Impacts of the Myriophyllum aquaticum based mixed filler on denitrification performance and greenhouse gas emissions in biofilters
This study aimed to address the low denitrification efficiency and associated greenhouse gas emissions in the use of biofilter systems for treating low carbon wastewater.By using the residues of Myriophyllum aquaticum and its biochar prepared from it as filter materials,small-scale denitrification biofilters were constructed.Different proportions of the two carbon sources were added,and simulated low carbon wastewater was continuously introduced to investigate the denitrification performance and greenhouse gas emission patterns of the denitrification biofilter.Monitoring results of the 85-day operation period showed that the ability of Myriophyllum aquaticum to decompose and release organic carbon was much higher than that of biochar.When Myriophyllum aquaticum was used as the sole filter material,the denitrification effect was optimal,with an average removal efficiency of 93.9％for nitrate nitrogen.The removal efficiency of nitrate nitrogen remained close to 100％for the first 60 days of the experiment,withan average total nitrogen removal efficiency of 76.4％.In contrast,when biochar was used as the sole filter material,there was only an initial removal effect for nitrate nitrogen and total nitrogen in the first 10 days,with little subsequent removal capability.When Myriophyllum aquaticum and its biochar were mixed in different proportions as filter materials,the average removal efficiency of nitrate nitrogen was above 80％throughout the entire experimental period.Compared with the condition that Myriophyllum aquaticum was used as the sole filter material,when the mass ratio of Myriophyllum aquaticum to biochar was 1︰1,the average emission fluxes of N2O,CH4 and CO2 decreased to 401.9 μg/(m2·h),197.8 mg/(m2·h)and 113.5 mg/(m2·h),respectively.The results of the study indicated that Myriophyllum aquaticum could serve as an external carbon source for treating low carbon wastewater in biofilter systems.When mixed with biochar,though it did not further enhance the denitrification performance of the denitrification biofilters,it did help reduce the greenhouse gas emissions.
Myriophyllum aquaticumbiochardenitrification biofilternitrogen removalgreenhouse gas
万方数据
维普
