(1) Pretreatment: firstly, the sewage is deslagging, and then it is adjusted by hydrolysis and acidification, so that the insoluble organic matter in the wastewater is converted into soluble organic matter;
(2) Biochemical treatment: the pretreated sewage is firstly treated by UASB, and then sequentially treated by a primary A/O treatment system, an intermediate sedimentation tank and a secondary A/O treatment system;
(3) dephosphorization and disinfection: the sewage after biochemical treatment is subjected to dephosphorization and flocculation treatment in turn to remove sediments, the upper liquid flows into the final sedimentation tank to further remove sediments, and the upper liquid flows into the pH adjusting tank to make the pH value of the liquid 6-9; Then sterilization treatment is carried out, and the discharge can reach the standard.
2. The method for treating aquaculture wastewater according to claim 1 is characterized by the following specific operations:
(1) pretreatment
1. 1 slag removal: firstly, the aquaculture wastewater is introduced into the slag separation tank to remove the suspended solid SS with larger particles in the wastewater; Then it flows into the water collection tank to mix the slag and liquid evenly, then it is pumped into the solid-liquid separator to separate the slag and water, and the filtrate is introduced into the primary sedimentation tank to precipitate the particles that the solid-liquid separator cannot remove, thus further removing SS from the sewage;
1.2 Hydrolytic acidification regulation: the liquid after the above slag removal treatment is introduced into the hydrolytic acidification regulation tank to improve the BOD/COD ratio of sewage, enhance the biodegradability of sewage and create conditions for subsequent biochemical treatment;
(2) Biochemical treatment
2. 1 UASB for removing organic pollutants: introducing the liquid adjusted by hydrolysis and acidification into the upflow anaerobic sludge bed UASB to remove organic pollutants in sewage;
2.2 removal of organic pollutants by primary A/O system: UASB effluent flows into primary A/O treatment system to further remove COD and BOD in sewage, and convert ammonia nitrogen into nitrogen to realize nitrogen removal;
2.3 sedimentation and reflux of activated sludge: the sewage treated by the primary A/O system flows into the intermediate sedimentation tank, so that the activated sludge generated by the primary A/O system is precipitated in the sedimentation tank and partially refluxed to the primary A/O system;
2.4 removal of organic pollutants by the secondary A/O system: the effluent from the intermediate sedimentation tank flows into the secondary A/O treatment system to further convert ammonia nitrogen into nitrogen and further remove nitrogen;
(3) dephosphorization and disinfection
3. 1 dephosphorization flocculation reaction: the sewage after the above biochemical treatment flows into a lime pool, and lime water is added to the sewage to make the pH value 8.5 ~ 10, so that Ca2+ reacts with phosphorus (PO43-) and residual ammonia nitrogen (NH4+) in the water to generate calcium ammonium phosphate precipitate, and then enters the coagulation pool, and PAM coagulant is added to the coagulation pool, after the reaction is complete.
3.2 Precipitation and sludge removal: the sewage after dephosphorization and flocculation treatment flows into the final sedimentation tank, so that the generated ammonium phosphate precipitation and the residual sludge from the secondary A/O system are fully precipitated and removed;
3.3 pH adjustment: finally, the effluent from the sedimentation tank flows into the pH adjustment tank to make the liquid pH value 6-9;
3.4 Discharge after disinfection: the liquid with adjusted pH value can be discharged after disinfection.
3. The method according to claim 1 or 2, characterized in that the primary sedimentation tank is a horizontal sedimentation tank with a surface load of 0.6- 1.5m3m-2h- 1 and a horizontal flow rate of less than 10 mm/s, and is equipped with a mobile sludge scraper and a sludge reflux system.
4. The method according to claim 1 or 2, characterized in that the specific process of hydrolytic acidification is as follows: the hydraulic retention time of sewage in the hydrolytic acidification regulating tank is 6-24 hours, and continuous aeration with a blower can make do.
5. The method according to claim 1 or 2, characterized in that the UASB adopts a circular tank with an enamel combined structure, with a volume load of1.5 ~10 kgcod/m3 d, a height of 7 ~ 9 meters, an upwelling speed of less than 0.5 meters/hour and a hydraulic retention time of 20.
6. The method according to claim 1 or 2, characterized in that the primary A/O system comprises a primary anoxic tank and a primary aerobic tank, and the specific operation process is as follows: the effluent of UASB first enters the primary anoxic tank, then flows into the primary aerobic tank, and Na2CO3 is added into the sewage of the primary aerobic tank to ensure the alkalinity required for nitrification reaction. Microorganisms in the primary aerobic pool can degrade COD and BOD in the pool water, and at the same time transform ammonia nitrogen into nitrate nitrogen. Part of the mixed liquor from the first-stage aerobic tank is refluxed to the first-stage anoxic tank to be mixed with the UASB effluent. Denitrifying bacteria in the primary anoxic tank can transform nitrate nitrogen into nitrogen under the condition of sufficient carbon source to achieve the purpose of nitrogen removal.
Among them, the ammonia nitrogen load of the primary anoxic tank is 0.01~ 0.1kgnh3-n/kgmlss d, the sludge concentration is 2000 ~ 4000 mg/L, the hydraulic retention time is 8 ~ 25 h, and it is equipped with a submersible stirring system. The BOD load of the primary aerobic tank is 0.05 ~ 0.2 kg BOD5/kg MLSS d, the hydraulic retention time is 8 ~ 30h, the DO is controlled at 2 ~ 3mg/L, and the mixed liquid reflux pump is 100 ~ 300%. It is equipped with two sets of aeration systems, alkalinity dosing system and mixed liquid reflux pump.
7. The method according to claim 1 or 2, characterized in that the intermediate sedimentation tank is a vertical sedimentation tank with a surface load of 0.6- 1.5m3m-2h- 1 and a sludge reflux ratio of 40- 150%, and is equipped with a mobile sludge scraper and a sludge reflux system.
8. The method according to claim 1 or 2, characterized in that the secondary A/O treatment system comprises a secondary anoxic tank and a secondary aerobic tank, and the specific operation process is the same as that of the primary A/O treatment system, wherein the ammonia nitrogen load of the secondary anoxic tank is 0.01~ 0.1kg NH3-n. Na2CO3 is added to the sewage of the secondary aerobic tank to ensure the alkalinity required for nitrification. The BOD load of the secondary aerobic tank is 0.05 ~ 0.2 kg BOD5/kg MLSS d, the hydraulic retention time is 8 ~ 30h, the DO is controlled at 2~3mg/L, the reflux ratio of mixed liquid is 100 ~ 300%, and it is equipped with aeration system, alkali adding system and stirring.
9. The method according to claim 1 or 2, characterized in that the final sedimentation tank is an inclined tube sedimentation tank, and the inclined tube filler is installed in the inclined tube sedimentation tank, and the surface load is 0.5-2.0m3m-2h-1.
10. The method according to claim 2, characterized in that the disinfected liquid in step 3.4 flows into the oxidation pond and is discharged after natural degradation. Or contact our He Jiang Chemical Company to make a sewage treatment plan, which will save time and worry.