As environmental awareness continues to grow, it is becoming more important to understand how we treat wastewater. Wastewater, including the water that flows into sewers and toilets, contains pollutants that can be harmful to the environment and public health if not handled properly.

Waste Water Treatment Process

The waste water treatment process plays a vital role in removing these pollutants and ensuring that the water discharged back into the environment is safe and clean. In this blog, we’ll take an in-depth look at the various stages of the wastewater treatment process, from collection and treatment to disposal and reuse.

Preliminary Treatment

Pretreatment in the wastewater treatment process is required to get rid of everything that might get in the way of subsequent systems and equipment. Pretreatment protects the raw water lift system and avoids pipe blockages, as well as preventing wear and tear problems on other treatment equipment.

The pretreatment reduces wear on mechanical parts and prolongs the life of sanitation infrastructure because it removes what interferes with subsequent treatment.

Pretreatment in the wastewater treatment process

At wastewater treatment facilities, pre-treatment is frequently the first unit activity utilized to remove debris to prevent damage and obstruction of downstream machinery and piping. In certain contemporary wastewater treatment facilities, coarse and fine screens can both be used.

Primary Treatment

The wastewater treatment process has several different treatment stages, and the methods used in each stage are also different. The first stage of wastewater treatment is to use physical methods (including screening, and crushing) to remove the densest impurities in the water, and to remove substances that float or tend to settle due to gravity.

When wastewater enters the factory, it first flows through a screen. Among them, the large floating objects will be removed, otherwise, they will block the pipeline and damage the processing equipment. After the wastewater is screened, it will enter the grit chamber, and then the cinder, sand, and small stones will be sunk to the bottom.

The first stage of wastewater treatment is to use physical methods

After the screening process is complete and the grit is removed, the wastewater still contains other suspended solids, as well as organic and inorganic matter. These substances will be removed in the next level of treatment.

Secondary Treatment

After the wastewater has undergone primary treatment, it is about to usher in the second stage, namely secondary treatment. Secondary wastewater treatment can remove more suspended solids and soluble organic matter.

The secondary treatment mainly uses bacteria to remove up to 85% of the organic matter in the water. Its primary treatment technologies include activated sludge process, chlorine gas disinfection, trickling filter, waste treatment, filtration, carbon adsorption, distillation, reverse osmosis, etc.

Secondary wastewater treatment

After the sewage leaves the sedimentation tank in the primary stage, it will flow or be pumped to the equipment for the next treatment process. People prefer to use activated sludge technology over trickling filters because activated sludge technology helps to speed up the treatment of bacteria.


Disinfection of wastewater treatment is a chemical treatment that can reduce the concentration of bacteria to an acceptable level. It should be known that although high levels of bacteria can decompose the sludge in the wastewater well, it is not conducive to the development of the environment.

The main methods of pollution disinfection are chlorination and ultraviolet system. Chlorination is the cheapest and most commonly used method, but these chemicals combine with other elements in the water and can contaminate water sources and fish, so chlorination is now used very rarely.

The main methods of pollution disinfection are chlorination and ultraviolet system

UV system, although more expensive, is a very viable alternative as it sanitizes instantly without changing the taste or odor of the water. Another option is ozone disinfection, which is very easy to break through the microbial film compared to chlorination disinfection.

Sludge Treatment

Sludge treatment in wastewater treatment involves treating the thickening sludge collected during primary and secondary treatment and separating water from this solid matter through further treatment.

First, the thickened sludge is placed into the digester tank which is continuously heated to a low oxygen environment of 98°F. In this environment, microorganisms digest the sludge, converting most of the material into methane gas namely biogas.

Sludge Treatment

After about half a month, the treated sludge can be dewatered, that is, the water is removed from the solids using a large centrifuge.


Methane gas is produced during the organic waste decomposition process when there is no oxygen present. Instead of being released into the environment, this methane can be trapped and used to create electricity.

For wastewater resource recovery plants, the biogas produced during sludge digestion can be used to generate heat and electricity. Once cleaned, it can be supplied to the community as renewable natural gas.

As part of our wastewater resource recovery operations, recovering and reusing biogas improves clean air operations and dramatically lowers greenhouse gas emissions.


In addition, A nutrient-rich “digestate” made from solid waste leftovers can also be put into the soil to promote plant development.


The wastewater treatment process is not only conducive to the recycling of water resources but also minimizes the pollution of the environment. And there are multiple stages in the wastewater treatment process, through which the filtration of water and gas also runs through it.

The filters used in different stages are also different, and it is necessary to choose according to the substances to be filtered and the purpose of filtration. Contact us now, our technical experts will provide you with the best solution for wastewater treatment and the required filtration products.

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