Abstract
A constructed wetland (CW) coupled microbial fuel cell (MFC) system that treats wastewater and generates electricity was constructed. The total phosphorus in the simulated domestic sewage was used as the treatment target, and the optimal phosphorus removal effect and electricity generation were determined by comparing the changes in substrates, hydraulic retention times, and microorganisms. The mechanism underlying phosphorus removal was also analyzed. The experimental results showed that the best removal efficiencies of the two CW-MFC systems that used magnesia and garnet as substrates were 80.3% and 92.4%, respectively. Phosphorus removal by the garnet matrix mainly depends on a complex adsorption process whereas the magnesia system relies on ion exchange reactions. The CW-MFC system can also generate electricity. The highest output voltage and stable voltage of the garnet system were both higher than those of the magnesia system. The maximum stable voltage of the garnet device was 500 mV, while that of the magnesia device was 290 mV. The microorganisms in the soil and in the electrode within the wetland sediments also substantially changed, indicating that microorganisms positively respond to the removal of organic matter and power generation. Combining the advantages of constructed wetlands and microbial fuel cells also improves phosphorus removal in the coupled system. Therefore, when studying a CW-MFC system, the selection of electrode materials, matrix, and system structure should be taken into account in order to find a method that will improve the power generation capacity of the system and remove phosphorus.
Removal of Phosphorus from Domestic Sewage by a Constructed Wetland Coupled Microbial Fuel Cell System
