Animal farm wastewater mainly comes from livestock and poultry manure and washing wastewater, which contains a large number of pollutants, such as heavy metals, residues of veterinary drugs, and a lot of pathogens, etc. In addition, livestock and poultry breeding wastewater contains much nitrogen, phosphorus, potassium and other nutrients.
Animal farm wastewater belongs to high concentration organic wastewater which is rich in a large number of pathogens (escherichia coli, hatched from eggs, etc.). It is inappropriate to directly discharge into water or storage place. The rain flushing into the water, it may cause serious deterioration of surface water and groundwater quality. Due to the strong leaching of livestock and poultry manure, and large amounts of nitrogen, phosphorus and water soluble organic matter in manure leaching, if not properly handled, it enters through the surface runoff and infiltration into the underground water, causing the pollution of groundwater.
Main influence for surface water is, that a large number of organic matter enters into water, after the decomposition of organic matter it will deplete the dissolved oxygen in the water, making water stink; If human and animal drink for a long time, it will cause the poisoning. And some of the toxic algae growth and large amounts of multiplying can discharge toxins in the water, causing massive death of aquatic animals, which seriously damages the water ecological balance; Some of urine bacteria and viruses can lead to the spreading of some epidemic with water flowing etc.
Water quality characteristics of animal farm wastewater is that it contains various kinds of organic substances, feces and sandy soil pollutants. This kind of wastewater treatment can achieve good treatment effect by combining biochemical and physicochemical.
Animal farm wastewater out from pig farms enters into the tank after flowing through the grid, the mesh to remove most large size of sundry. In the biogas tank, organics conduct hydrolysis under the conditions of anaerobic, bio-refractory macromolecule organics being transformed into bio-degradation micro-molecule organics for the follow-up process. Biogas tank produces a certain amount of biogas, collected by biogas equipment for recycling. Animal farm wastewater is sent by the lift pump into the hydrolysis acidification tank after balancing water quality and water yield in the adjusting tank. Hydrolysis acidification tank adopts up-flow anaerobic sludge bed (UASB) reactor, the sewage from bottom up across the sludge bed formed by the microorganism in the tank, (organic) pollutants in wastewater is trapped by the sludge bed, macromolecule and complex organics are resolved into low simple molecular organics ( such as organic acid) by decomposition, absorption and decomposition. At the same time, the mixture contacting oxidation tank back conducts denitrification under the action of denitrifying bacteria to achieve the action of denitrifying bacteria.
Wastewater out from UASB reactor enters into the MBR. MBR is composed of oxygen and MBR reaction tank. Water production in the MBR tank can meet the standard for discharge or reused in piggery back flushing after sterilization killing the bacteria in the wastewater.