JPH0679713B2 - Biological treatment method of organic wastewater - Google Patents
Biological treatment method of organic wastewaterInfo
- Publication number
- JPH0679713B2 JPH0679713B2 JP2068460A JP6846090A JPH0679713B2 JP H0679713 B2 JPH0679713 B2 JP H0679713B2 JP 2068460 A JP2068460 A JP 2068460A JP 6846090 A JP6846090 A JP 6846090A JP H0679713 B2 JPH0679713 B2 JP H0679713B2
- Authority
- JP
- Japan
- Prior art keywords
- sludge
- treatment
- neutral
- treatment step
- nitrification
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Lifetime
Links
- 238000000034 method Methods 0.000 title claims description 48
- 239000002351 wastewater Substances 0.000 title claims description 19
- 239000010802 sludge Substances 0.000 claims description 62
- 230000007935 neutral effect Effects 0.000 claims description 36
- 239000010865 sewage Substances 0.000 claims description 4
- 238000003672 processing method Methods 0.000 claims 1
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 22
- OKKJLVBELUTLKV-UHFFFAOYSA-N Methanol Chemical compound OC OKKJLVBELUTLKV-UHFFFAOYSA-N 0.000 description 15
- 238000005273 aeration Methods 0.000 description 14
- 238000006243 chemical reaction Methods 0.000 description 13
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 10
- 244000005700 microbiome Species 0.000 description 10
- 238000004062 sedimentation Methods 0.000 description 10
- 241000894006 Bacteria Species 0.000 description 9
- HEMHJVSKTPXQMS-UHFFFAOYSA-M Sodium hydroxide Chemical compound [OH-].[Na+] HEMHJVSKTPXQMS-UHFFFAOYSA-M 0.000 description 9
- 230000018044 dehydration Effects 0.000 description 7
- 238000006297 dehydration reaction Methods 0.000 description 7
- 239000000852 hydrogen donor Substances 0.000 description 7
- 239000007788 liquid Substances 0.000 description 7
- XKMRRTOUMJRJIA-UHFFFAOYSA-N ammonia nh3 Chemical compound N.N XKMRRTOUMJRJIA-UHFFFAOYSA-N 0.000 description 6
- 210000002700 urine Anatomy 0.000 description 6
- JVMRPSJZNHXORP-UHFFFAOYSA-N ON=O.ON=O.ON=O.N Chemical compound ON=O.ON=O.ON=O.N JVMRPSJZNHXORP-UHFFFAOYSA-N 0.000 description 5
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 5
- 238000002474 experimental method Methods 0.000 description 5
- 229910052757 nitrogen Inorganic materials 0.000 description 5
- 239000001301 oxygen Substances 0.000 description 5
- 229910052760 oxygen Inorganic materials 0.000 description 5
- QGZKDVFQNNGYKY-UHFFFAOYSA-N Ammonia Chemical compound N QGZKDVFQNNGYKY-UHFFFAOYSA-N 0.000 description 4
- IOVCWXUNBOPUCH-UHFFFAOYSA-M Nitrite anion Chemical compound [O-]N=O IOVCWXUNBOPUCH-UHFFFAOYSA-M 0.000 description 4
- 230000000694 effects Effects 0.000 description 4
- 238000000926 separation method Methods 0.000 description 4
- 238000005119 centrifugation Methods 0.000 description 3
- 239000003795 chemical substances by application Substances 0.000 description 3
- 230000000241 respiratory effect Effects 0.000 description 3
- ZPLCXHWYPWVJDL-UHFFFAOYSA-N 4-[(4-hydroxyphenyl)methyl]-1,3-oxazolidin-2-one Chemical compound C1=CC(O)=CC=C1CC1NC(=O)OC1 ZPLCXHWYPWVJDL-UHFFFAOYSA-N 0.000 description 2
- 241000193830 Bacillus <bacterium> Species 0.000 description 2
- CURLTUGMZLYLDI-UHFFFAOYSA-N Carbon dioxide Chemical compound O=C=O CURLTUGMZLYLDI-UHFFFAOYSA-N 0.000 description 2
- 241000589565 Flavobacterium Species 0.000 description 2
- NBIIXXVUZAFLBC-UHFFFAOYSA-N Phosphoric acid Chemical compound OP(O)(O)=O NBIIXXVUZAFLBC-UHFFFAOYSA-N 0.000 description 2
- CDBYLPFSWZWCQE-UHFFFAOYSA-L Sodium Carbonate Chemical compound [Na+].[Na+].[O-]C([O-])=O CDBYLPFSWZWCQE-UHFFFAOYSA-L 0.000 description 2
- MMDJDBSEMBIJBB-UHFFFAOYSA-N [O-][N+]([O-])=O.[O-][N+]([O-])=O.[O-][N+]([O-])=O.[NH6+3] Chemical compound [O-][N+]([O-])=O.[O-][N+]([O-])=O.[O-][N+]([O-])=O.[NH6+3] MMDJDBSEMBIJBB-UHFFFAOYSA-N 0.000 description 2
- 239000002253 acid Substances 0.000 description 2
- 229910021529 ammonia Inorganic materials 0.000 description 2
- 230000001580 bacterial effect Effects 0.000 description 2
- 238000010586 diagram Methods 0.000 description 2
- -1 methanol Chemical compound 0.000 description 2
- 230000000813 microbial effect Effects 0.000 description 2
- QJGQUHMNIGDVPM-UHFFFAOYSA-N nitrogen group Chemical group [N] QJGQUHMNIGDVPM-UHFFFAOYSA-N 0.000 description 2
- 230000003647 oxidation Effects 0.000 description 2
- 238000007254 oxidation reaction Methods 0.000 description 2
- 239000003002 pH adjusting agent Substances 0.000 description 2
- 238000001556 precipitation Methods 0.000 description 2
- 239000000126 substance Substances 0.000 description 2
- OYPRJOBELJOOCE-UHFFFAOYSA-N Calcium Chemical compound [Ca] OYPRJOBELJOOCE-UHFFFAOYSA-N 0.000 description 1
- 229910021578 Iron(III) chloride Inorganic materials 0.000 description 1
- FYYHWMGAXLPEAU-UHFFFAOYSA-N Magnesium Chemical compound [Mg] FYYHWMGAXLPEAU-UHFFFAOYSA-N 0.000 description 1
- 229910002651 NO3 Inorganic materials 0.000 description 1
- NHNBFGGVMKEFGY-UHFFFAOYSA-N Nitrate Chemical compound [O-][N+]([O-])=O NHNBFGGVMKEFGY-UHFFFAOYSA-N 0.000 description 1
- 241000589516 Pseudomonas Species 0.000 description 1
- VGPSUIRIPDYGFV-UHFFFAOYSA-N [N].O[N+]([O-])=O Chemical compound [N].O[N+]([O-])=O VGPSUIRIPDYGFV-UHFFFAOYSA-N 0.000 description 1
- 239000003513 alkali Substances 0.000 description 1
- 229910000147 aluminium phosphate Inorganic materials 0.000 description 1
- 229920001222 biopolymer Polymers 0.000 description 1
- 230000003139 buffering effect Effects 0.000 description 1
- 239000011575 calcium Substances 0.000 description 1
- 229910052791 calcium Inorganic materials 0.000 description 1
- AXCZMVOFGPJBDE-UHFFFAOYSA-L calcium dihydroxide Chemical compound [OH-].[OH-].[Ca+2] AXCZMVOFGPJBDE-UHFFFAOYSA-L 0.000 description 1
- 239000000920 calcium hydroxide Substances 0.000 description 1
- 229910001861 calcium hydroxide Inorganic materials 0.000 description 1
- 235000011116 calcium hydroxide Nutrition 0.000 description 1
- 150000001722 carbon compounds Chemical class 0.000 description 1
- 239000001569 carbon dioxide Substances 0.000 description 1
- 229910002092 carbon dioxide Inorganic materials 0.000 description 1
- 230000001143 conditioned effect Effects 0.000 description 1
- 238000007796 conventional method Methods 0.000 description 1
- 230000007423 decrease Effects 0.000 description 1
- 230000003247 decreasing effect Effects 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 238000007429 general method Methods 0.000 description 1
- 239000003673 groundwater Substances 0.000 description 1
- 239000010800 human waste Substances 0.000 description 1
- RBTARNINKXHZNM-UHFFFAOYSA-K iron trichloride Chemical compound Cl[Fe](Cl)Cl RBTARNINKXHZNM-UHFFFAOYSA-K 0.000 description 1
- 239000011777 magnesium Substances 0.000 description 1
- 229910052749 magnesium Inorganic materials 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 239000012528 membrane Substances 0.000 description 1
- 230000001546 nitrifying effect Effects 0.000 description 1
- 230000001590 oxidative effect Effects 0.000 description 1
- 230000036284 oxygen consumption Effects 0.000 description 1
- 238000010979 pH adjustment Methods 0.000 description 1
- 239000007793 ph indicator Substances 0.000 description 1
- 229920000642 polymer Polymers 0.000 description 1
- 239000002244 precipitate Substances 0.000 description 1
- 239000000047 product Substances 0.000 description 1
- 239000002893 slag Substances 0.000 description 1
- 229910000029 sodium carbonate Inorganic materials 0.000 description 1
- 241000894007 species Species 0.000 description 1
- 238000004065 wastewater treatment Methods 0.000 description 1
Classifications
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02W—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO WASTEWATER TREATMENT OR WASTE MANAGEMENT
- Y02W10/00—Technologies for wastewater treatment
- Y02W10/10—Biological treatment of water, waste water, or sewage
Landscapes
- Activated Sludge Processes (AREA)
Description
【発明の詳細な説明】 〔産業上の利用分野〕 本発明は、有機性汚水の処理方法に係り、特に、有機性
廃水の余剰汚泥量が少なく、かつ汚泥脱水性の良好なる
生物学的処理方法に関する。Description: TECHNICAL FIELD The present invention relates to a method for treating organic wastewater, and particularly to a biological treatment in which the amount of excess sludge in organic wastewater is small and sludge dewaterability is good. Regarding the method.
従来、有機性廃水の処理方法としては、生物学的処理が
最も普遍的な方法として採用され、広く普及している。
しかしながら、この方法では、多量の余剰汚泥が発生
し、その処分が問題となっている。Conventionally, biological treatment has been adopted as the most general method for treating organic wastewater, and is widely used.
However, with this method, a large amount of excess sludge is generated, and its disposal is a problem.
すなわち、有機性廃水が、生物学的処理工程へ導かれて
生物処理を受け、沈殿池にて活性汚泥が分離される。そ
して、余剰汚泥として引抜かれた汚泥は、脱水工程にお
いて、高分子凝集剤又は塩化第２鉄や消石灰などが添加
され、ベルトプレス、遠心脱水機、フィルタプレスなど
で機械脱水される。しかしながら、従来の生物処理工程
から排出される余剰汚泥の脱水性はきわめて悪く、ま
た、汚泥生成量も多いため、その処分に要するコストも
高額となる。That is, the organic wastewater is guided to a biological treatment process and subjected to biological treatment, and activated sludge is separated in a sedimentation tank. The sludge drawn out as excess sludge is added with a polymer flocculant, ferric chloride, slaked lime, or the like in the dehydration step, and mechanically dehydrated with a belt press, a centrifugal dehydrator, a filter press, or the like. However, the dehydration property of the excess sludge discharged from the conventional biological treatment process is extremely poor, and the amount of sludge generated is large, so that the cost required for its disposal is also high.
また、曝気槽の汚泥濃度を、10,000mg/l以上の高濃度で
運転する場合には、沈殿池での汚泥分離が容易でないた
め、遠心分離、UF膜などの機械的分離操作を利用するの
が一般的であった。In addition, when operating the sludge concentration in the aeration tank at a high concentration of 10,000 mg / l or more, it is not easy to separate sludge in the sedimentation tank, so use a mechanical separation operation such as centrifugation or UF membrane. Was common.
本発明は、前記のような従来技術の課題を解決し、有機
性汚水の処理において、余剰汚泥の脱水性のよい、ま
た、その生成量も少ない生物学的処理方法を提供するこ
とを目的とする。An object of the present invention is to solve the above-mentioned problems of the prior art and to provide a biological treatment method in which, in the treatment of organic sewage, the excess sludge has a good dewatering property and the production amount thereof is small. To do.
上記目的を達成するために、本発明では、有機性汚水
を、少なくともアルカリ性条件下での生物学的処理工程
と、中性条件下での生物学的処理工程との二工程によっ
て処理することを特徴とする有機性汚水の処理方法とし
たものである。In order to achieve the above object, in the present invention, the organic wastewater is treated by two steps of at least a biological treatment step under alkaline conditions and a biological treatment step under neutral conditions. This is a characteristic organic wastewater treatment method.
また、本発明では、有機性汚水を、少なくともアルカリ
性条件下での生物学的処理工程によって処理したのち、
中性条件下での生物学的処理工程で処理することを特徴
とする有機性汚水の処理方法としたものである。Further, in the present invention, after treating the organic wastewater by a biological treatment step under at least alkaline conditions,
This is a method for treating organic sewage, which is characterized by treatment in a biological treatment step under neutral conditions.
上記処理方法において、中性条件下での生物学的処理工
程で発生する余剰汚泥の少なくとも一部を、アルカリ条
件下での生物学的処理工程に導くのがよい。In the above treatment method, at least a part of the excess sludge generated in the biological treatment step under neutral conditions is preferably introduced into the biological treatment step under alkaline conditions.
また、上記処理方法において、アルカリ性条件下として
は、pH8.5〜11好ましくは９〜10で行うのがよく、ま
た、中性条件下としては、pH6.5〜８で行うのがよい。In the above treatment method, it is preferable to carry out under alkaline conditions at pH 8.5 to 11 and preferably at pH 9 to 10, and under neutral conditions at pH 6.5 to 8.
次に、本発明を図面を参照にして詳細に説明する。Next, the present invention will be described in detail with reference to the drawings.
第１図は、本発明の一例を示すフロー概略図である。FIG. 1 is a schematic flow chart showing an example of the present invention.
第１図において、有機性廃水１は、返送汚泥２ととも
に、高pH（アルカリ性）処理工程５の曝気槽６に流入す
る。曝気槽６はpH8.5以上に維持されており、ここで、
原水中のBODは、BOD酸化菌の作用により酸化され、沈殿
池７にて固液分離される。残部BOD成分を含む沈殿池７
からの越流水は、返送汚泥３とともに、pH中性処理工程
８の曝気槽９に流入し、ここで完全にBOD成分を除去
し、沈殿池10にて固液分離された後、放流水17として放
流される。In FIG. 1, the organic wastewater 1 flows into the aeration tank 6 of the high pH (alkaline) treatment step 5 together with the returned sludge 2. The aeration tank 6 is maintained at pH 8.5 or above, where
BOD in the raw water is oxidized by the action of BOD-oxidizing bacteria, and solid-liquid separated in the settling tank 7. Sedimentation basin 7 containing the remaining BOD components
The effluent from the effluent flows into the aeration tank 9 of the pH neutral treatment step 8 together with the returned sludge 3 where the BOD component is completely removed and solid-liquid separation is carried out in the settling tank 10 and then the effluent 17 Released as.
余剰汚泥は、高pH処理工程５およびpH中性処理工程８の
各々の沈殿池７、10から、別々に排泥しても構わない
が、pH中性処理工程８の沈殿池10から、高pH処理工程５
の曝気槽６へ汚泥を返送する工程４を設け、高pH処理工
程５とpH中性処理工程８への汚泥返送量を調整すること
で、高pH処理工程５の沈殿池７のみから排泥しても良
い。高pH処理工程から排出される汚泥は、脱水性、沈降
性に優れ、また汚泥発生量も、従来のpH中性域の生物処
理に比べて20〜40％少ないことから、特に高濃度の有機
物を含む廃水の生物処理には、汚泥処理の面から著しい
改善をもたらすものである。Excess sludge may be discharged separately from the settling basins 7 and 10 of the high pH treatment step 5 and the pH neutral treatment step 8, respectively. pH treatment step 5
By providing step 4 for returning sludge to the aeration tank 6 of the above and adjusting the amount of sludge returned to the high pH treatment step 5 and the pH neutral treatment step 8, the sludge is discharged only from the settling basin 7 of the high pH treatment step 5. You may. The sludge discharged from the high pH treatment process has excellent dehydration and sedimentation properties, and the sludge generation amount is 20 to 40% less than conventional biological treatment in the neutral pH range. The biological treatment of wastewater containing slag brings significant improvements in terms of sludge treatment.
高pH処理工程から排出される汚泥の脱水性が優れている
理由は、現時点では明らかではないが、次のような理由
が考えられる。高pH処理工程では、廃水中に含まれる
マグネシウム、カルシウム、リン酸、溶存二酸化炭素等
が、不溶性の沈殿物を生じるため、これらが脱水助剤と
して作用している。高pH処理工程に出現する微生物群
は、従来のpH中性処理の微生物群とは異なり、脱水性に
優れた特質を有する。高pH条件では、微生物表面の親
水性バイオポリマが液側に溶出してしまうため、結果と
して脱水性が向上する。The reason why the sludge discharged from the high pH treatment process is excellent in dewatering property is not clear at present, but the following reasons are considered. In the high pH treatment step, magnesium, calcium, phosphoric acid, dissolved carbon dioxide and the like contained in the waste water produce an insoluble precipitate, and these act as a dehydration aid. The microorganism group appearing in the high pH treatment step has a characteristic of being excellent in dehydration, unlike the microorganism group of the conventional pH neutral treatment. Under high pH conditions, the hydrophilic biopolymer on the surface of the microorganisms elutes to the liquid side, resulting in improved dehydration.
これらのうち、については、汚泥の沈降性にも関与し
ていると思われる。第３図はpHの異なる条件で馴養した
汚泥の沈降速度変化を示すグラフである。第３図の汚泥
沈降曲線から明らかなように、高pH条件で馴養した汚泥
は、高濃度であるにもかかわらず、沈降性は良好で、遠
心分離等の機械的濃縮操作を利用せずに容易に固液分離
できる。Of these, it seems that sludge sedimentation is also involved. FIG. 3 is a graph showing changes in sedimentation speed of sludge acclimated under different pH conditions. As is clear from the sludge settling curve in Fig. 3, sludge acclimated under high pH conditions has a high settling property, despite its high concentration, and without using mechanical concentration operations such as centrifugation. Solid-liquid separation can be performed easily.
第４図は、高pH処理工程のpHを変化させた場合の汚泥発
生量と含水率との関係を示すグラフである。図から明ら
かなように、pH8.5を境に高pHになるほど含水率および
汚泥発生量ともに減少し、高pH処理の有効性が確認され
た。FIG. 4 is a graph showing the relationship between the sludge generation amount and the water content when the pH in the high pH treatment step is changed. As is clear from the figure, both the water content and the amount of sludge produced decreased with increasing pH at pH 8.5, confirming the effectiveness of high pH treatment.
次に、本発明の他の一例を示すフロー概略図である第２
図について説明する。Next, it is a second schematic flow diagram showing another example of the present invention.
The figure will be described.
第２図において、窒素含有有機性廃水１は、返送汚泥２
とともに脱窒槽18に流入する。硝化槽19はpH8.5以上に
維持されており、ここで原水中のアンモニア態窒素は硝
化菌の作用により硝化されるが、高pHのため硝酸態窒素
はほとんど生成されず、亜硝酸態窒素が蓄積する。この
際、原水中に高濃度のアンモニア態窒素を含有する廃水
の場合、長期間高濃度の遊離アンモニアに汚泥がさらさ
れると、硝化活性が失活する場合もあるので、後続のpH
中性処理工程８からの返送汚泥の一部を、高pH処理工程
の脱窒槽18に返送することで、安定的に硝化反応が進行
する。In FIG. 2, the nitrogen-containing organic wastewater 1 is the returned sludge 2
Together with this, it flows into the denitrification tank 18. The pH of the nitrification tank 19 is maintained at 8.5 or higher, where ammonia nitrogen in the raw water is nitrified by the action of nitrifying bacteria, but nitric acid nitrogen is hardly produced due to the high pH, and nitrite nitrogen is not generated. Accumulates. At this time, in the case of wastewater containing a high concentration of ammonia nitrogen in the raw water, if the sludge is exposed to a high concentration of free ammonia for a long period of time, the nitrification activity may be inactivated, so the subsequent pH
By returning a part of the sludge returned from the neutral treatment step 8 to the denitrification tank 18 in the high pH treatment step, the nitrification reaction proceeds stably.
生成された循環硝化液23中の亜硝酸態窒素は、原水中の
BOD成分を水素供与体として、脱窒槽18で脱窒される。
残部のアンモニア態窒素は、後続の中性処理工程８にお
いて、残部BODとともに酸化され、脱窒槽21においてメ
タノール24を水素供与体として完全に除去される。脱窒
液は再曝気槽22、沈殿池10を経由して放流される。な
お、原水中のアンモニア態窒素の濃度が低い場合には、
必ずしもpH中性処理工程から汚泥を返送する必要はな
い。The nitrite nitrogen in the produced circulating nitrification liquid 23 is
It is denitrified in the denitrification tank 18 using the BOD component as a hydrogen donor.
In the subsequent neutral treatment step 8, the balance of ammonia nitrogen is oxidized together with the balance of BOD, and methanol 24 is completely removed in the denitrification tank 21 as a hydrogen donor. The denitrification liquid is discharged via the re-aeration tank 22 and the settling tank 10. If the concentration of ammonia nitrogen in the raw water is low,
It is not always necessary to return the sludge from the pH neutral treatment process.
なお、前記の説明は、アルカリ条件下で処理したのち、
中性条件下で処理しているが、中性条件下での処理をし
たのち、アルカリ条件下での処理をするようにしてもよ
い。In addition, the above description, after treating under alkaline conditions,
Although the treatment is carried out under neutral conditions, the treatment may be carried out under alkaline conditions after the treatment under neutral conditions.
BODや窒素分の生物学的除去技術は、通常pH中性付近の
条件で行なわれていた。これは、BOD酸化やアンモニア
態窒素の硝化（酸化）、さらにはNOx（亜硝酸態窒素、
硝酸態窒素）の脱窒に関与する微生物の至適pHが一般に
中性付近に存在するためである。BOD and nitrogen bioremoval techniques were usually carried out under conditions near pH neutrality. This is BOD oxidation and nitrification (oxidation) of ammonia nitrogen, and further NOx (nitrite nitrogen,
This is because the optimum pH of microorganisms involved in the denitrification of (nitrate nitrogen) is generally near neutral.
特に硝化反応は、炭素化合物を酸化する場合と異なり、
（１）式に示されるように、アンモニア１当量に対し
て、２当量のH+を生じる生酸反応である。硝化の進行に
伴ないpHは徐々に低下し、pH5程度では硝化反応はほと
んど停止する。そのため、順調な硝化反応を維持するた
めには、硝化槽のpHを中性に維持しなければならない。Especially, the nitrification reaction is different from the case of oxidizing carbon compounds,
As shown in the formula (1), this is a reaction of a raw acid which produces 2 equivalents of H + with respect to 1 equivalent of ammonia. The pH gradually decreases with the progress of nitrification, and the nitrification reaction almost stops at about pH 5. Therefore, in order to maintain a smooth nitrification reaction, the pH of the nitrification tank must be kept neutral.
硝化・脱窒の反応過程を化学量論的に表わすと、次式の
ようになる。The reaction process of nitrification and denitrification is stoichiometrically expressed as follows.
NH4 +＋1.5O2→NO2 -＋H2O＋2H+ …亜硝酸菌（１） NO2 -＋0.5O2→NO3 - …硝酸菌（２） 〔脱窒反応（嫌気的条件）〕 NO3 -＋H2→NO2 -＋H2O …脱窒菌（３） NO2 -＋1.5H2→0.5N2↑＋H2O＋OH-…脱窒菌（４） 硝化工程では、通常アンモニア態窒素を硝酸態窒素にま
で硝化しているが、上記（１）〜（４）式からわかるよ
うに、硝化には酸素、脱窒には水素供与体の供給が必要
となるため、硝酸態窒素にまで硝化することは、亜硝酸
窒素への硝化にとどめる場合に比べて、多くの酸素供給
動力費、メタノール等の水素供与体、pH調整用の薬品代
など、有価な工業製品を消費することになり、運転経費
のうえから大きな問題となっている。特に、生し尿等の
多量の窒素分を含有する廃水を処理する場合には、その
経済的デメリットは大きい。したがって、硝化を、亜硝
酸窒素でとどめて脱窒処理する方が、硝化のための酸素
供給量、脱窒のための水素供与体供給量ともに少なくて
済み、運転経費の点で有利である。すなわち、NO2型硝
化の酸素量はNO3型硝化の3/4（1.5O2／2O2）で済み、ま
た、脱窒反応で消費される水素供与体量も、NO2はNO3の
3/5（1.5H2／2.5H2）で足りる。NH 4 + ＋ 1.5O 2 → NO 2 − ＋ H 2 O ＋ 2H + … Nitrite bacteria (1) NO 2 – ＋ 0.5O 2 → NO 3 – … nitrite bacteria (2) [Denitrification reaction (anaerobic condition)] NO 3 - + H 2 → NO 2 - + H 2 O ... denitrifying bacteria (3) NO 2 - + 1.5H 2 → 0.5N 2 ↑ + H 2 O + OH - ... the denitrifying bacteria (4) nitrification step, nitrate normal ammonium nitrogen Nitrification is performed up to nitrogen, but as can be seen from the above formulas (1) to (4), oxygen is required for nitrification, and a hydrogen donor is required for denitrification. Therefore, nitrification is performed up to nitrate nitrogen. Compared with the case of only nitrification to nitrogen nitrite, it consumes a lot of power supply cost of oxygen, hydrogen donor such as methanol, cost of chemicals for pH adjustment, and valuable industrial products. It is a big problem because of the expense. In particular, when treating wastewater containing a large amount of nitrogen such as raw urine, its economic demerits are great. Therefore, it is more advantageous to limit the nitrification with nitrogen nitrite and perform the denitrification treatment, since both the oxygen supply amount for nitrification and the hydrogen donor supply amount for denitrification are smaller, and the operating cost is lower. That is, the amount of oxygen NO 2 type nitrification requires only 3/4 of the NO 3 type nitrification (1.5O 2 / 2O 2), also hydrogen donor amount consumed by denitrification reactions, NO 2 is the NO 3
3/5 (1.5H 2 /2.5H 2 ) is enough.
自然界には、高pH（アルカリ性）域の生息条件を好む微
生物が多数存在する。第５図は、5lの反応槽を用いて、
１か月間、回分的に生し尿を添加し、pH7およびpH10のp
H条件で曝気した際の、微生物呼吸活性を調べたグラフ
である。In nature, there are many microorganisms that prefer habitat conditions in high pH (alkaline) regions. Fig. 5 shows the results of using a 5 liter reaction vessel.
For one month, add raw urine in batches, add pH 7 and pH 10
It is a graph which investigated the microbial respiratory activity at the time of aeration under H condition.
第５図から明らかなように、pH10の条件でも、pH7系と
同等の呼吸活性があり、耐アルカリ性の微生物が出現し
ているのではなく、好アルカリ性の微生物が優占してい
ることがわかる。また、pH7の肉汁培地とpH10の肉汁培
地（１％炭酸ナトリウム添加）をそれぞれ調整し、各汚
泥中の細菌相を調べたところ、pH7の培地では、バチル
ス（Bacillus）属やシュードモナス（Pseudomonas）属
等が優占種として出現したが、pH10では黄色のコロニー
を生じるフラボバクテリウム（Flavobacterium）属が特
徴的に出現し、pH7系とは異なる細菌相を示した。一般
に、好アルカリ性細菌としては、バチルス（Bacillus）
属が高頻度に出現すると言われているが、生し尿を原水
として馴養した汚泥の場合、そのような傾向は認められ
なかった。As is clear from FIG. 5, even under the condition of pH 10, the respiratory activity is equivalent to that of the pH 7 system, and alkali-resistant microorganisms do not appear, but alkali-philic microorganisms dominate. . In addition, when pH 7 broth medium and pH 10 broth medium (1% sodium carbonate added) were adjusted, and the bacterial flora in each sludge was examined, it was found that in the pH 7 medium, Bacillus genus and Pseudomonas genus were found. , Etc. appeared as the dominant species, but at pH 10, flavobacterium (Flavobacterium) genus producing yellow colonies appeared characteristically and showed a bacterial flora different from that of pH 7. Generally, as an alkalophilic bacterium, Bacillus
It is said that the genus frequently appears, but in the case of sludge acclimatized with raw urine as raw water, such a tendency was not observed.
また、一般に好アルカリ性細菌は、その生息環境を自ら
の至適pH条件に変えてしまう性質をもつと言われてい
る。pH10で馴養した汚泥を、pH指示薬であるBTB（ブロ
モチモールブルー）を含む肉汁培地（pH7）に接種した
ところ、コロニーの生長とともに培地の色調は、緑色
（中性）から濃青色（アルカリ性）に変化した。これは
微生物が自らの至適pH条件であるアルカリ性に、培地の
pHを変えてしまったためと思われる。In addition, it is generally said that alkalophilic bacteria have the property of changing their habitat to their optimum pH conditions. When sludge conditioned at pH 10 was inoculated into a broth medium (pH 7) containing BTB (bromothymol blue), which is a pH indicator, the color tone of the medium changed from green (neutral) to dark blue (alkaline) along with the growth of colonies. changed. This is because the microorganisms have an optimum pH condition of alkaline,
Probably because the pH has been changed.
このように好アルカリ性細菌を利用すれば、有価なアル
カリ剤を多量に消費することなく、反応槽のpHをアルカ
リ側に維持することができる。しかしながら、生し尿等
緩衝能が強い廃水の場合には、微生物だけでは所定のpH
条件を維持することが出来ない場合があるため、NaOH等
のアルカリ剤を添加する必要がある。この際、経済性と
効果の点からpH9前後が望ましい。In this way, by using alkalophilic bacteria, the pH of the reaction tank can be maintained on the alkaline side without consuming a large amount of valuable alkaline agent. However, in the case of wastewater with a strong buffering capacity such as live urine, only the microorganisms have
Since it may not be possible to maintain the conditions, it is necessary to add an alkaline agent such as NaOH. At this time, a pH of around 9 is desirable in terms of economy and effect.
以上のように、有機性廃水を高pH条件で処理することに
より、汚泥処理および窒素除去の点で、著しく改善がも
たらされるが、pH11.0以上では微生物がほとんど失活し
てしまうため、本発明のごとく、pH8.5〜11.0に維持す
ることが必要となる。As described above, treating organic wastewater under high pH conditions brings about a remarkable improvement in terms of sludge treatment and nitrogen removal, but at pH 11.0 and above, microorganisms are almost inactivated, so As in the invention, it is necessary to maintain the pH at 8.5-11.0.
以下、本発明を実施例により具体的に説明するが、本発
明はこれらの実施例に限定されない。Hereinafter, the present invention will be specifically described by way of examples, but the present invention is not limited to these examples.
実施例−１ 本発明の１実施例について説明する。第１図において、
高pH処理工程５とpH中性処理工程８の各々の沈殿池７、
10から余剰汚泥を引き抜き、中性処理工程８の沈殿池10
から、高pH処理工程５の曝気塔に汚泥を返送しないフロ
ーで実験を行なった。実施の条件は次のとおりである。Example-1 One example of the present invention will be described. In FIG.
High-pH treatment step 5 and pH-neutral treatment step 8, respectively
Excess sludge is extracted from 10 and settling tank 10 for neutral treatment step 8
From the above, the experiment was performed in a flow in which the sludge was not returned to the aeration tower in the high pH treatment step 5. The conditions of implementation are as follows.
（１）原水 Ｋ県Ｋ市の団地下水（BOD 200〜250mg/
l、SS 200〜300mg/l （２）pH調整用薬剤 NaOH溶液、H2SO4溶液 （３）装置 第１図において、高pH処理工程およびpH
中性処理工程ともに10l容の曝気槽を用いた。(1) Raw water Groundwater in K city, K prefecture (BOD 200-250mg /
l, SS 200-300mg / l (2) pH adjusting agents NaOH solution, H 2 SO 4 solution (3) Equipment In Figure 1, high pH treatment process and pH
A 10 l aeration tank was used for both the neutral treatment process.
（４）流量 原水流入量は10l/日とし、汚泥返送量は
高pH処理工程5l/日、pH中性処理工程10l/日とした。(4) Flow rate The raw water inflow rate was 10 l / day, and the sludge return rate was 5 l / day for the high pH treatment process and 10 l / day for the pH neutral treatment process.
（５）設定pH 高pH処理工程pH9.0、pH中性処理工程
7.0 （６）反応槽温度 高pH、pH中性処理工程ともに20℃ 実施結果を表−１に示す。(5) Set pH High pH treatment process pH 9.0, pH neutral treatment process
7.0 (6) Reaction tank temperature 20 ℃ for both high pH and pH neutral treatment process Table 1 shows the results.
このとき、高pH処理工程沈殿池から引抜いた余剰汚泥の
含水率は77.1％であり、高pH処理工程での汚泥発生量は
0.225g MLSS/g △BODであった。このように、水質的に
は高pH処理工程のみでは、BODで約10％SSでは約20％が
残存するが、pH中性処理と組み合わせることで、従来の
中性処理単独の処理方法と同等の水質が得られた。一
方、汚泥処理の面からは、高pH処理工程で生成する汚泥
は、含水率で約３〜７％、汚泥発生量として、約20〜40
％従来法より値が低いため、著しい改善がもたらされ
た。 At this time, the water content of the excess sludge extracted from the settling basin of the high pH treatment process was 77.1%, and the amount of sludge generated in the high pH treatment process was
It was 0.225 g MLSS / g BOD. In this way, in terms of water quality, only in the high pH treatment step, about 10% in BOD remains about 20% in SS, but by combining with pH neutral treatment, it is equivalent to the conventional treatment method of neutral treatment alone. Quality of water was obtained. On the other hand, from the viewpoint of sludge treatment, the sludge produced in the high pH treatment process has a water content of about 3 to 7% and a sludge generation amount of about 20 to 40%.
% A lower value than the conventional method resulted in a significant improvement.
実施例−２ 本発明の他の実施例について説明する。第２図におい
て、中性処理工程８から排泥12は行なわず、返送汚泥の
一部を高pH処理工程５へ導入するフローで実験を行なっ
た。実施の条件は次のとおりである。Example-2 Another example of the present invention will be described. In FIG. 2, the experiment was conducted by a flow in which the sludge 12 is not carried out from the neutral treatment step 8 and a part of the returned sludge is introduced into the high pH treatment step 5. The conditions of implementation are as follows.
（１）原水 Ｋ県Ｚ市し尿処理場に搬入される生し尿
（BOD 9,000〜12,000mg/l、SS 4,500〜6,500mg/l、PO4
3--P 190〜210mg/l、NH4-N 2,300〜2,500mg/l）を原水
として供した。(1) Raw water Raw urine (BOD 9,000 ~ 12,000mg / l, SS 4,500 ~ 6,500mg / l, PO 4
3-- P 190 to 210 mg / l, NH 4 -N 2,300 to 2,500 mg / l) were used as raw water.
（２）pH調整用薬剤 NaOH溶液、H2SO4溶液 （３）水素供与体 メタノール（中性処理工程での脱
窒に使用） （４）装置 第２図において、高pH処理工程は20l
（硝化槽、脱窒槽各々10l）、中性処理工程は30l（硝化
槽、脱窒槽、再曝気槽各々10l）とした。(2) pH adjusting agent NaOH solution, H 2 SO 4 solution (3) Hydrogen donor Methanol (used for denitrification in neutral treatment step) (4) Equipment In Figure 2, high pH treatment step is 20 liters.
(Nitrification tank, denitrification tank 10 liters each), and neutral treatment process was 30 liters (nitrification tank, denitrification tank, re-aeration tank 10 liters each).
（５）流量 原水流入量は5l/日、循環硝化液量150l/
日、高pH処理工程からの汚泥返送量5l/日、中性処理工
程沈殿から高pH処理工程脱窒槽への汚泥返送量3l/日、
同じく中性処理硝化槽への汚泥返送量2l/日 （６）設定pH 高pH処理工程pH9.0、pH中性処理工程
7.0 （７）反応槽温度 高pH、pH中性処理工程ともに32℃ （８）実験方法 高pH処理工程はpH7.0から実験を開
始し、十分な硝化活性を確認した後、徐々にpHを上げ
て、約４週間後にpH9.0とし、その状態で更に６ケ月間
実験を継続した。(5) Flow rate Raw water inflow is 5l / day, circulating nitrification solution is 150l / day
5 l / day of sludge returned from high pH treatment process, 3 l / day of sludge returned from neutral treatment process precipitation to high pH treatment process denitrification tank,
Similarly, sludge returned to the neutralized nitrification tank 2l / day (6) Set pH High pH treatment process pH 9.0, pH neutral treatment process
7.0 (7) Reaction tank temperature 32 ℃ for both high pH and pH neutral treatment process (8) Experimental method In the high pH treatment process, the experiment was started from pH 7.0, and after sufficient nitrification activity was confirmed, the pH was gradually increased. After about 4 weeks, the pH was adjusted to 9.0, and the experiment was continued for 6 months in that state.
実施結果を表−２に示す。The execution results are shown in Table-2.
生し尿等の高濃度有機物、窒素含有廃水を高pH条件で処
理し、かつpH中性工程から汚泥を一部返送することで、
長期間安定に亜硝酸型硝化が維持され、取り残されたBO
D、窒素分も後続の中性処理工程においてほとんどが除
去され、処理水中のSS量も大幅に低減できた。また、高
pH処理工程から引抜いた余剰汚泥の含水率および高pH処
理工程での汚泥発生量は、それぞれ77.2％および0.342g
MLSS/g △BODであり、従来のし尿処理方法と比較し
て、含水率で約４〜６％、汚泥発生量は20〜40％低い値
いであった。 By treating high-concentration organic substances such as raw urine and nitrogen-containing wastewater under high pH conditions, and returning part of the sludge from the pH neutral process,
BO left behind because nitrite type nitrification was stably maintained for a long period of time
Most of the D and nitrogen components were removed in the subsequent neutral treatment process, and the amount of SS in the treated water could be greatly reduced. Also high
The water content of excess sludge extracted from the pH treatment process and the amount of sludge generated in the high pH treatment process were 77.2% and 0.342 g, respectively.
MLSS / g ΔBOD, which was about 4 to 6% lower in water content and 20 to 40% lower in sludge generation amount than the conventional human waste treatment method.
以上のように、本発明により有機性廃水の処理方法を次
のように経済的に改良することができた。As described above, according to the present invention, the method for treating organic wastewater can be economically improved as follows.
高pH処理工程から排出される余剰汚泥の脱水性は、著
しく良好で、汚泥発生量も従来の処理法に比べ、20〜40
％低い、そのため後続の汚泥処理工程の負担を大幅に改
善できた。The dehydration property of excess sludge discharged from the high pH treatment process is extremely good, and the sludge generation amount is 20-40% compared to the conventional treatment method.
% Low, which greatly reduced the burden on the subsequent sludge treatment process.
高pH条件では、高濃度の曝気槽汚泥でも、その沈降性
は良好で、遠心分離等の機械的濃縮操作は不要であり、
重量沈殿のみで固液分離が可能であった。Under high pH conditions, even a high-concentration aeration tank sludge has a good sedimentation property and does not require mechanical concentration operations such as centrifugation.
Solid-liquid separation was possible only by weight precipitation.
本法を硝化脱窒処理に適用した場合には、硝化型式が
亜硝酸型になるため、硝化に必要な酸素消費量が少な
く、酸素供給動力費を節減することができ、メタノール
添加量も減少することができた。When this method is applied to nitrification and denitrification treatment, the nitrification type becomes nitrite type, so the oxygen consumption required for nitrification is small, the oxygen supply power cost can be saved, and the amount of methanol added is also reduced. We were able to.
第１図及び第２図は、本発明の一例を示すフロー概略図
であり、第３図は、pHの異なる条件で馴養した汚泥の沈
降速度の変化を示すグラフであり、第４図は、汚泥発生
量と含水率との関係を示すグラフであり、第５図は、pH
条件による微生物呼吸活性を示すグラフである。 １……原水、２、３、４……返送汚泥、５……高pH処理
工程、６……曝気槽、７……沈殿池、８……pH中性処理
工程、９……曝気槽、10……沈殿池、11、12……余剰汚
泥、13……アルカリ剤、14……酸、15、16……散気板、
17……処理水、18、21……脱窒槽、19、20……硝化槽、
22……再曝気槽、23……循環硝化液、24……メタノー
ル、25、26、27……散気板1 and 2 are schematic flow diagrams showing an example of the present invention, FIG. 3 is a graph showing changes in the sedimentation speed of sludge acclimated under conditions of different pH, and FIG. 4 is FIG. 5 is a graph showing the relationship between the amount of sludge generated and the water content, and FIG.
It is a graph which shows microbial respiratory activity by conditions. 1 ... Raw water, 2, 3, 4 ... Return sludge, 5 ... High pH treatment process, 6 ... Aeration tank, 7 ... Sedimentation tank, 8 ... pH neutral treatment process, 9 ... Aeration tank, 10 ... Sedimentation basin, 11, 12 ... Excess sludge, 13 ... Alkaline agent, 14 ... Acid, 15, 16 ... Air diffuser,
17 …… Treated water, 18, 21 …… Denitrification tank, 19, 20 …… Nitrification tank,
22 …… Re-aeration tank, 23 …… Circulating nitrification solution, 24 …… Methanol, 25,26,27 …… Diffuser
Claims (3)
下での生物学的処理工程と、中性条件下での生物学的処
理工程との二工程によって処理することを特徴とする有
機性汚水の処理方法。1. An organic wastewater treated by two steps, at least a biological treatment step under alkaline conditions and a biological treatment step under neutral conditions. Processing method.
下での生物学的処理工程によって処理したのち、中性条
件下での生物学的処理工程で処理することを特徴とする
有機性汚水の処理方法。2. A treatment of organic sewage, which comprises treating the organic sewage by a biological treatment step under at least alkaline conditions and then by a biological treatment step under neutral conditions. Method.
生する余剰汚泥の少なくとも一部を、前記アルカリ条件
下での生物学的処理工程に導くことを特徴とする請求項
１又は２記載の有機性汚水の処理方法。3. The method according to claim 1, wherein at least a part of the excess sludge generated in the biological treatment step under the neutral condition is introduced into the biological treatment step under the alkaline condition. 2. The method for treating organic wastewater according to 2.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2068460A JPH0679713B2 (en) | 1990-03-20 | 1990-03-20 | Biological treatment method of organic wastewater |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2068460A JPH0679713B2 (en) | 1990-03-20 | 1990-03-20 | Biological treatment method of organic wastewater |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH03270789A JPH03270789A (en) | 1991-12-02 |
| JPH0679713B2 true JPH0679713B2 (en) | 1994-10-12 |
Family
ID=13374328
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP2068460A Expired - Lifetime JPH0679713B2 (en) | 1990-03-20 | 1990-03-20 | Biological treatment method of organic wastewater |
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| Country | Link |
|---|---|
| JP (1) | JPH0679713B2 (en) |
Families Citing this family (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20030094298A1 (en) | 2001-11-20 | 2003-05-22 | Commscope Properties, Llc | Toneable conduit and method of preparing same |
| US7361835B2 (en) | 2001-11-20 | 2008-04-22 | Commscope, Inc. Of North America | Toneable conduit and method of preparing same |
| JP4815827B2 (en) * | 2005-03-11 | 2011-11-16 | 栗田工業株式会社 | Biological treatment method of organic wastewater |
| JP4815826B2 (en) * | 2005-03-11 | 2011-11-16 | 栗田工業株式会社 | Biological treatment method of organic wastewater |
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| JPH03270789A (en) | 1991-12-02 |
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