What is Wastewater?

Wastewater or waste-water is any water which is not good for human use. Wastewater is any used water for domestic, industrial, commercial or farming purposes.

It means that, wastewater is a byproduct of domestic, industrial, commercial or farming activities. Wastewater can contain chemical, physical and organic pollutants.

Types of Wastewater.

Types of wastewater include:

  • Domestic
  • Industrial

Domestic wastewater contains household, commercial and municipal wastewater which is called as Sewage.

Industrial wastewater contains wastewater generated in industrial processes.


Domestic sources

  • Blackwater, which contains human waste (feces and urine) mixed with toilet paper.
  • Sullage or Greywater, which contains wash water from kitchen, clothes, floors, dishes, etc.

Industrial sources

  • Process water
  • Cooling water
  • Bio degradable waste (Organic)
  • Inorganic waste
  • Toxic waste
  • Solids and emulsion
  • Extreme pH waste


Pollutants are classified in two types

  • Chemical or Physical
  • Organic

Chemical or physical

  • Inorganic particles, such as sand, metal particle, etc.
  • Soluble inorganic material
  • Soluble organic material
  • Organic particle
  • Heavy metals
  • Gases
  • Emulsion
  • Toxic materials


  • Human waste
  • Waste from food industry

Wastewater management

In most countries, it is controlled by respective government bodies. In India, Central Pollution Control Board (CPCB) is the ultimate authority for defining various norms.

CPCB defines waste generation limits, waste disposal to environment.

Following areas must be improved to reduce waste

  • Preventive practice
  • Segregation and capture
  • Treatment
  • Recycle and reuse
  • Awareness

Preventive practice

Policies and laws should be designed such as to encourage to reduce generation.

Segregation and capture

Proper practice should be adapted to segregate waste water at source. This is the best way to capture and to treat.


Segregated waste water is easy to treat. It can be treated either biological or physico chemical treatment. It is completely depends on the nature of waste water generated.

Recycle and reuse

Recycle involves treatment of wastewater either of physical, chemical and biological. Type of waste water decides treatment scheme. After treatment, treated water is suitable for reuse.


It is the best way to reduce, recycle and reuse.

Effects of Wastewater

In developing countries, it is pumped directly to the natural water bodies like fresh water lake, river or sea. The effects of this act can be classified as

  • Pollution
  • Imbalance to eco system
  • Freshwater scarcity
  • Health of population


Due to discharge of pollutants, fresh and marine water bodies getting polluted. This is unsafe for human use.

Imbalance to ecosystem

All ecosystem is interconnected. They all are depends on water. If one part of the system is destroyed, it can affect the entire food chain.

Freshwater scarcity

The waste discharged on lands can leach into underground water system. It potentially polluting underground sources. If discharged in freshwater bodies, it contaminate freshwater sources.

Health of population

It is a big health issue, as polluted water carries tons of diseases and illness.


It is believed that, around 80% of waste produced is discharged into the environment untreated.

There are various methods that can be used to treat or clean up waste depending on the type of contaminants. It can be treated in wastewater treatment plants which includes biological or physico – chemical treatment processes.

Municipal wastewater is treated in sewage treatment plants. Industrial waste is treated in industrial waste water treatment plants.

Sewage Treatment

Sewage treatment is the process of removing contaminants from household sewage plus some industrial sewage.

Normally physical, chemical, and biological processes are used to remove contaminants and produce treated effluent that is safe enough for release into the environment or reuse.

A by-product of sewage treatment is sewage sludge. The sludge has to treat before being suitable for disposal.

Industrial Waste Water Treatment

Industrial waste water treatment used for treating waste water that is produced by industries as an by-product.

After treatment, the treated industrial waste water (or effluent) reused for gardening or released to a sewer or to a surface water in the environment.

By Krunal

Krunal Bhosale is crazy about new gadgets and try them as soon as they are available in market. You can trust him because he uses those products and write reviews about products. He is a Water and Wastewater treatment expert from Pune, India. He received his Chemical Engineering from University of Pune. You can contact him by email krunal (at) waterengineer.co.in

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