Why Is It Important To Treat Wastewater and How Can It Be Done? Wastewater contains a variety of pollutants and waste products, like debris, soap, human waste, oil and other chemicals. They need to be treated before flushing the water to rivers, or oceans.
Why is wastewater treated? The major aim to treat waster is to protect the environment and keep the water bodies clean and healthy. If pollutants in the wastewater are not eliminated, they can directly flow into our waterways which can threaten fisheries, wildlife habitat, and public health. For our quality of life it is crucial to remove two major components of the water:
Total suspended solids (TSS) It refers to particles of matter – large as well as small present in the wastewater. These particles carry pathogens that can make wastewater harder to disinfect. In
addition, they also use oxygen in the water while breaking down. Solids sometimes sink, accumulating at the bottom of the rivers and oceans, destroying the habitat of marine life.
Biochemical oxygen demand (BOD) Organic materials – solid or dissolved when break down in the wastewater use oxygen. Biochemical oxygen demand measures the amount of oxygen consumed by biodegradable materials in the water. If it is too high, too much oxygen is consumed causing problems for aquatic animals as they need oxygen to survive in the water. This problem is addressed through biological nutrient removal process where wastewater is regularly monitored to abide by the provincial standards.
How is wastewater treated? The process involves several steps.
Screening It is the first stage of wastewater treatment where large objects, like, diapers, sanitary items, broken bottles, plastics, and rugs are removed which may block or damage the equipment. Special equipment is also used to remove grit.
Primary treatment In the second stage, the organic solid matter is separated from the wastewater. It is done by putting the wastewater in a large settlement tank where solids are made to sink at the bottom. Large scrappers are continuously made to scrape the floor of the tank and sludge to the center of the tank which is further pumped away.
Secondary treatment Water is flushed to large rectangular tanks, called aeration tanks. Air is pumped into the water to facilitate bacterial to break down the sludge.
Final treatment Almost treated water is passed through a settlement tank where more sludge is collected at the bottom of the tank. Water at this stage is almost free from harmful substance and chemicals and can be flowed to a water body. This is how water treatment takes place.