Whole-set Equipment for Domestic Waste Leachate Treatment

(1) The new efficient anaerobic reactor is comprised of water distribution system, reaction zone, 2-stage 3-phase separator, liquid-gas separation system, internal and external circulating system, etc. The water distribution system is situated at the bottom of the whole reactor into which inlet water and reclaimed water flow, and shoulders the task of even water distribution and agitation, forming a certain ascending flow rate and providing shearing force for the formation of granular sludge. Wastewater to be treated flows into the reactor from the bottom of anaerobic sludge blanket and is mixed with sludge in the sludge layer. Microorganisms in the sludge decompose organics in the wastewater and turn them into biogas. Biogas rises to the deflector plate at the bottom of separator and it is deflected to places around the plate. Then biogas passes through the aqueous layer to the gas chamber where it is concentrated and discharged by conduit. After deflecting, the aqueous-solid mixture goes to the settling area of separator, and sludge in wastewater is subjected to flocculation and settling as a result of gravity as its particle size gradually increases. After separation, the gas-liquid mixture rises to the gas-liquid separation system where biogas is discharged and the liquid returns to the bottom of reactor through conduit, forming the internal circulation and intensifying hydraulic stirring. Wastewater at the upper part of stage-1 three-phase separator is pumped to return pipes that are connected to inlet pipes at the bottom to continuously supply a stable ascending flow rate, intensify hydraulic stirring, increase the contact between sludge and wastewater, improve COD removal efficiency, and remarkably decrease sludge production. Treated wastewater is drained from the upper overflow weir.
(2) The advanced membrane filtration and concentrate quantity reduction system: in recent years, with increasingly strict requirements of environmental protection, requirements of filtrate recycling and zero emission are put forth for the waste leachate treatment system. The UF filtrate still contains a large amount of undecomposed organics, COD, BOD and other pollutants and thus cannot meet the standards of reclaimed water. Only by adopting the NF and RO membrane process, can the standards be met. But this will bring about the issue of concentrate treatment and disposal. NF concentrate mainly contains humic acid, fulvic acid and divalent ions. Bivalent salts can be removed through humic acid extraction, quantity reduction, coagulation and settling successively, and the supernate and NF filtrate enter the RO system to realize concentrate quantity reduction. The RO concentrate is mainly univalent salts. Given different features of these two concentrates, the NF concentrate quantity reduction membrane process is applied to NF concentrate while the DTRO process is applied to RO concentrate. During actual operation, one or two out of these two processes can be selected to connect in series to the NF and RO membrane process in the upstream so as to improve the system's recovery rate.