Emerging Materials in Photo-bio catalytic systems for Futuristic Wastewater Treatment

Abstract

By the end of the year 2040, the water stress score reveals that 33 countries including the middle east and developed countries like Singapore and San Marino would be facing high levels of water stress. A critical issue that has to be addressed in the coming decades would be sustainable water management. Water’s abundance makes it an ideal universal solvent for cleaning and flushing. This incorporates numerous natural and anthropogenic activities that have imparted pollution which highly affects the quality of water. Though remediation process is available they are slow, hence sophisticated reactors are employed to speed up the treatment process more sustainably and effectively. Several different designs of bioreactors are being developed to treat diverse categories of wastewater and their effluents. The most recent ones are the coupling of photocatalysis and bioreactors. The combined advantages of nanoparticles to be highly oxidizing and non-selective while that of micro-organisms to be economical and sustainable couples these different techniques in one system. Although such system possesses challenges such as lack of process knowledge, design limitation, and characteristic differences, but do have several advantages when considering their applications in the treatment of wastewater and emerging pollutants. In this study, cotton processing wastewater has been treated by a coupled photo-catalytic bioreactor containing nanoparticles and algal biomass for 15 days, and >80% COD removal efficiency was noted by the microalgae Chlamydomonas sp whereas maximum removal of 88% and 84% COD was observed by using Titanium dioxide, and Palladium doped tungstate under solar light and visible light source respectively. An effort is made to delineate the efficiency, limitations, and future readiness of these systems for the abatement of priority pollutants (with emphasis on cotton processing wastewater). A timely investigation of such emerging technologies promotes progress, provides theoretical insights, and deciphers principles for future application of this technology for wastewater treatment.