Effect Of Nitrogen On The Process Of Denitrifying Phosphorus Removal And Electrogenesis In Multi-cathode Chamber

Activated sludge denitrifying phosphorus removal and electrogeneisis in multi-cathode chamber（MDPRE）is a generate energy and wastewater purification process.This process combines activated sludge denitrifying phosphorus removal process（DPR）with microbial fuel cell（MFC）process.It not only enhances the removal efficiency of COD,NH₄⁺-N and PO₄^3--P in domestic sewage,but also improves the performance of electricity production and has many advantages such as energy saving and emission reduction.After the denitrifying phosphorus removal and electrogeneisis in multi-cathode chamber system was installed and started successfully,the effect of nitrogen on the MDPRE system was studied in this experiment.The influent ammonia nitrogen concentration was maintained at 30,40,50 and 60mg/L respectively to study the effects of ammonia nitrogen on COD removal,phosphorus removal,nitrogen removal and electricity production,as well as the effect of nitrate nitrogen on phosphorus removal and electricity production.When the influent ammonia nitrogen concentration increased from 30mg/L to 40,50 and60mg/L,the average removal rate of ammonia nitrogen increased from 74.73%to 77.19%,76.17%and 78.19%,which was basically stable.When the influent ammonia nitrogen concentration increased from 30mg/L to 40,50mg/L,the average removal rate of COD increased from 74.18%to 77.81%and 78.25%,the average removal rate of PO₄^3--P increased from 68.77%to 72.30%and 72.79%,but when the influent ammonia nitrogen concentration increased to 60mg/L,the average removal rate of COD decreased to 71.18%,the average removal rate of PO₄^3--P decreased to 69.39%.It can be seen that when the influent ammonia nitrogen concentration is 50mg/L,the system has the best removal effect of COD and phosphorus.With the increase of influent ammonia nitrogen concentration from 30mg/L to 40mg/L,50mg/L and 60mg/L,the average voltage of aerobic tank increased from 0.54V to 0.57V,0.62V and 0.66V,the average voltage of secondary sedimentation tank increased from 0.55V to 0.58V,0.63V and 0.67V,and the average voltage of anoxic tank increased from 0.08V to0.09V,0.10V and 0.12V.With the increase of influent ammonia nitrogen concentration from 30mg/L to 40mg/L,50mg/L,the nitrate nitrogen concentration in the anoxic tank increased from 16.26mg/L to21.37mg/L,26.80mg/L,and 31.34mg/L,the average removal rate of phosphate in the effluent increased from 68.77%to 72.30%and 72.79%,but when the influent ammonia nitrogen concentration increased to 60mg/L,the nitrate nitrogen concentration was 31.34mg/L,and the removal rate decreased to 64.02%.Therefore,properly increasing the concentration of nitrate nitrogen is beneficial to the removal of phosphate in the multi-cathode chamber denitrifying phosphorus removal and electrogenesis process.