The Role of Bacteria in the Breakdown of Carcinogenic Substances (PCBs) in Wastewater for Safe Recycling Purposes - A Review

Water is one of the most essential natural resources for daily human activities, yet it is so scarce. Treated wastewater and untreated sewage contain bacteria that can be advantageous to the recycling process. The composition of effluent originates from various industries, such as pharmaceutical industries, mining industries, agricultural sector, household waste, chemical industries, and various manufacturing industries, including the oil manufacturers. These introduce potential health-threatening compounds to wastewater. These compounds that remain for a long time without being broken down or changed in their chemical composition and/or structure in the environment are referred to as recalcitrant compounds. Polychlorinated Biphenyls (PCBs) are examples of such compounds. These compounds have serious negative health effects on humans (act as mutagens and carcinogens). The capacity of Polychlorinated Biphenyl’s (PCBs) degradation by bacteria (biodegradation) depends on the diversity and characteristics of naturally occurring populations and their response to environmental conditions. Conventional physical and chemical methods that are used to decontaminate wastewater contaminated by these substances are time and energy consuming. The use of Moringa oleifera seeds, which is currently under trial, is also very costly and not sustainable. This threatens the economic security of most developing countries. Biodegradation is the metabolic ability of microorganisms to transform or mineralize organic contaminants into less harmful, non-hazardous substances, which are then integrated into natural biochemical cycles. This process is not only cost effective, but it is also environmentally friendly. Wastewater that has gone through effective biodegradation can be fully recycled, thus conserving raw water and at the same time ensuring safe available water for all.