Step by Step Sewage/Wastewater Treatment Process

Have you ever thought about what happens to the wastewater that you flush from the toilet, bathing, washing sinks, and general cleaning at your home or office? Well, you might be aware of the fact that this wastewater goes down the drain and into a pipe, which then joins a larger sewer pipe underground. The least people know that these larger pipes are connected to a primary pipe that takes the wastewater to the sewage treatment plants. And rare people are aware of the processes that take place at the treatment center.

We will explain all the processes involved in the treatment of sewage or wastewater plant. Let’s begin:

Step 1: Screening of WasteWater

After reaching the plant facility, the sewage/wastewater is initially screened in its first stage. Within this, large waste objects such as cotton buds, sanitary items, nappies, diapers, face wipes, bottle tops, broken bottles, plastics, and rags are removed. It’s essential to remove all these objects as they may damage or block the equipment employed in the plant facility.

Further, special equipment is utilized to eliminate the grit in the wastewater.

Step 2: Primary Treatment

The stage two of the treatment process involves the separation of solid organic matter (more commonly known to as human waste) from the wastewater. To perform this task, the wastewater is collected into large settlement tanks for letting the solids to sink and settle down at the bottom of the tank. The settled solid waste is referred to as ‘Sludge.’ Within these circular tanks, large scrappers continuously scrape the floor of the container. It helps in pushing the sludge towards the center of the tank so that it can be pumped away for further treating process. The rest of the water is then transferred to the secondary treatment stage.

Step 3: Secondary Treatment

Within the secondary treatment phase, the water is put into large rectangular tanks, which are known as aeration lanes. In these tanks, the air is pumped inside to encourage bacterial break down of the tiny bits of slime that escaped the scraping process in the primary phase.

Step 4: Final Treatment

In the final treatment process, the ‘almost’ treated wastewater is passed through a settlement tank again. Due to bacterial action, more sludge is formed at the bottom of the tank. A process similar to the primary treatment phase is repeated by scraping the sludge and collecting it from the center for further treatment — the water at this stage free from almost all the significant impurities, chemicals, and harmful substances. 

Lastly, the water is allowed to flow over a wall. There it’s distilled through a bed of sand to eliminate any additional particles which might have escaped from the previous treatment stages.