Sewage
A strong organic or sewage like odor can indicate a sanitary sewer leak or overflow . Wastewater and sewage enter aquatic systems from sources ranging from surface runoff and septic systems to wastewater treatment facilities and storm drain outfalls . Sewage destroys aquatic ecosystems , and may also threaten human health . Biological oxygen demand and nutrient loading from sewage may deplete oxygen in the water to levels too low to sustain life .
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