Chapter 3: Biofiltration of water pollutants

Biofiltration is an environmentally friendly method for eliminating contaminants from water, utilising the natural abilities of microorganisms and plant-based systems. This process involves the filtration of contaminated water through biologically active media, such as sand, gravel or artificial substrates, which facilitate microbial colonies that effectively degrade organic pollutants and immobilise inorganic contaminants. A wide range of pollutants, such as harmful microorganisms, heavy metals, nutrients (most notably nitrogen and phosphorus) and organic waste, can be effectively eliminated through the use of biofilters. Hydraulic retention time, filter medium composition and structure, in addition to environmental characteristics such as pH, temperature and oxygen availability, are all factors that influence the efficacy of biofiltration systems. Advancements in biofilter design, particularly through the integration of biochar and nanomaterials, have improved pollutant removal efficiency and expanded the range of treatable contaminants. This technology has been effectively utilised in municipal wastewater treatment, stormwater management and industrial effluent remediation. Biofiltration systems are cost-effective, require minimal maintenance and enhance ecological sustainability by reducing reliance on chemical treatment methods. This chapter aims to optimise biofilter designs and assess the potential of genetically modified bacteria in addressing chronic pollution. Biofiltration represents a viable approach to addressing water pollution, supporting initiatives aimed at enhancing clean water accessibility and promoting environmental conservation.