation tank 6 is provided separately like FIG. Here, the polymer flocculant 4 may be added. By providing the agglomeration tank 6 in this manner, the polymer flocculant can be effectively diffused and flocked, so that the polymer flocculant can be used efficiently.

  EXAMPLES Next, although an Example demonstrates this invention further in detail, this invention is not limited at all by these examples.

  Table 1 shows polymer flocculants used in Examples and Comparative Examples. A-1 to A-4, B and E are prepared by dissolving the monomer in pure water, adding 2,2′-azobis (2-amidinopropane) dihydrochloride as an initiator and heating in a nitrogen atmosphere. Then, solution polymerization was performed, and the polymer solution obtained was dried and pulverized. C was obtained by seed polymerization of a monomer in an aqueous solution of ammonium sulfate having a concentration of 20% by weight, and was obtained as an aqueous polymer dispersion (dispersion) having a polymer concentration of 20% by weight. . Then, D is polymerized by dissolving the monomer in pure water, adding 2,2′-azobis (2-amidinopropane) dihydrochloride as an initiator and heating in a nitrogen atmosphere. A suspension obtained by adding hydrochloric acid to the precipitated suspension and amidating it was used. In addition, after melt | dissolving all the polymer flocculants so that it might become 0.1 weight% in conversion of a pure part, it used for experiment below.

注）１）ＤＡＡ：アクリロイルオキシエチルトリメチルアンモニウムクロリド（前記式［１］において、Ｒ^１が水素、Ｒ^２〜Ｒ^４がメチル基、Ｘが酸素、ＹがＣＨ_２ＣＨ_２、Ｚが塩素のアクリル系カチオン単量体）
２）ＡＡｍ：アクリルアミド
３）ＤＡＭ：メタクリロイルオキシエチルトリメチルアンモニウムクロリド（前記式［１］において、Ｒ^１がメチル基、Ｒ^２〜Ｒ^４がメチル基、Ｘが酸素、ＹがＣＨ_２ＣＨ_２、Ｚが塩素のメタクリル系カチオン単量体）
４）ＤＡＡＢｚ：アクリロイルオキシエチルジメチルベンジルアンモニウムクロリド（前記式［１］において、Ｒ^１が水素、Ｒ^２およびＲ^３がメチル基、Ｒ^４がベンジル基、Ｘが酸素、ＹがＣＨ_２ＣＨ_２、Ｚが塩素のアクリル系カチオン単量体）
５）ポリアミジン：アクリルニトリル５０ｍｏｌ％とＮ−ビニルホルムアミド５０ｍｏｌ％との共重合物を塩酸で変性したもの。コロイド当量値は４．８ｍｅｑ．／ｇ
６）ＤＡＤＭＡＣ：ジアリルジメチルアンモニウムクロリド
７）［η］：Ａ−１〜Ａ−４、ＢおよびＥは３０℃、１Ｎ−ＮａＮＯ_３で測定した固有粘度であり、Ｃは３０℃、０．１Ｎ−ＮａＮＯ_３で測定した固有粘度で、Ｄは３０℃、１Ｎ−ＮａＣｌで測定した固有粘度である。
〔実験例１〕

Note) 1) DAA: acryloyloxyethyltrimethylammonium chloride (in the above formula [1], R ¹ is hydrogen, R ^{2 to} R ⁴ are methyl groups, X is oxygen, Y is CH ₂ CH ₂ , and Z is chlorine) Cationic monomer)
2) AAm: Acrylamide 3) DAM: Methacryloyloxyethyltrimethylammonium chloride (in the above formula [1], R ¹ is a methyl group, R ^{2 to} R ⁴ are methyl groups, X is oxygen, Y is CH ₂ CH ₂ , Z Is a methacrylic cationic monomer of chlorine)
4) DAABz: acryloyloxyethyldimethylbenzylammonium chloride (in the above formula [1], R ¹ is hydrogen, R ² and R ³ are methyl groups, R ⁴ is a benzyl group, X is oxygen, Y is CH ₂ CH ₂ , Acrylic cationic monomer with Z as chlorine)
5) Polyamidine: a product obtained by modifying a copolymer of 50 mol% acrylonitrile and 50 mol% N-vinylformamide with hydrochloric acid. The colloid equivalent value is 4.8 meq. / G
6) DADMAC: diallyldimethylammonium chloride 7) [η]: A-1 to A-4, B and E are intrinsic viscosities measured at 30 ° C. and 1N—NaNO ₃ , C is 30 ° C., 0.1 N— It is an intrinsic viscosity measured with NaNO ₃ , and D is an intrinsic viscosity measured at 30 ° C. and 1N-NaCl.
[Experimental Example 1]

  A predetermined amount of polymer flocculant is added to 100 mL of aeration tank sludge at the A sewage treatment plant that employs the flow shown in FIG. Dilute and transfer to a 1 L graduated cylinder (65 mm in diameter, 300 mm in height), gently mix and agitate, immediately after standing, measure the sedimentation rate of the aggregated flocs, and after 30 minutes have passed, Turbidity was measured. The results are shown in Table 2.

以上の結果より、高分子凝集剤を添加することで上澄濁度は改善されることがわかる。特に、（メタ）アクリロイルオキシエチレントリメチルアンモニウムクロリド２０〜５０ｍｏｌ％とアクリルアミド５０〜８０ｍｏｌ％との共重合物であるＡ−２、Ａ−３およびＢの上澄濁度改善効果が高いことがわかる。なお、上澄濁度は、沈降分離し難い微小懸濁物の濃度と相関があり、上澄濁度の高い改善効果は、微小懸濁物質の高い凝集性を示している。
〔実験例２〕

From the above results, it is understood that the supernatant turbidity is improved by adding the polymer flocculant. In particular, it can be seen that the effect of improving the turbidity of supernatants of A-2, A-3 and B, which are copolymers of 20 to 50 mol% of (meth) acryloyloxyethylenetrimethylammonium chloride and 50 to 80 mol% of acrylamide, is high. The supernatant turbidity correlates with the concentration of a microsuspension that is difficult to settle and separate, and the effect of improving the supernatant turbidity indicates a high cohesiveness of the microsuspended material.
[Experiment 2]

  In the A sewage treatment plant where sludge was collected in Experimental Example 1, the polymer flocculant A-2 was added to the mixed solution from the aeration tank in the transfer path 8 connecting the aeration tank 1 to the settling tank 2 as shown in FIG. It was continuously added to 5 mg / L and operated for 1 year. Before the addition of the polymer flocculant, the transparency of the treated water was 20 to 30 cm, but after the addition, the transparency of the treated water was 50 to 80 cm. I found it improved.

  The organic wastewater treatment method and treatment apparatus according to the present invention has high water quality such as transparency of treated water in biological treatment of organic wastewater such as sewage, human waste, landfill leachate, food factory wastewater, and chemical factory wastewater. The amount of sludge generation can be reduced while maintaining.

Organic drainage treatment apparatus in an embodiment of the present invention Organic drainage treatment apparatus in another embodiment of the present invention

Explanation of symbols

1 Aeration tank 2 Settling tank 3 Reforming tank 6 Coagulation tank

Claims (4)

A biological treatment tank for treating organic wastewater with microorganisms, a polymer flocculant addition means for adding a polymer flocculant to the liquid mixture from the biological treatment tank, and a liquid mixture to which the polymer flocculant has been added as sludge. A solid-liquid separation unit that separates into a treatment liquid, a reforming unit that modifies at least a part of the sludge separated by the solid-liquid separation unit and / or a sludge drawn from the biological treatment tank to be easily biodegradable; An organic wastewater treatment apparatus comprising a modified sludge return means for returning quality sludge to a biological treatment tank. 2. The polymer flocculant according to claim 1, wherein the polymer flocculant is composed of 20-50 mol% of a (meth) acrylic cationic monomer represented by the following formula [1] and 50-80 mol% of a nonionic monomer. An organic drainage treatment apparatus characterized by being a polymer.

(In the formula [1], R ¹ is a hydrogen atom or a methyl group, R ² and R ³ are each independently a methyl group or an ethyl group, R ⁴ is a hydrogen atom, a methyl group, an ethyl group or a benzyl group, and X is an oxygen atom. NH or Y is an alkylene group or hydroxyalkylene group having 2 to 4 carbon atoms, and Z is a counter anion.) A biological treatment process for treating organic wastewater with microorganisms, a polymer flocculant addition process for adding a polymer flocculant to the mixed liquid from the biological treatment process, and a liquid mixture to which the polymer flocculant is added as sludge A solid-liquid separation step for separating into a treatment liquid, a reforming step for reforming at least a part of the sludge separated into solid and liquid and / or a sludge extracted from a biological treatment step to biodegradability, and a modified sludge An organic drainage treatment method comprising a modified sludge return step for returning to a biological treatment step. 4. The polymer flocculant according to claim 3, wherein the polymer flocculant is composed of 20-50 mol% of a (meth) acrylic cationic monomer represented by the following formula [1] and 50-80 mol% of a nonionic monomer. An organic drainage treatment method, which is a polymer.

(In the formula [1], R ¹ is a hydrogen atom or a methyl group, R ² and R ³ are each independently a methyl group or an ethyl group, R ⁴ is a hydrogen atom, a methyl group, an ethyl group or a benzyl group, and X is an oxygen atom. NH or Y is an alkylene group or hydroxyalkylene group having 2 to 4 carbon atoms, and Z is a counter anion.)

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