Biochemical denitrifying method for wastewater

Abstract

The invention dislcoses a biochemical denitrifying method for wastewater. According to the biochemical denitrifying method, an improved A / O biochemical denitrifying process is combined with a chemical method (namely a zeolite adsorption ammonia nitrogen method) to efficiently remove ammonia nitrogen in wastewater, denitrification liquid flowing from an anoxic denitrification tank enters an aerobic nitrification tank to form internal circulation, and residual denitrification liquid directly enters a sedimentation tank to be subjected to solid-liquid separation; by combining ionic adsorption with biologic regeneration, total nitrogen in effluent water is less than or equal to 5mg / L, the removal rate of total nitrogen is higher than 90%, and thus the requirement that total nitrogen in effluent water of a chemical industrial park of a Tai Lake area is superior to the standard A of 'discharge standard of pollutants for municipal wastewater treatment plant' (GB18918-2002) is stably met.

Description

technical field [0001] The invention belongs to the technical field of environmental engineering, and in particular relates to a method for biochemical denitrification of wastewater. Background technique [0002] With the rapid economic development of the Taihu Lake Basin, the amount of wastewater discharged by chemical and other industries is increasing, the water quality is complex, nitrogen exists as a nutrient element in large quantities, the wastewater is difficult to degrade, has high salinity, and poor biodegradability, which is the cause of nitrogen pollution in the Taihu Lake Basin. The main source, thus causing serious eutrophication and pollution of Taihu Lake water, leading to the outbreak of blue-green algae. Water pollution has brought serious harm to aquatic organisms and the surrounding environment. In response to this problem, combined with special investigation results, the environmental protection department of Jiangsu Province organized and formulated the...

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Problems solved by technology

However, under such process conditions, 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, resulting in a low removal rate of total nitrogen; In the sludge, only a part of the sludge has experienced a complete anoxic and aerobic process. The sludge age of the system sludge cannot be too short due to the growth of nitrifying bacteria, which makes it difficult to further improve the denitrification effect.

Therefore, the traditional A / O process usually has many technical problems such as nitrate nitrogen in the effluent, insufficient alkalinity, and different sludge ages required for biological denitrification. There is still a long way to go in accordance with the requirements of the first-level A standard (especially TN ≤ 5mg / L) of the National Waste Emission Standard (GB18918-2002).

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