Multi-unit Design And Operation Control Strategy Of Sulfur Autotrophic Denitrification Biofilter

This subject adopts the test method of small-scale design-pilot test verification,and comprehensively analyzes and inspects the overall design of sulfur autotrophic denitrification filter to practical engineering application.Generally speaking,this subject takes the small-scale reactor as the design basis,and then carries out actual verification with the pilot reactor,and obtains and perfects a set of operation strategy of pilot-scale sulfur autotrophic denitrification filter,which can not only ensure that the effluent of the filter reaches the standard,but also reduce the economic cost of filter operation.This strategy has practical reference significance for the practical engineering application of sulfur autotrophic denitrification filter.（1）Design-Firstly,the nitrogen removal efficiency of the pilot reactor was investigated by introducing simulated wastewater at different temperatures to provide a theoretical basis for the design and operation strategy of the pilot filter.At 30℃,the average nitrate-nitrogen removal was 7.5 mg/L;when the water temperature was reduced to 10℃,the average nitrate-nitrogen removal was only 0.89 mg/L;further,we improved the nitrogen removal efficiency at low temperature by extending the EBCT of the reactor,and found that at 20℃,the EBCT was extended to 0.33 h without the risk of exceeding the emission standard;while at the lowest temperature of 10℃,the EBCT had to be extended to 1.5 h.Designed the pilot filter as a three-units parallel adjustable EBCT,and each unit can reduce the NO₃^--N concentration from 15 to 10 mg/L at 20℃with 0.25 h EBCT,and the EBCT can be adjusted by adjusting the number of units of the filter to ensure the effluent quality of the pilot filter meets the standard under low temperature conditions.This ensures that the effluent quality of the pilot filter meets the standard at low temperature.（2）Validation strategy-based on the experimental basis of the pilot reactor,we designed and operated a multi-unit sulfur autotrophic denitrification pilot filter based on actual rural decentralized point source wastewater treatment.Then,we investigated the denitrification efficiency of the pilot filter and found that when the filter water temperature was 17-20℃,only one unit could be opened to meet the discharge standard;as the filter water temperature decreased,two units could be opened to ensure the discharge standard at 13-17℃,and finally,three units could be opened to ensure the discharge standard at 9-13℃.Based on this,we obtained the operation strategy to ensure the effluent of the pilot filter to meet the standard and avoid excessive denitrification under different temperature ranges,and at the same time,the pilot filter also has certain treatment capacity for COD,TP and SS,and these pollutants can meet the standard discharge after the filter treatment.