Wastewater treatment and the urban aquatic environment

Abstract

Populated areas ranging from rural-residential communities to urban centers all require reliable access to a supply of freshwater that is used for many residential and industrial purposes, treated to remove many contaminants and then returned to aquatic ecosystems directly or indirectly as effluent. Urban wastewater effluent reaches aquatic ecosystems from both point sources and nonpoint sources. Point sources include discrete conveyances (e.g., treated sewage effluent drained through pipes), typically derived from domestic or industrial infrastructure. Nonpoint sources originate from numerous and diffuse locations such as stormwater runoff, leaking pipes, or improperly functioning septic systems. Wastewaters derived from urban areas contribute a diverse array of pollutants to aquatic ecosystems including personal care products and pharmaceuticals (Bruchet et al. 2002), natural and synthetic hormones (Jackson and Sutton 2008; Hijosa-Valsero et al. 2010; Weyrauch et al. 2010), fire retardants (Lawrence and LaFontaine 2010), plasticizers (Semard et al. 2008), and property maintenance chemicals (Lawrence and LaFontaine 2010). Industrial facilities can produce comparatively large volumes of wastewater that often contain sewage and potentially toxic pollutants such as solvents, heavy metals, or organochlorines (Morace 2006). Aquatic ecosystems receiving wastewater effluent can experience increased nutrient and microbial concentrations, and changes in hydrology wastewater effluent are a substantial proportion of the flow (Carey and Migliaccio 2009). As urban populations increase in size and in their demand for water, the volume of wastewater effluent they produce may pose significant risks to aquatic ecosystems and the services they provide (Daigger 2009; Van Drecht et al. 2009; Pasqualino et al. 2010).