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

The activated sludge process multi-cathode chamber denitrification phosphorus removal power generation technology is a new wastewater treatment technology proposed for the coexistence of water pollution and energy shortage.This technology integrates the principle of microbial fuel cells into the activated sludge process denitrification phosphorus removal.In the process,while strengthening the removal of organic matter,nitrogen,phosphorus and other pollutants in sewage while improving the power generation performance,the same system has many advantages such as energy saving,emission reduction and environmental protection.Because the carbon source is not only an important influencing factor for the denitrification and phosphorus removal process,but also an important parameter for microbial fuel cells,it is particularly important to study the impact of the carbon source on the multi-cathode chamber denitrification and phosphorus removal power generation system.First,the continuous flow method was used to cultivate denitrifying polyphosphate bacteria?DPAOs?and nitrified sludge,and the successfully domesticated sludge was placed in the corresponding reaction tank in the MDPRE device to control the anaerobic tank anode chamber and aerobic tank.The dissolved oxygen concentration in the cathode chamber and the anoxic chamber is 0.20mg/L,2.00?2.50mg/L,and 0.50mg/L.The water temperature in the device is controlled at 25^oC,and the external resistance is set to 900?.After 60 days of testing,The device started successfully.The removal rates of COD,NH₄⁺-N and phosphorus fluctuate within the ranges of 71.54%?77.40%,63.32%?74.16%,and 58.68%?63.12%,respectively.The voltage value generated by the cathode chamber of the system aerobic pool is 0.44?0.49V,and the current The value is 0.49?0.54m A,the power density is 21.51?26.68m W/m²;the voltage value generated by the cathode chamber of the second sink of the system is 0.42?0.45V,the current value is 0.47?0.50m A,and the power density is19.60?22.50m W/m²;The system has a weak power generation effect in the cathode chamber of the anoxic tank and the cathode chamber of the final sink tank.The voltage values generated by the cathode chamber of the anoxic tank and the cathode chamber of the final sink tank are 0.10?0.13V and 0.10?0.12V,respectively.It is 0.11?0.14m A and 0.11?0.13m A,the power density is 1.11?1.88m W/m² and 1.11?1.60m W/m² respectively.Secondly,sodium acetate,sodium propionate and glucose were used as the carbon sources of the three systems,and the C/N ratios were controlled to be 5,6,and 7 with an error range of±0.5.When the carbon sources are sodium acetate and sodium propionate,the optimal C/N of MDPRE is 6 and their differences in wastewater treatment are small.The COD removal rate can reach about 80.00%and the ammonia nitrogen removal rate is 75.00%.The phosphorus removal rate reached about 70.00%,and the voltage generated in the aerobiccell cathode room and the anaerobic cell anode room and the secondary sink tank and the anaerobic cell anode room reached about 0.45V.The best C/N of glucose for this system is 7,among which the removal rate of phosphorus is only 50.26%,which is the worst treatment effect among the 3 systems.However,it has a good electricity generation effect and the aerobic pool cathode The room and the anaerobic cell anode chamber and the secondary sink tank and the anaerobic cell anode chamber generate a voltage of about 0.50V.Finally,the effects of different types of carbon sources on the MDPRE system at their optimal C/N were studied,and it was found that the stable operation of the MDPRE system has a good ability to withstand the impact of carbon source transformation,and the effluent water quality and power generation effect are good When the carbon source of the influent was changed from sodium acetate to sodium propionate,the effect on the system was small,and the removal rate of phosphorus decreased from 70.87%to 68.63%.The aerobic tank cathode chamber and anaerobic tank anode chamber,and the secondary sink The average output voltage of the cathode room of the cell and the anode room of the anaerobic cell is about 0.49V,and the average output voltage of the cathode room of the anoxic cell and the anaerobic cell,and the anode chamber of the final sink tank and the anaerobic cell is about0.10V.When the carbon source was changed from sodium propionate to glucose,the phosphorus removal effect of the MDPRE system decreased from 68.63%to 51.48%,but the electricity generation effect of each cell was better,such as the aerobic cell cathode room and the anaerobic cell anode room and the secondary sink.The average output voltage of the cathode chamber of the cell and the anode chamber of the anaerobic tank is about 0.51V,and the average output voltage of the cathode chamber of the anoxic tank and the anode chamber of the anaerobic cell,and the cathode chamber of the final sink tank and the anode chamber of the anaerobic cell is about 0.11V.It can be seen that the best carbon source of the MDPRE system is sodium acetate.