Soy protein wastewater is a kind of high-concentration organic wastewater that is difficult to treat. In the process of processing soybean protein wastewater, a variety of water purification agents are needed, such as: polyaluminum chloride (PAC), polyaluminum ferric chloride (PFS), polyacrylamide, etc. The polyacrylamide model used is generally cationic polyacrylamide. These agents cooperate with each other to efficiently coagulate and purify the impurities and pollutants in the soybean protein wastewater, and reduce the load for the later biological treatment unit to a greater extent.

1. Overview of cationic polyacrylamide

Cationic polyacrylamide is a white powder particle with a strong flocculation effect, so it is widely used in domestic sewage treatment, metallurgy, papermaking, petroleum, chemical, textile, mineral processing and other fields. Cationic polymer flocculant is a linear polymer compound soluble in water, with a molecular weight of 6-10 million, soluble in methanol and ethanol, but insoluble in organic solvents such as ketones, esters, and hydrocarbons. It is positively charged in acidic or alkaline media, which effectively flocculates and sediments suspended particles in wastewater with negatively charged wastewater. Polyacrylamide for soybean protein wastewater.

2. Characteristics and hazards of soybean protein wastewater

Soy protein wastewater contains a large amount of protein, organic matter and other substances, and the COD content of soybean protein wastewater is very high.

If the soybean protein wastewater is not treated in time, the protein in it will react with the oxygen dissolved in the water, consume oxygen, and make the water too nutritious. Over time, the water body will deteriorate and stink. Such protein wastewater is extremely harmful to the environment.

3. Cationic polyacrylamide for soybean protein wastewater treatment

In recent years, the problem of water pollution in the soybean protein production industry has become more and more serious. The content of organic matter in the wastewater is very high, and the main ingredients are protein and oligosaccharides. Such soybean protein wastewater is suitable for treatment with cationic polyacrylamide.

The reason why cationic polyacrylamide is selected to treat soybean protein wastewater is because the soybean protein wastewater is organic wastewater and the water is acidic.

Cationic polyacrylamide is a macromolecular compound. Because it has a variety of active groups, it can have affinity with many substances and adsorb to form hydrogen bonds. Cationic polyacrylamide has positive (negative) electric groups, which neutralizes the mutual repulsion of particles in water due to the same electric properties, reduces its electric potential, makes it in an unstable state, and uses Its polymerized nature makes these particles concentrated and separated. To achieve the purpose of flocculation sedimentation and water purification.

If the protein content in the wastewater is too high, the traditional method of treating the organic wastewater is physical sedimentation and biochemical fermentation. In the biochemical treatment process, a polymer flocculant is used for sludge dehydration treatment. The polymer flocculant used in this treatment is generally cationic polyacrylamide with high ionicity. Dongguan Capitel Chemical is a company that focuses on the selection of soybean protein wastewater treatment, and can provide customers with accurate selection .

The invention discloses a method for processing soybean protein sewage, which includes the following steps: workshop wastewater is initially treated in a regulating tank and then enters a first-stage air flotation treatment, polyaluminum chloride and anionic polyacrylamide are added, and the suspended solids content in the effluent drops to 1800mg /L; The first-stage air flotation effluent is mixed with aerobic activated sludge in the biological adsorption tank, and after the reaction is completed, it enters the second-stage air flotation for mud-water separation; after the mud-water separation, the clean water enters the anaerobic reaction section for treatment to reduce the COD in the water To 600mg/L; after that, a series A/O process is carried out to control the sludge concentration of 3000mg/L and the dissolved oxygen to 3mg/L; the COD in the aerobic effluent is reduced to 60mg/L. In the treatment method provided by the present invention, a biological adsorption tank is added after the air flotation treatment and the air floatation is used to separate the mud from the biological adsorption tank. The use of the biosorption tank greatly improves the biodegradability of the anaerobic influent. Second, the use of air flotation for mud-water separation minimizes the content of organic matter in the water and avoids the rise of organic matter content. Polyacrylamide for soybean protein wastewater.

　　 1. A method for treating soybean protein sewage, characterized in that it comprises the following steps:

　　A. After preliminary treatment in the conditioning tank, the workshop wastewater enters the first-level air flotation treatment, and polyaluminum chloride and anionic polyacrylamide are added, and the suspended solids content in the effluent drops to 1800mg/L;

　　B. The first-stage air flotation effluent is mixed with aerobic activated sludge in the biosorption tank, and after the reaction is completed, it enters the second-stage air flotation for mud-water separation;

　　C. After the muddy water is separated, the clean water enters the anaerobic reaction section for treatment, so that the COD in the water is reduced to 600mg/L;

　　D, after that, a series A/O process is carried out to control the sludge concentration 3000mg/L, dissolved oxygen 3mg/L; aerobic effluent COD is reduced to 60mg/L.

　　2. The treatment method according to claim 1, wherein the reaction time, sludge concentration and dissolved oxygen in step b are respectively controlled at 30-40 min, 5000 mg/L-7000 mg/L, 0.7 mg/L.

　　3. The processing method according to claim 1, characterized in that: in the step a, a defoamer is added to the regulating tank to control the level of the scum.

　　4. The treatment method according to claim 1, characterized in that: in the step b, the aerobic sludge and the air flotation treated water are mixed in a mass ratio of 0.6:1.

　　 manual

　　A method for treating soybean protein sewage

　　Technical field

"The present invention relates to a method for treating sewage, and more precisely, to a method for treating soybean protein sewage.

Background technique

The pH value of soybean protein wastewater is between 4.3-4.5, which is acid wastewater. The COD content in wastewater is relatively high, about 20,000 mg/L, and the water contains a large number of protein molecules that have not been acidified and decomposed. The C/N is low. It is suitable for the growth requirements of anaerobic sludge. In the existing soybean protein wastewater pretreatment process, the removal rate of COD is low, generally between 20%-30%, and the pH value of the wastewater will be further reduced during the treatment process, resulting in a large amount of use in the pump room Of liquid caustic soda to adjust the pH. In addition, in the pretreatment process, factors such as the addition of defoamers or workshop cleaning often lead to poor pretreatment effects, which affect the subsequent stable anaerobic operation.

　　 One of the existing methods is: the soybean water discharged from the workshop passes through the adjustment tank to adjust the water quality and water quantity, and then enters the air flotation machine for pretreatment. By adding PAC to the water to destroy the colloid in the water and make the suspended matter charged, then by adding PAM- to flocculate the suspended matter in the water, and then the large suspended matter formed by the air bubbles released by the aerator or the dissolved gas tank will float to the water surface, Finally, the scum is scraped away by a scraper, so as to achieve the purpose of reducing COD and SS. After the flotation water enters the pump room, the pH value is adjusted to 3.8-4.3 by adding alkali, and then the feed is pumped to the anaerobic tank. This approach has the following problems:

1. Existing air flotation treatment technology does not have a high COD removal rate for bean water, and during air flotation treatment, due to the PAC used, the content of aluminum in the flotation water will increase, which will affect the subsequent anaerobic treatment Disposal of good sludge brings adverse effects;

2. The existing air flotation treatment has weak impact resistance. Once the water quality of the workshop changes (pH value rises or excessive defoaming agent is added), the air flotation effect will be poor, and the suspended solids in the effluent will rise sharply. There are no effective emergency measures outside the drainage pool;

　　 3. After the air flotation treatment, the pH value of the water is further reduced due to the addition of PAC, so it is necessary to add alkali in the pump room to adjust the pH value, which leads to an increase in operating costs.

　　Invention content

"In order to solve the problems in the prior art, the present invention provides a new treatment method, which can remove 40% of the organic matter and organic nitrogen in the anaerobic influent water while also providing the pH value of the water. An additional benefit of this method is that it can provide timely and effective emergency measures when the effect of air flotation treatment suddenly drops significantly.

　　 In order to achieve the above-mentioned purpose, the technical solution of the present invention is: a processing method of soybean protein sewage, including the following steps:

　　A. After preliminary treatment in the conditioning tank, the workshop wastewater enters the first-level air flotation treatment, and polyaluminum chloride and anionic polyacrylamide are added, and the suspended solids content in the effluent drops to 1800mg/L;

　　B. The first-stage air flotation effluent is mixed with aerobic activated sludge in the biosorption tank, and after the reaction is completed, it enters the second-stage air flotation for mud-water separation;

　　C. After the muddy water is separated, the clean water enters the anaerobic reaction section for treatment, so that the COD in the water is reduced to 600mg/L;

　　D, after that, a series A/O process is carried out to control the sludge concentration 3000mg/L, dissolved oxygen 3mg/L; aerobic effluent COD is reduced to 60mg/L.

"It is preferable that the reaction time, sludge concentration and dissolved oxygen in step b are controlled at 30-40 min, 5000 mg/L-7000 mg/L, 0.7 mg/L, respectively."

　　 Preferably, in the step a, a defoamer is added to the regulating tank to control the liquid level of the scum.

"It is preferable that the aerobic sludge and the air flotation treated water in the step b are mixed in a mass ratio of 0.6-0.8:1."

　　 The treatment method provided by the present invention adds a biosorption treatment after the air flotation treatment to further reduce the content of organic matter and organic nitrogen in the water, and at the same time serves as a gatekeeper for the pretreatment stage. The first-stage air flotation water enters the biological adsorption tank together with the aerobic return sludge. After the reaction is completed, air flotation (using cationic polyacrylamide) is used for rapid sludge water separation. After separation, the sludge enters the desilter for dehydration and transport. Enter the pump room. In the treatment method of the present invention, after the air flotation treatment, a biological adsorption tank is added and the air floatation is used to separate the mud from the biological adsorption tank. The use of biological adsorption tanks greatly improves the biodegradability of anaerobic influent. Second, the use of air flotation for mud-water separation minimizes the content of organic matter in the water and avoids the rise of organic matter content.