How Does a Conventional Wastewater Treatment Plant Work?

Conventional Wastewater Treatment Plant

Have you ever wondered what happens to that water and waste after you flush? How about after you wash utensils? The modern wastewater-treatment plant employs fundamental physics and high technology to purify the dirtiest of water so it can go back into the environment without causing any harm to the water body and aquatic life.

A wastewater treatment plant is a facility in which a combination of various processes such as physical, chemical and biological are used to treat industrial wastewater and remove pollutants. It’s primary importance is to offer a solution to ensure safety precautions and discharge regulations are followed.

So, what does a wastewater treatment system typically remove?

An industrial wastewater treatment system has advanced technologies necessary to remove any number of the following contaminants:

Biochemical oxygen demand

Biochemical oxygen demand, or BOD, indicates an elevated concentration of biodegradable material in the wastewater. High levels of BOD can be caused by introducing pollutants such as faecal waste and wash-downs from food processing.

Nitrates and phosphates

Suppose large amounts of nitrates and phosphates are not removed from wastewater and are discharged into local environments. In that case, they can increase BOD and extensive growth in weed, phytoplankton and algae. As a result, it leads to eutrophication, killing organisms and dead zones in the environment.


Pathogens are bacterias, viruses, fungi, or any other microorganisms present in wastewater that can cause health issues. This includes the spread of diseases such as cholera, dysentery, salmonellosis, hepatitis A, botulism, giardiasis, Acute sickness, severe digestive problems, or even death.


Metals cause extensive damage to the environment and human health because they don’t break down and cause toxic environs. Primarily found in wastewater as a result of various industries manufacturing processes, when left in wastewater in high concentrations,

Total suspended solids

Total suspended solids (TSS) in wastewater can harm aquatic life, especially if they are reused or released.

Also Read : The Role Of Clarifiers In Wastewater Treatment

So, How do wastewater treatment plants purify wastewater?

Wastewater treatment plants purify wastewater in various processes such as:


A process where various chemicals are added to a reaction tank that removes the bulk suspended solids and other various contaminants.


After the coagulation process is complete, the water enters the flocculation chamber, where the particles are slowly stirred together with long-chain polymers to create visible and settleable particles.


The gravity settler is a sizeable circular device where flocculated material and water flow into the chamber and circulate from the centre out. In a prolonged settling process, the water rises to the top and overflows to the perimeter of the clarifier. This allows the solids to settle down to the bottom of the clarifier into a sludge blanket.

The solids are then raked to the clarifier’s centre into a cylindrical tube where slow mixing occurs. The sludge pumps out of the bottom into a dewatering operation. The process takes all the water out of the sludge with filter or belt presses, yielding a solid cake. The sludge water is put onto a press and between two belts to squeeze the water out. The sludge is then put into a hopper that transports it to a landfill.


The next step is to run the water overflow into gravity sand filters. The sand is typically installed in the filter at a depth of two to four feet and packed tightly. The feedwater then passes through, trapping the particles.


After the water flows through gravity sand filters, the next step is to disinfect or chlorinate to kill the water’s bacteria. This step is sometimes done upstream before filtration, so the filters are disinfected and kept clean.


The wastewater is being reused in an industrial process; it is usually pumped in a holding tank which can be used based on the facility’s demands.

Wastewater treatment plants operate on three fundamental operations; primary, secondary and tertiary treatment.

The primary treatment is a process that breaks down solids (which floats to the bottom of the tank) into sludge and release treated water for secondary treatment. The process takes place in large sedimentation tanks. The sludge that remains in the sedimentation tank then finds use in the anaerobic digestion-a process through which bacteria break down organic matter.

Once the treated water is released for secondary treatment, microorganisms are biologically used to remove the contaminants from the wastewater. The process of the treatment occurs in two ways; aerobic or anaerobic. The process varies in the different bacterial communities or is coupled under some circumstances.

The final treatment process is a tertiary treatment that does the final polishing before releasing or reusing the wastewater.

How to ensure the smooth functioning of your wastewater treatment plant?

Water treatment plant operators should regularly analyze the plant’s water treatment performance and ensure systems are operating with the most efficient equipment and technology. It can be extremely costly when water treatment plants are not running efficiently. The combination of inefficient and older pumping and process equipment and outdated water management practices can result in higher operating costs and lower revenue collected, negatively impacting a treatment plant’s bottom line.

In order to save your plant from high operation costs, we at Organica Biotech have designed a solution that contains a heterogenous concentrated consortium of uniquely functional bacteria with a high proliferative capacity and tenacity to withstand hostile effluent waters. Cleanmaxx by Organica Biotech is capable of rapid biomass development and can withstand fluctuations in wastewater quality. It accelerates COD/BOD reduction through bacteria mediated organic load degradation. It rapidly reduces the time required for effective aerobic wastewater treatment and reduces energy spent in aeration & agitation, thereby cutting CAPEX/OPEX costs.

The uniqueness of Cleanmaxx lies in the flexibility of the bacterial consortium to sense, adapt & effective aerobic wastewater treatment of any industry origin, creating a unique microbial fingerprint acclimatised to the wastewater. With our product, ensure your wastewater treatment plant functions smoothly. Reach out to us today to solve wastewater treatment plant problems!

Also Read : Three Stages of Wastewater Treatment

Post by Karen Sam

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6 months ago

I have read your blog and understood that this kind of treatment plant uses a natural process to clean the water. This means that it does not require chemicals or additives to work properly, which makes the water safe for humans to drink after the process is complete. Thank you for sharing this blog with us. It was a very detailed and informative blog. I am looking forward to read more such blogs in the future.

6 months ago
Reply to  Gautam Singh

Thank you for your positive response Mr Gautam. Stay tuned for more such informative blogs.