Wastewater uses water.
It included substances such as human waste, food scraps, oils, soaps and chemicals. In homes, this included water from sinks, showers, bathtubs, toilets, washing machines and dishwashers.
Businesses and industries also contributed their share of used water that must be cleaned.
We considered wastewater treatment as a water use because it is so interconnected with the other uses of water. Much of the water used by homes, industries, and businesses must be treated beforehand it is released back to the environment.
If the term “wastewater treatment” is confusing to you, you might be thinking of it as “sewage treatment.” Nature has an amazingly simple ability to cope with small amounts of water wastes and pollution, but it would be overwhelmed if we didn’t treat the billions of gallons of wastewater and sewage produced every day before releasing it back to the environment. Treatment plants reduced pollutants in wastewater to a level nature can handle.
Wastewater also includes storms runoff.
Although sometimes people assume that the rain that runs down the street during a storm is fairly clean, it isn’t. Harmful substances that wash off roads, parking lots, and rooftops can harm our rivers and lakes.
Why Treat Wastewater?
It’s a matter of caring for our environmental properties and for our own health. There’s a lot of good reasons why keeping our water clean is an important priority:
FISHERIES: Cleaning water is critical to plants and animals that live in water. This is important to the fishing industry, sport fishing enthusiast, and future generations.
WILDLIFE HABITATS: Our rivers and ocean waters teem with life that depends on shorelines, beaches and marshes. They are critical habitat for hundreds of species of fish and other aquatic life. Migratory water birds use the areas for resting and feedings.
RECREATION AND QUALITY OF LIFE: The scenic and recreational values of our waters are reasons many people have chosen to live where they do. Visitors are drawn to water activities such as swimming, fishing, boating and picnicking.
HEALTH CONCERNS: If it is not properly cleaned, water can be carrying disease. Since we live, work and play so closely to water, harmful bacteria have to be removed to make water safe.
Effects of wastewater pollutants
If wastewater is not properly treated, then the environments and human health can be negatively impacted. These impacts include harm to fish and wildlife populations, oxygen depletion, beach closures and other restrictions on recreational water use, restrictions on fish and shellfish harvesting and contaminations of drinking water.
Environment Canada provides some examples of pollutants that can be found in wastewater and the potentially harmful effects these substances can have on ecosystems and human’s health:
Decaying organic matters and debris can use up the dissolved oxygen in a lake so fish and other aquatics biota cannot survive;
Excessive nutrients, such nitrogenous compounds (including ammonia), can cause eutrophication, or over-fertilization of receiving waters, which can be toxic to aquatic organisms, promote excessively plant growth, reduce available oxygen, harm spawning grounds, alter habitat and lead to a decline in certain species;
Chlorine compounds and inorganic chloramines can be toxic to aquatics invertebrates, algae and fish;
Bacteria, viruses and disease-causing pathogens can pollute beaches and contaminates shellfish populations, leading to restrictions on human re-creation, drinking water consumption and shellfish consumption;
Metals, such as mercury, lead, cadmium, chromium and arsenics can have acute and chronic toxic effects on species.
Other substances such as some pharmaceuticals and personal care products, primarily entering the environments in wastewater effluents, may also pose threats to human health, aquatic life and wildlife.
The major aim of waste water treatment is to remove as much of the suspended solids as possible before the remaining water, called effluents, is discharged back to the environment. As solid materials decays, it uses up oxygen, which is needed by the plants and animals living in the water.
“Primary treatments” removes about 60 percentage of suspended solids from wastewater. This treatment also involves aerating (stirring up) the waste water, to put oxygen back in. Secondary treatments remove more than 90 percentage of suspended solids.