Nitrogen and phosphorus removal system and method for treating low-carbon-nitrogen-ratio domestic wastewater by A2O-MBBR (anaerobic-anoxic-oxic-moving bed biofilm reactor) combined chemical process

Abstract

The invention discloses a nitrogen and phosphorus removal system and a method for treating low-carbon-nitrogen-ratio domestic wastewater by an A2O-MBBR (anaerobic-anoxic-oxic-moving bed biofilm reactor) combined chemical process, belongs to the field of city wastewater treatment and regeneration, and solves the problem of poor nitrogen and phosphorus removal effect of an existing water purification process for treating the low-carbon-nitrogen-ratio domestic wastewater. The nitrogen and phosphorus removal system comprises an A2O reactor, an intermediate settling pond, an MBBR, a chemical phosphorus removal pond and a final settling pond. According to the method, the MBBR is arranged behind the intermediate settling pond, a nitrifying process is finished, and an inorganic metal salt agent is added into the chemical phosphorus removal pond; all active sludge subjected to standing and settling by the chemical phosphorus removal pond flows back to the A2O reactor, so that the number of phosphorus-accumulating bacteria cannot be reduced; then, electron acceptors are provided for the denitrifying effect and the anoxic phosphorus uptake effect by flowing part of outlet water of the MBBR back to an anoxic zone of the A2O reactor. By the nitrogen and phosphorus removal system, the removal rate of ammonia nitrogen and total phosphorus can reach more than 90%.

Description

technical field [0001] The invention belongs to the field of urban sewage treatment and regeneration, and in particular relates to a treatment system and method for simultaneously and efficiently removing organic matter, nitrogen and phosphorus in domestic sewage with a low carbon-to-nitrogen ratio. Background technique [0002] In recent years, with the rapid development of the economy and the continuous improvement of people's living standards, the dietary structure has changed, causing the nitrogen content in urban domestic sewage to increase sharply, and the phenomenon of low carbon-nitrogen ratio in domestic sewage has appeared, making the nitrogen removal of sewage at the same time Phosphorus removal is more difficult. Coupled with the increasingly stringent national sewage discharge standards, many traditional processes have failed to meet the nitrogen and phosphorus standards in the effluent. It is imminent to find an efficient method for nitrogen and phosphorus remo...

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Problems solved by technology

[0005] The purpose of the present invention is to solve the problem that the denitrification and dephosphorization effect of the existing water purification process for processing low-carbon nitrogen ratio domestic sewage is poor, and to provide A 2 Nitrogen and phosphorus removal system and method for treating domestic sewage with low carbon-to-nitrogen ratio by O-MBBR combined with chemical method

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