JP3403348B2 - Treatment method for nitrogen-containing wastewater - Google Patents
Treatment method for nitrogen-containing wastewaterInfo
- Publication number
- JP3403348B2 JP3403348B2 JP33136298A JP33136298A JP3403348B2 JP 3403348 B2 JP3403348 B2 JP 3403348B2 JP 33136298 A JP33136298 A JP 33136298A JP 33136298 A JP33136298 A JP 33136298A JP 3403348 B2 JP3403348 B2 JP 3403348B2
- Authority
- JP
- Japan
- Prior art keywords
- nitrogen
- manganese dioxide
- reaction
- chlorine
- containing wastewater
- 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 - Fee Related
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- Catalysts (AREA)
- Removal Of Specific Substances (AREA)
- Treatment Of Water By Oxidation Or Reduction (AREA)
Description
【０００１】[0001]
【発明の属する技術分野】本発明は、下水の二次処理
水、スクラバー排水、産業排水などであって有機物の含
有量が比較的少なく、硝酸分あるいは亞硝酸分などの窒
素分を比較的多く含む排水からその窒素分を除去するこ
とができる窒素含有排水の処理方法に関する。TECHNICAL FIELD The present invention relates to secondary treated water of sewage, scrubber drainage, industrial drainage, etc., which has a relatively low content of organic substances and a relatively high content of nitrogen such as nitric acid or nitric acid. The present invention relates to a method for treating nitrogen-containing wastewater capable of removing its nitrogen content from the wastewater containing the nitrogen.
【０００２】[0002]
【従来の技術】従来、このような窒素分を除去するため
の窒素含有排水の処理方法としては、通常、図２に例示
する活性汚泥を利用した硝化液循環法が利用されてい
る。この方法では、第１脱窒槽１１と硝化槽１２を並設
し、この第１脱窒槽１１には、後段の沈殿槽１３から抜
き出された返送汚泥を混合した原水を導入して、攪拌し
ながら嫌気状態で生物処理して脱窒する。この処理液は
硝化槽１２に送られ、散気装置１４から十分な空気の供
給を受けて曝気され、好気状態で生物処理され有機性窒
素、アンモニア性窒素を酸化して亞硝酸性窒素、硝酸性
窒素に変換する。この際、硝化液の一部は第１脱窒槽１
１に返送され循環することになる。2. Description of the Related Art Hitherto, as a method for treating nitrogen-containing wastewater for removing such a nitrogen component, a nitrification solution circulation method using activated sludge illustrated in FIG. 2 has been generally used. In this method, a first denitrification tank 11 and a nitrification tank 12 are installed side by side, and raw water mixed with return sludge extracted from a settling tank 13 at a subsequent stage is introduced into the first denitrification tank 11 and stirred. While biologically treating in an anaerobic state to denitrify. This treatment liquid is sent to the nitrification tank 12, is aerated by receiving sufficient air from the air diffuser 14, and is biologically treated in an aerobic state to oxidize organic nitrogen and ammonia nitrogen, and nitric acid nitrogen, Converts to nitrate nitrogen. At this time, a part of the nitrification solution is used in the first denitrification tank 1.
It will be returned to 1 and will be circulated.
【０００３】さらに脱窒の必要がある場合には、第２脱
窒槽１５で脱窒処理を行いと再曝気槽１６で有機物等の
除去を行って、その後沈殿槽１３に送り込み、フロック
などを活性汚泥として沈降させる。ここで固形分を除去
した処理水は適宜に放流されるが、沈降分離した汚泥
は、抜き出して、その所要分を返送汚泥として原水の混
和するため返送する一方、余剰汚泥分は廃棄する。この
ような第２脱窒槽１５の操作には生物処理のためメタノ
ールなどの有機物が添加される。If further denitrification is required, denitrification treatment is performed in the second denitrification tank 15 and organic substances are removed in the re-aeration tank 16 and then sent to the precipitation tank 13 to activate flocs and the like. Settle as sludge. Here, the treated water from which the solid content has been removed is appropriately discharged, but the sludge that has settled and separated is withdrawn and the required amount is returned as return sludge for mixing with the raw water, while the excess sludge is discarded. For such operation of the second denitrification tank 15, an organic substance such as methanol is added for biological treatment.
【０００４】このように、硝化液循環法では、循環硝化
液と活性汚泥を利用しながら硝化処理で含有窒素分を硝
酸型に変換後、含有有機物を利用して脱窒処理し硝酸型
窒素を窒素ガスとして除去する方法であるが、次のよう
な問題があった。
（１）下水の場合、窒素分の大部分は有機性窒素、アン
モニア性窒素の形態で含まれるが、これらを一旦、亞硝
酸型あるいは硝酸型窒素まで酸化した後で脱窒するた
め、曝気処理に多量に空気を必要とし、処理槽の大型化
が避けられず、長時間の処理時間が必要でもあった。As described above, in the nitrification solution circulation method, the nitrogen content contained is converted to nitric acid type by nitrification while using the circulating nitrification solution and activated sludge, and then denitrification treatment is carried out using the contained organic matter to convert nitric acid type nitrogen. Although it is a method of removing it as nitrogen gas, it has the following problems. (1) In the case of sewage, most of the nitrogen content is contained in the form of organic nitrogen or ammonia nitrogen, but these are once aerated to nitric acid type or nitric acid type nitrogen and then denitrified, so aeration treatment is required. In addition, a large amount of air is required, the size of the processing tank cannot be increased, and a long processing time is required.
【０００５】（２）有機物を脱窒に利用するため硝化液
の循環が行われるが、脱窒効率が硝化液循環率に左右さ
れ、また、脱窒を十分に行おうとすると、図２に鎖線で
示した第２の硝化プロセスが必要となり、設備が複雑、
大型化する他、メタノールなどの有機物の添加が必要で
あった。(2) The nitrification solution is circulated in order to utilize the organic matter for denitrification. However, the denitrification efficiency depends on the circulation rate of the nitrification solution, and if sufficient denitrification is attempted, the chain line in FIG. The second nitrification process shown in is required, and the equipment is complicated.
In addition to the increase in size, it was necessary to add organic substances such as methanol.
【０００６】（３）この方法では、硝化処理、脱窒処理
とも生物的処理であることから、冬季に水温が著しく低
下したとときには、処理効率が低下することになる。ま
た、処理速度が比較的小さいため、窒素分が高濃度に含
まれる排水の場合には、処理設備の設置面積を大きくし
なければならないという問題があった。(3) In this method, both nitrification treatment and denitrification treatment are biological treatments, so that when the water temperature is significantly lowered in winter, the treatment efficiency is lowered. In addition, since the treatment speed is relatively low, there is a problem that the installation area of the treatment equipment must be increased in the case of wastewater containing a high concentration of nitrogen.
【０００７】[0007]
【発明が解決しようとする課題】本発明は、上記の問題
点を解決するためになされたものであり、有機性窒素や
アンモニア性窒素を亞硝酸型あるいは硝酸型窒素に酸化
する曝気処理の省略を図るとともに、処理液の循環また
は汚泥の循環をも省略して、装置を簡素化するととも
に、処理効率を高くすることが可能となる物理化学的処
理に基づく窒素含有排水の処理方法を提供する。SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and omits aeration treatment for oxidizing organic nitrogen or ammonia nitrogen to nitric acid type or nitric acid type nitrogen. In addition, it is possible to simplify the apparatus by omitting the circulation of the treatment liquid or the circulation of the sludge, and to provide a treatment method of nitrogen-containing wastewater based on a physicochemical treatment that can improve the treatment efficiency. .
【０００８】[0008]
【課題を解決するための手段】上記の問題を解決した本
発明の窒素含有排水の処理方法は、下記の化学的処理に
より窒素分を含む原水を処理することを特徴とするもの
である。（１）原水に塩化コバルトを添加する工程。 （２）亜硫酸ナトリウムを混和して、原水中の溶存酸素
を除去する工程。 （３）ｐＨを酸性に調整する工程。 （４）金属鉄に接触させ、溶存する硝酸分、亞硝酸分を
アンモニアに還元するとともに、一部を窒素ガスにまで
還元して除去する工程。 （５）ｐＨをほぼ中性に調整する工程。 （６）塩素系酸化剤の存在下に二酸化マンガン層に接触
させ、鉄フロックを除去するとともに有機性窒素分をア
ンモニアに分解し、かつ塩素系酸化剤による不連続点塩
素化反応と二酸化マンガンによる酸化触媒反応によりア
ンモニア分を窒素ガスとして除去する工程。 The method for treating nitrogen-containing wastewater according to the present invention, which has solved the above problems, is characterized by treating raw water containing nitrogen by the following chemical treatment. (1) A step of adding cobalt chloride to raw water. (2) Dissolved oxygen in raw water by mixing sodium sulfite
The step of removing. (3) Step of adjusting pH to acidic. (4) Contacting metallic iron to remove dissolved nitric acid and nitric acid
Reduced to ammonia and partially converted to nitrogen gas
Step of reducing and removing. (5) A step of adjusting pH to almost neutral. (6) Contact with manganese dioxide layer in the presence of chlorine-based oxidizing agent
To remove iron flocs and to remove organic nitrogen.
Decomposes into ammonia and is a discontinuous point salt due to chlorine-based oxidizer
By the oxidization reaction and the oxidation catalytic reaction with manganese dioxide,
The process of removing ammonia as nitrogen gas.
【０００９】[0009]
【００１０】[0010]
【発明の実施の形態】次に、本発明の窒素含有排水の処
理方法に係る実施形態について、図１以降を参照しなが
ら説明する。本発明は、（１）原水に塩化コバルトを添
加する工程、（２）亜硫酸ナトリウムを混和して、原水
中の溶存酸素を除去する工程、（３）ｐＨを酸性に調整
する工程、（４）金属鉄に接触させ、溶存する硝酸分、
亞硝酸分をアンモニアに還元するとともに、一部を窒素
ガスにまで還元して除去する工程、（５）ｐＨをほぼ中
性に調整する工程、および（６）塩素系酸化剤の存在下
に二酸化マンガン層に接触させ、鉄フロックを除去する
とともに有機性窒素分をアンモニアに分解し、かつ塩素
系酸化剤による不連続点塩素化反応と二酸化マンガンに
よる酸化触媒反応によりアンモニア分を窒素ガスとして
除去する工程、からなる窒素含有排水の処理方法であっ
て、原水中の各種形態の窒素分が処理可能な方法であ
り、先ずその処理の原理を以下に説明する。BEST MODE FOR CARRYING OUT THE INVENTION Next, an embodiment of the method for treating nitrogen-containing wastewater according to the present invention will be described with reference to FIG. The present invention includes (1) a step of adding cobalt chloride to raw water, (2) a step of mixing sodium sulfite to remove dissolved oxygen in the raw water, (3) a step of adjusting pH to acidic, (4) Nitric acid dissolved in contact with metallic iron,
A step of reducing the nitric acid content to ammonia and removing a part of it to nitrogen gas, (5) a step of adjusting the pH to almost neutral, and (6) a step of oxidizing in the presence of a chlorine-based oxidizing agent. Contact with the manganese layer to remove iron flocs, decompose organic nitrogen into ammonia, and remove ammonia as nitrogen gas by discontinuous point chlorination reaction by chlorine-based oxidizer and oxidation catalytic reaction by manganese dioxide. The method is a method for treating nitrogen-containing wastewater comprising steps, and is capable of treating various forms of nitrogen content in raw water. First, the principle of the treatment will be described below.
【００１１】溶存酸素（ＤＯ）の除去。
ＤＯは、後工程の還元反応を阻害するので、先ずこれを
触媒Ｃｏの存在下で、次の反応により捕捉、除去する。
Ｎａ２ＳＯ３＋Ｏ＋（Ｃｏ） → Ｎａ２ＳＯ４＋（Ｃｏ）Removal of dissolved oxygen (DO). Since DO inhibits the reduction reaction in the subsequent step, it is first captured and removed by the next reaction in the presence of the catalyst Co. Na 2 SO 3 + O + (Co) → Na 2 SO 4 + (Co)
【００１２】アンモニア還元と窒素ガス除去。
被処理液を酸性または酸性領域に保ち、下記反応にて、
亞硝酸または硝酸形態の窒素分を金属鉄にてアンモニア
に還元するとともに、一部は窒素ガスにまで還元、除去
する。
（アンモニア還元反応）
３ＮＯ２ −＋４Ｆｅ＋１２Ｈ＋ → ３ＮＨ４ ＋２Ｆｅ２Ｏ３
ＮＯ３ −＋２Ｆｅ＋ ４Ｈ＋ → ＮＨ４ ＋Ｆｅ２Ｏ３
（窒素ガス除去反応）
６ＮＯ２ −＋８Ｆｅ → ３Ｎ２＋４Ｆｅ２Ｏ３
２ＮＯ３ −＋４Ｆｅ → Ｎ２＋２Ｆｅ２Ｏ３
なお、アンモニア還元反応は、ｐＨが酸性領域で進みや
すく、また窒素ガス除去反応は中性領域で進み易い特長
がある。Ammonia reduction and nitrogen gas removal. Keep the liquid to be treated acidic or in the acidic range, and in the following reaction,
Nitrogen or nitric acid in the form of nitrogen is reduced to ammonia with metallic iron, and part of it is reduced to nitrogen gas and removed. (Ammonia reduction reaction) 3NO 2 − + 4Fe + 12H + → 3NH 4 + 2Fe 2 O 3 NO 3 − + 2Fe + 4H + → NH 4 + Fe 2 O 3 (nitrogen gas removal reaction) 6NO 2 − + 8Fe → 3N 2 + 4Fe 2 O 3 2NO 3 - Note + 4Fe → N 2 + 2Fe 2 O 3, ammonia reduction reaction, pH tends proceeds in an acidic region, the nitrogen gas elimination reaction is liable Features proceeds in a neutral region.
【００１３】中和処理。
前段の処理液をアルカリ薬剤で中和する。この場合、次
工程の塩素化反応に要するアルカリ性塩素系酸化剤をこ
の段階で添加すると、中和用のアルカリ薬剤が節約でき
る。この中和処理により、前段の処理液にはＦｅ分が
溶出しているので、次の反応によってＦｅ（ＯＨ）３の
フロックが生成する。
Ｆｅ３＋＋３ＯＨ− → Ｆｅ（ＯＨ）３ Neutralization treatment. The treatment liquid in the first stage is neutralized with an alkaline chemical. In this case, if the alkaline chlorine-based oxidizing agent required for the chlorination reaction in the next step is added at this stage, the alkaline chemical for neutralization can be saved. By this neutralization treatment, Fe content is eluted in the treatment liquid of the previous stage, so that Fe (OH) 3 flocs are generated by the next reaction. Fe 3+ + 3OH − → Fe (OH) 3
【００１４】二酸化マンガン処理。
この段階で、被処理液を二酸化マンガン粒子反応層を通
過させ、先に添加した塩素系酸化剤とアンモニア分との
不連続点塩素化反応による窒素ガス化と、二酸化マンガ
ンとの酸化触媒反応による窒素ガス化の両方を進行さ
せ、窒素分を除去する。
（不連続点塩素化反応）
２ＮＨ４ ＋＋２ＨＣｌＯ → ２ＮＨ２Ｃｌ＋２Ｈ＋＋２Ｈ２Ｏ
（遊離塩素） （結合塩素）
２ＮＨ２Ｃｌ＋ＨＣｌＯ → Ｎ２＋３Ｈ＋＋３Ｃｌ−＋Ｈ２Ｏ
（酸化触媒反応）
２ＭｎＯ２＋２ＮＨ４ ＋ → ２ＭｎＯ＋Ｎ２＋４Ｈ＋＋２Ｈ２Ｏ
この場合、二酸化マンガンは、次の反応により触媒賦活
される。
２ＭｎＯ＋２ＨＣｌＯ → ２ＭｎＯ２＋２ＨＣｌ
そして、前段で発生したＦｅ（ＯＨ）３のフロックは、
この二酸化マンガン粒子反応層の粒子間に捕捉され除去
されるのである。Manganese dioxide treatment. At this stage, the liquid to be treated is passed through the reaction layer of manganese dioxide particles, and nitrogen gasification by the discontinuous point chlorination reaction between the chlorine-based oxidizing agent and the ammonia component added previously and the oxidation catalytic reaction with manganese dioxide are performed. Both nitrogen gasification is carried out to remove the nitrogen content. (Discontinuous point chlorination reaction) 2NH 4 + + 2HClO → 2NH 2 Cl + 2H + + 2H 2 O (free chlorine) (combined chlorine) 2NH 2 Cl + HClO → N 2 + 3H + + 3Cl − + H 2 O (oxidation catalytic reaction) 2MnO 2 + 2NH 4 + → 2MnO + N 2 + 4H + + 2H 2 O In this case, manganese dioxide is catalytically activated by the following reaction. 2MnO + 2HClO → 2MnO 2 + 2HCl Then, the flock of Fe (OH) 3 generated in the previous stage is
The manganese dioxide particles are trapped and removed between the particles in the reaction layer.
【００１５】なお、一般に不連続点塩素化反応では、触
媒のない状態で前記不連続点塩素化反応の第１段反応が
進行して残留塩素（遊離塩素＋結合塩素）が増加した
後、第２段が進行して、残留塩素が減少し極小値（不連
続点：アンモニア性窒素に対して７．６倍の塩素注入
点）を経て、再び増加し始める付近で前記第２段の反応
が完結するような反応を意味するが、本発明では、前記
した酸化触媒反応も並行して進行するため、不連続点塩
素化反応により処理すべきアンモニア性窒素が減少する
ことから見掛け上の不連続点が低下するような反応をも
含む概念である。In general, in the discontinuous point chlorination reaction, after the first stage reaction of the discontinuous point chlorination reaction proceeds in the absence of a catalyst to increase residual chlorine (free chlorine + combined chlorine), As the second stage progresses, residual chlorine decreases and reaches a minimum value (discontinuity point: 7.6 times chlorine injection point with respect to ammonia nitrogen), and then the second stage reaction occurs when it begins to increase again. In the present invention, the above-mentioned oxidation catalyst reaction also proceeds in parallel, so that the ammoniacal nitrogen to be treated is reduced by the discontinuous point chlorination reaction, so that the apparent discontinuity occurs. It is a concept that includes reactions that reduce points.
【００１６】次に本発明の実施形態を図１、図３〜８を
参照しつつ詳細に説明する。
（１）塩化コバルトの添加工程。
原水を混和槽２に導入する。ここでは、導入前または導
入直後に、塩化コバルトを添加する。この塩化コバルト
の添加は、後工程の亜硫酸ナトリウムの添加に先立って
行われないと目的のＤＯ除去が速やかに行えない。また
その添加量は、塩化コバルト添加量と混和液のＤＯの関
係を表す図３に示すように、原水に対して１〜２ｍｇ／
ｌが適当である。Next, an embodiment of the present invention will be described in detail with reference to FIGS. 1 and 3 to 8. (1) Addition process of cobalt chloride. Raw water is introduced into the mixing tank 2. Here, cobalt chloride is added before or immediately after the introduction. If the cobalt chloride is not added prior to the subsequent addition of sodium sulfite, the target DO cannot be removed quickly. In addition, the addition amount thereof is 1 to 2 mg / raw water as shown in FIG. 3, which shows the relationship between the addition amount of cobalt chloride and the DO of the mixed solution.
l is suitable.
【００１７】（２）溶存酸素の除去工程。
次いで、亜硫酸ナトリウムを添加、混和して、原水中の
溶存酸素を除去する。その適正添加量は、原水の当初の
ＤＯ濃度によって変化するが、亜硫酸ナトリウム添加量
と混和液のＤＯの関係を表す図４のように、その変動を
考慮しても５０〜１００ｍｇ／ｌとするのが好ましい。(2) A step of removing dissolved oxygen. Then, sodium sulfite is added and mixed to remove dissolved oxygen in the raw water. The appropriate addition amount varies depending on the initial DO concentration of the raw water, but is 50 to 100 mg / l even when the variation is taken into consideration as shown in FIG. 4 showing the relationship between the addition amount of sodium sulfite and the DO of the mixed solution. Is preferred.
【００１８】（３）ｐＨ調整工程。
次いで、塩酸を添加してｐＨを酸性に調整する。調整の
範囲は、ｐＨ２〜３とし、亞硝酸、硝酸型の窒素分の多
い原水であれば次工程の還元反応の効率を考慮してｐＨ
３付近が好ましく、それらの少ない原水であればアンモ
ニア化に促進を考慮してｐＨ２付近に調整するのが好ま
しい。（金属鉄接触処理における反応ｐＨと処理水Ｎ濃
度の関係を表す図５を参照のこと）(3) pH adjusting step. Next, hydrochloric acid is added to adjust the pH to be acidic. The range of adjustment is pH 2-3, and pH of nitric acid or nitric acid-type raw water containing a large amount of nitrogen is adjusted in consideration of the efficiency of the reduction reaction in the next step.
Around 3 is preferable, and if the amount of raw water is small, it is preferable to adjust the pH to around 2 in consideration of promotion of ammonia formation. (Refer to FIG. 5 showing the relationship between the reaction pH and the N concentration of the treated water in the metallic iron contact treatment)
【００１９】（４）還元工程。
前記混和槽２で処理された被処理水は、次の鉄接触槽３
に導入される。ここで金属鉄粒子の反応層３１を通過さ
せて、金属鉄に接触させることにより、溶存する硝酸
分、亞硝酸分をアンモニアに還元するとともに、一部を
窒素ガスにまで還元して除去する。ここでは、先の図５
に例示するように、ｐＨによって主たる反応が変化する
のであるが、金属鉄接触処理における反応時間と処理水
Ｎ濃度の関係を表す図６に示すように、その反応時間は
１０〜３０分程度でよく、１０分未満の短時間では目的
の反応が完結しない。(4) Reduction step. The water to be treated that has been treated in the mixing tank 2 is used in the following iron contact tank 3
Will be introduced to. Here, by passing through the reaction layer 31 of metallic iron particles and bringing them into contact with metallic iron, the dissolved nitric acid content and nitric acid content are reduced to ammonia, and a part thereof is also reduced to nitrogen gas for removal. Here, in FIG.
As shown in FIG. 6, the main reaction changes depending on the pH, but as shown in FIG. 6 showing the relationship between the reaction time in the metallic iron contact treatment and the N concentration of the treated water, the reaction time is about 10 to 30 minutes. Well, the desired reaction is not completed in a short time of less than 10 minutes.
【００２０】なお、この金属鉄粒子の反応層・３１は、
直径０．８〜１．５ｍｍ程度の金属鉄粒子を積層して形
成するのが望ましい。また、この工程が進行するに従い
反応層３１には固形物が堆積して反応効率が低下するの
で、常法により洗浄用空気配管３２または洗浄水配管３
３から空気または洗浄水を供給して１回／日程度の頻度
で洗浄するのが好ましい。The reaction layer 31 of the metallic iron particles is
It is desirable to stack and form metallic iron particles having a diameter of about 0.8 to 1.5 mm. Further, as this process progresses, solid substances are deposited on the reaction layer 31 and the reaction efficiency is reduced, so that the cleaning air pipe 32 or the cleaning water pipe 3 is formed by a conventional method.
It is preferable to supply air or washing water from No. 3 to wash once or about once a day.
【００２１】（５）中和工程。
次いで、中和槽４でカセイソーダなどのアルカリ薬剤を
添加してｐＨ７程度に中和処理する。この場合、液中に
溶存している鉄分がフロック化する。なお、この工程に
おいて、次工程の不連続点塩素化反応に必要な塩素系酸
化剤、例えば次亜塩素酸ナトリウムなどを予め添加すれ
ば、その塩素系酸化剤のアルカリ分を中和に役立てるこ
とができ、中和用の前記アルカリ薬剤の添加量を削減す
ることができる利点がある。(5) Neutralization step. Next, an alkaline chemical such as caustic soda is added in the neutralization tank 4 to neutralize the pH to about 7. In this case, the iron content dissolved in the liquid becomes flocs. In this step, if a chlorine-based oxidizing agent necessary for the discontinuous point chlorination reaction in the next step, such as sodium hypochlorite, is added in advance, the alkali content of the chlorine-based oxidizing agent can be used for neutralization. It is possible to reduce the addition amount of the alkaline chemical for neutralization.
【００２２】この塩素系酸化剤の添加量は、二酸化マン
ガン処理におけるＮａＣｌＯ添加率とＴ−Ｎ除去率の関
係を表す図７に示すように、Ｃｌ２換算で、原水中の全
窒素量（Ｔ−Ｎ）の５〜７倍とするのが好ましい。な
お、不連続点塩素化反応においては、その理論的添加量
はアンモニア窒素の７．６倍とされているが、本発明に
おいては、後記の通り二酸化マンガンによる酸化触媒反
応も進行するので、酸化剤の添加量を約２０％も節減で
きる利点がある。As shown in FIG. 7, which shows the relationship between the NaClO addition rate and the TN removal rate in the manganese dioxide treatment, the amount of the chlorine-based oxidant added is calculated as Cl 2 and the total amount of nitrogen in the raw water (T -N) is preferably 5 to 7 times. In addition, in the discontinuous point chlorination reaction, the theoretical addition amount is set to 7.6 times that of ammonia nitrogen, but in the present invention, since the oxidation catalyst reaction by manganese dioxide also proceeds as described later, There is an advantage that the added amount of the agent can be reduced by about 20%.
【００２３】（６）二酸化マンガン処理工程。
中和された被処理水は二酸化マンガン接触槽５に導入さ
れる。ここでは、先ず内蔵した二酸化マンガン層５１に
よって前記鉄フロックが捕捉され、除去される。次い
で、塩素系酸化剤の存在下に二酸化マンガン層に接触さ
せることにより、液中の有機性窒素分をアンモニアに分
解し、かつ塩素系酸化剤による不連続点塩素化反応と二
酸化マンガンによる酸化触媒反応によりアンモニア分を
窒素ガスとして除去することができる。この反応時間
は、二酸化マンガン処理における反応時間とＴ−Ｎ除去
率の関係を表す図８に示すように、２〜１０分の短時間
で所要の反応が完結する。かくして、窒素除去処理され
た液は、処理済水として放流することができるようにな
る。(6) Manganese dioxide treatment step. The neutralized water to be treated is introduced into the manganese dioxide contact tank 5. Here, the iron flocs are first captured and removed by the built-in manganese dioxide layer 51. Then, by contacting the manganese dioxide layer in the presence of a chlorine-based oxidizing agent, the organic nitrogen content in the liquid is decomposed into ammonia, and the discontinuous point chlorination reaction by the chlorine-based oxidizing agent and the oxidation catalyst by manganese dioxide are performed. Ammonia can be removed as nitrogen gas by the reaction. As for this reaction time, as shown in FIG. 8 showing the relationship between the reaction time in the manganese dioxide treatment and the TN removal rate, the required reaction is completed in a short time of 2 to 10 minutes. Thus, the nitrogen-removed liquid can be discharged as treated water.
【００２４】この二酸化マンガン層５１としては、直径
１〜５ｍｍ程度のものを積層して形成すればよく、また
鉄フロックなどによる目詰まり防止のため、１回／１〜
２日程度の割合で洗浄用空気配管５２または洗浄水配管
５３から空気または水を供給して定期的に洗浄するのが
よい。また、この二酸化マンガン層の入口側の直後に、
例えば１０〜３０ｃｍ程度中に入った部位に洗浄水を供
給できるように洗浄水配管５４を設けておき、前記定期
的洗浄の間において、中間的な逆洗浄を行うようにすれ
ば、二酸化マンガン層の入口側に捕捉されている鉄フロ
ックを効果的に除去することができる。The manganese dioxide layer 51 may be formed by laminating layers having a diameter of about 1 to 5 mm, and once per 1 to 1 to prevent clogging due to iron flock or the like.
It is advisable to supply air or water from the cleaning air pipe 52 or the cleaning water pipe 53 at a rate of about 2 days for periodic cleaning. Also, immediately after the inlet side of this manganese dioxide layer,
For example, if a washing water pipe 54 is provided so that washing water can be supplied to a portion that has entered the inside of about 10 to 30 cm and intermediate back washing is performed between the periodic washings, a manganese dioxide layer can be obtained. The iron flocs trapped on the inlet side of the can be effectively removed.
【００２５】[0025]
【実施例】次に、本発明の１実施例を消化液循環法のよ
る従来法との比較で表１に示す。これによれば、所要処
理時間は、従来法の３６０分に対して、本発明で５０分
と約７分の１に短縮でき、大幅な処理能力の向上あるい
は設備規模のコンパクト化が期待できるようになった。
さらに、全窒素（Ｔ−Ｎ）の除去において、従来法６２
％であったものが本発明９０％という顕著な除去率を得
ることができた。また、併せてＣＯＤの除去において
も、従来３１％→本発明５６％に向上した。EXAMPLES Next, one example of the present invention is shown in Table 1 in comparison with a conventional method of digestive juice circulation method. According to this, the required processing time can be shortened to 50 minutes or about 1/7 in the present invention, compared with 360 minutes in the conventional method, and it is expected that the processing capacity can be greatly improved or the facility scale can be made compact. Became.
Furthermore, in removing total nitrogen (TN), the conventional method 62
%, The remarkable removal rate of 90% of the present invention could be obtained. In addition, also in the removal of COD, it was improved from the conventional 31% to the present invention 56%.
【００２６】[0026]
【表１】
注１：従来例としては硝化液循環法を採用した。この場
合、硝化液循環率＝原水比：１００％、汚泥返送率＝原
水比：３０％、曝気槽活性汚泥濃度＝１２００ｍｇ／ｌ
であった。
注２：本発明における薬品添加率は、ＣｏＣｌ２＝２ｍ
ｇ／ｌ、Ｎａ２ＳＯ３＝１００ｍｇ／ｌ、ＮａＣｌＯ
（Ｃｌ２として）＝原水のＴ−Ｎの６倍とした。[Table 1] Note 1: As a conventional example, the nitrification solution circulation method was adopted. In this case, nitrification solution circulation rate = raw water ratio: 100%, sludge return rate = raw water ratio: 30%, aeration tank activated sludge concentration = 1200 mg / l
Met. Note 2: The chemical addition rate in the present invention is CoCl 2 = 2 m
g / l, Na 2 SO 3 = 100 mg / l, NaClO
(As Cl 2 ) = 6 times TN of raw water.
【００２７】さらに本発明では、次の有利な点が指摘で
きる。
（１）従来の消化液循環法のような硝化槽や硝化用の空
気の供給が必要でなく、また硝化液や活性汚泥の返送、
循環も必要でないから、装置自体が単純に構成できる。
（２）不連続点塩素化反応と二酸化マンガンによる酸化
触媒反応も同時に進行するので、不連続点塩素化反応単
独の場合に比較して酸化剤の添加量を約２０％も節減で
きる。
（３）従来法では、窒素除去率を向上させるにはメタノ
ール添加などの多段階処理が必要であったが、本発明で
は、そのような複雑な装置、方法によらず、大幅な窒素
除去率の向上が可能となる。
（４）本発明は生物学的処理ではないので、反応速度が
大きいから、処理能力アップまたは装置自体をコンパク
トにすることができる他、冬期のような低水温季節にお
いても、安定した除去処理が可能である。Furthermore, the following advantages can be pointed out in the present invention. (1) It is not necessary to supply a nitrification tank or air for nitrification as in the conventional digestive liquid circulation method, and to return the nitrification liquid or activated sludge,
Since no circulation is required, the device itself can be constructed simply. (2) Since the discontinuous point chlorination reaction and the oxidation catalyst reaction with manganese dioxide also proceed at the same time, the addition amount of the oxidizing agent can be reduced by about 20% as compared with the case of the discontinuous point chlorination reaction alone. (3) In the conventional method, a multi-step treatment such as addition of methanol was required to improve the nitrogen removal rate, but in the present invention, a significant nitrogen removal rate is obtained regardless of such a complicated apparatus and method. Can be improved. (4) Since the present invention is not a biological treatment, since the reaction rate is high, the treatment capacity can be increased or the apparatus itself can be made compact, and stable removal treatment can be performed even in low water temperature seasons such as winter. It is possible.
【００２８】[0028]
【発明の効果】本発明の窒素含有排水の処理方法は、以
上に説明したように構成されているので、従来法より優
れた窒素除去率およびＣＯＤ除去率を実現し、かつ処理
速度を大幅に短縮するなどが可能となり、処理能力改善
または装置のコンパクト化が達成できるという優れた効
果がある。よって本発明は従来の問題点を解消した窒素
含有排水の処理方法として、その工業的価値は極めて大
なるものがある。Since the method for treating nitrogen-containing wastewater of the present invention is configured as described above, it is possible to realize a nitrogen removal rate and a COD removal rate which are superior to those of the conventional methods and to significantly increase the treatment rate. It has an excellent effect that it can be shortened and the processing capacity can be improved or the apparatus can be made compact. Therefore, the present invention has a very great industrial value as a method for treating nitrogen-containing wastewater that solves the conventional problems.
【図１】本発明の実施形態を説明するための装置配置
図。FIG. 1 is a device layout view for explaining an embodiment of the present invention.
【図２】硝化液循環法をを説明するための装置配置図。FIG. 2 is an apparatus layout diagram for explaining a nitrification solution circulation method.
【図３】実施形態における塩化コバルト添加量と混和液
のＤＯの関係FIG. 3 shows the relationship between the amount of cobalt chloride added and the DO of the mixed solution in the embodiment.
【図４】同じく亜硫酸ナトリウム添加量と混和液のＤＯ
の関係[Fig. 4] Similarly, the amount of sodium sulfite added and the DO of the mixed solution
connection of
【図５】同じく金属鉄接触処理における反応ｐＨと処理
水Ｎ濃度の関係[Fig. 5] Similarly, the relationship between the reaction pH and the N concentration of treated water in the metallic iron contact treatment.
【図６】同じく金属鉄接触処理における反応時間と処理
水Ｎ濃度の関係[Fig. 6] Similarly, the relationship between reaction time and N concentration of treated water in metallic iron contact treatment
【図７】同じく二酸化マンガン処理におけるＮａＣｌＯ
添加率とＴ−Ｎ除去率の関係[FIG. 7] Similarly, NaClO in manganese dioxide treatment
Relationship between addition rate and TN removal rate
【図８】同じく二酸化マンガン処理における反応時間と
Ｔ−Ｎ除去率の関係FIG. 8 is a relationship between reaction time and TN removal rate in the manganese dioxide treatment.
２ 混和槽、３ 鉄接触槽、３１ 反応層、３２ 洗浄
用空気配管、３３ 洗浄水配管、４ 中和槽、５ 二酸
化マンガン接触槽、５１ 二酸化マンガン層、５２ 洗
浄用空気配管、５３ 洗浄水配管、５４ 洗浄水配管。2 mixing tank, 3 iron contact tank, 31 reaction layer, 32 cleaning air piping, 33 cleaning water piping, 4 neutralization tank, 5 manganese dioxide contacting tank, 51 manganese dioxide layer, 52 cleaning air piping, 53 cleaning water piping , 54 Wash water piping.
───────────────────────────────────────────────────── フロントページの続き (58)調査した分野(Int.Cl.7，ＤＢ名) C02F 1/70 C02F 1/72 C02F 1/58 ─────────────────────────────────────────────────── ─── Continuation of the front page (58) Fields surveyed (Int.Cl. 7 , DB name) C02F 1/70 C02F 1/72 C02F 1/58
Claims (5)
理することを特徴とする窒素含有排水の処理方法。 （１）原水に塩化コバルトを添加する工程。 （２）亜硫酸ナトリウムを混和して、原水中の溶存酸素
を除去する工程。 （３）ｐＨを酸性に調整する工程。 （４）金属鉄に接触させ、溶存する硝酸分、亞硝酸分を
アンモニアに還元するとともに、一部を窒素ガスにまで
還元して除去する工程。 （５）ｐＨをほぼ中性に調整する工程。 （６）塩素系酸化剤の存在下に二酸化マンガン層に接触
させ、鉄フロックを除去するとともに有機性窒素分をア
ンモニアに分解し、かつ塩素系酸化剤による不連続点塩
素化反応と二酸化マンガンによる酸化触媒反応によりア
ンモニア分を窒素ガスとして除去する工程。 1. A method for treating nitrogen-containing wastewater, which comprises treating raw water containing nitrogen by the following steps. (1) A step of adding cobalt chloride to raw water. (2) A step of admixing sodium sulfite to remove dissolved oxygen in the raw water. (3) Step of adjusting pH to acidic. (4) A step of bringing into contact with metallic iron to reduce the dissolved nitric acid content and nitric acid content to ammonia, and at the same time, to reduce a part thereof to nitrogen gas to remove it. (5) A step of adjusting pH to almost neutral. (6) Contact with a manganese dioxide layer in the presence of a chlorine-based oxidant to remove iron flocs, decompose organic nitrogen into ammonia, and discontinue point chlorination reaction with a chlorine-based oxidizer and manganese dioxide. A step of removing the ammonia content as nitrogen gas by an oxidation catalyst reaction.
いて、アルカリ性の塩素系酸化剤を添加した後、アルカ
リ剤を添加する請求項１に記載の窒素含有排水の処理方
法。 2. The method for treating nitrogen-containing wastewater according to claim 1 , wherein, in the step of adjusting the pH to be substantially neutral, an alkaline chlorine-based oxidizing agent is added and then an alkaline agent is added.
処理水との接触時間が１０〜３０分であり、かつ前記二
酸化マンガン層と処理水との接触時間が２〜１０分であ
る請求項１または２に記載の窒素含有排水の処理方法。 3. The metallic iron is a particle layer of metallic iron,
The method for treating nitrogen-containing wastewater according to claim 1 or 2, wherein the contact time with the treated water is 10 to 30 minutes, and the contact time between the manganese dioxide layer and the treated water is 2 to 10 minutes.
／ｌ、前記亜硫酸ナトリウムの添加量が５０〜１００ｍ
ｇ／ｌ、および前記塩素系酸化剤の添加量がＣｌ２ 換
算で原水中の全窒素量の５〜７倍である請求項１〜３の
いずれかに記載の窒素含有排水の処理方法。 Wherein said amount of cobalt chloride 1~2mg
/ L, the amount of sodium sulfite added is 50 to 100 m
The treatment of nitrogen-containing wastewater according to any one of claims 1 to 3, wherein g / l and the amount of the chlorine-based oxidizing agent added are 5 to 7 times the total amount of nitrogen in the raw water in terms of Cl2. Method.
に洗浄水および同空気を供給して逆洗浄を行うととも
に、前記二酸化マンガン層の入口側部分について、前記
逆洗浄よりも頻度高く洗浄を行う請求項１〜４のいずれ
かに記載の窒素含有排水の処理方法。About wherein said manganese dioxide layer, performs the wash water and backwash by supplying the air in the opposite direction, said the inlet section of the manganese dioxide layer, wherein performing frequency higher cleaning than the backwashing Item 5. A method for treating nitrogen-containing wastewater according to any one of Items 1 to 4 .
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|---|---|---|---|
| JP33136298A JP3403348B2 (en) | 1998-11-20 | 1998-11-20 | Treatment method for nitrogen-containing wastewater |
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| KR100734035B1 (en) | 2003-05-30 | 2007-07-02 | 주식회사 한성엔이티 | Method for reducing nitrogen in nitrate solution |
| JP5192656B2 (en) * | 2006-04-21 | 2013-05-08 | 本荘ケミカル株式会社 | Method for removing nitrogen compounds in aqueous lithium halide solution |
| JP5580704B2 (en) * | 2010-04-01 | 2014-08-27 | 株式会社神戸製鋼所 | Purification method of contaminated water |
| CN110407357A (en) * | 2019-07-23 | 2019-11-05 | 个旧兴华锌业有限公司 | The solution chloride ion minimizing technology of waste acid containing chlorine |
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