JPS586292A - Treatment of water - Google Patents

Abstract

PURPOSE:To eliminate the nitrogen compds. and BOD components in water to be treated by returning said water which is removed of the BOD components by an activated sludge treatment and ammoniac nitrogen nitrification and is controlled of pH to a denitrification tank at prescribed reflux ratios. CONSTITUTION:Water to be treated contg. ammoniac nitrogen, org. nitrogen compds., BOD components, etc. is introduced through an introduction line 18 into a denitrification tank 11, and alcohol, etc. are added to this through a line 19 and these are agitated with an agitator 11A whereby BOD components are removed and org. nitrogen substances are reduced to ammoniac nitrogen. This water is introduced into a nitrating tank 12, where it is aerated with an aeration means 12A; at the same time, an alkali is added thereto through a line 20 to prevent the decrease in pH and to oxidize the ammoniac nitrogen to nitrate nitrogen. The water is returned through a line 16 into the tank 11 at prescribed reflux ratios, where the residual BOD components are removed and the nitrate nitrogen is reduced to gaseous nitrogen, whereby denitrification is executed.

Description

【発明の詳細な説明】 本発明は例えば塵埃埋立地の浸出水のようなりＯＤ成分
濃度が比較的低いが窒素化合物を高濃度に含む被処理水
の窒素化合物およびＢＯＤ成分を除去する水処理方法に
関するものである。DETAILED DESCRIPTION OF THE INVENTION The present invention provides a water treatment method for removing nitrogen compounds and BOD components from water to be treated, such as leachate from a dust landfill, which has a relatively low concentration of OD components but contains a high concentration of nitrogen compounds. It is related to.

従来は第１図に示すように第１脱窒槽（１）ＫＢＯＤ成
分、アンモニア性憲素、有機窒素化合物等を含む被処理
水Ｔを導入し、活性汚泥および炭素源としてア〃コーμ
ムを添加し、攪拌機（１）ムによって混合してＢＯＤ成
分を除去し、かつ有機窒素化合物をアンモニア性窒素に
還元し、次いで硝化槽（２）において＠気手段（２）人
によって曝気すると共にアルカリＢを添加して系のＰＨ
低下を防止しつつ被処理水中のアンモニア性窒素を硝酸
性窒素に酸化し、かつ残存するＢＯＤ成分を更に除去し
、更に第２脱窒槽（３）において炭素源としてアμコー
μムを被処理水に添加し、攪拌機（３）ムによって混合
し、被処理水中の硝酸性窒素を窒素ガスに迄還元するこ
とによって脱窒を行い、再び再曝気槽（４）にて再曝気
することによって被処理水中のアμコーμを含ムＢ　Ｏ
Ｄ成分を完全に除去し、被処理水中のＡ［，８８は沈澱
槽（５）Ｋよって沈降分離し、所定量を返送汚泥として
再び第１脱窒槽（１）に返送径路（７）を介して返送す
るもので、この際硝化槽（２）の硝酸性窒素を含む被処
理水を循還径路（６）を介してポンプ（６）ムによって
第１脱窒槽（１）に所定の還流比によって戻し第１脱窒
槽（１）によって脱窒を行い、脱窒によって生ずるｏｆ
を硝化槽（２）におけるＰＨ低下防止のためのアルカリ
の一部として利用して省アルカリを図るものである。Conventionally, as shown in Figure 1, treated water T containing KBOD components, ammoniacal elements, organic nitrogen compounds, etc., was introduced into the first denitrification tank (1), and Acco μ was used as activated sludge and carbon source.
and mixed by a stirrer (1) to remove BOD components and reduce organic nitrogen compounds to ammonia nitrogen, and then aerated by human means (2) in a nitrification tank (2). The pH of the system is adjusted by adding alkali B.
Ammonia nitrogen in the water to be treated is oxidized to nitrate nitrogen while preventing denitrification, and remaining BOD components are further removed, and Aμ comb is used as a carbon source in the second denitrification tank (3). It is added to the water, mixed with the stirrer (3), denitrified by reducing the nitrate nitrogen in the water to be treated to nitrogen gas, and then re-aerated in the re-aeration tank (4). Contains AμCOμ in the treated water BO
After completely removing the D component, the A [, 88 in the water to be treated is separated by sedimentation in the sedimentation tank (5) K, and a predetermined amount is returned as sludge to the first denitrification tank (1) via the return path (7). At this time, the water to be treated containing nitrate nitrogen from the nitrification tank (2) is returned to the first denitrification tank (1) at a predetermined reflux ratio by a pump (6) via a circulation path (6). The denitrification is carried out in the first denitrification tank (1), and the of produced by the denitrification is
The purpose is to save alkali by using it as a part of the alkali to prevent a decrease in pH in the nitrification tank (2).

このように脱窒槽を二段に設けることは主としてＢＯＤ
成分濃度が１００００　ｐｐｍ程度でかつ窒素化合物濃
度が３０００ｐｐｍ程度のいわゆる高ＢＯＤ高Ｎ含有被
処理水、例えば希釈展間のような被処理水を対象とした
場合には必須のものであったが、例えば塵埃埋立地の浸
出水のよう［ＢＯＤ成分濃度が５０〜３００ｐｐｍ。Providing two stages of denitrification tanks in this way is mainly used for BOD
This was essential when treating water with a component concentration of about 10,000 ppm and a nitrogen compound concentration of about 3,000 ppm, so-called high BOD and high N content, such as water used for dilution. For example, leachate from a dust landfill [BOD component concentration is 50 to 300 ppm.

窒素化合物濃度が１００〜４００ｐｐｍ程度のいわゆる
低ＢＯＤ高Ｎ含有被処理水゛に対してはこのような二段
方式の脱窒槽は性能過剰である。Such a two-stage denitrification tank has excessive performance for so-called low BOD, high N-containing treated water having a nitrogen compound concentration of about 100 to 400 ppm.

本発明は特にかかる低ＢＯＤ高Ｎ含有被処理水を対象と
するもので、かかる被処理水を処理するに適した装置を
提供することを目的とし、脱窒槽を一段とすることを骨
子とするものである。The present invention is particularly directed to such low BOD and high N content water to be treated, and aims to provide a device suitable for treating such water, and its main feature is to provide a denitrification tank in one stage. It is.

本発明を＠２図に示す一実施例によって説明すれば、■
は脱窒槽であシ攪拌４Ｉ（ロ）ムが内部に取付けられ、
（２）は硝化槽であシ底部には曝気手段（ロ）ムが設け
られ、（至）は沈澱槽である。アンモニア性窒素、およ
び蛋白質、ペプチド、アミン等の有機窒素化合物、硝酸
性窒素、およびＢＯＤ成分等を含む被処理水はまず導入
径路（至）よシ脱窒槽（ロ）に導入され、アルコ−μの
添加径路（至）よシ低沸点のアルコ−〃、例えばメタノ
−μが微生物の戻素源として根石され、また沈澱槽（至
）から沈降分離された活性汚泥が返送径路＠より返送さ
れて添加され攪拌機Ｑｌ）ムによって攪拌混合される。To explain the present invention using an embodiment shown in Figure @2,
is a denitrification tank with a stirring 4I (Rom) installed inside.
(2) is a nitrification tank, the bottom of which is provided with aeration means, and (2) is a settling tank. The water to be treated containing ammonia nitrogen, organic nitrogen compounds such as proteins, peptides, and amines, nitrate nitrogen, and BOD components is first introduced into the denitrification tank (b) through the introduction path (to), and then Low boiling point alcohols, such as methano-μ, are used as a return source for microorganisms through the addition route, and activated sludge that has been sedimented and separated from the settling tank is returned through the return route. and stirred and mixed by a stirrer Ql).

かくして被処理水中に含まれるＢＯＤ成分は除去され、
かつ有機窒素化合物はアンモニア性窒素に還元される０
次いで被処理水は脱窒槽（ＩＩ）カーら硝化槽（２）に
導入され曝気手段（２）ムによって曝気されつつＰＨ低
下を防止するためアルカリの添加径路（転）よりカセイ
ソーダ、力士イカリ等のアμカリ水溶液を添加混合され
る。In this way, BOD components contained in the water to be treated are removed,
and organic nitrogen compounds are reduced to ammonia nitrogen.
Next, the water to be treated is introduced from the denitrification tank (II) to the nitrification tank (2), where it is aerated by the aeration means (2), and in order to prevent the pH from decreasing, caustic soda, sumo ikali, etc. Aqueous caustic solution is added and mixed.

かくして硝化槽（２）においては被処理水中に含まれる
アンモニア性窒素は酸化されて硝酸性窒素となり、同時
に被処理水中に残存するＢＯＤ成分は活性汚泥によυ生
物学的に分解除去される。Thus, in the nitrification tank (2), ammonia nitrogen contained in the water to be treated is oxidized to nitrate nitrogen, and at the same time, the BOD components remaining in the water to be treated are biologically decomposed and removed by the activated sludge.

硝化槽（２）中の被処理水は循還径路α呻を介してポン
プαφムによって所定の還流比（通常は被処理水の流入
量の２〜１０倍）によって脱窒槽（ロ）に戻され、脱窒
槽Ｑｌ）において更に残存するＢＯＤ成分が除去される
とともに含有する硝酸性窒素は窒素ガスに還元され脱窒
される。脱窒の際に生じたＯＨは硝化槽（２）における
硝化の際にアルカリの一部として用いられ得るから硝化
槽（２）におけるアルカリの添加量はそれだけ削減され
る。The water to be treated in the nitrification tank (2) is returned to the denitrification tank (b) via the circulation path α by a pump αφ at a predetermined reflux ratio (usually 2 to 10 times the inflow of water to be treated). The remaining BOD components are further removed in the denitrification tank Ql), and the nitrate nitrogen contained therein is reduced to nitrogen gas and denitrified. Since the OH generated during denitrification can be used as part of the alkali during nitrification in the nitrification tank (2), the amount of alkali added in the nitrification tank (2) is reduced accordingly.

かくして処理された被処理水中のＭＬ８８は沈澱槽（至
）によって沈降分離され、一部は返送径路Ｑ′１）を介
して返送汚泥として脱窒槽（ロ）忙返送される。The ML88 in the water thus treated is sedimented and separated in the settling tank (2), and a portion is returned to the denitrification tank (2) as return sludge via the return path Q'1).

前記した従来法によれば一般的に処理時間は第１脱窒で
１０時間、硝化で１７時間、第２脱窒で５時間、再曝慨
で２時間、沈降分離で８時間、肚４２時間の処理時間と
なるが、本発明では脱窒で１０時間、硝化で１７時間、
沈降分離で８時間、計３５時間に処理時間が短縮される
。According to the conventional method described above, the treatment time is generally 10 hours for the first denitrification, 17 hours for the nitrification, 5 hours for the second denitrification, 2 hours for the re-exposure, 8 hours for the sedimentation, and 42 hours for the final treatment. However, in the present invention, the treatment time is 10 hours for denitrification, 17 hours for nitrification,
Sedimentation separation reduces the processing time to 8 hours, a total of 35 hours.

そして処理能力においても窒素濃度２００ｐｐＨｌｌ。In terms of processing capacity, the nitrogen concentration is 200ppHll.

ＢＯＤ成分濃度２００ｐｐｍの被処理水の場合、本発明
の方法で処理を行った結果窒素濃度９ｐｐｍ、ＢＯＤ成
分濃＆　１５　ｐ　ｐ　ｍＫ低下１．Ｃｅ来法の窒素濃
度９ＰＰｍ％ＢＯＤ成分膿度１０ｐｐｍに比して殆んど
変わらない。In the case of treated water with a BOD component concentration of 200 ppm, the treatment according to the method of the present invention resulted in a nitrogen concentration of 9 ppm, BOD component concentration & 15 ppmK reduction1. There is almost no difference compared to the conventional Ce method, which has a nitrogen concentration of 9 PPm% and a BOD component purulence of 10 ppm.

かくして本発明は処理槽が従来の４檜から２槽に減り装
置コストが大巾に低減され、また装置占有空間も当然約
半分程度になり、アルコ−１ｖ添加手段は脱窒槽に一個
所設ければよいから省メンテナンス、および省機材の効
果があシ、更に脱窒に要する攪拌動カ屯略半減し、しか
も再＠気に要するエネルギーも不要となる。Thus, in the present invention, the number of treatment tanks is reduced from the conventional four cypress tanks to two, which greatly reduces the equipment cost.Also, the space occupied by the equipment is naturally reduced to about half, and the alcohol 1v addition means is provided in one place in the denitrification tank. This has the effect of saving maintenance and equipment, and furthermore, the stirring force required for denitrification is reduced by almost half, and the energy required for re-treatment is also unnecessary.

【図面の簡単な説明】[Brief explanation of the drawing]

第１図は従来の系統概略図、第２図は本発明の一実施例
の系統概略図である。 図中、αト・・・脱窒槽、（２）・・・・硝化槽、（イ
）ム・・・・曝気手段 特許出願人　大同特殊鋼株式会社 第１図FIG. 1 is a schematic diagram of a conventional system, and FIG. 2 is a schematic diagram of a system according to an embodiment of the present invention. In the figure, α... denitrification tank, (2)... nitrification tank, (i) m... aeration means patent applicant Daido Steel Co., Ltd. Figure 1

Claims (1)

【特許請求の範囲】[Claims] 被処理水を脱窒槽に導ひき、活性汚泥を添加して被処理
水中のＢＯＤ成分を除去し、次いで硝化槽に導びいて曝
気しつつ被処理水中に含まれるアンモニア性窒素を硝化
すると共に被処理水中の残存ＢＯＤ成分を除去し、９ｅ
かつアルカリを添加して被処理水のＰＲの低下を防止し
、かくして硝酸性窒素を含む硝化槽中の被処理水は所定
の還流比によって脱窒槽に還流せしめ、脱窒槽において
揮発性炭素源を活性汚泥に補給しつつ硝酸性窒素を窒素
ガスに分解することを特徴とする水処理方法。The water to be treated is led to a denitrification tank, activated sludge is added to remove BOD components in the water, and then the water is led to a nitrification tank where ammonia nitrogen contained in the water is nitrified while being aerated. Removal of residual BOD components in treated water, 9e
In addition, alkali is added to prevent a decrease in the PR of the water to be treated, and thus the water to be treated in the nitrification tank containing nitrate nitrogen is returned to the denitrification tank at a predetermined reflux ratio, and the volatile carbon source is removed in the denitrification tank. A water treatment method characterized by decomposing nitrate nitrogen into nitrogen gas while replenishing activated sludge.