Stages of Waste Water Treatment

Waste water is a common thing, especially for large facilities and factories. When it comes to the collection and treatment of the sewage water, this is taken care of the sewage treatment plants and there are guidelines and standards that are set by the local and federal government regarding this. There are different types of treatment in these plants, but local sewage treatment facilities use biofilters, septic tanks or anaerobic treatment systems. If these are not available, the waste water is collected by the main sewage treatment plants run by the municipal government in an area. For developed countries, it is common that every city has specific pipe infrastructures for this purpose.

If you have ever thought about where the household and domestic wastewater goes to be treated so it can be recycled and reused, then the answer is definitely the sewage treatment plants. The sewage treatment plants are responsible for isolating the contaminants from the wastewater and treat it so it can be safe to deposit. Domestic wastewater usually has liquid and solid wastes from the toilet, bathroom, the kitchen and laundry station. There are two classifications of domestic wastewater which are: greywater and blackwater. The greywater is from taking a shower, washing clothes and the dishes. The blackwater consists of wastes like urine and feces.

The main focus of sewage treatment technology these facilities is the blackwater. This is where the bacteria and other contaminants can be harmful when not treated or disposed of properly. Before the water can be disposed of into other water reservoirs like the river, lakes and streams it needs to undergo proper treatment and disinfection. This process involves three stages of treatment: primary, secondary and tertiary.


In the first part of the treatment, the main objective is separating the solid wastes from the liquid waste. This is necessary because solid and liquid wastes differ in treatment. These wastes are separated using the sedimentation process. The sewage is stores in sedimentation tanks and they are big enough that the lighter solid wastes such as grease and oil fats also float up along with the liquid matter while the sludge stays at the base of the tank.


Once the liquid waste is afloat, they are skimmed off then the secondary phase starts. This is where the dissolved biological elements are removed. This is achieved through the use of natural water-born microorganisms. The solid wastes on the other hand are treated so it can be disposed or reused accordingly.


This is the part where the quality of the water that has undergone the secondary stage is enhanced. Chemical and physical agents are used to eliminate the remaining contaminants and unnecessary mass.

Once all the other toxins are completely eliminated from sewage treatment facility, the liquid is then cleaned before it can be discharged to natural reservoirs or reused for other purposes.