JP2010172882A - Coagulant, and method of treating muddy effluent - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a coagulant for use in cleaning muddy effluent, capable of accelerating the forming of coarse settling floc and of producing clear treated water, and a method of treating muddy effluent using the same. <P>SOLUTION: The coagulant including a mixture comprising organic polymeric coagulant powder, aluminum sulfate powder, gypsum powder, sodium carbonate powder, and sodium silicate powder, has the following composition of its constituents: (1) 3 to 6 wt.% of organic polymeric coagulant powder, (2) 45 to 60 wt.% of gypsum powder, (3) 15 to 30 wt.% of sodium carbonate powder, (4) 12 to 20 wt.% of aluminum sulfate powder, and (5) 4 to 10 wt.% of sodium silicate powder. The method of producing clear water includes adding/mixing the coagulant into muddy effluent having a suspended substance (SS) concentration of 50 to 20,000 mg/litter, in an amount in a range of 100 to 30,000 ppm under high speed agitation, and subsequently keeping the mixture in a static state to sediment and separate the suspended substances (SS) in a form of coarse floc. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

The present invention relates to a flocculant for water treatment of various types of contaminated wastewater and a method for treating contaminated wastewater using the same.
It is particularly suitable for the treatment of various types of construction sludge, dredged sludge from rivers and harbors, water purification plant sludge, industrial wastewater sludge, and other construction wastewater generated at construction sites. The present invention relates to an excellent water treatment flocculant capable of further speeding up the clarification rate and various wastewater water treatment methods using the flocculant.

  Sewage pollution wastewater, human waste and organic industrial pollution wastewater that can be used in sewage treatment plants etc. are highly treated and discharged into rivers, seas, etc. In addition, ground improvement, tunnel excavation, construction / contamination waste (or mud award) wastewater generated at building construction sites, dredging mud aspiration at construction sites such as rivers and harbors, and factory wastewater purification equipment in various industries, etc. Various industrial polluted wastewater generated in Japan is also highly treated and used as recycled or reused water or discharged into rivers, seas, etc.

  The flocculant for water treatment used for the final treatment of such sludge / polluted wastewater is used to effectively settle turbid suspended matter floating in the sludge / polluted wastewater into clear water. Yes.

Examples of such water treatment flocculants include inorganic flocculants such as sulfate band, polyaluminum chloride (PAC), aluminum chloride, ferric chloride, and polyferric sulfate (polyiron). Nonionic, anionic, and cationic organic polymer flocculants are used in combination to treat contaminated wastewater.
And these flocculants are those which are simply added to sludge / polluted wastewater, and the suspended turbid matter is flocculated, settled and clarified.

  For example, as the treatment step, organic sludge such as sulfuric acid band, polyaluminum chloride (PAC), aluminum chloride, polyferric sulfate (polyiron), etc., conventionally used alone or in combination of two or more kinds Next, when adding an organic polymer flocculant and dehydrating and filtering, after adding an inorganic flocculant until the pH becomes 4 or less, an alkali agent is added to adjust the pH to 4-7. Then, the amphoteric polymer flocculant is added, and the suspended sludge is treated as a low moisture content filter cake (Patent Document 1).

JP-A-5-269500

  Conventionally, a coagulant for water treatment that settles and clarifies sludge / polluted wastewater is usually used in combination with a coagulant aid including a coagulant main agent and a polymer coagulant. In other words, conventional iron salt-type flocculants such as ferric sulfate, ferric chloride, and polyferric sulfate (polyiron) alone cannot provide a sufficient agglomeration effect. PH adjustment is required, and basic admixing flocculants such as aluminum sulfate and iron sulfate, polyaluminum chloride (PAC), and silicic acid sol (or colloidal silica) of alkaline silicate aqueous solution, etc. Liquid flocculants are not universal because of their advantages and disadvantages. In addition, all of these flocculants have an action such as “hydration reaction” → “sol / gelation” → “floc agglomeration” depending on the pH range of wastewater, that is, zeta such as iron ions and aluminum ions. It acts as a flocculant under potential adjustment. Therefore, in the past, performance evaluation has been made in association with the zeta potential for such agglomeration / floc / sedimentation of sludge and pollutants that float and disperse. As a result evaluation, in order to increase the flocking promoting effect and the floc particle size, a polymer flocculant that exhibits a crosslinking action by combining polymer flocculants such as anionic, cationic, and nonionic, respectively. It is also true that combination is essential.

  The purpose of the present invention is to agglomerate a large floc formation rate, a large final floc particle size, a fast sedimentation rate, and a supernatant liquid in a short time for the treatment of various domestic wastewater and industrial wastewater. It is to provide an agent and a method for treating polluted wastewater using the agent.

That is, this invention is the processing method of the following flocculants and the polluted wastewater using the same.
[1] A flocculant composed of a mixture of organic polymer flocculant powder, aluminum sulfate powder, gypsum powder, sodium carbonate powder and sodium silicate powder, and its component composition is as follows: Flocculant.
(1) Organic polymer flocculant powder 3-6w%
(2) Gypsum powder 45-60w%
(3) Sodium carbonate powder 15-30w%
(4) Aluminum sulfate powder 12-20w%
(5) Sodium silicate powder 4-10w%
[2] The flocculant according to [1], wherein the organic polymer flocculant powder is acrylamide, the gypsum powder is hemihydrate gypsum powder, and the sodium silicate is a dried product of water glass.
[3] The flocculant according to [1] or [2], wherein the polymer flocculant powder has an average particle size of 60 to 200 μm.
[4] 100 to 30 of the flocculant according to any one of [1] to [3] under high-speed stirring per 1000 ml of contaminated wastewater having a suspension (SS) concentration of 50 to 20,000 mg / liter. A method for treating polluted wastewater, comprising adding and mixing within a range of 000 ppm, and allowing to settle and separate the suspension (SS) as floc to obtain clarified water.

In the water treatment flocculant of the present invention,
(1) Known organic polymer flocculant powders are used, but acrylamide type powders are particularly preferred. The blending amount is preferably 3 to 6% by weight. Examples of the powdery polymer flocculant include anionic and nonionic types such as anionic type; sodium polyacrylate, polysulfomethylated polyacylamide, and nonionic type: polyacryamide, polyethylene poxide. Can be mentioned.
(2) As gypsum powder, hemihydrate gypsum is preferable, and the blending amount is preferably 45 to 60 w%.
(3) Although a commercially available sodium carbonate powder may be used, the blending amount is preferably 15 to 30 w%.
(4) The aluminum sulfate powder may be commercially available, but the blending amount is preferably 12 to 20 w%.
(5) As a sodium silicate powder, the dried material of water glass is preferable, and the compounding quantity has preferable 4-10 w%.
In particular, this dried water glass is obtained by drying and dehydrating liquid water glass, which is an important component in the flocculant of the present invention, and contributes to generation of flocs and increase in size. is there. Water glass powder, which is a dried product of water glass, can be obtained, for example, by drying water glass of No. 1 to No. 3 by, for example, a spray drying method.

  According to the present invention, the suspension (SS) can be rapidly flocculated and separated by settling under high-speed stirring.

  Compared with conventional flocculants, the water treatment flocculant of the present invention can rapidly generate flocs and increase in size, and more completely floculate the suspension to obtain clear treated water. it can.

Below, the best mode concerning the implementation is further demonstrated about the coagulant | flocculant by this invention.

The component blend composition of the examples of the flocculant of the present invention is as follows.
(1) Organic polymer flocculant powder 0.4kg
(2) Hemihydrate gypsum powder 5.0kg
(3) Sodium carbonate powder 2.5kg
(4) Aluminum sulfate powder 1.5kg
(5) Sodium silicate powder 0.6kg
Each powder of said (1)-(5) was weighed, and they were mixed with the stirrer, and the flocculant of this invention was manufactured.
Next, the flocculant obtained in the above example is added to the polluted waste water having a suspension (SS) concentration of 50 to 20,000 mg / liter in the range of 100 to 30,000 ppm with high-speed stirring.・ Mixed and allowed to stand.
Immediately after high-speed stirring, a suspension (SS) was formed as a large floc.
When the stirring was stopped, the flocs settled to the bottom in a few seconds, and transparent clear water having a suspension (SS) concentration of 10 to 50 ppm or less was formed thereon.
As described above, the flocculant of the present invention can be rapidly flocculated and settled and separated by adding and mixing the suspension with vigorous stirring.

The high-speed stirring is preferably a stirring speed of 120 rpm or higher, and various types of contaminated wastewater can be treated by such a treatment method.

Claims (5)

A flocculant comprising a mixture of organic polymer flocculant powder, aluminum sulfate powder, gypsum powder, sodium carbonate powder, and anhydrous sodium silicate powder, and the composition of the components is as follows: .
(1) Organic polymer flocculant powder 3-6w%
(2) Gypsum powder 45-60w%
(3) Sodium carbonate powder 15-30w%
(4) Aluminum sulfate powder 12-20w%
(5) Anhydrous sodium silicate powder 4-10w%   The flocculant according to claim 1, wherein the anhydrous sodium silicate powder has a particle size of 5.0 to 0.01 µm.   The flocculant according to claim 1, wherein the organic polymer flocculant powder is acrylamide, the gypsum powder is hemihydrate gypsum powder, and the sodium silicate is a dried product of water glass.   The flocculant according to any one of claims 1 to 3, wherein the polymer flocculant powder has an average particle size of 60 to 200 µm. The flocculant according to any one of claims 1 to 4 is added in a range of 100 to 30,000 ppm under high-speed stirring to contaminated wastewater having a suspension (SS) concentration of 50 to 20,000 mg / 1 liter. A method for treating contaminated wastewater, characterized in that after mixing, the mixture is allowed to stand to settle and separate the suspension (SS) as floc to obtain clear water.