JPH0218907B2 - - Google Patents
Info
- Publication number
- JPH0218907B2 JPH0218907B2 JP23692486A JP23692486A JPH0218907B2 JP H0218907 B2 JPH0218907 B2 JP H0218907B2 JP 23692486 A JP23692486 A JP 23692486A JP 23692486 A JP23692486 A JP 23692486A JP H0218907 B2 JPH0218907 B2 JP H0218907B2
- Authority
- JP
- Japan
- Prior art keywords
- amount
- calcium
- added
- wastewater
- oxalate
- 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
- MUBZPKHOEPUJKR-UHFFFAOYSA-N Oxalic acid Chemical compound OC(=O)C(O)=O MUBZPKHOEPUJKR-UHFFFAOYSA-N 0.000 claims description 37
- 239000011575 calcium Substances 0.000 claims description 36
- 238000000034 method Methods 0.000 claims description 23
- 239000002351 wastewater Substances 0.000 claims description 22
- OYPRJOBELJOOCE-UHFFFAOYSA-N Calcium Chemical compound [Ca] OYPRJOBELJOOCE-UHFFFAOYSA-N 0.000 claims description 17
- 229910052791 calcium Inorganic materials 0.000 claims description 17
- 235000006408 oxalic acid Nutrition 0.000 claims description 12
- 150000003839 salts Chemical class 0.000 claims description 4
- 230000001112 coagulating effect Effects 0.000 claims 1
- 230000001376 precipitating effect Effects 0.000 claims 1
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 18
- HEMHJVSKTPXQMS-UHFFFAOYSA-M Sodium hydroxide Chemical compound [OH-].[Na+] HEMHJVSKTPXQMS-UHFFFAOYSA-M 0.000 description 15
- XEEYBQQBJWHFJM-UHFFFAOYSA-N iron Substances [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 14
- 238000002474 experimental method Methods 0.000 description 7
- 239000000126 substance Substances 0.000 description 7
- BHPQYMZQTOCNFJ-UHFFFAOYSA-N Calcium cation Chemical compound [Ca+2] BHPQYMZQTOCNFJ-UHFFFAOYSA-N 0.000 description 6
- 229910001424 calcium ion Inorganic materials 0.000 description 6
- QXDMQSPYEZFLGF-UHFFFAOYSA-L calcium oxalate Chemical compound [Ca+2].[O-]C(=O)C([O-])=O QXDMQSPYEZFLGF-UHFFFAOYSA-L 0.000 description 6
- 238000001556 precipitation Methods 0.000 description 6
- 229910021578 Iron(III) chloride Inorganic materials 0.000 description 5
- 239000003795 chemical substances by application Substances 0.000 description 5
- RBTARNINKXHZNM-UHFFFAOYSA-K iron trichloride Chemical compound Cl[Fe](Cl)Cl RBTARNINKXHZNM-UHFFFAOYSA-K 0.000 description 5
- 235000011121 sodium hydroxide Nutrition 0.000 description 5
- 238000013459 approach Methods 0.000 description 4
- 230000015271 coagulation Effects 0.000 description 4
- 238000005345 coagulation Methods 0.000 description 4
- 238000007796 conventional method Methods 0.000 description 4
- 229910052742 iron Inorganic materials 0.000 description 4
- 125000000896 monocarboxylic acid group Chemical group 0.000 description 4
- 238000005341 cation exchange Methods 0.000 description 3
- VEPSWGHMGZQCIN-UHFFFAOYSA-H ferric oxalate Chemical compound [Fe+3].[Fe+3].[O-]C(=O)C([O-])=O.[O-]C(=O)C([O-])=O.[O-]C(=O)C([O-])=O VEPSWGHMGZQCIN-UHFFFAOYSA-H 0.000 description 3
- 230000003472 neutralizing effect Effects 0.000 description 3
- 238000004062 sedimentation Methods 0.000 description 3
- 239000010865 sewage Substances 0.000 description 3
- 229910001220 stainless steel Inorganic materials 0.000 description 3
- 239000010935 stainless steel Substances 0.000 description 3
- 238000003756 stirring Methods 0.000 description 3
- VBIXEXWLHSRNKB-UHFFFAOYSA-N ammonium oxalate Chemical compound [NH4+].[NH4+].[O-]C(=O)C([O-])=O VBIXEXWLHSRNKB-UHFFFAOYSA-N 0.000 description 2
- 238000006243 chemical reaction Methods 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 239000008394 flocculating agent Substances 0.000 description 2
- 238000005189 flocculation Methods 0.000 description 2
- 230000016615 flocculation Effects 0.000 description 2
- 239000007788 liquid Substances 0.000 description 2
- 229910052751 metal Inorganic materials 0.000 description 2
- 239000002184 metal Substances 0.000 description 2
- 150000002739 metals Chemical class 0.000 description 2
- 239000000203 mixture Substances 0.000 description 2
- 229920000642 polymer Polymers 0.000 description 2
- 239000002244 precipitate Substances 0.000 description 2
- ZNCPFRVNHGOPAG-UHFFFAOYSA-L sodium oxalate Chemical compound [Na+].[Na+].[O-]C(=O)C([O-])=O ZNCPFRVNHGOPAG-UHFFFAOYSA-L 0.000 description 2
- 229940039790 sodium oxalate Drugs 0.000 description 2
- 239000006228 supernatant Substances 0.000 description 2
- KCXVZYZYPLLWCC-UHFFFAOYSA-N EDTA Chemical compound OC(=O)CN(CC(O)=O)CCN(CC(O)=O)CC(O)=O KCXVZYZYPLLWCC-UHFFFAOYSA-N 0.000 description 1
- 239000003513 alkali Substances 0.000 description 1
- AZDRQVAHHNSJOQ-UHFFFAOYSA-N alumane Chemical class [AlH3] AZDRQVAHHNSJOQ-UHFFFAOYSA-N 0.000 description 1
- 229910052782 aluminium Inorganic materials 0.000 description 1
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 1
- DIZPMCHEQGEION-UHFFFAOYSA-H aluminium sulfate (anhydrous) Chemical compound [Al+3].[Al+3].[O-]S([O-])(=O)=O.[O-]S([O-])(=O)=O.[O-]S([O-])(=O)=O DIZPMCHEQGEION-UHFFFAOYSA-H 0.000 description 1
- 230000000052 comparative effect Effects 0.000 description 1
- 239000008139 complexing agent Substances 0.000 description 1
- 239000013078 crystal Substances 0.000 description 1
- 230000007423 decrease Effects 0.000 description 1
- 238000011161 development Methods 0.000 description 1
- 229940079593 drug Drugs 0.000 description 1
- 239000003814 drug Substances 0.000 description 1
- 229960004887 ferric hydroxide Drugs 0.000 description 1
- 239000010842 industrial wastewater Substances 0.000 description 1
- 150000002506 iron compounds Chemical class 0.000 description 1
- -1 iron ions Chemical class 0.000 description 1
- RUTXIHLAWFEWGM-UHFFFAOYSA-H iron(3+) sulfate Chemical compound [Fe+3].[Fe+3].[O-]S([O-])(=O)=O.[O-]S([O-])(=O)=O.[O-]S([O-])(=O)=O RUTXIHLAWFEWGM-UHFFFAOYSA-H 0.000 description 1
- IEECXTSVVFWGSE-UHFFFAOYSA-M iron(3+);oxygen(2-);hydroxide Chemical compound [OH-].[O-2].[Fe+3] IEECXTSVVFWGSE-UHFFFAOYSA-M 0.000 description 1
- 229910000360 iron(III) sulfate Inorganic materials 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 230000000873 masking effect Effects 0.000 description 1
- 238000006386 neutralization reaction Methods 0.000 description 1
- 229940039748 oxalate Drugs 0.000 description 1
- 150000003891 oxalate salts Chemical class 0.000 description 1
- 239000002245 particle Substances 0.000 description 1
- 238000002203 pretreatment Methods 0.000 description 1
- 230000001105 regulatory effect Effects 0.000 description 1
- 230000002000 scavenging effect Effects 0.000 description 1
Description
（産業上の利用分野）
本発明はごみ埋立地浸透排水、産業廃水、下水
等のカルシウム含有汚水の処理方法に関するもの
である。
（従来の技術）
カルシウム含有汚水の処理方法としては、用水
廃水便覧（用水廃水便覧編集委員会編、丸善(株)、
昭39年）にも記載されているように、沈澱除去
法、錯塩法、カチオン交換法等が知られている。
しかし沈澱除去法は汚水中にカセイソーダを加え
ることによりCaCO3の沈澱を生じさせるもので
あるが、汚水中に含まれるカルシウム及びその他
の共存物質の種類や濃度によつて処理能率が変化
して不安定であるうえ、PH11〜13の高アルカリで
処理するために中和のための後処理を必要とし、
薬品費が高価なものとなる欠点がある。また錯塩
法はEDTAのような錯化剤を汚水に加えること
によりカルシウムと反応させる方法であるが、他
の金属とも反応するのでカルシウム以外の金属が
多い場合には処理能率が変化して不安定となり、
またこの方法はカルシウムの除去法というよりも
マスキング法であるので、処理水が放流等により
水質変化した場合にはカルシウムが再析出してス
ケールを生ずることがある等の欠点があつた。更
にまたカチオン交換法は汚水中のSS濃度が高い
場合にはSSがカチオン交換剤を被覆して処理能
率が低下するため、SS除去のための前処理を必
要とし、設備費及びランニングコストが高くなる
欠点があつた。
（発明が解決しようとする問題点）
本発明はこのような従来の問題点を解決して、
共存物質に左右されることなく常に安定してカル
シウムを除去することができ、しかも処理費用が
安価なカルシウム含有汚水の処理方法を目的とし
て完成されたものである。
（問題点を解決するための手段）
本発明はカルシウムを含有する汚水に対して、
除去すべきCa++量に対する理論量に相当する蓚
酸またはその塩を添加したのち、Fe+++とAl+の
一方または双方を含む無機凝集剤を所定の濃度と
なるまで添加し、PH５以上の条件下で凝集沈澱を
行わせることを特徴とするものである。
本発明においては、処理すべき汚水に対して、
蓚酸または蓚酸アンモニウム、蓚酸ナトリウム等
の蓚酸塩が除去すべきカルシウムイオン量に相当
する量だけ添加される。なお除去すべきカルシウ
ムイオン量とは、処理前の汚水中に含有されるカ
ルシウムイオン量から処理後の汚水中に含有され
るカルシウムイオン量を差引いたカルシウムイオ
ン量をいう。処理後の汚水中のカルシウムイオン
量は規制値や使用目的に応じて設定されるもので
あり、通常50〜100mg／に設定される。このよ
うに蓚酸をカルシウム含有汚水に添加すると次の
とおりの反応が生じ水に不溶性の蓚酸カルシウム
が生成される。（COOH）2・2H2O＋Ca++→
（COOH）2Ca＋2H2O＋2H+従つて理論量は
Ca+++40ｇに対して、蓚酸は126ｇ、蓚酸アンモ
ニウムは140ｇ、蓚酸ナトリウムは134ｇであり、
また濃度ベースではCa++1mg／に対して、それ
ぞれ3.15mg／、3.5mg／、3.35mg／である。
なお蓚酸の添加量とCa除去率との関係は後述の
実施例及び第１図のグラフに示されるとおりであ
つて、理論量を同程度以上を添加したときに除去
率が100％に近付く。
また汚水中に２価の鉄が共存すると次のように
反応して水に不溶性の蓚酸鉄（）を生ずるため
２価の鉄イオンの除去も行なわれる。
（COOH）2・2H2O＋Fe+++→（COOH）2Fe＋2H2O＋2H+
ところがこのようにして生成された蓚酸カルシ
ウム及蓚酸鉄（）は微細な結晶であつてこのま
までは沈降分離が難しいので、本発明においては
３価のアルミニウムの一方または双方を含む無機
凝集剤が100mg／以上の濃度となるまで添加さ
れ、更に中和剤を添加してPHを５以上とした条件
下で凝集沈澱が行われる。無機凝集剤としては３
価の鉄化合物である塩化第２鉄のほか硫酸第２
鉄、３価のアルミニウム化合物である硫酸バン
土、PACなどを用いることもできる。このよう
な無機凝集剤を添加すると大きいフロツクが形成
され蓚酸カルシウムや、蓚酸鉄をその中に取込ん
で除去することが容易となる。ここで無機凝集剤
の濃度をFe+++またはAl+++として75mg／以上
としたのは、第２図に示されるように75mg／未
満ではCa除去率が60〜70％下となるためである。
なお高分子凝集剤が必要に応じて付加的に添加さ
れる。高分子凝集剤は生成した蓚酸カルシウムの
補捉にはそれ程効果がないが、無機凝集剤により
生成されたフロツクの沈降速度を高めることがで
きる。また本発明においてはNaOH等の中和剤
の添加によりPH５以上の条件下で凝集沈澱を行わ
せるが、これは第３図に示されるようにPH４以上
で塩化第２鉄が水酸化第２鉄のフロツクに変化し
て蓚酸カルシウムの粒子を捕捉するが、PH５以上
にすることによつてより確実に効果的に捕捉する
ためである。
以上の各処理薬剤の添加順序は、蓚酸または蓚
酸塩、無機凝集剤、中和剤の順序であることが好
ましいが、蓚酸カルシウムの生成はほぼ瞬間的に
起こるので、各処理薬剤のすべてを同時に添加し
ても何等支障はない。また処理薬剤添加後の凝集
操作は120rpm×５分＋60rpm×10分、あるいは
60rpm×15分等の常法に従えばよく、凝集操作後
の沈澱操作も30分間で十分である。
（実施例）
次に、各処理薬剤の添加量等とCa除去率との
関係を調べるために下記の実験を行つた。
＜実験１＞
ごみ埋立地浸透用排水であるPH6.6、SS68mg／
、Fe57.2mg／、Ca121mg／の水質の源水１
と、同じくごみ埋立地浸透排水であるPH6.7、
SS270mg／、Fe485mg／、Ca1270mg／の原
水２とをそれぞれ200容量のステンレス鋼製ド
ラム缶中に200ずつ採取し、撹拌機をセツトし
て60rpmで撹拌し、第１表に示す分量の蓚酸を添
加した。次に塩化第２鉄をFe+++濃度が100mg／
となるよう添加するとともに高分子凝集剤を１
mg／添加し、NaOHを表中に記した量ずつ加
えてPHを７前後に調整して60rpm×15分の撹拌を
継続した。撹拌終了後30分間静置し、上澄液をサ
イホンで分離して処理水とし、その水質を分析し
て表中に記した。これにより、蓚酸を理論量と同
程度以上添加したときにCa除去率が100％に近付
くことが分かる。
＜実験２＞
次に同上の原水１、原水２について蓚酸の添加
量を理論量の0.94倍及び0.99倍に固定し、無機凝
集剤としての塩化第２鉄の添加量を第２表に記し
たとおり変化させて同様に凝集沈澱を行わせ、処
理水の水質を分析した。これにより無機凝集剤の
添加量をFe+++として100mg／以上としたとき
Ca除去率が100％に近付くことが分かる。
＜実験３＞
無機凝集剤としてPACを用い、そのAl+++とし
ての添加量を第３表に記したとおり変化させて＜
実験２＞と同様にその影響を調べた。PACを用
いた場合にもAl+++として75mg／以上を添加す
ればFeCl3を用い場合と同様に優れたCa除去率が
達成されることが分かる。
〈実験４〉
次に蓚酸の添加量と無機凝集剤の添加量とを固
定し、NaOHの添加量を変化させてPHを第３表
に記したとおり変化させてこれによるCa除去率
の変動を調べた。これにより、PHが５以上のとき
にCa除去率が100％に近付くことが分かる。
＜比較例＞
上記の実験に用いたと同一の原水１、原水２を
従来技術として示した沈澱除去法により処理し
た。即ち、原水をステンレス鋼製ドラム缶中に
200入れ、60rpmで撹拌し、第５表に示す分量
のNaOH（16％）を添加して所定のPHに調整した
うえ15分間撹拌を継続した。その後30分間静置
し、上澄液をサイホンにて別の200容量のステ
ンレス鋼製ドラム缶に移し、更に第５表に示す分
量のH2SO4（20％）を添加し、PHを7.5〜８に調整
して処理水とした。この従来法に比較して本発明
方法によれば優れたCa除去率が達成されること
が明らかであろう。また従来法は多量の薬品を必
要とするので原水１m3を処理するに要する費用が
本発明方法に比較して原水１の場合には約10倍、
原水２の場合には約２倍となり、ランニングコス
トの点においても本発明の利点は著しいものがあ
る。
(Field of Industrial Application) The present invention relates to a method for treating calcium-containing sewage such as wastewater from a landfill, industrial wastewater, and sewage. (Prior art) As a method for treating calcium-containing wastewater, the Water and Wastewater Handbook (edited by the Water and Wastewater Handbook Editorial Committee, Maruzen Co., Ltd.),
As described in 1962), the precipitation removal method, complex salt method, cation exchange method, etc. are known.
However, in the precipitation removal method, CaCO 3 is precipitated by adding caustic soda to the wastewater, but the treatment efficiency changes depending on the type and concentration of calcium and other coexisting substances contained in the wastewater, resulting in inefficiency. In addition to being stable, it requires post-treatment for neutralization because it is treated with a high alkali with a pH of 11 to 13.
The disadvantage is that the drug costs are high. In addition, the complex salt method is a method in which a complexing agent such as EDTA is added to wastewater to react with calcium, but it also reacts with other metals, so if there are many metals other than calcium, the treatment efficiency changes and becomes unstable. Then,
Furthermore, since this method is a masking method rather than a method for removing calcium, it has drawbacks such as when the quality of the treated water changes due to discharge or the like, calcium may re-precipitate and form scale. Furthermore, in the cation exchange method, when the SS concentration in wastewater is high, the SS coats the cation exchange agent and the treatment efficiency decreases, so pre-treatment is required to remove SS, and the equipment cost and running cost are high. There was a drawback. (Problems to be solved by the invention) The present invention solves these conventional problems,
This method was developed with the aim of providing a method for treating calcium-containing sewage that can always and stably remove calcium without being affected by coexisting substances and that is inexpensive to process. (Means for solving the problems) The present invention provides solutions for wastewater containing calcium.
After adding oxalic acid or its salt in a theoretical amount relative to the amount of Ca ++ to be removed, an inorganic flocculant containing one or both of Fe +++ and Al + is added to a predetermined concentration, and the pH is 5 or higher. This method is characterized by coagulation and precipitation under the following conditions. In the present invention, for wastewater to be treated,
Oxalic acid or an oxalate salt such as ammonium oxalate or sodium oxalate is added in an amount corresponding to the amount of calcium ions to be removed. Note that the amount of calcium ions to be removed refers to the amount of calcium ions obtained by subtracting the amount of calcium ions contained in the wastewater after treatment from the amount of calcium ions contained in the wastewater before treatment. The amount of calcium ions in wastewater after treatment is set according to regulatory values and intended use, and is usually set at 50 to 100 mg/. When oxalic acid is added to calcium-containing wastewater in this manner, the following reaction occurs to produce water-insoluble calcium oxalate. (COOH) 2・2H 2 O＋Ca ++ →
(COOH) 2 Ca+2H 2 O+2H + Therefore, the theoretical amount is
For 40 g of Ca +++ , oxalic acid is 126 g, ammonium oxalate is 140 g, and sodium oxalate is 134 g.
In addition, on a concentration basis, they are 3.15 mg/, 3.5 mg/, and 3.35 mg/, respectively, for 1 mg/ of Ca ++ .
The relationship between the amount of oxalic acid added and the Ca removal rate is as shown in the Examples described below and the graph in FIG. 1, and the removal rate approaches 100% when the same or more theoretical amount is added. Further, when divalent iron coexists in wastewater, the following reaction occurs to produce water-insoluble iron oxalate (2), so that divalent iron ions are also removed. (COOH) 2・2H 2 O+Fe +++ → (COOH) 2 Fe+2H 2 O+2H + However, the calcium oxalate and iron oxalate () produced in this way are fine crystals and are difficult to separate by sedimentation as they are. In the present invention, an inorganic flocculant containing one or both of trivalent aluminum is added to a concentration of 100 mg or more, and coagulation and precipitation are performed under conditions where a neutralizing agent is further added to raise the pH to 5 or more. be exposed. 3 as an inorganic flocculant
In addition to ferric chloride, which is a high-value iron compound, ferric sulfate
It is also possible to use iron, trivalent aluminum compounds such as aluminum sulfate, PAC, and the like. When such an inorganic flocculant is added, a large floc is formed, and calcium oxalate and iron oxalate can be easily taken into the floc and removed. The reason why the concentration of the inorganic flocculant was set to 75 mg/or more as Fe +++ or Al +++ is because, as shown in Figure 2, if it is less than 75 mg/, the Ca removal rate will drop by 60 to 70%. It is.
Note that a polymer flocculant may be additionally added as necessary. Although polymeric flocculants are not very effective in scavenging the produced calcium oxalate, inorganic flocculants can increase the sedimentation rate of the flocs produced. In addition, in the present invention, coagulation and precipitation are carried out under conditions of pH 5 or higher by adding a neutralizing agent such as NaOH, but as shown in Figure 3, ferric chloride becomes ferric hydroxide at pH 4 or higher. The purpose is to trap particles of calcium oxalate more reliably and effectively by setting the pH to 5 or higher. It is preferable that the above treatment chemicals be added in the following order: oxalic acid or oxalate, an inorganic flocculant, and a neutralizing agent. However, since the production of calcium oxalate occurs almost instantaneously, all of the treatment chemicals are added at the same time. There is no problem in adding it. In addition, the flocculation operation after adding treatment chemicals is 120 rpm x 5 minutes + 60 rpm x 10 minutes, or
It is sufficient to follow a conventional method such as 60 rpm x 15 minutes, and 30 minutes is sufficient for the precipitation operation after the flocculation operation. (Example) Next, the following experiment was conducted to investigate the relationship between the amount of each treatment agent added and the Ca removal rate. <Experiment 1> PH6.6, SS68mg/wastewater for infiltrating a garbage landfill
, Fe57.2mg/, Ca121mg/ source water 1
and PH6.7, which is also wastewater from a landfill.
Raw water 2 containing 270 mg of SS, 485 mg of Fe, and 1270 mg of Ca was collected in 200-capacity stainless steel drums, a stirrer was set, the mixture was stirred at 60 rpm, and oxalic acid was added in the amount shown in Table 1. . Next, add ferric chloride to Fe +++ concentration of 100mg/
At the same time, add 1 part of polymer flocculant.
The pH was adjusted to around 7 by adding NaOH in the amount shown in the table, and stirring was continued at 60 rpm for 15 minutes. After stirring, the mixture was allowed to stand for 30 minutes, and the supernatant liquid was separated using a siphon to obtain treated water.The quality of the water was analyzed and recorded in the table. This shows that the Ca removal rate approaches 100% when oxalic acid is added in an amount equal to or greater than the theoretical amount. <Experiment 2> Next, for raw water 1 and raw water 2, the amount of oxalic acid added was fixed at 0.94 times and 0.99 times the theoretical amount, and the amount of ferric chloride added as an inorganic flocculant was listed in Table 2. The water quality of the treated water was analyzed by performing coagulation and sedimentation in the same manner. As a result, when the amount of inorganic flocculant added is 100mg/or more as Fe +++
It can be seen that the Ca removal rate approaches 100%. <Experiment 3> Using PAC as an inorganic flocculant, the amount added as Al +++ was varied as shown in Table 3.
The effect was investigated in the same manner as in Experiment 2>. It can be seen that when PAC is used, as well as when FeCl 3 is used, an excellent Ca removal rate can be achieved if 75 mg/or more of Al +++ is added. <Experiment 4> Next, the amount of oxalic acid added and the amount of inorganic flocculant added were fixed, and the amount of NaOH added was changed to change the pH as shown in Table 3, and the resulting fluctuations in the Ca removal rate were investigated. Examined. This shows that the Ca removal rate approaches 100% when the pH is 5 or higher. <Comparative Example> Raw water 1 and raw water 2, which were the same as those used in the above experiment, were treated by the precipitate removal method shown as the prior art. That is, raw water is placed in a stainless steel drum.
200, stirred at 60 rpm, added NaOH (16%) in the amount shown in Table 5 to adjust the pH to a predetermined value, and continued stirring for 15 minutes. After that, it was left to stand still for 30 minutes, and the supernatant liquid was transferred using a siphon to another 200-capacity stainless steel drum, and the amount of H 2 SO 4 (20%) shown in Table 5 was added to adjust the pH to 7.5-7.5. 8 and used as treated water. It is clear that a superior Ca removal rate can be achieved by the method of the present invention compared to this conventional method. In addition, since the conventional method requires a large amount of chemicals, the cost required to treat 1 m 3 of raw water is about 10 times that of the method of the present invention in the case of raw water 1.
In the case of raw water 2, it is approximately twice as high, and the present invention has a significant advantage in terms of running costs as well.
【表】【table】
【表】【table】
【表】【table】
【表】【table】
【表】
（発明の効果）
本発明は以上の説明からも明らかなように、共
存物質の種類や濃度にほとんど影響されることな
く汚水中のカルシウムを効率的かつ安定的に除去
できるものであり、カルシウムのほかに２価の鉄
やSSも処理できること、処理費用が従来法より
も安価であること等の利点をも有するものであ
る。よつて本発明は従来の問題点を解消したカル
シウム含有汚水の処理方法として、産業の発展に
寄与するところは極めて大きいものである。[Table] (Effects of the Invention) As is clear from the above explanation, the present invention is capable of efficiently and stably removing calcium from wastewater almost unaffected by the types and concentrations of coexisting substances. This method also has the advantages of being able to treat divalent iron and SS in addition to calcium, and that the treatment cost is lower than that of conventional methods. Therefore, the present invention greatly contributes to the development of industry as a method for treating calcium-containing wastewater that solves the conventional problems.
第１図は理論量に対する蓚酸添加倍率とCa除
去率との関係を示すグラフ、第２図は塩化第２鉄
とCa除去率との関係を示すグラフ、第３図は処
理PHとCa除去率との関係を示すグラフである。
Figure 1 is a graph showing the relationship between the addition ratio of oxalic acid and Ca removal rate relative to the theoretical amount, Figure 2 is a graph showing the relationship between ferric chloride and Ca removal rate, and Figure 3 is a graph showing the relationship between treatment PH and Ca removal rate. It is a graph showing the relationship between
Claims (1)
べきCa++量に対する理論量に相当する蓚酸また
はその塩を添加したのち、Fe+++とAl+++の一方
または双方を含む無機凝集剤を所定の濃度となる
まで添加し、PH５以上の条件下で凝集沈澱を行わ
せることを特徴とするカルシウム含有汚水の処理
方法。 ２ 無機凝集剤の濃度をFe+++またはAl+++とし
て75mg／とした特許請求の範囲第１項記載のカ
ルシウム含有汚水の処理方法。[Claims] 1. After adding oxalic acid or its salt in a theoretical amount to the amount of Ca ++ to be removed to wastewater containing calcium, one of Fe +++ and Al +++ or A method for treating calcium-containing wastewater, which comprises adding an inorganic flocculant containing both to a predetermined concentration, and coagulating and precipitating it under conditions of pH 5 or higher. 2. The method for treating calcium-containing wastewater according to claim 1, wherein the concentration of the inorganic flocculant is 75 mg/Fe +++ or Al +++ .
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP23692486A JPS6391193A (en) | 1986-10-03 | 1986-10-03 | Treatment of sewage containing calcium |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP23692486A JPS6391193A (en) | 1986-10-03 | 1986-10-03 | Treatment of sewage containing calcium |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS6391193A JPS6391193A (en) | 1988-04-21 |
| JPH0218907B2 true JPH0218907B2 (en) | 1990-04-27 |
Family
ID=17007769
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP23692486A Granted JPS6391193A (en) | 1986-10-03 | 1986-10-03 | Treatment of sewage containing calcium |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS6391193A (en) |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH07100155B2 (en) * | 1987-04-15 | 1995-11-01 | 株式会社クボタ | Organic wastewater treatment method |
| JP4342119B2 (en) * | 2000-04-06 | 2009-10-14 | 株式会社神戸製鋼所 | Protective cover plate during drilling and printed wiring board drilling method using the same |
-
1986
- 1986-10-03 JP JP23692486A patent/JPS6391193A/en active Granted
Also Published As
| Publication number | Publication date |
|---|---|
| JPS6391193A (en) | 1988-04-21 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| JP2683991B2 (en) | Dyeing wastewater treatment method | |
| JP2004141799A (en) | Silica-containing waste water treatment method | |
| JP4374636B2 (en) | Treatment method of waste liquid containing heavy metal complex | |
| JP4863694B2 (en) | Method and apparatus for fluorinating chelating agent-containing water | |
| JP4351867B2 (en) | Fluorine or phosphorus-containing water treatment equipment | |
| US5451327A (en) | Compound and method for treating water containing metal ions and organic and/or inorganic impurities | |
| JP2002316173A (en) | Method for treating wastewater containing arsenic and hydrogen peroxide | |
| JPS59166290A (en) | Method for removing harmful component in waste water of smoke scrubbing | |
| JP3642516B2 (en) | Method and apparatus for removing COD components in water | |
| JP3334786B2 (en) | Treatment method for wastewater containing insoluble and soluble lead, chromium and zinc | |
| JPH0218907B2 (en) | ||
| KR100395476B1 (en) | A manufacturing method of a organic-inorganic polymeric flocculant for a waste water treatment | |
| JP4086297B2 (en) | Boron-containing wastewater treatment method and chemicals used therefor | |
| JP4034218B2 (en) | Wastewater treatment method | |
| JPS61161191A (en) | Treatment of heavy metal ion-containing solution | |
| JPS6339307B2 (en) | ||
| JP4110295B2 (en) | Method for simultaneously treating copper etching waste liquid and resist waste liquid and chemicals used therefor | |
| JPH03186393A (en) | Treatment of waste water containing fluorine | |
| JPH0141110B2 (en) | ||
| JP4407236B2 (en) | Treatment method of wastewater containing antimony | |
| JPH0460717B2 (en) | ||
| JP2003260475A (en) | Method for removing and recovering copper by treating wastewater and chemical agent used therein | |
| JP4348116B2 (en) | Fluorine or phosphorus-containing water treatment equipment | |
| JP2003047972A (en) | Method for treating fluorine-containing wastewater | |
| JP3501843B2 (en) | Treatment of oil-containing wastewater |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| LAPS | Cancellation because of no payment of annual fees |