JPS6244998B2 - - Google Patents
Info
- Publication number
- JPS6244998B2 JPS6244998B2 JP53099617A JP9961778A JPS6244998B2 JP S6244998 B2 JPS6244998 B2 JP S6244998B2 JP 53099617 A JP53099617 A JP 53099617A JP 9961778 A JP9961778 A JP 9961778A JP S6244998 B2 JPS6244998 B2 JP S6244998B2
- Authority
- JP
- Japan
- Prior art keywords
- sludge
- concentration
- wastewater
- flotation
- liquid
- 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
Links
- 239000010802 sludge Substances 0.000 claims description 47
- 238000000034 method Methods 0.000 claims description 43
- 238000005188 flotation Methods 0.000 claims description 24
- 239000002351 wastewater Substances 0.000 claims description 23
- 239000007788 liquid Substances 0.000 claims description 22
- 239000003638 chemical reducing agent Substances 0.000 claims description 9
- 239000007789 gas Substances 0.000 claims description 8
- 238000004062 sedimentation Methods 0.000 claims description 5
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 claims description 4
- 239000007787 solid Substances 0.000 claims description 3
- GRYLNZFGIOXLOG-UHFFFAOYSA-N Nitric acid Chemical compound O[N+]([O-])=O GRYLNZFGIOXLOG-UHFFFAOYSA-N 0.000 claims description 2
- 229910017604 nitric acid Inorganic materials 0.000 claims description 2
- 229910052757 nitrogen Inorganic materials 0.000 claims description 2
- 239000000203 mixture Substances 0.000 claims 2
- 230000001546 nitrifying effect Effects 0.000 claims 2
- 238000001556 precipitation Methods 0.000 claims 1
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 16
- 239000000126 substance Substances 0.000 description 5
- 239000012141 concentrate Substances 0.000 description 4
- QTBSBXVTEAMEQO-UHFFFAOYSA-N Acetic acid Chemical compound CC(O)=O QTBSBXVTEAMEQO-UHFFFAOYSA-N 0.000 description 3
- OKKJLVBELUTLKV-UHFFFAOYSA-N Methanol Chemical compound OC OKKJLVBELUTLKV-UHFFFAOYSA-N 0.000 description 3
- 238000006243 chemical reaction Methods 0.000 description 3
- 239000005416 organic matter Substances 0.000 description 3
- LFQSCWFLJHTTHZ-UHFFFAOYSA-N Ethanol Chemical compound CCO LFQSCWFLJHTTHZ-UHFFFAOYSA-N 0.000 description 2
- 230000008901 benefit Effects 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 230000005484 gravity Effects 0.000 description 2
- 244000005700 microbiome Species 0.000 description 2
- 238000000926 separation method Methods 0.000 description 2
- 239000006228 supernatant Substances 0.000 description 2
- 241000894006 Bacteria Species 0.000 description 1
- NINIDFKCEFEMDL-UHFFFAOYSA-N Sulfur Chemical compound [S] NINIDFKCEFEMDL-UHFFFAOYSA-N 0.000 description 1
- BZHJMEDXRYGGRV-UHFFFAOYSA-N Vinyl chloride Chemical compound ClC=C BZHJMEDXRYGGRV-UHFFFAOYSA-N 0.000 description 1
- 150000001298 alcohols Chemical class 0.000 description 1
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 238000002474 experimental method Methods 0.000 description 1
- 239000000852 hydrogen donor Substances 0.000 description 1
- 238000009434 installation Methods 0.000 description 1
- 238000012423 maintenance Methods 0.000 description 1
- -1 methanol and ethanol Chemical class 0.000 description 1
- 230000000813 microbial effect Effects 0.000 description 1
- 230000001590 oxidative effect Effects 0.000 description 1
- 239000001301 oxygen Substances 0.000 description 1
- 229910052760 oxygen Inorganic materials 0.000 description 1
- 230000011514 reflex Effects 0.000 description 1
- 239000010865 sewage Substances 0.000 description 1
Landscapes
- Physical Water Treatments (AREA)
- Purification Treatments By Anaerobic Or Anaerobic And Aerobic Bacteria Or Animals (AREA)
- Treatment Of Sludge (AREA)
Description
本発明は、下水その他の廃水を処理する硝化・
脱窒活性汚泥法において、汚泥を浮上濃縮する方
法に関するものである。
一般に活性汚泥法において、余剰汚泥の濃縮
は、浮上濃縮法と重力沈降式の濃縮法に大別され
る。浮上濃縮法は、重力沈降法に比べ、短時間で
高濃度に濃縮できるという利点を有するが、従来
の加圧浮上式汚泥濃縮では第１図に示されるよう
に加圧ポンプ、空気導入装置、空気飽和タンクな
どの諸々の装置を設備しなければならず、かつこ
れらの運転に多大のエネルギーを要し、さらには
汚泥と加圧水の接触時の撹乱のため分離液が汚濁
するという欠点を有する。
殊に通常通性嫌気性菌として知られる脱窒菌は
次式に示される脱窒反応を生じるN2ガスの気泡
を発生する。
2NO3＋5H2→N2↑＋20H-＋4H2O―
上記反応は嫌気的条件下で行なわれ、かつこの
反応にはNOXの還元剤となる水素供与体（H2）の
存在が必要である。還元剤としては通常、メタノ
ール、エタノールなどのアルコール類、廃水に含
有されているBOD物質などの有機物、あるいは
硫黄粉末などの無機物が有効であるが、この還元
剤としての効果は小さく微生物の細胞内物質も利
用される（内呼吸型脱窒）。上記脱窒現象が活性
汚泥処理装置の沈殿池で生ずると、汚泥が浮上す
るため、装置の正常な運転が不可能となり、大き
な問題となる。
本発明は、これら従来の諸欠点を除去しようと
するもので微生物の脱窒現象によつて生ずるN2
ガスを用いて、極めて簡単なプロセスで経済的に
汚泥を浮上分離濃縮することができる有効な方法
を提供することを目的とするものである。
本発明の他の目的は脱窒現象による汚泥の浮上
をむしろ積極的に利用することによつて、従来の
加圧浮上濃縮法の欠点を一挙に解消しうる方法と
することにある。
本発明は、廃水を廃水中の窒素分を硝化あるい
は硝化脱窒する生物処理工程、浮上濃縮工程、沈
殿工程で活性汚泥処理するものにおいて、活性汚
泥混合液の一部を、廃水の一部あるいは廃水の
SS（浮遊固形物）を濃縮した液とともに前記浮
上濃縮工程に導入し、該導入混合液中のNOXを嫌
気条件下で生物学的に脱窒せしめ、生じたN2ガ
スを用いて前記浮上濃縮工程に流入した汚泥を浮
上濃縮するとともに、濃縮により得られた分離液
を前記生物処理工程に返送することを特徴とする
汚泥の濃縮法である。
次に本発明方法の一実施態様を第２図を参照し
つつ説明すると、廃水１は沈殿池４からの返送汚
泥５とともに好気的条件にある硝化工程２に流入
し、廃水中のBOD物質が酸化され、NH4がNOXに
硝化されたのち、NOXを含有する活性汚泥混合液
は嫌気的条件にある脱窒工程３に流入し、NOXの
還元剤となる物質、例えばメタノールなどが添加
されて脱窒が完了したのち、混合液は沈殿池４に
流入し、固液分離されたのち、上澄水は処理水７
として放流され、沈降汚泥の一部又は全部は硝化
工程２へ返送される。前記硝化工程２のNOXを含
有する混合液の１部は混合工程１２へ導びかれ、
原水９としての廃水の一部或いは廃水のSSを濃
縮した液又はこれらと前述の還元剤６とを併用し
たものが浮上濃縮工程８に導かれ、NOXの還元
（脱窒現象）によつて生ずるN2ガスが汚泥に付着
し、汚泥は浮上分離濃縮される。分離液１１は硝
化工程あるいは脱窒工程３に流入し、残存する
NOXとBOD成分は処理される。また浮上濃縮工
程のNOX濃度が低い場合にはNOXを含有する廃水
あるいは工業用硝酸溶液を混合工程１２へ注入す
ればよい。混合工程１２の原水９として最初沈殿
池の生汚泥を用いると、浮上濃縮工程８で、混合
液汚泥に加えて生汚泥も同時に濃縮できるので、
一層効果的である。
第１図においてＡは空気圧縮機、Ｂは気―液エ
ジエクタ、Ｃは飽和タンク、Ｄは液―液エジエク
タ、Ｅは汚泥浮上濃縮タンク、Ｆは汚泥濃縮タン
ク、Ｇは分離液タイプ、Ｈは加圧水ポンプ、Ｉは
処理水、Ｊは雑廃水、ｋは濃縮汚泥、Ｌは汚泥を
示す。
以上述べたように本発明方法ではNOXの存在す
る生物処理工程の混合液を浮上濃縮工程に導入し
て、汚泥の浮上濃縮に利用する生物学脱窒作用を
促進するため、該浮上濃縮工程に廃水の一部ある
いは廃水のSS分を濃縮した液を導入することに
より汚泥の浮上濃縮が生物学脱窒によつて生成さ
れるN2ガスによるものであり、生物学的にNOX
をN2ガスに還元する活性（速度）が、易生物分
解性の有機物（還元剤）の存在によつて大幅に高
まることで廃水の分離も容易で脱窒活性を大幅に
高められ高効率で安定した浮上濃縮を行うことが
できると共に易生物分解性の有機質に富んだ廃水
のSSを濃縮した液も脱窒の還元剤としている
が、これによつて廃水中のSSも同時に浮上分離
を行うことができるので、汚泥処理全体が極めて
容易となる。しかも脱窒に際してNOX中の酸素で
それらの有機質を酸化分解することによつて廃水
中のSSを衛生的に改善することができるほか脱
窒に消費された分だけ廃水中の有機物濃度が低下
するので、生物処理工程の有機物負荷が軽減さ
れ、より浄化された処理水を得ることが可能とな
る。微生物の生理反応の一つである脱窒現象を巧
みに利用して汚泥を浮上濃縮するものであり、加
圧浮上法で必要とされている加圧ポンプ、空気導
入装置、空気飽和装置などを一切使用せず、極め
て簡単な装置で経済的に汚泥を浮上濃縮すること
ができ、汚泥の脱水あるいは消化処理にとつて極
めて有益で、しかも穏やかに汚泥を浮上分離でき
るため極めて清澄化された分離水を得て安定した
濃縮処理ができて維持管理も著しく簡便であるな
どの利益がある。
次に本発明の１実施例を実施態様について示
す。脱窒活性汚泥処理の実験は、硝化槽20、脱
窒槽20、原水流量、返送汚泥量それぞれ200
／日、水温30±１℃で行なつた。脱窒用の還元
剤には酢酸を用いた。汚泥の浮上試験は第３図に
示される透明塩化ビニル製円筒（下口付）ｄを用
いて回分操作で行なつた。脱窒活性汚泥処理の各
水質の性状は次のとおりである。尚、原水は人工
廃水を用いた。
The present invention provides nitrification and treatment for sewage and other wastewater.
This invention relates to a method of flotation and concentration of sludge in the denitrification activated sludge method. Generally, in the activated sludge method, the concentration of excess sludge is roughly divided into flotation concentration method and gravity sedimentation type concentration method. The flotation concentration method has the advantage of being able to concentrate to a high concentration in a short time compared to the gravity sedimentation method, but the conventional pressurized flotation method requires a pressure pump, an air introduction device, This method requires the installation of various devices such as an air saturation tank, requires a large amount of energy to operate these devices, and has the further drawback that the separated liquid becomes polluted due to disturbance when the sludge and pressurized water come into contact with each other. In particular, denitrifying bacteria, commonly known as facultative anaerobes, generate N 2 gas bubbles that cause the denitrification reaction shown by the following equation. 2NO 3 +5H 2 →N 2 ↑+20H - +4H 2 O- The above reaction is carried out under anaerobic conditions, and this reaction requires the presence of a hydrogen donor (H 2 ), which acts as a reducing agent for NO . Normally, alcohols such as methanol and ethanol, organic substances such as BOD substances contained in wastewater, or inorganic substances such as sulfur powder are effective as reducing agents, but their effectiveness as reducing agents is small and they do not interfere with microbial cells. Substances are also used (endo-respiratory denitrification). When the denitrification phenomenon described above occurs in the settling tank of an activated sludge treatment device, the sludge floats to the surface, making normal operation of the device impossible and causing a serious problem. The present invention aims to eliminate these conventional drawbacks, and aims to reduce the amount of N2 produced by the denitrification phenomenon of microorganisms.
The object of the present invention is to provide an effective method for economically flotation separation and concentration of sludge in an extremely simple process using gas. Another object of the present invention is to provide a method that can eliminate the drawbacks of the conventional pressurized flotation concentration method at once by positively utilizing the flotation of sludge due to the denitrification phenomenon. The present invention treats wastewater with activated sludge through a biological treatment process, a flotation concentration process, and a sedimentation process to nitrify or denitrify the nitrogen content in the wastewater. waste water
SS (suspended solids) is introduced into the flotation concentration process together with the concentrated liquid, NOx in the introduced mixed liquid is biologically denitrified under anaerobic conditions, and the generated N2 gas is used to remove the NOx from the flotation concentration process. This sludge concentration method is characterized in that the sludge that has flowed into the concentration step is floated and concentrated, and the separated liquid obtained by the concentration is returned to the biological treatment step. Next, one embodiment of the method of the present invention will be explained with reference to FIG. 2. Wastewater 1 flows into the nitrification step 2 under aerobic conditions together with the returned sludge 5 from the settling tank 4, and the BOD in the wastewater is is oxidized and NH 4 is nitrified to NO is added and denitrification is completed, the mixed liquid flows into the settling tank 4, where it is separated into solid and liquid, and the supernatant water is transferred to the treated water 7.
Some or all of the settled sludge is returned to the nitrification process 2. A part of the mixed liquid containing NO x in the nitrification step 2 is led to a mixing step 12,
A part of the wastewater as raw water 9, a concentrated solution of wastewater SS, or a combination of these and the above-mentioned reducing agent 6 is led to a flotation concentration step 8, where NOx is reduced (denitrification phenomenon). The resulting N2 gas adheres to the sludge, and the sludge is floated and concentrated. The separated liquid 11 flows into the nitrification process or denitrification process 3 and remains
NOx and BOD components are processed. If the concentration of NOx in the flotation concentration step is low, wastewater or industrial nitric acid solution containing NOx may be injected into the mixing step 12. If raw sludge from the first settling tank is used as the raw water 9 in the mixing step 12, the raw sludge can be simultaneously concentrated in addition to the mixed liquid sludge in the flotation concentration step 8.
Even more effective. In Figure 1, A is an air compressor, B is a gas-liquid ejector, C is a saturation tank, D is a liquid-liquid ejector, E is a sludge flotation concentration tank, F is a sludge concentration tank, G is a separated liquid type, and H is a Pressurized water pump, I indicates treated water, J indicates miscellaneous waste water, k indicates thickened sludge, and L indicates sludge. As described above, in the method of the present invention, the mixed liquid of the biological treatment process containing NO By introducing a part of the wastewater or a liquid that concentrates the SS content of the wastewater, the floating concentration of sludge is caused by N2 gas generated by biological denitrification, and biologically NO
The activity (rate) of reducing N2 gas to N2 gas is greatly increased by the presence of easily biodegradable organic matter (reducing agent), making it easy to separate wastewater and greatly increasing denitrification activity, resulting in high efficiency. Stable flotation and concentration can be performed, and a concentrated solution of SS in wastewater, which is rich in easily biodegradable organic matter, is also used as a reducing agent for denitrification, and with this, SS in wastewater can also be separated by flotation at the same time. This makes the entire sludge treatment extremely easy. Moreover, during denitrification, by oxidizing and decomposing those organic substances with the oxygen in NO Therefore, the organic matter load in the biological treatment process is reduced, making it possible to obtain more purified treated water. This method skilfully utilizes the denitrification phenomenon, which is one of the physiological reactions of microorganisms, to float and concentrate sludge. It is possible to economically concentrate sludge by flotation using extremely simple equipment without using anything, and it is extremely useful for dewatering or digesting sludge. Furthermore, it is an extremely clarified separation method because sludge can be separated by flotation gently. There are benefits such as being able to obtain water and perform stable concentration treatment, and maintenance and management is extremely simple. Next, an embodiment of the present invention will be described. The denitrification activated sludge treatment experiment consisted of 20 nitrification tanks, 20 denitrification tanks, 200 ml of raw water flow rate, and 200 ml of returned sludge.
/day at a water temperature of 30±1°C. Acetic acid was used as the reducing agent for denitrification. The sludge flotation test was conducted in batch operation using a transparent vinyl chloride cylinder (with a bottom opening) d shown in FIG. The properties of each water quality for denitrification activated sludge treatment are as follows. Note that artificial wastewater was used as the raw water.
【表】
単位は mg／
回分試験は、上表の混合液、汚泥を用いて、混
合槽で混合したのち、円筒内（１）で２時間静
置して浮上分離し、分離液を下口よりとり出し、
残部を浮上汚泥量とした。シリンダーにおける汚
泥量の経時変化を第４図に示す。[Table] Unit is mg/
In the batch test, the mixed liquid and sludge shown in the table above were mixed in a mixing tank, then allowed to stand in the cylinder (1) for 2 hours to float and separate, and the separated liquid was taken out from the bottom.
The remainder was taken as the amount of floating sludge. Figure 4 shows the change in the amount of sludge in the cylinder over time.
【表】
実施例の結果から、本発明によつて汚泥は高濃
度にしかも短時間に濃縮されることがわかる。ま
た上澄水もSSの少ない清澄化されたものをえる
ことができた。[Table] From the results of the Examples, it can be seen that the present invention allows sludge to be concentrated to a high concentration and in a short time. In addition, we were able to obtain purified supernatant water with less SS.
第１図は従来例の汚泥濃縮工程のフローシー
ト、第２図は本発明方法のフローシートである。
第３図は実験装置のフローシート、第４図は汚泥
濃縮過程の経時変化を示す説明図である。
１……廃水、２……硝化工程、３……脱窒工
程、４……沈殿池、５……返送汚泥、６……還元
剤、７……処理水、８……汚泥浮上濃縮工程、９
……原水、１０……汚泥処理工程、１１……分離
液、１２……混合工程。
FIG. 1 is a flow sheet of a conventional sludge concentration process, and FIG. 2 is a flow sheet of the method of the present invention.
FIG. 3 is a flow sheet of the experimental apparatus, and FIG. 4 is an explanatory diagram showing changes over time in the sludge concentration process. 1... Wastewater, 2... Nitrification process, 3... Denitrification process, 4... Sedimentation tank, 5... Return sludge, 6... Reducing agent, 7... Treated water, 8... Sludge flotation concentration process, 9
...Raw water, 10...Sludge treatment process, 11...Separated liquid, 12...Mixing process.
Claims (1)
窒する生物処理工程、浮上濃縮工程、沈殿工程で
活性汚泥処理するものにおいて、活性汚泥混合液
の一部を、廃水の一部あるいは廃水のSS（浮遊
固形物）を濃縮した液とともに前記浮上濃縮工程
に導入し、該導入混合液中のNOXを嫌気条件下で
生物学的に脱窒せしめ、生じたN2ガスを用いて
前記浮上濃縮工程に流入した汚泥を浮上濃縮する
とともに、濃縮により得られた分離液を前記生物
処理工程に返送することを特徴とする汚泥の濃縮
法。 ２ 前記混合液の一部に沈殿工程の沈殿汚泥の一
部を混入して浮上濃縮する特許請求の範囲第１項
記載の方法。 ３ 前記浮上濃縮工程にNOX含有液、硝酸、有機
性廃水、還元剤の少なくとも１つを添加して脱窒
を促進するものである特許請求の範囲第１項又は
第２項記載の方法。[Scope of Claims] 1. In activated sludge treatment of wastewater through a biological treatment process for nitrifying or nitrifying and denitrifying the nitrogen content in the wastewater, a flotation concentration process, and a sedimentation process, a part of the activated sludge mixture is added to the wastewater. A part of the SS (suspended solids) of the wastewater is introduced into the flotation concentration process together with the concentrated liquid, and NOx in the introduced mixed liquid is biologically denitrified under anaerobic conditions, resulting in N2 gas. A method for concentrating sludge, characterized in that the sludge that has flowed into the flotation concentration step is floated and concentrated using a floatation concentration method, and the separated liquid obtained by the concentration is returned to the biological treatment step. 2. The method according to claim 1, wherein a part of the settled sludge from the precipitation step is mixed into a part of the liquid mixture and floated and concentrated. 3. The method according to claim 1 or 2, wherein at least one of a NOx- containing liquid, nitric acid, organic wastewater, and a reducing agent is added to the flotation and concentration step to promote denitrification.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP9961778A JPS5527062A (en) | 1978-08-16 | 1978-08-16 | Concentration of sludge |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP9961778A JPS5527062A (en) | 1978-08-16 | 1978-08-16 | Concentration of sludge |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS5527062A JPS5527062A (en) | 1980-02-26 |
| JPS6244998B2 true JPS6244998B2 (en) | 1987-09-24 |
Family
ID=14252045
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP9961778A Granted JPS5527062A (en) | 1978-08-16 | 1978-08-16 | Concentration of sludge |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS5527062A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH0418107U (en) * | 1990-06-05 | 1992-02-14 |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5864198A (en) * | 1981-10-15 | 1983-04-16 | Hitachi Plant Eng & Constr Co Ltd | Method and apparatus for biologically denitrifying waste water |
| GB9508400D0 (en) * | 1995-04-25 | 1995-06-14 | Agronova As | Fertilizer and process for production thereof |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5152668A (en) * | 1974-11-01 | 1976-05-10 | Sato Zoki Co Ltd | |
| JPS5527052A (en) * | 1978-08-15 | 1980-02-26 | Ebara Infilco Co Ltd | Sludge floatation and concentration |
| JPS5527050A (en) * | 1978-08-15 | 1980-02-26 | Ebara Infilco Co Ltd | Sludge concentration |
-
1978
- 1978-08-16 JP JP9961778A patent/JPS5527062A/en active Granted
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5152668A (en) * | 1974-11-01 | 1976-05-10 | Sato Zoki Co Ltd | |
| JPS5527052A (en) * | 1978-08-15 | 1980-02-26 | Ebara Infilco Co Ltd | Sludge floatation and concentration |
| JPS5527050A (en) * | 1978-08-15 | 1980-02-26 | Ebara Infilco Co Ltd | Sludge concentration |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH0418107U (en) * | 1990-06-05 | 1992-02-14 |
Also Published As
| Publication number | Publication date |
|---|---|
| JPS5527062A (en) | 1980-02-26 |
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