Study On The Electricity Generation And Ammonia Wastewater Treatment In Photosynthetic Algal Microbial Fuel Cell With Immobilized Chlorella Vularis

Energy crisis、shortage of water resource and environmental pollution problems seriously restrict the development of human. People pay much attention to alternative energy sources and wastewater management. Microbial fuel cells are one alternative energy technology which can recover electrical energy directly during wastewater treatment. Microalgae can fulfill the wastewater treatment simultaneously produce the biomass. Recent research shows that by combining microalgae cultivation and MFC technologies, the photosynthetic algal fuel cell (PAMFC) performs the advantages of both the microalgae and MFC which can harvest biomass and electricity with the simultaneous wastewater treatment. This can provide a new, economical and effective method for the humanity facing the energy, the water resources and the environment these three major problems.Currently, the microalgae used are all in suspension, which is difficult to separate the biomass from the culture media to recycle and utilize. In the present work, immobilized Chloralla vulgaris was used to improve the algae cell density and mass transfer performance, at the same time, the feasibility of PAMFC using immobilized Chloralla vulgaris was investigated. The influence factors were optimized for the growth of Chloralla vulgaris and power generation. Subsequently, the study on the ammonia wastewater treatment efficiency with PAMFC also investigated.Firstly, we optimized the immobilized conditions for electricity generation and Chloralla vulgaris growth. The results showed that PAMFC performed best at5%sodium alginate and2%calcium chloride as immobilization matrix concentration,106cell/mL initial inoculation concentration and4h cross-linking time. It could achieve an84.7%COD removal, and simultaneously the maximum power density reached1811.90mW/m3at a current density of5.5A/m3and the Coulombic efficiency was8.78%.Secondly, we examined the impact of environmental factors on the electricity output with immobilized Chloralla vulgaris PAMFC. The main conclusions were as follows:1. The appropriate dosage of immobilized Chlorella vulgaris was600and the COD load was1000mg/L。2. In the range of25-35℃, PAMFC operated well and this was little difference in power density output. Overall, the performance was best at30℃.3. Appropriate light intensity can largely improve the power output, the maximum power density was2572.82mW/m3under5000lux.Thirdly, the performance of PAMFC with immobilized C.vulgaris was superior to that suspended. The maximum power density was2485.35mW/m3and the Coulombic efficiency was9.40%, which were88%and57.7%greater than that with suspended Chloralla vulgaris, respectively.At last, PAMFC with immobilized Chloralla vulgaris can fulfil the ammonia wastewater treatment with electricity generation and the effect was better than with suspended. pH was between6-8and the ammonia concentration was90mg/L, we achieved the maximum power density of1565.79mW/m3and98.8%of the ammonia was removed.