Biotreatment

Biotreatment refers to the use of living organisms or their enzymes to remove, transform, or immobilize pollutants from air, water, soil, or waste streams. It relies on the natural metabolic processes of microorganisms such as bacteria, fungi, and algae, sometimes augmented with enzymes or biomass support materials, to reduce pollutant concentrations or toxicity in an environmentally compatible manner.

In air and water treatment, biotreatment commonly includes biological wastewater processes such as activated sludge, anaerobic digestion, trickling filters, and aerated lagoons, as well as constructed wetlands that provide a habitat for pollutant-transforming microbes. In soil and groundwater remediation, bioremediation uses microbes to degrade organic contaminants; strategies such as biostimulation (adding nutrients or electron donors) and bioaugmentation (adding specialized strains) aim to enhance the natural biodegradation rates. Composting and biofiltration are other biotechnical approaches used to stabilize organic waste and remove odorous compounds.

The effectiveness of biotreatment depends on factors including temperature, pH, oxygen supply, nutrient balance, contaminant toxicity, and the presence of inhibitory substances. Mechanisms include biodegradation, where pollutants are metabolized to harmless products; sorption or biosorption to biomass; and, in anaerobic systems, anaerobic digestion producing biogas (primarily methane and carbon dioxide).

Applications span municipal and industrial wastewater treatment, soil and groundwater cleanup, air purification, and waste management. Advantages include lower energy use and chemical consumption, potential recovery of energy and nutrients, and relatively simple operation for suitable loads. Limitations include longer treatment times, sensitivity to toxic compounds or shock loads, complex process control, and the need for careful monitoring and regulatory compliance.