TECHNOLOGY FOCUS - BIOLOGY - Preferred Compositions: Amount of biological species released in per 666 m2 circulating water treatment pond is 500-2000 crucian carp or common carp, 300-500 silver carp, 50-100 bighead carp, 500-1500 Pelteobagrus fulvidraco, 10-50 black carp, 20-50 grass carp with fish size of 30-500 g/fish, and aquatic vegetable planting variety is water spinach.    TECHNOLOGY FOCUS - ENVIRONMENT - Preferred Processes: Circulating water treatment pond is constructed by calculating pond size based on maximum number of pig herds in pig farm with each pig supported by 1-2 m2 primary treatment pond and 1-2 m2 secondary treatment pond and constructing rectangular circulating water primary treatment pond and circulating water secondary treatment pond with pond depth of 2-3 m, water depth of 1.5-2.5 m by forming pond walls using soil tamping or hardened cement and forming pond floor using soil tamping in which pond length is consistent with the width of 2 groups of bio-beds, circulating water primary treatment pond is capable of supplying water to bio-bed, and secondary treatment pond is capable of accommodating bio-bed water discharge. Assorted equipment is installed by installing 30-50 L floating microbial culture tank per 1000 m2 pond, installing microporous aerator machine to each pond, installing 1 disk aeration tube/100-200 m2 pond, fixing aeration tube 10-20 cm from pond sediment, installing control instrument for remotely detecting dissolved oxygen and aerator switch for controlling aeration to each pond, installing aquatic vegetable floating bed to each pond with floating bed size of 10-20% of the size of pond water surface, setting sluice between ponds to control flow of water, setting sewage outfall between primary treatment pond sewage inlet and poultry and livestock breeding farm, setting drain pump between bio-bed water inlet and primary treatment pond, setting drain outlet between bio-bed and secondary treatment pond, and installing water pump on secondary treatment pond for pumping water to farms. Equipment use in circulating water treatment pond is optimized by setting automatic control of dissolved oxygen by automatically starting aerator when dissolved oxygen content in water reaches 3.5 mg/L and automatically stopping aerator when dissolved oxygen content in water reaches 5 mg/L, inoculating microbial culture tank with aerobic probiotic bacteria, loading culture medium and biofilm attachment base for aerobic probiotic bacteria, and checking equipment operating conditions every day to ensure normal automatic operation. Bio-bed is constructed by calculating bio-bed size based on maximum number of pig herds in pig farm with each pig supported by 6-10 m2 of bio-bed and constructing 2 groups of 30-40 rectangular bio-beds arranged in parallel with area of 40-300 m2, length of 10-75 m, and width of 2-6 m in which water-tight soil ridge or cement ridge with width of 10-20 cm is built around bio-bed, one end of bio-bed contains inlet port, other end of bio-bed contains outlet port, bio-bed has slope of 0.5-1% from inlet port to outlet port, inlet port and outlet port are set with fencing to prevent fish, shrimp, and biological predators from entering, and annular groove for water discharge is dug around edge of bio-bed. Nutrient base is laid by paving layer of straw or crop residue with thickness of 5-10 cm on bio-bed, placing 5-10 kg/m2 livestock manure on surface, and raking surface.