Slaughtering wastewater is generally reddish brown, with a bad smell, which contains a lot of blood, grease, hair, meat, bone, visceral debris, undigested food, feces and other dirt, with high content of suspended solids. Slaughtering wastewater has high content of organic matter and good biodegradability, but the high concentration of organic matter is not easy to degrade, so it is difficult to treat. The nutrients in slaughterhouse wastewater are mainly nitrogen and phosphorus, in which nitrogen mainly exists in the form of organic matter or ammonium salt, while phosphorus mainly exists in the form of phosphate.
(1) Coagulation method:
The coagulants commonly used in coagulation treatment are aluminum salt, iron salt, etc. among them, PFS has a better effect in Treating Slaughterhouse Wastewater. In order to reduce the use of aluminum salt, polyaluminum chloride and polyethylene ammonium can also be used as coagulant. In the synthesis of polyferric sulfate, aluminum salt of any proportion, silicate of certain proportion and polyacrylamide are added to form a new coagulant, This composite inorganic polymer coagulant has a wide range of value and temperature application. When it is used as coagulant to treat slaughterhouse wastewater, the chroma removal rate can reach to that of pure coagulation treatment. There is an obvious problem that the blood water produced in slaughtering process is difficult to be removed, and a large amount of sludge and waste residue are produced at the same time Appropriate denaturation treatment, followed by ferrous sulfate and calcium oxide composite coagulant treatment, has better treatment effect. Coagulation process has low cost and good treatment effect at low temperature. This method is mostly used to treat low concentration wastewater or as pretreatment of high concentration wastewater to reduce the load of subsequent biological treatment.
(2) SBR method
SBR treatment of slaughterhouse wastewater is a more economical and effective method. However, because slaughterhouse wastewater contains a lot of grease, blood water, carbon and nitrogen ratio and carbon and phosphorus ratio are large, and nitrogen and phosphorus are relatively insufficient. At this time, oily foam is prone to cause sludge to loose and exponentially increase, which is prone to high viscosity expansion, resulting in sludge loss. In order to obtain high nitrogen removal efficiency, SBR process must be equipped with stirring device, and sludge floating phenomenon is inevitable. The removal effect of chroma is not ideal, so the post-treatment process must be supplemented. Therefore, air floatation degreasing becomes a necessary treatment unit for slaughterhouse wastewater treatment by SBR process. After SBR treatment, the content of ammonia nitrogen in wastewater is still very high. If necessary, it can be removed by chemical method after the process.
(3) Sequencing batch biofilm process
Sequencing batch biofilm process has good denitrification and denitrification function, good hydraulic conditions, strong impact resistance, high biological concentration, and can be suitable for the growth of digestive bacteria with a long generation (under the same operating conditions, the treatment effect of biofilm system is better than that of activated sludge system).
(4) Aerobic biological treatment
Aerobic biological treatment of organic wastewater requires sufficient oxygen supply, but the traditional way of oxygen supply is difficult to meet the oxygen demand of high concentration organic wastewater. It has the advantages of fast reaction speed, small floor area, low capital construction cost, convenient operation and management and stable effluent quality.
(5) Anaerobic biological treatment
Anaerobic biological treatment is mainly used to treat high concentration organic wastewater. Many improved anaerobic processes are used in the treatment of slaughterhouse wastewater. According to the characteristics of various treatment processes of slaughterhouse wastewater.
(6) Combined process of pressurized biological contact oxidation coagulation sedimentation
The process is suitable for the treatment of slaughterhouse wastewater with medium concentration. After being treated by pressurized biological contact oxidation, the degradation rate of dissolved oxygen and organic matter in wastewater is increased, and then the secondary discharge of existing enterprises can be achieved after coagulation and sedimentation.
(7) Two stage high speed upflow anaerobic sludge bed UASB Process and dissolved air flotation upflow anaerobic sludge bed process
This process is an improved process on a single UASB Process, which is suitable for the treatment of slaughterhouse wastewater containing high concentration suspended solid fat particles and grease. The first stage of UASB Process of two-stage high-speed upflow anaerobic sludge bed is UASB reactor using flocculant sludge, which can remove insoluble cod such as fat particles and oil. The second stage is cod using granular sludge.
(8) Hydrolysis acidification biosorption regeneration contact oxidation process
This process is especially suitable for the treatment of slaughterhouse wastewater with high concentration and large variation of water quality and quantity. Using ab two-stage combined process, the load of a section is high, the sludge floc has strong adsorption capacity and good sedimentation performance, strong anti shock load capacity, has a great buffer effect on toxic substances, but the amount of sludge is high, so corresponding sludge treatment measures should be taken. A small amount of exfoliated biofilm which is difficult to settle in the effluent of the secondary sedimentation tank of section B is further removed by air flotation to improve the effluent water.
(9) Upflow anaerobic sludge bed filter sequencing batch activated sludge process
The process is suitable for wastewater treatment with high protein content and high fluctuation of water quality. The upflow anaerobic sludge filter is a reactor which combines up flow anaerobic sludge bed and up flow anaerobic sludge bed filter sequencing batch activated sludge process and anaerobic filter. The process is suitable for slaughterhouse wastewater with intermittent influent.
