Industrial wastewater has an adverse impact on the environment. This has become a huge concern for all over the world as the wastewater released is toxic in more than one ways and affects all lifeforms dramatically. This is why safe disposal of industrial wastewater hold a huge significance for the environment. Strict adherence to industrial and government standards should be met all times to prevent and reduce water and soil pollution. This has led to invention of treatment of the industrial wastewater that will protect the ecosystem.
To reduce the effect of the wastewater released from industries on the environment, the wastewater is redirected to water treatment plant where the water is treated to remove the hazardous chemicals and released into the sewer or water sources. In recent times, the wastewater treated is reused for a variety of purposes within the industry. This minimizes the use of water from natural waterbodies.
The degree to which the wastewater is treated depends on the environmental conditions and standards in that region. If wastewater is treated to avert the deterioration of the waterbody the wastewater is released tolake, river, stream, pond or sea, stream standard is applied to treat the industrial wastewater. When the treatment is based on stream standards, the wastewater is treated for oxygen, acidity, turbidity, toxic chemicals and microorganisms. On the other hand, when the wastewater is discharged into the sewer, it is treated only for acidity, microbes, suspended solids and biochemical oxygen demand.
Generally, the process of industrial wastewater treatment is done in three stages to remove all the dangerous contaminants and make the water fit for discharge into sewer or waterbodies.
In this stage, the wastewater from industries is passed through screens or filtering devices that eliminates grits and coarse solids. These filtered materials are not bio solids. They are usually sedimentation that needs to be removed from the wastewater. About 50% of the solids suspended in the water are removed in this stage. The filtered material are called as primary sludge which them undergo bio solid treatment.
In this stage, the biodegradable materials are removed using a biological process. This stage involves microorganisms that are fed into the wastewater. These microbes feed on the suspended organic matter and produces carbon dioxide and other byproducts. The microbes separate the clarified water from the unwanted constituents which settle at the bottom of the tank along with the microorganisms. The settled constituents are known as secondary or biological sludge.
In this stage of water treatment, chemicals are added to remove residuals and final affluent. The industrial wastewater undergoes this treatment only when the water treated here is discharged into drinking waterbodies. The residues filtered in this stage are not added to the bio solids.
The bio solids that are formed as a result of the primary and secondary water treatment are used primarily in one of the following two ways. They are used as natural fertilizer or soil conditioners in farming and cultivation. They are also used as a landfill or used for energy production. The bio solids may also undergo incineration where they are broken down into simple substances and dispersed into the environment through air, water or soil.