A method for efficient biochemical denitrification and dephosphorization of wastewater

Abstract

The invention discloses an efficient biochemical nitrogen and phosphorus removal method for waste water. Ammonia nitrogen and phosphorus in waste water are efficiently removed by combining a modified A2 / O biological nitrogen and phosphorus removal technology and a chemical method, namely, zeolite adsorbing ammonia nitrogen method; the denitrification liquid flowing out from an anoxic denitrification tank enters an aerobic nitration tank to form internal circulation; the residual denitrification liquid directly enters a sedimentation tank for solid-liquid separation; phosphorus-accumulating bacteria directly flows back to an anaerobic tank from the sludge of a sedimentation tank, and then enters the anoxic nitration tank. Ion adsorption and biological regeneration treatment are combined; water outlet total nitrogen is less than or equal to 5 mg / L; the removal ratio of total nitrogen and total phosphorus is more than 90%; requirements that water outlet total nitrogen in Taihu basin chemical engineering zone is superior to the primary standard, namely, the A standard, of the urban sewage treatment plant pollutant discharge standard (GB18918-2002) are met stably.

Description

technical field [0001] The invention belongs to the technical field of environmental engineering, and in particular relates to a method for highly efficient biochemical denitrification and dephosphorization of wastewater. Background technique [0002] The wastewater discharged by enterprises in the chemical industry park in the Taihu Lake Basin has complex water quality, large fluctuations in water quality, and many refractory substances. Nitrogen and phosphorus elements exist as nutrients in large quantities, and their biodegradability is extremely poor. Simple and imperfect, there are many problems. The effluent pollutant index is high, which leads to water pollution and has a great impact on aquatic organisms and the surrounding environment. In this regard, the Taihu Basin Chemical Industry Park requires enterprises to strictly implement the first-level A standard (especially TN≤5mg / L) of the "Pollutant Discharge Standards for Urban Sewage Treatment Plants" (GB18919-2002)...

AI Technical Summary

Problems solved by technology

Since the nitrification liquid in the aerobic nitrification tank directly enters the sedimentation tank for precipitation and separation, the effluent contains nitrate nitrogen and nitrite nitrogen. In addition, the mixed solution entering the sedimentation tank usually needs to maintain a certain concentration of dissolved oxygen to prevent the precipitation in the sedimentation tank. Denitrification and sludge anaerobic phosphorus release, but this will cause a certain amount of dissolved oxygen in the return sludge and return mixed liquor to affect anaerobic phosphorus release. At the same time, only a part of the remaining sludge discharged from the system has undergone a complete anaerobic and aerobic process, which affects the full phosphorus uptake of the sludge; the sludge age of the system is due to the consideration of the nitrifying bacteria growth and cannot be too short, making it difficult to further improve the phosphorus removal effect

So the traditional A 2 The / O process usually has many technical problems such as insufficient carbon source and alkalinity, anaerobic tanks cannot guarantee an absolute anaerobic environment, and different sludge ages required for biological nitrogen and phosphorus removal. There is still a long way to go to meet the requirements of the first-level A standard (especially TN≤5mg / L) of the "Pollutant Discharge Standards for Urban Sewage Treatment Plants" (GB18918-2002)

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