A state-of-the-art review of the electrocoagulation technology for wastewater treatment

The continued increase in urbanisation and industrialisation across the world has dramatically increased the amount and variety of waste, and, in particular, wastewater, being generated. Wastewaters contain a large variety of both organic and inorganic contaminants. Various wastewater treatment technologies have been developed over the last few decades to address the increasing concern around effective contaminant removal from wastewater. Electrocoagulation (EC) is one such technology that is broad-based, highly reliable, and cost-effective. It also has a high pollutant removal efficiency and generates less sludge when compared with other techniques. However, despite being effectively used to treat a wide range of wastewater, a thorough examination of its efficiency under various process variables has not been critically examined. Various operating factors, such as pH, current density, the conductivity of the solution, electrode material, and mixing conditions, impact the electrocoagulation system. This paper aims to provide a comprehensive overview of the electrocoagulation technique and examine the current challenges to the efficiency of the technique due to the various operating conditions. Some recent advances in the EC technology that present opportunities to improve treatment efficiency and increase the scope to treat newer varieties of wastewater are addressed

Enhanced Bio-P removal: Past, present, and future – A comprehensive review

Excess amounts of phosphorus (P) and nitrogen (N) from anthropogenic activities such as population growth, municipal and industrial wastewater discharges, agriculture fertilization and storm water runoffs, have affected surface water chemistry, resulting in episodes of eutrophication. Enhanced biological phosphorus removal (EBPR) based treatment processes are an economical and environmentally friendly solution to address the present environmental impacts caused by excess P present in municipal discharges. EBPR practices have been researched and operated for more than five decades worldwide, with promising results in decreasing orthophosphate to acceptable levels. The advent of molecular tools targeting bacterial genomic deoxyribonucleic acid (DNA) has also helped us reveal the identity of potential polyphosphate-accumulating organisms (PAO) and denitrifying PAO (DPAO) responsible for the success of EBPR. Integration of process engineering and environmental microbiology has provided much-needed confidence to the wastewater community for the successful implementation of EBPR practices around the globe. Despite these successes, the process of EBPR continues to evolve in terms of its microbiology and application in light of other biological processes such as anaerobic ammonia oxidation and on-site carbon capture. This review provides an overview of the history of EBPR, discusses different operational parameters critical for the successful operation of EBPR systems, reviews current knowledge of EBPR microbiology, the influence of PAO/DPAO on the disintegration of microbial communities, stoichiometry, EBPR clades, current practices, and upcoming potential innovations