Industrial wastewater treatment

Industrial wastewater treatment is the process used to handle wastewater created as an undesired byproduct of industry. After treatment, the industrial wastewater (or effluent) might be recycled or dumped into the environment’s surface water or sanitary sewer. Some industrial facilities’ effluent can be treated at sewage treatment facilities.

Most industrial processes, including chemical and petrochemical plants, petroleum refineries, and chemical and petrochemical plants, have their own specialised facilities for treating their wastewater, so that pollutant concentrations meet the requirements for wastewater disposal into sewers, oceans, rivers and lakes.. 

This holds true for businesses that generate wastewater with high amounts of nutrients, hazardous contaminants, such as heavy metals and volatile organic compounds, or organic materials (like oil and grease) (e.g., ammonia). Before releasing the partially treated trash, some businesses utilise a pre-treatment system to remove some impurities (such as toxic compounds).

The step-by-step processes used in industrial wastewater treatment are as follows:

Step 1: Screening & pumping

In this first step, screening equipment filters out oil, plastics, wood chips, and other items from the incoming wastewater. Before being dumped in a landfill, the removed material is cleaned and compressed. The screened wastewater is then subjected to the grit removal stage.

Step 2: Grit removal

In this stage, sand, gravel, and other heavy but fine materials are removed from the effluent. A landfill is also used to dispose of this garbage.

Step 3: Chemical addition

In this stage, the wastewater is cleaned using biological or chemical processes with chemical additives. Then, as sewage deposits decompose and emit gases like hydrogen sulphide, chemical treatments are applied to oxidise the gases and lessen their bad odours.

Step 4: Coagulation & flocculation 

To remove turbidity or murkiness from the water, chemicals are used to treat wastewater during the coagulation and flocculation process. This process allows water to be sterilised more quickly and helps enhance the water’s flavour and odour. To produce larger, denser particles known as floc, a coagulant is typically added to the wastewater to bind smaller particles together.

Step 5: Sedimentation & clarification

Gravity helps heavier particles (produced during the coagulation and flocculation stage) fall to the bottom of the sedimentation basin during the sedimentation process, where they may be removed more easily. Water moves slowly through, giving the floc time to settle and land at the bottom of the basin for simple removal. The clarified water can reach the filtration stage above it.

Step 6: Filtration

Any lingering particles or undesired organic materials from wastewater are removed during the filtration process. During this stage, the water is processed through a fine, sand-like substance or carbon granules. Only pure water can pass through because the carbon retains undesirable particles.