JP2010172883A - 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 powder of an anhydrous silicate of alkali metal, 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 powder of anhydrous potassium water glass or of anhydrous lithium water glass. 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 floc. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

The present invention relates to a flocculant for water treatment of various polluted wastewater and a method for treating polluted wastewater using the same.
It is particularly suitable for the treatment of various construction sludge, dredged sludge from rivers and harbors, water purification plant sludge, factory wastewater sludge, and other wastewater generated at various construction sites and construction sites. The present invention relates to an excellent water treatment flocculant capable of further increasing the clarification speed, and a water treatment method for various polluted waste water using the flocculant.

  Sewage polluted wastewater, human waste and organic industrial polluted wastewater at sewage treatment plants etc. are highly treated and discharged into rivers, seas, etc. Also, 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, 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, and the like.

  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 aluminum sulfate, polyaluminum chloride (PAC), aluminum chloride, ferric chloride, and polyferric sulfate (polyiron). Nonionic, anionic and cationic organic polymer flocculants are used in combination to treat polluted wastewater and polluted wastewater.
And these flocculants will be agglomerated, settled, and clarified by adding suspended flakes to sludge / polluted wastewater.

  For example, as the treatment step, a single or two or more kinds of inorganic flocculants conventionally used such as organic sludge, aluminum sulfate, polyaluminum chloride (PAC), aluminum chloride, polyferric sulfate (polyiron), etc. 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 the basic admixing flocculants of aluminum sulfate and iron sulfate, polyaluminum chloride (PAC), and silicic acid sol (or colloidal silica) of alkali 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 a combination is essential.

  The object of the present invention is to treat various types of domestic wastewater and industrial wastewater with a large floc formation speed, a large final floc diameter, a high sedimentation speed, and a powdery agglomeration that can obtain a supernatant in a short time. It is to provide an agent and a method for treating polluted waste water using the agent.

That is, this invention is the processing method of the following flocculants and the polluted waste water using the same.
[1] A flocculant obtained by adding and mixing anhydrous alkali metal silicate powder in a flocculant from a mixture of organic polymer flocculant powder and inorganic flocculant powder.
[2] A flocculant composed of a mixture of organic polymer flocculant powder, aluminum sulfate powder, gypsum powder, sodium carbonate powder and anhydrous alkali metal silicate powder, and the composition of the components is as follows: A characteristic 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) Anhydrous alkali metal silicate powder 4-10w%
[3] The flocculant according to [1] or [2], wherein the anhydrous alkali metal silicate powder has a particle size of 5.0 to 0.01 μm.
[4] The organic polymer flocculant powder is acrylamide, the gypsum powder is hemihydrate gypsum powder, and the anhydrous alkali metal silicate is a dried product of potassium water glass [1] to [3] The flocculant of any one of these.
[5] The organic polymer flocculant powder is acrylamide, the gypsum powder is hemihydrate gypsum powder, and the anhydrous alkali metal silicate is a dried product of lithium water glass [1] to [3] The flocculant of any one of these.
[6] The flocculant according to any one of [1] to [5], wherein the polymer flocculant powder has an average particle diameter of 60 to 200 μm.
[7] The flocculant according to any one of the above [1] to [6] is added to a polluted waste water having a suspension (SS) concentration of 50 to 20,000 mg / 1 liter with high speed stirring at 100 to 30. A method for treating polluted wastewater, comprising adding and mixing within the range of 1,000 ppm, and then allowing to stand to settle and separate the suspension (SS) as coarse floc to obtain clear 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.
As the inorganic flocculant powder, known powders are used. For example, aluminum sulfate, gypsum, sodium carbonate and the like are used.
(2) In the present invention, anhydrous alkali metal silicate powder is added and mixed, but a dry product of potassium water glass or lithium water glass is preferable, and its blending amount is preferably 4 to 10% by weight. In particular, these water glass dried products are obtained by drying these liquid water glasses, and the water glass powder can be obtained by drying the water glass by, for example, a spray drying method. It contributes to the coarsening of. The particle size of the anhydrous alkali metal silicate powder is preferably fine, and preferably 5.0 to 0.01 μm. The finer it is, the shorter the floc generation time, which is preferable for rapid sludge separation.
(3) As gypsum powder, hemihydrate gypsum is preferable, and the blending amount is preferably 45 to 60 w%.
(4) The sodium carbonate powder may be commercially available, but the blending amount is preferably 15 to 30 w%.
(5) The aluminum sulfate powder may be commercially available, but the blending amount is preferably 12 to 20 w%.

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

  Compared with conventional flocculants, the water treatment flocculant of the present invention can generate coarse flocs more rapidly, and more completely suspends sludge in coarse water to obtain clear treated water. it can.

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

Example 1:
The composition of the components of the flocculant of the examples 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) Anhydrous potassium 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 more, and various polluted wastewater can be treated by such a treatment method.

Example 2:
The composition of the components of the flocculant of the examples 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) Anhydrous lithium 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 added to and mixed in the suspension under vigorous stirring, so that the coarse flocculation of the suspension and its sedimentation can be performed quickly.
The high-speed stirring is preferably a stirring speed of 120 rpm or more, and various polluted wastewater can be treated by such a treatment method.

Claims (7)

  A flocculant obtained by adding and mixing anhydrous alkali metal silicate powder in a flocculant from a mixture of an organic polymer flocculant powder and an inorganic flocculant powder. A flocculant composed of a mixture of organic polymer flocculant powder, aluminum sulfate powder, gypsum powder, sodium carbonate powder and anhydrous alkali metal silicate powder, characterized in that 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) Anhydrous alkali metal silicate powder 4-10w%   The flocculant according to claim 1 or 2, wherein the anhydrous alkali metal silicate powder has a particle size of 5.0 to 0.01 µm.   The organic polymer flocculant powder is acrylamide, the gypsum powder is hemihydrate gypsum powder, and the anhydrous alkali metal silicate is a dried product of potassium water glass. The flocculant described in 1.   The organic polymer flocculant powder is acrylamide, the gypsum powder is hemihydrate gypsum powder, and the anhydrous alkali metal silicate is a dried product of lithium water glass. The flocculant described in 1.   The flocculant according to any one of claims 1 to 5, wherein the polymer flocculant powder has an average particle diameter of 60 to 200 µm. The flocculant according to any one of claims 1 to 6 is added in a range of 100 to 30,000 ppm under high-speed stirring to sludge drainage having a suspension (SS) concentration of 50 to 20,000 mg / 1 liter. -A method for treating sludge drainage, characterized in that, after mixing, the suspension (SS) is settled and separated as coarse flocs to obtain clarified water.