Anything that runs down the drains of our sinks, showers, toilets, washing machines and dishwashers becomes wastewater. Wastewater contains pharmaceuticals, plastics and microplastics, heavy metals, soaps and detergents, nutrients like phosphorus and nitrogen, human and food waste, sulphides, fats, oils, grease, pathogens and microorganisms. These contaminants come from commonly used products like paint thinner, car oil, bleach, nail polish remover and other products we use in our homes and businesses.
Stormwater consists of precipitation – like rain, hail and snow – that falls to the ground. It can be absorbed by soil or bodies of water, or it can run off hard surfaces like pavement. When it runs off hard surfaces it collects contaminants from roadways, parking lots and other types of infrastructure. In some places this toxic mixture will flow into the wastewater treatment system, but in others, significant quantities can go untreated and flow directly into local waterways. Heavy storms can increase the volume of untreated stormwater that flows into local waters.
Contaminants in wastewater and stormwater can disrupt hormones and cause mutations, cancer and other serious, long-term health and developmental impacts in humans and wildlife. Fortunately, it is possible to remove contaminants from wastewater and stormwater with proper treatment.