Enhancing water quality treatment capacity of cold-water fish circulating aquaculture system by microbial electrolysis pool method
In order to solve the problem of low removal efficiency of ammonia nitrogen and nitrate in the treatment of aquaculture waste water by traditional aeration biological filters,the effects of diffe-rent carbon sources and voltage intensities on the removal efficiency of chemical oxygen demand(COD),ammonia nitrogen(NH3-N),nitrate nitrogen(NO3--N),total nitrogen(TN)and total phosphorus(TP)in microbial electrolysis cell(MEC)system are investigated by using MEC me thod at low temperatures.The aim is to explore how MEC enhance water treatment capacity of fresh-water cold-water fish culture system under the conditions of optimal carbon source and voltage in-tensity,and to explore its removal mechanism.The results show that when sodium acetate is carbon source,the removal rates of COD,NH3-N,NO3--N and TP reach 82.10%,87.56%,98.64%and 73.64%respectively.When the voltage intensity is 0.30 V,the removal rates of COD,NH3-N,NO3--N and TP are 81.01%,73.15%,76.74%and 83.97%respectively.Marco gene sequen-cing results show that under the optimal carbon source and voltage intensity,Streptomyces,Pseudo-monas and Burkholderia are the dominant genera in the microbial community at genus level.The key functional genes amoCAB,nxrAB,nirBD,nrfA and nifDHK involved in the nitrogen metabolism path-way show that MEC system mainly undergoes nitrogen removal metabolism through the pathway of simultaneous nitrification and denitrification.
cold-water fish farmingmicrobial electrolysis cell(MEC)carbon sourceapplied voltagemicrobial community