What are wastewater inputs?

Urbanization often involves the input of wastewaters into streams and rivers. Common wastewater sources in urban streams include:

Wastewater treatment plant (WWTP) effluents: permitted municipal sewage discharges (Fig 10), treated to varying degrees (see Table 3)

Industrial effluents: permitted discharges from industrial facilities

Accidental or unpermitted discharges

Sanitary sewer overflows: wet weather overflows resulting in direct discharge of domestic and other wastewaters into streams and rivers

Combined sewer overflows (CSOs): wet weather overflows resulting in direct discharge of surface runoff and domestic and other wastewaters into streams and rivers

Sewer pipes: leakage from broken, blocked or aging infrastructure

Septic systems: leachate from septic tanks (usually in less densely developed areas)

Stressors associated with wastewater inputs

Numerous stressors may be associated with wastewater inputs, including:

• ↑ nutrients
  [Gücker et al. 2006, Carey & Migliaccio 2009]
• ↓ dissolved oxygen (↑ biological oxygen demand)
  [Ortiz & Puig 2007]
• ↑ pathogens
  [Gibson et al. 1998, Frenzel & Couvillion 2002]
• ↑ metals (e.g., copper, mercury, cadmium, lead, iron)
  [Nedeau et al. 2003]
• ↑ pharmaceuticals and personal care products
  [Kolpin et al. 2002, Watkinson et al. 2009]
• ↑ toxics (e.g., alkylphenols, pesticides, PAHs)
  [Kolpin et al. 2002, Phillips & Chalmers 2009]
• ↑ dissolved solids (e.g., chloride, sulfate, specific conductance)
  [Hur et al. 2007, Rose 2007]
• ↑ stream discharge
  [Nedeau et al. 2003, Barber et al. 2006, Carey & Migliaccio 2009]
• ↑ temperature
  [Nedeau et al. 2003, Kinouchi 2007]

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