A new solar-driven biological wastewater treatment technology based on the synergy of photosensitizers and non-photosynthetic bacteria

Abstract

With the discovery of the synergy of photosensitizers and non-photosynthetic bacteria under visible light, a new solar-driven biological wastewater treatment (SDBWT) technology is proposed and reviewed as a promising sustainable wastewater treatment technology. The SDBWT can take advantage of photosensitizers acting as a bridge to capture energy from light as a driving force for biological wastewater treatment. The unique electronic structure gives photosensitizers the roles of either electron donors or acceptors, which have directly or indirectly enhancing effects on the extracellular electron transfer efficiency of non-photosynthetic bacteria. Moreover, owing to the suitable electrical conductivity of some photosensitizers, the spatial connection between non-photosynthetic bacteria and electron acceptors can be improved, which enables accelerated electron transfer to enhance biodegradation efficiency. At present, SDBWT is proven to be suitable for not only elimination of many pollutants, but also improvement of the energy recovery efficiency from wastewater treatment process. This review systematically summarizes the state-of-the-art progress of SDBWT from working principles, system configurations and light-driven electron transfer mechanisms. Furthermore, the challenges and future directions in this interesting field are also given. This review will provide theoretical principles and valuable insights for the better future design and application of SDWBT in the wastewater treatment field.