ABSTRACT
Raw water from various sources is conveyed by pipelines to waterworks, where it is chemically treated, filtered, and disinfected. This treatment kills harmful microorganisms and viruses in water and makes it clear, sparkling, odorless, colorless, and safe for consumption. Biological treatment is used to remove electron donors (biological instability) from water. These electron donors include biodegradable organic matter (BOM), ammonium, ferrous iron, manganese (II), and sulfides. Donors of electrons for denitrification can be organic substances such as methanol, ethanol, acetate, or inorganic substances such as H2, S, H2S, or Fe2+ (autotrophic denitrification). The chemical oxygen demand (COD) is the amount of oxygen required to oxidize organic matter in water chemically. The biological oxygen demand (BOD) is the amount of oxygen required to oxidize organic matter in water biologically. Theoretical oxygen demand (TCOD) for a substance of known content can be estimated from the stoichiometry of the complete oxidation of carbon to CO2 and nitrogen to nitrate. Rapid filters, slow sand filters, and soil biofiltration are active in the removal of biological instability of water as well as micropollutants of water such as hydrocarbons, surfactants, endocrine disruptors, bad taste and odor compounds, and cyanobacterial toxins. A quiz bank is added to this chapter.
