What Are the Best Methods to Treat Water Pollution?
Aug 07 2021
As the resource upon which all life on planet Earth depends for survival, water is a precious commodity which must be conserved as much as possible. This means treating groundwater, wastewater and other sources of unclean water to make them potable for human and animal consumption, as well as suitable for other purposes such as irrigation, cleaning and bathing.
Of course, the first step in addressing water pollution is quantifying its extent. When it comes to drinking water, there are a number of analytical methods aimed at identifying different pollutants. For example, ion chromatography is often used to determine perchlorate levels, while phthalates such as DEHP can be classified by deploying high performance liquid chromatography.
Once the issues have been identified, it then falls to wastewater treatment plants to employ the most suitable method to treat the pollution. Here are a handful of the most common, many of which are often combined to produce better end results:
Coagulation and flocculation
During this treatment method, a coagulant such as alum or liquid aluminium sulphate is mixed with the untreated water. This encourages the dirty particles in the water to coagulate or stick together. Once they have done so, the larger clumps (called flocs) can be more easily removed via one of the methods below.
After the flocs have been created, they are funnelled into sedimentation basins. The slow pace of the water’s movement encourages larger flocs to fall to the bottom of the basin, becoming sludge. This sludge is transported to drying lagoons, where it will be dried before undergoing further treatment to render it useful as a fuel source, fertiliser or other commodity.
As the name suggests, this method relies on the use of a substantial filter which catches larger particles of pollution as the water passing through it. The filter is normally made from sand, gravel or crushed anthracite, forming a porous membrane through which the water can pass but the pollutants cannot. Filters are cleaned regularly by backwashing them.
While most larger contaminants can be removed via a combination of any or all of the three aforementioned processes, they are not effective at tackling bacteria, viruses and other microscopic pollutants. To do this, a chemical (normally chlorine) is added to the water to kill off any organisms without affecting the taste or quality of the water itself.
The presence of fluoride in drinking water is key to helping maintain healthy teeth and reducing cavities among the people who are exposed to it. It’s for that reason that many toothpastes and some drinking water supplies have fluoride added to them in a process called fluoridation, thus boosting the water’s nutritional content and making it healthier and safer for people to drink.