How to do wastewater treatment in farms to meet standards?

1. Grid Pool Many large foreign bodies, such as the vas deferens, are usually entrained in the aquaculture sewage, which need to be pre-removed.
2. Manure collection tank After the sewage passes through the grille tank, it enters the manure collection tank, which is used to adjust the water quality and quantity. The submersible mixer is installed to mix the sewage and manure evenly, and the cutting pump is used to lift the manure to the solid-liquid separator.
3. Solid-liquid separator The manure water collected in the manure collection tank contains a large amount of pig hair and other solids that are not conducive to fermentation and easy to block water pumps and valves. A solid-liquid separation is set behind the manure collection tank. Removal of undigested crude fiber and pig hair. This part of pollutants are difficult to decompose no matter anaerobic or aerobic. The residence time of anaerobic biochemical reaction must reach more than 40 days. At the same time, a large amount of biogas residue will be produced, aerobic biochemical reaction There is almost no degradation ability for such substances, and at the same time it is easy to cause the system to be paralyzed. Removal of this part of the pollutants directly reduces the load of the subsequent sewage treatment system, and it is the best raw material for organic fertilizer. This program uses a vibrating screen solid-liquid separator with a 30-mesh screen and a filter particle size of only 0.65mm.
4. Intelligent integrated processing equipment for livestock and poultry manure fermentation The basic principle of the tank-type sealed fermentation technology is: put fresh pig manure in a tank-type sealed stainless steel container, add high-efficiency aerobic bacteria, perform high-temperature aerobic fermentation, biodegrade, evaporate water, and obtain muscle fat.
5. Black film biogas digester The black membrane anaerobic fermentation pond is an anaerobic reactor formed by using high-quality HDPE materials on the basis of excavated earthwork and sealed by a bottom membrane and a top membrane. Black film biogas chemistry has excellent chemical stability and is widely used in sewage treatment, chemical reaction tanks, and landfills. High and low temperature resistance, asphalt, oil and tar resistance, acid, alkali, salt and more than 80 kinds of strong acid and alkali chemical media corrosion. In the black film anaerobic fermentation pond, sewage organic matter is degraded and transformed into biogas under the action of microorganisms. The system is equipped with biogas purification and utilization facilities, as well as sludge collection and drying facilities. Anti-aging performance has excellent anti-aging, anti-ultraviolet, anti-decomposition ability, can be used naked, and the service life of the material can reach 60-80 years, which provides a good material guarantee for environmental seepage prevention. With the in-depth research on the theory of anaerobic digestion, people have successively developed a variety of high-efficiency anaerobic bioreactors. The black membrane biogas digester is used for fermentation and gas storage. HDPE impermeable membranes are used to completely seal the entire anaerobic pond and use biogas to generate electricity The waste heat and black film have good effect of absorbing sunlight, increasing temperature and keeping warm, and there is an automatic mud draining device at the bottom of the pool. The use of biogas technology to treat farm sewage has the advantages of less sludge and low operating costs. At the same time, it can control the flow of pollutants in the production process, reduce the degree of pollution of crops, control diseases, and achieve zero discharge of sewage. Agricultural waste is in After anaerobic digestion treatment and precipitation, organic fertilizer is produced, and finally “zero discharge” of manure is achieved. Use the effect of anaerobic bacteria in the black film biogas digester to hydrolyze, acidify and methanize organic matter, remove organic matter in wastewater, decompose high molecular organic matter into small molecular organic matter, and improve the biodegradability of wastewater, which is conducive to subsequent good Oxygen treatment. The subsequent aerobic biochemical system is easy to control, simple to operate, and stable in operation. With sufficient anaerobic reaction, the COD removal rate can reach more than 60%, that is, the anaerobic tank enters COD 15000mg/L, and the anaerobic tank effluent COD can be reduced to below 6000mg/L. If the anaerobic tank has a long reaction time and full reaction, COD can be reduced to below 2000mg/L The impact of high-molecular organic matter in the wastewater treatment system is manifested in the turbidity of the water body, the large amount of flocculants used and the poor effect, and the sludge cannot be decomposed after being absorbed in the aerobic biochemical process, which seriously affects the biochemical system. It is often manifested that the aerobic biochemical system gradually deteriorates after a period of normal operation and finally becomes paralyzed, causing the sludge to disintegrate and suspend in the water without sedimentation, the effluent is turbid, the color is dark, and the SS is high. The anaerobic degradation process of macromolecular organic matter can be divided into four stages: hydrolysis stage, fermentation (or acidification) stage, acetic acid production stage and methane production stage. Through the above-mentioned four-stage reaction, the high-molecular organic matter in the wastewater is decomposed into small molecules, the organic matter in the wastewater is removed, and the biological load of the subsequent biological treatment is reduced and its biochemical properties are improved.
6. Air floatation separator

Because the aquaculture wastewater has certain characteristics, the concentration of suspended solids is very high, and the suspension has a great influence on the biochemical system, so an air flotation separation device is installed at the front of the biochemical tank to remove suspended solids.

7. Black film biological denitrification and oxidation pond

The back end of the anaerobic system is equipped with an air flotation separation and purification system, and the removal rate of suspended solids, non-degradable substances and phosphorus is more than 90%. Set up a biological denitrification oxidation pond at the back end of the air flotation separation as a pretreatment process for ammonia nitrogen degradation. Special photobiological strains and algae species cultivated in the oxidation pond are added, which is easy to operate, has a strong denitrification ability, and improves overall The biodegradability of sewage meets the basic requirements of aerobic biochemistry,

Biological denitrification oxidation pond is an enhanced ecosystem formed by screening and cultured chlorella and photosynthetic bacteria, which is mainly used to remove ammonia nitrogen and part of phosphorus in water bodies. The photobiological oxidation pond has low investment cost and stable operation. The photosynthetic bacteria and algae in the photobiological oxidation pond absorb ammonia nitrogen, phosphorus and other organic matter to synthesize their own protein growth and reproduction process, which can effectively reduce the pollutant indicators such as ammonia nitrogen. The ammonia nitrogen in the wastewater can be maintained at About 300-400mg/L, it can effectively adjust the nutrient ratio of sewage and create suitable biochemical system conditions. After the degradation of the photobiological oxidation pond, the biodegradability of wastewater is greatly improved, making the subsequent biochemical system easier and simpler and more stable.

8. Two-stage A/O biochemical process

The improved 2-level A/O biochemical tank adjusts the design parameters of the tank body and adjusts the reflux ratio according to the different concentrations of aquaculture wastewater to enhance the denitrification and denitrification capacity. At the same time, the activated sludge in the system does not cause excessive aerobic and solves the instability of the previous biochemical system At the same time, it greatly improves the ability to remove pollutants, improves the stability of the biochemical system, reduces the difficulty of debugging and operation, and ensures the stable discharge of the effluent.

The A/O process is an anoxic and aerobic alternate operation. It is composed of an anoxic tank and an aerobic tank. It is currently the mainstream process technology that can remove nitrogen and phosphorus while removing organic matter at home and abroad.

Anoxic tank (also known as facultative aerobic tank) refers to the mixed liquid returned from the aerobic tank under anoxic conditions with low dissolved oxygen contained in wastewater. Through the adsorption of facultative microorganisms and biochemical degradation, the returned wastewater is returned to the wastewater. The NO3-N and NO2-N undergo denitrification and biochemical reactions and are converted into nitrogen. Therefore, in addition to partially degrading organic matter in wastewater, the most important role of anoxic reaction is to completely remove NH3-N (removal of total nitrogen) in wastewater.

The aerobic tank means that when the wastewater has sufficient dissolved oxygen, the organic matter in the wastewater is oxidized and decomposed under the action of aerobic microorganisms, the concentration of organic matter decreases, and the amount of microorganisms increases. The organic matter in the wastewater is first adsorbed on the surface of the biofilm of the activated sludge and comes into contact with the microbial cells. Under the action of the enzyme, it enters the microbial cell body through the cell wall. Small molecular organic matter can directly enter the microbial body through the cell wall. The macromolecular organic matter must be hydrolyzed into small molecules under the action of extracellular enzyme-hydrolase before being taken into the cell body by microorganisms. The organic matter is finally decomposed into CO2 and H2O, and activated sludge is produced. At the same time, the ammonia nitrogen and nitrogen-containing organic matter in the waste water generate NO3-N or NO2-N under the action of nitrifying bacteria in the aerobic tank, and form a nitrification-denitrification system by reacting with the denitrification in the anaerobic and anoxic tank to achieve denitrification. The purpose of nitrogen.

9. Sludge dewatering system

The sludge produced by the biogas slurry, biogas residue, sedimentation tank and other processing units in the system is concentrated in the sludge tank and separated by the sludge dewatering of the snails to remove the anaerobic undigested solid matter and anaerobic sludge. The pressure filtration of the remaining sludge discharged from the later sedimentation system, biochemical system and sedimentation system. Through this link, the separation efficiency of biogas slurry and residue can reach more than 95%, COD can be directly reduced to 1500-3000mg/L, and the suspended solids SS Below 600mg/L. This link directly removes sludge from the anaerobic system and aerobic system, and the phosphorus removal rate is over 85%.

10. MBR system

The MBR process is a new type of wastewater treatment technology that combines membrane separation technology and biotechnology. It uses membrane separation equipment to intercept the activated sludge and macromolecular organics in the biochemical reaction tank, the concentration of activated sludge can be greatly increased, the hydraulic retention time (HRT) and sludge retention time (SRT) can be controlled separately, and it is difficult to degrade The substances in the reactor continue to react and degrade. Therefore, the membrane-bioreactor process greatly strengthens the function of the bioreactor through membrane separation technology.

The advantages of membrane-bioreactor in optimizing biochemical effects:

1) The removal rate of pollutants is high, the ability to resist sludge expansion is strong, the effluent water quality is stable and reliable, and there is no suspended matter in the effluent;

2) The membrane bioreactor realizes the complete separation of the reactor sludge age STR and the hydraulic retention time HRT, and the design and operation are greatly simplified;

3) The mechanical interception effect of the membrane avoids the loss of microorganisms. The high sludge concentration can be maintained in the bioreactor, which can increase the volume load and reduce the sludge load. The MBR process omits the secondary settling tank and greatly reduces the area occupied. area;

4) Due to the long SRT, the bioreactor again functions as a “sludge nitrification tank”, thereby significantly reducing the sludge output, the remaining sludge output is low, and the sludge treatment cost is low;

5) SRT is prolonged due to the interception effect of the membrane, creating a slow proliferation of microorganisms. For example, the environment where the nitrifying bacteria grows can improve the nitrification capacity of the system, and at the same time help to improve the treatment efficiency of difficult-to-degrade macromolecular organic matter and promote its thorough decomposition;

6) The activated sludge in the MBR aeration tank will not be lost due to water production. During operation, the activated sludge will change due to changes in the concentration of organic matter and reach a dynamic balance, which makes the system effluent stable and resistant. Characteristics of impact load;

7) Larger hydraulic circulation results in uniform mixing of sewage, so that the activated sludge has a good dispersibility, and the specific surface area of the activated sludge is greatly increased. The high dispersion of activated sludge in the MBR system is another reason to improve the effect of water treatment. This is difficult to compare with the formation of larger bacterial micelles by ordinary biochemical water treatment technology;

8) Membrane bioreactor is easy to integrate, easy to realize automatic control, and easy to operate and manage;

11. RO system

1) Reverse osmosis water supply pump

This system is equipped with a low-pressure pump to provide the necessary power source for reverse osmosis inflow.

2) Reductant dosing system

Since the oxidizing bactericide NaClO is added to the system, it is highly oxidizable and can oxidize the reverse osmosis membrane, causing irreversible damage, which must be removed. This system adopts the method of adding a reducing agent to the water to remove residual chlorine to ensure that the reverse osmosis influent water does not contain residual chlorine.

The reducing agent is NaHSO3, and the reaction is as follows: NaHSO3+HClO—→ NaHSO4 +HCl

Add a reducing agent to the reverse osmosis feed water to reduce the remaining oxidant in the feed water to ensure the safe operation of the system.

The dosage of reducing agent depends on the added bactericidal dosage.

3) Antiscalant dosing system

The function of the antiscalant dosing device is to add a high-efficiency special antiscalant before the pretreated raw water enters the reverse osmosis to prevent scaling on the reverse osmosis concentrated water side.

The working process of reverse osmosis is that raw water flows from one end to the other on one side of the membrane. Water molecules permeate the surface of the membrane, from the raw water side to the other side, while the inorganic salt ions stay on the original side and gradually get the raw water. Concentration, water molecules are continuously removed from the raw water, and the salt content left in the raw water gradually increases, that is, the raw water is gradually concentrated, and finally becomes concentrated water, which is discharged from the device. After the concentrated water is concentrated, the concentration of various ions will increase exponentially. In natural water sources, Ca2+, Mg2+, Ba2+, Sr2+, HCO3-, SO42-, SiO2 and other ion concentration products that tend to cause scaling are generally less than their equilibrium constant, so there will be no scaling, but after concentration, various The concentration product of ions may greatly exceed the equilibrium constant, so serious fouling will occur.

The criteria for judging water scaling are: a) For carbonates, the Langelier Saturation Index (LSI) on the concentrated water side is used as the benchmark; when LSI<0, no scaling occurs, and when LSI>0, scaling occurs; b) For sulfuric acid Salt scale is determined by the saturation index. The ratio of the concentration product of cations and anions in the water to the equilibrium constant is the saturation index. When the saturation index is less than 1, no fouling will occur, otherwise fouling will occur.