How to treat slaughterhouse wastewater?

Slaughterhouse wastewater is generally reddish brown, with a bad smell, which contains a lot of blood, oil, hair, meat, bone, visceral debris, undigested food, feces and other pollutants, high content of solid suspended solids. Slaughterhouse 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 process

The commonly used coagulants for coagulation treatment include aluminum salt, ferric salt, etc. Polymeric ferric sulfate has a better effect in Treating Slaughterhouse Wastewater. In order to reduce the use of aluminum salt, polyaluminum chloride and ammonium polyvinylammonium can also be used as coagulants. In the synthesis of polymeric ferric sulfate, a new coagulant is formed by adding any proportion of aluminum salt, a certain proportion of silicate and a small amount of polyacrylamide.

The composite inorganic polymer coagulant has a wide range of value and temperature application. When it is used as coagulant to treat slaughter wastewater, the chroma removal rate can reach respectively. There is an obvious problem in simple coagulation treatment, that is, it is difficult to remove the blood produced in the slaughter process, and a large amount of sludge and waste residue are produced at the same time (so if the slaughter wastewater is treated before using coagulant) Appropriate denaturation treatment, and then using ferrous sulfate and calcium oxide composite coagulant treatment, has better treatment effect. Coagulation process has low cost and good treatment effect at low temperature. It 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 process

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 achieve high nitrogen removal efficiency, SBR process must be equipped with stirring device, and the phenomenon of sludge floating is inevitable. The removal effect of chroma is not ideal, and it must be assisted by the post-treatment process. Therefore, the air floatation degreasing has become a necessary treatment unit when SBR process is used to treat slaughterhouse wastewater. After SBR treatment, the content of ammonia nitrogen in wastewater is still very high. If necessary, it can be removed by chemical method after this process.

(3) Sequencing batch biofilm process

Sequencing batch biofilm process has good denitrification and nitrogen removal function, good hydraulic conditions, strong shock load resistance and high biological concentration, which is suitable for the growth of digestive bacteria with long generation time (under the same operation 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 oxygen supply method is difficult to meet the oxygen demand of high concentration organic wastewater. It has the advantages of fast reaction, small floor area, low capital construction cost, convenient operation and management, and stable effluent quality.

(5) Anaerobic biological treatment

Anaerobic biological treatment method is mainly used to treat high concentration organic wastewater. Many improved anaerobic methods are used in the treatment of slaughterhouse wastewater.

(6) Combined process of pressurized biological contact oxidation and coagulation sedimentation

The process is suitable for the treatment of medium concentration slaughterhouse wastewater. The effluent is first treated by pressurized biological contact oxidation to improve the degradation rate of dissolved oxygen and organic matter in the wastewater, and then coagulated and precipitated to reach the secondary discharge of existing enterprises.

(7) UASB method and dissolved air flotation upflow anaerobic sludge bed method

The process is an improved process on a single UASB method, which is suitable for the treatment of slaughtering wastewater containing high concentration suspended solid fat particles and oils. The first stage of the second stage of high-speed up flow anaerobic sludge bed UASB Process is UASB reactor using flocculant sludge, which can remove the insoluble cod such as fat particles and oils. The second stage is cod using granular sludge.

(8) Hydrolysis acidification biosorption regeneration contact oxidation process

The process is especially suitable for the treatment of high concentration slaughtering wastewater, and the water quality and quantity change greatly. The combination of AB and B processes shows that the load of section a is high, sludge flocs have strong adsorption capacity and good settling performance, and have strong impact resistance load capacity, which has a great buffer effect on toxic substances. However, the sludge volume is high, so corresponding sludge treatment measures are required. A small amount of falling off biofilm in the effluent of the second sedimentation tank in Section B is further removed by air flotation treatment to improve the effluent water.

(9) Upflow anaerobic sludge bed filter sequencing batch activated sludge method

The process is suitable for wastewater treatment with high fluctuation of water quality and high protein content. The upflow anaerobic sludge filter is a reactor which combines the upflow anaerobic sludge bed and the upflow anaerobic sludge bed filter sequence batch activated sludge method and anaerobic filter. The process is suitable for the slaughter wastewater with intermittent inflow.