JP2598456B2 - Treatment method for phosphate-containing water - Google Patents
Treatment method for phosphate-containing waterInfo
- Publication number
- JP2598456B2 JP2598456B2 JP63112990A JP11299088A JP2598456B2 JP 2598456 B2 JP2598456 B2 JP 2598456B2 JP 63112990 A JP63112990 A JP 63112990A JP 11299088 A JP11299088 A JP 11299088A JP 2598456 B2 JP2598456 B2 JP 2598456B2
- Authority
- JP
- Japan
- Prior art keywords
- phosphate
- slaked lime
- added
- ppm
- containing water
- 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
Links
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- Removal Of Specific Substances (AREA)
Description
【発明の詳細な説明】 〔技術分野〕 本発明は、リン酸含有水とくに高濃度リン酸含有廃水
の処理方法に関する。Description: TECHNICAL FIELD The present invention relates to a method for treating phosphoric acid-containing water, particularly high-concentration phosphoric acid-containing wastewater.
リン酸を含有する廃水の処理技術としては従来から、
石灰等による凝集沈殿法、生物学的処理法、鉄、アルミ
ニウム等の金属塩による凝集沈殿法、吸着剤による吸着
処理法等が採用されている。As a treatment technology for wastewater containing phosphoric acid,
A coagulation sedimentation method using lime or the like, a biological treatment method, a coagulation sedimentation method using a metal salt such as iron or aluminum, an adsorption treatment method using an adsorbent, and the like are employed.
これらのうち石灰等による凝集沈殿法においては、た
とえば特開昭53−107151号公報や特開昭57−187092号公
報記載の技術が知られている。Among these, in the coagulation precipitation method using lime or the like, for example, the techniques described in JP-A-53-107151 and JP-A-57-187092 are known.
特開昭53−107151号公報の技術は、リン酸含有廃水に
アルカリとして石灰のかわりに塩化カルシウムを投入
し、pHを4.5〜７に調整することにより、リン酸水素カ
ルシウムを形成させ、これにより沈殿物が分離性のよい
板状結晶になる点を特徴とするものである。The technique of JP-A-53-107151 discloses that calcium hydrogen phosphate is formed by adding calcium chloride instead of lime as an alkali to phosphoric acid-containing wastewater and adjusting the pH to 4.5 to 7, thereby forming calcium hydrogen phosphate. It is characterized in that the precipitate becomes plate-like crystals with good separability.
又、特開昭57−187092号公報の技術は、リン酸含有廃
水に石灰を添加してpHを5.5〜6.5に調整したのちさらに
高分子凝集剤を添加してスラッジを凝集沈降せしめて分
離、脱水する一次処理およびスラッジを分離したのちの
一次処理からの上澄水に石灰を添加してpH10以上に調整
したのちさらに高分子凝集剤を添加してスラッジを凝集
沈降せしめて分離する二次処理からなり、二次処理で分
離したスラッジを脱水することなく一次処理のpH調整工
程へ返送することを特徴とするものである。Further, the technology of JP-A-57-187092 discloses a method in which lime is added to phosphoric acid-containing wastewater to adjust the pH to 5.5 to 6.5, and then a polymer flocculant is further added to coagulate and settle sludge to separate the sludge. From the primary treatment for dehydration and the secondary treatment after separating sludge, adding lime to the supernatant water and adjusting the pH to 10 or more, then adding a polymer flocculant to coagulate and settle the sludge and separate it. The sludge separated in the secondary treatment is returned to the pH adjustment step of the primary treatment without being dewatered.
しかしながら、これらの先行技術では、いずれも固液
分離槽が複数必要であり、加えて処理水の水質も充分満
足できるものではなかった。However, these prior arts all require a plurality of solid-liquid separation tanks, and in addition, the quality of treated water is not sufficiently satisfactory.
本発明の目的は、リン酸含有廃水を消石灰中和法によ
り効率的に処理する方法を提供することである。An object of the present invention is to provide a method for efficiently treating phosphoric acid-containing wastewater by slaked lime neutralization.
リン酸塩とカルシウム塩は次式のように反応して難溶
性の塩を生成する。The phosphate and the calcium salt react as shown in the following formula to form a sparingly soluble salt.
5Ca2+＋3PO4 3-＋OH→Ca5（PO4）3OH ところが、リン酸塩の濃度が高い場合には、消石灰表
面に難溶性のカルシウムヒドロキシアパタイトなどが析
出し、消石灰が溶解せず、結果としてCa2+が溶出しない
ため上記の反応式が進行せず、リン酸イオンの処理がで
きなくなる。消石灰を大過剰に加えれば、一応反応は進
行するが消石灰の消費量、汚泥発生量の増大のため、実
用的な方法ではない。5Ca 2+ + 3PO 4 3- + OH → Ca 5 (PO 4 ) 3 OH However, when the phosphate concentration is high, poorly soluble calcium hydroxyapatite etc. precipitate on the slaked lime surface, and the slaked lime does not dissolve. As a result, the above reaction formula does not proceed because Ca 2+ is not eluted, so that phosphate ion treatment cannot be performed. If slaked lime is added in a large excess, the reaction proceeds temporarily, but is not a practical method due to an increase in slaked lime consumption and sludge generation.
そこで、本発明の第二の目的は、消石灰を大過剰に使
用することなく、リン酸塩含有廃水を処理する方法を提
供する点にある。Therefore, a second object of the present invention is to provide a method for treating phosphate-containing wastewater without using slaked lime in a large excess.
本発明は、リン酸含有量500ppm以上のリン酸塩含有水
に、酸と消石灰を添加してpHを５以下に調整し、生成す
る懸濁性リン酸カルシウム系結晶種を分離することな
く、ついでアルカリ剤を添加してpHを９以上とし、生成
するリン酸カルシウム系沈殿物を分離することを特徴と
するリン酸塩含有水の処理方法にある。The present invention adjusts the pH to 5 or less by adding an acid and slaked lime to a phosphate-containing water having a phosphoric acid content of 500 ppm or more, without separating the resulting suspended calcium phosphate crystal seeds, The method for treating phosphate-containing water is characterized in that the pH is adjusted to 9 or more by adding an agent, and the generated calcium phosphate-based precipitate is separated.
すなわち、本発明は、あらかじめ後段におけるリン酸
イオンの処理に必要な消石灰を添加すると同時に消石灰
の溶解のための酸を添加するとともに系のpHを５以下に
調整し、生成したヒドロキシアパタイトなどのリン酸カ
ルシウム系結晶種を懸濁含有するとともにリン酸イオン
とカルシウムイオンをも含有する系を、ひきつづきアル
カリを加えてpHを９以上、好ましくは10以上とし、リン
酸イオンとカルシウムイオンをヒドロキシアパタイト等
のリン酸カルシウム系沈殿物として沈殿させ、これを分
離するものである。That is, the present invention is to add slaked lime necessary for the treatment of phosphate ions in the subsequent stage and simultaneously add an acid for dissolving slaked lime and adjust the pH of the system to 5 or less, and to form calcium phosphate such as hydroxyapatite produced. The pH of the system containing phosphate ions and calcium ions as well as the suspension containing the system seeds is adjusted to pH 9 or higher, preferably pH 10 or higher by adding alkali, and the phosphate ions and calcium ions are converted to calcium phosphate such as hydroxyapatite. It precipitates as a system precipitate and separates it.
中和のために用いる酸が硫酸の場合には、本発明はお
おむねつぎの反応式により進行する。When the acid used for neutralization is sulfuric acid, the present invention generally proceeds according to the following reaction formula.
Ca（OH）２＋H2SO4→Ca2+＋SO4 2-＋2H2O 9Ca2+＋6PO4 3-＋Ca（OH）２→2Ca5（PO4）３（OH） 本発明の方法では、一段目の反応により生成した懸濁
状のリン酸カルシウムが二段目の反応生成物に対する晶
析のための種晶として作用するものと考えられる。な
お、明細書における懸濁状とは、コロイド状態のものを
含み、これらは極めて活性に富む。又、一段目の反応で
系中である程度のリン酸イオンが捕捉、固定されるた
め、二段目でpHが９以上に調整される結果、反応が円滑
に進行し、ヒドロキシアパタイトが形成され、これに微
量のリン酸イオンまでも吸着されるものと考えらえる。
二段目で添加するアルカリ剤としては苛性ソーダ、苛性
カリ、消石灰など公知のアルカリ剤が使用できるが、消
石灰を用いるとカルシウムイオンをさらに補給できるの
で好ましい。Ca (OH) 2 + H 2 SO 4 → Ca 2+ + SO 4 2− + 2H 2 O 9Ca 2+ + 6PO 4 3− + Ca (OH) 2 → 2Ca 5 (PO 4 ) 3 (OH) In the method of the present invention, It is considered that the suspended calcium phosphate generated by the eye reaction acts as a seed crystal for crystallization of the second-stage reaction product. The term “suspension” in the specification includes those in a colloidal state, which are extremely active. In addition, since a certain amount of phosphate ions are captured and fixed in the system in the first-stage reaction, as a result of adjusting the pH to 9 or more in the second stage, the reaction proceeds smoothly, and hydroxyapatite is formed, It is considered that even a small amount of phosphate ion is adsorbed on this.
Known alkali agents such as caustic soda, caustic potash and slaked lime can be used as the alkali agent to be added in the second stage. However, slaked lime is preferable because calcium ions can be further replenished.
本発明は、とくに原廃水がリン酸塩含有量500ppm以上
といった高濃度廃水である場合にすばらしい能力を発揮
する。The present invention performs particularly well when the raw wastewater is a highly concentrated wastewater with a phosphate content of 500 ppm or more.
又、二段目のpHを９以上にて沈殿を生成させる工程に
おいては、ポリアクリルアミド部分加水分解物などの公
知の高分子凝集剤を添加することもできる。In the second step of forming a precipitate at a pH of 9 or more, a known polymer flocculant such as polyacrylamide partial hydrolyzate may be added.
本発明を図面にもとづいて説明すると、第１図は本発
明方法の処理工程を示すものである。処理対象廃水であ
る原水は、第１槽１に送られ、ここで消石灰と酸の添加
によるpH≦５にするための調整と種晶の生成を行う。つ
いで廃液は第２槽２に送られ、ここで、アルカリ剤を添
加してpH≧９以上とすることにより残留するリン酸イオ
ンを沈殿や晶析等により不溶性化合物にかえ、これを沈
殿槽３に送って沈殿させるものである。The present invention will be described with reference to the drawings. FIG. 1 shows the processing steps of the method of the present invention. Raw water, which is the wastewater to be treated, is sent to the first tank 1, where adjustment for adjusting the pH to 5 or less by adding slaked lime and acid and generation of seed crystals are performed. Next, the waste liquid is sent to the second tank 2, where an alkaline agent is added to adjust the pH to 9 or more to convert the remaining phosphate ions into insoluble compounds by precipitation or crystallization. And settled.
pH6.3、PO4−P 2000ppm、Zn 10ppm、COD 500ppmの表
面処理廃水を第１槽に入れ、これに、Ca（OH）2 8000pp
m、H2SO4 12000ppmになるように消石灰と硫酸を注意深
く加えた後、10分間撹拌した。系のpHは4.8となってい
た。 pH6.3, PO 4 -P 2000ppm, Zn 10ppm, put a surface treatment wastewater COD 500 ppm in the first tank, to, Ca (OH) 2 8000pp
After adding slaked lime and sulfuric acid carefully so as to obtain 12,000 ppm of H 2 SO 4 , the mixture was stirred for 10 minutes. The pH of the system was 4.8.
この混合液を第２槽に移し、Ca（OH）２が2500ppmに
なるように注意深く消石灰を加え、10分間撹拌した。第
２槽のpHは11であった。The mixed solution was transferred to a second tank, and slaked lime was carefully added so that Ca (OH) 2 became 2500 ppm, followed by stirring for 10 minutes. The pH in the second tank was 11.
第２槽の液を過し、処理水のPO4−Ｐを測定したと
ころ、PO4−P 0.09ppmを示した。Spent liquid of the second tank, by measurement of PO 4 -P treated water showed a PO 4 -P 0.09 ppm.
比較例１ 実施例１と同一の廃水に一段目の工程をはぶき、いき
なり２段目のアルカリ剤を添加する工程を実施した。ア
ルカリ剤としてはCa（OH）２およびNaOHをそれぞれ使用
し、添加後の系のpH、PO4−Ｐの濃度を測定した。その
結果を第１表に示す。Comparative Example 1 The first-step process was applied to the same wastewater as in Example 1, and a second-step process of adding an alkaline agent was immediately performed. Examples of the alkali agent used Ca (OH) 2 and NaOH, respectively, the system pH of the post-addition, to determine the concentration of PO 4 -P. Table 1 shows the results.
なお、PO4−P 2000ppmがヒドロキシアパタイトを生成
するためのCa（OH）２の必要量は5Ca（OH）2/3P≒8100p
pmである。The amount of Ca (OH) 2 required to produce hydroxyapatite with 2000 ppm PO 4 -P is 5Ca (OH) 2 / 3P ≒ 8100p
pm.
この表から、リン酸イオン除去効果が極めて低いこと
が理解されよう。 From this table, it can be understood that the phosphate ion removing effect is extremely low.
比較例２ 実施例１と同一の廃水に消石灰5000ppmを添加した。
この時のpHは6.8であった。生成する沈殿を分離した
後、再度消石灰を6000ppm添加し、pHを11とした。沈殿
を分離した後の上澄液のPO4−Ｐは0.9ppmであった。Comparative Example 2 5000 ppm of slaked lime was added to the same wastewater as in Example 1.
The pH at this time was 6.8. After separating the formed precipitate, slaked lime was added again at 6000 ppm to adjust the pH to 11. After the precipitate was separated, the supernatant had PO 4 -P of 0.9 ppm.
本発明により、従来の石灰中和法では処理できないよ
うな高濃度リン酸イオンの除去が、理論量に対しごく少
過剰量の消石灰により達成できる。According to the present invention, the removal of high-concentration phosphate ions that cannot be treated by the conventional lime neutralization method can be achieved with a very small amount of slaked lime relative to the theoretical amount.
第１図は、本発明の実施態様図を示すものである。 FIG. 1 shows an embodiment of the present invention.
───────────────────────────────────────────────────── フロントページの続き (72)発明者 堀内 克泰 岡山県倉敷市水島川崎通１丁目（番地無 し） 川崎製鉄株式会社水島製鉄所内 (72)発明者 白井 真一 岡山県倉敷市水島川崎通１丁目（番地無 し） 川崎製鉄株式会社水島製鉄所内 (56)参考文献 特開 昭62−250990（ＪＰ，Ａ) ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Katsuyasu Horiuchi 1-chome, Mizushima Kawasaki-dori, Kurashiki-shi, Okayama Pref. (72) Inside Mizushima Works, Kawasaki Steel Corp. 1-chome (No address) Kawasaki Steel Corporation Mizushima Works (56) References JP-A-62-250990 (JP, A)
Claims (1)
水に、酸と消石灰を添加してpHを５以下に調整し、生成
する懸濁性リン酸カルシウム系結晶種を分離することな
く、ついでアルカリ剤を添加してpHを９以上とし、生成
するリン酸カルシウム系沈殿物を分離することを特徴と
するリン酸塩含有水の処理方法。1. An acid and slaked lime are added to a phosphate-containing water having a phosphate content of 500 ppm or more to adjust the pH to 5 or less, and the resulting suspended calcium phosphate crystal seeds are not separated. Then, an alkaline agent is added to adjust the pH to 9 or more, and a generated calcium phosphate-based precipitate is separated.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP63112990A JP2598456B2 (en) | 1988-05-09 | 1988-05-09 | Treatment method for phosphate-containing water |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP63112990A JP2598456B2 (en) | 1988-05-09 | 1988-05-09 | Treatment method for phosphate-containing water |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH01284390A JPH01284390A (en) | 1989-11-15 |
| JP2598456B2 true JP2598456B2 (en) | 1997-04-09 |
Family
ID=14600660
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP63112990A Expired - Fee Related JP2598456B2 (en) | 1988-05-09 | 1988-05-09 | Treatment method for phosphate-containing water |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP2598456B2 (en) |
Families Citing this family (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2535744B2 (en) * | 1990-10-12 | 1996-09-18 | 工業技術院長 | Treatment method for wastewater containing phosphate ions |
| JP4591695B2 (en) * | 2005-07-12 | 2010-12-01 | 株式会社日立プラントテクノロジー | Method for treating wastewater containing phosphoric acid and zinc |
| JP4824058B2 (en) * | 2008-07-03 | 2011-11-24 | オルガノ株式会社 | Phosphoric acid-containing water treatment apparatus and phosphoric acid-containing water treatment method |
| JP7467161B2 (en) * | 2020-02-27 | 2024-04-15 | 太平洋セメント株式会社 | Waste liquid treatment method |
| JP7477995B2 (en) * | 2020-03-11 | 2024-05-02 | 太平洋セメント株式会社 | Waste liquid treatment method |
Family Cites Families (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5554087A (en) * | 1978-10-17 | 1980-04-21 | Ebara Infilco Co Ltd | Removing method for phosphoric acid in liquid |
| JPS57167787A (en) * | 1981-04-09 | 1982-10-15 | Tsukishima Kikai Co Ltd | Removing method for phosphoric acid ion |
| JPS62250990A (en) * | 1986-04-25 | 1987-10-31 | Ataka Kogyo Kk | Treatment of waste water containing phosphate ion |
-
1988
- 1988-05-09 JP JP63112990A patent/JP2598456B2/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| JPH01284390A (en) | 1989-11-15 |
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