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Despite being simple, water is the most crucial element in existence, with only three atoms. The arrangement of atoms in the water molecule is primarily responsible for its exceptional significance as a universal solvent. Water is essential to all living processes. Many ionic chemicals, as well as other substances capable of establishing hydrogen bonds with water, respond well to the solvent properties of water. These unique features of water also make it highly susceptible to toxic chemicals, which readily pollute water.

According to the UN, 4.2 billion people need access to safe, managed sanitation, and 2.2 billion lack access to safe, managed drinking water (clean water and sanitation goal). Treatment facilities for drinking water and waste play important roles in the urban water cycle and in providing access to clean water. It is crucial to characterize the contaminants to have a deeper knowledge of the intricate interactions and treatment procedures that take place within the unit operation. Before reusing or releasing them into the environment, the treatment process comprises applying technical and scientific principles to remove or reduce pollutants to an acceptable level.

Why is Water Treatment necessary?

Water treatment is necessary to eliminate pollutants, coarse particles, toxicants, and microbes from water. It also makes it safe to use for humans as well as to be discharged into the environment. Water treatment for drinking purposes is necessary to remove excessive nutrients or chemicals that can cause certain diseases. Waste treatment helps to eliminate various kinds of chemicals, coarse materials, and organic matter, such as feces, from water, which can otherwise result in the form of various environmental hazards such as eutrophication, bioaccumulation, biomagnification, and death of aquatic organisms. Some significant importance of water treatment are as follows;

  • Reduction of waste
  • Production of clean, potable water
  • Energy generation
  • Production of organic fertilizers from sewage and treated water
  • Prevention from waterborne disease
  • A clean, healthy environment with the least amount of contaminants
  • Protection of local communities
  • Protection of the ecosystem

Water Treatment and Sustainability

Water treatment and provision of clean water is the United Nation’s one of the top priorities these days. The sixth sustainable development goal by the United Nations (SDG – 6) explains the importance of the provision of clean water, as well as the role of the United Nations in this matter. One of the most practical approaches for improving water sustainability is the treatment of wastewater, as water is one of the most crucial commodities to be used wisely.


Importance of Clean Water for Communities

Despite the fact that water continues to be one of the planet’s most abundant natural resources, access is never universal. The availability of clean, sustainable water is limited for those who live in arid and semi-arid regions.

The SDGs for wastewater treatment include developing an integrated water resource management system, lowering the number of people vulnerable to water scarcity, and improving water quality by providing clean water. Water treatment can produce clean water for drinking, cooking, washing, and another household. Additionally, especially in locations with a water shortage, treated wastewater can increase the availability of clean water for local communities. The global population’s exposure to the numerous problems caused by water scarcity has decreased due to the rising usage of treated water. Thus, wastewater treatment is a critical step in reaching sustainable development objectives of communities and enhancing global health.

Wastewater treatment also plays a pivotal role in achieving economic benefits for a community by facilitating a circular economy. Reuse and regeneration of materials and products are given priority in the circular economy to lower the dependence on natural resources such as water and promote environmental sustainability. Wastewater treatment helps communities achieve a circular economy by reducing waste in water bodies and by producing energy in the form of biogas from WWTPs. Hence, it totally becomes a win-win process for communities.

Drinking Water Vs. Wastewater Treatment

The drinking water treatment process is different from the treatment of wastewater in the following respects.


Water Treatment

Wastewater Treatment

Type of Polluted Water

These plants deal with groundwater, surface water, or rainwater

Clean, grey and blackwater that requires a high level of sanitation to be made acceptable for reuse goes through a wastewater treatment facility.

Treatment Time

(i.e., Pre or Post)

It is done before water is sent to communities for usage

It is performed after communities use water for their domestic and commercial purposes

Standards for treated water

Treatment standards for water are usually high to avoid any potential health impacts on communities

Treatment standards for wastewater treatment are lower than potable water as this type of treated water is usually released into the environment.

Treatment Processes

  • Coagulation

  • Flocculation

  • Sedimentation

  • Filtration

  • Disinfection

  • Preliminary treatment

  • Primary treatment

  • Secondary treatment

  • Tertiary treatment

  • Sludge treatment 

Treatment Flow Rate

Treatment flow rates of drinking water are usually constant

Treatment flow rates of drinking water are usually highly dynamic

Municipal Vs. Industrial Wastewater Treatment

Municipal wastewater possesses different characteristics compared to industrial wastewater. Based on their influent type, the treatment methods for both also exhibit the following differences.


Municipal Wastewater Treatment

Industrial Wastewater Treatment

Influent Toxicity

Municipal wastewater is usually less toxic.

Industrial wastewater is highly toxic and needs extensive treatment

Type of Wastewater

It deals with the treatment of domestic or household wastewater

It deals with wastewater from industries containing high amounts and a variety of toxic chemicals

Usage of Treated water

Treated municipal wastewater can be used for agricultural purposes

Treated industrial wastewater isn’t completely safe to be used for agricultural purposes

Treatment Processes

  • Preliminary

  • Primary

  • Secondary

  • Absorption

  • Coagulation

  • Ion exchange

  • Ozonation

  • Membrane Filtration

  • Chemical Oxidation

  • Biological Treatment

Treatment Responsibility

As per standards provided by the Environment Protection Authority (EPA), the treatment of municipal wastewater is the responsibility of the local government.

As per EPA standards, industrial wastewater treatment is the responsibility of the concerned industry itself.

If the industry doesn’t comply with standards, it will be held accountable as per law.