Study of Microbial Communities in Degrading Toxic Pollutants in the Wastewater and Solid Waste Treatment Industries

Wastewater Treatment Plants from industrial and municipal facilities are intended to remove diverse chemical and physical contaminants by using multistep processes. For a long time, research and development were focused on removal efficiency based on indicators like the chemical oxygen demand and the biochemical oxygen demand, among many others to comply with water quality criteria. Biological processes like activated sludge have been used to remove organic matter. It has been demonstrated that some microbial communities can degrade some persistent organic pollutants and remove nutrients. Solid waste management includes several strategies that intend to degrade organic matter and reduce the toxic effects of landfills (the most used system for solid waste). Composting is another strategy to generate high-value by-products like fertilizers. Furthermore, bioremediation technologies should be included in this list as a strategy specifically designed to remove contaminants from soils. Therefore, this chapter covers the following topics: (a) novel approaches for evaluating remediation technologies, (b) methods to evaluate the efficacy of remediation employing microbes, and (c) an analysis of the role of bioremediation by microorganisms. Metagenomics approaches allowed the identification of microbes and their metabolic pathways that are involved in the efficient treatments of solid waste and wastewater. The list includes strains from diverse genera of bacteria (Brevundimonas, Burkholderia, Cellulosimicrobium, Citrobacter, Flavobacterium, Marinobacte, among others), fungi (Aspergillus, Candida, Curvularia, Fusarium, Mucor, Penicillium, Rhizopus, etc.), and microalgae (i.e., Chlorella, Scenedesmus or Selenastrum). Other microbes are also included and their roles in bioremediation are discussed. Among toxic pollutants in solid waste or wastewater are heavy metals and metalloids, distillery industry wastewater, wastewater from the paper and pulp industry, fertilizers and pesticides, pharmaceuticals, and oil sludge. Some novel approaches to evaluating remediation technologies employing microbes and microalgae are discussed herein. The fundamental role of microorganisms in situ bioremediation for removing common pollutants is addressed.