Water is LIFE. Around 70% of Earth is covered with water. It’s present on the planet in two forms, i.e. freshwater – glaciers, rivers, lakes, and groundwater – and saline water – oceans. Out of 70%, only 2.5% is used by humans for industrial, agriculture, and household purpose. But, this small fraction is becoming polluted day by day. Water pollution is a serious issue of today’s world as it affects plants, animals, and humans. Minamata is the worst case of water pollution in history. Methylmercury discharged in water that causes neurological disorder in humans and animals. Sustainable Development Goal 6, “Clean Water and Sanitation,” deals with water and other issues related to it.
According to WHO, 2.5 billion people do not have access to clean water. In developing countries, waste is discharged into water bodies without treatment and increases the burden of disease. So, the treatment of used water is the only solution as the world is facing two issues side by side, water scarcity and water pollution. This article will explore some water cleaning techniques. But before that, let’s learn how water pollution occurs and affects life.
More than 80% of sewage and 70% of industrial waste in developing countries is discharged untreated.
The addition of any harmful substance to water bodies beyond their dilution capacity is pollution. Harmful substances could be any industrial waste, agricultural waste, or sewage. Sources of water pollution are numerous. Industrial waste contains an enormous amount of toxic materials. About 80% of water pollution is caused only due to domestic sewage. Mining is a key source of lake and river pollution. Dumping of radioactive and plastic waste in water bodies is also the cause of water pollution. Agricultural waste is one of the causes of biological and chemical contamination in water. The rapid discharge of hazardous industrial waste accounts for more pollution. The polluted water is used for drinking purposes; thus, the burden of water-borne disease increases. Diarrhea, cholera, dysentery, and jaundice are some water-borne diseases. Furthermore, microbes and physical contaminants are also present in water that might cause health issues. According to WHO, diarrhea is the second leading cause of under five years death. Polluted water retards the growth of plants and causes the death of aquatic animals and plants also.
Water can be cleaned and reused for drinking and other household purposes. Following are some general water cleaning techniques used worldwide.
Nanotechnologies for Water Treatment
Harvesting Saline water
Water cleaning techniques:
More than 80% of sewage and 70% of industrial waste in developing countries is discharged untreated. Innovative water technologies can help to combat the issue of water pollution. Nearly all water sources require treatment before they’re consumed to ensure that no health risk is present.
The water treatment or cleaning process is not a difficult process. Coagulation, sedimentation, and flocculation are some simple techniques used to remove turbidity and microorganisms. By adding coagulants, the suspended particles settle down and are removed. Water treatment plants are designed depending upon the type of contaminants. Physical contaminants include suspended solids, sediments, and metals. Chemical contaminants include pesticides, pharmaceutical or biomedical waste, and industrial chemicals. Lastly, biological contaminants are viruses, bacteria, and parasites. Activated carbon, Reverse osmosis, Nanofiltration, and UV water treatment are some water treatment and purification techniques discussed there.
1- Reverse Osmosis:
Reverse osmosis is a water purification process. A semi-permeable membrane is used to filter out contaminants and sediments from water. Water flows along the membrane surface under pressure. Pure water leaves the membrane while concentrated water discharges back to the drain. This is the most simple and cost-effective method for water purification. Israel has the world’s largest RO desalination plant built-in 2013. Its output is 165 million gallons per day.
2- Ion exchange:
This technique is useful for industrial water treatment. The process removes salts and heavy metals by replacing their ions with less objectionable ionic substances. It’s considered one of the most powerful techniques to remove inorganic ions and is relatively inexpensive. However, it generates ion exchange beds that are dumped into the environment.
3-Nanotechnologies for Water Treatment:
Ensuring safe drinking water to a growing population is the biggest challenge. Nanotechnology plays a vital role in the purification of water. It’s a broad range of tools and techniques applied for water treatment. Nanomaterials applied for water technologies include adsorbents, nanometals, and their oxides and membranes.
Textile wastewater contains dyes and other chemicals that can be removed efficiently with nano adsorbents. Polymeric nano adsorbents are utilized to remove organic and heavy metals from water. These are non-toxic, biodegradable, and can remove dyes up to 99%.
Clean water and sanitation are the right of every person on Earth. UV is an effective disinfectant technique to treat biological contamination from water. So, it reduces the health risk from bacteria and viruses. It’s the simplest technique that destroys microorganisms present in water and purifies it. UV light of a particular wavelength passes through water and effectively destroys 99.9% of microorganisms present in water. It’s a chemical-free and environmental-friendly technique.
5- Harvesting Saline water:
Over 97% of Earth’s water is found in the ocean. Harvesting saline water by removing salts has become common practice around the world to combat the issue of water scarcity. Salinity can remove from water by Reverse Osmosis (RO) system.
The prevention cost of pollution is always less than the cleaning cost. The best way to save water is to prevent pollution at the source. Pollution prevention can be done in many ways at home, in industries, and by farmers. The use of natural fertilizer as a substitute for chemicals can reduce the considerable amount of pollutants added to water each year. Reuse and recycle of water can reduce the water scarcity issue.
The exponential increase in the world’s population has increased industrial activities. A large amount of agricultural and industrial waste is discharged into the water each day that makes water unfit for use. Based on pollutants, water pollution can be physical, chemical, and biological in nature. Reverse osmosis, nanotechnology, and UV treatment are some common methods to treat water pollution. However, pollution prevention must be the prime method to avoid pollution. It’s not only economical but a sustainable step also.