ABSTRACT
This chapter provides a background on the fundamentals of wastewater treatment including basic chemistry and the characteristics of wastewater. It discusses the characteristics of domestic wastewater and the regulatory standards that control the quality of effluent discharges. Tertiary or advanced treatment significantly reduces the concentrations of nitrate, phosphorous and pharmaceutical contaminants, and generally requires lower concentrations of biological oxygen demand and total suspended solids than required for secondary effluent. The organic matter in domestic wastewater is heterogeneous but composed primarily of proteins, carbohydrates and lipids. Constructed wetlands and conventional wastewater treatment systems use bacteria to consume organic material, and this occurs in either oxygen-rich or low-oxygen environments, although it occurs more rapidly under aerobic conditions. Understanding the transformational sequence of organic nitrogen (organic matter) and various types of nitrogen is critical to understanding the purposes and design features of the various kinds of constructed wetlands used for water quality improvement.
