Wastewater treatment is a very important practice. But do you know what exactly wastewater is? To be very simple, wastewater is nothing but used water. It comes from households, from the bathrooms, toilets, sinks, dishwashers and also from various industries and businesses. The wastewater may contain all sorts of substances like chemicals, oil, food scraps and various other things and these can be very harmful for the environment. So it is necessary to treat this wastewater before we release it back to the environment. This not only saves the environment but is also a step to take care of our own health.
The wastewater has negative impacts on human health and the environment. Effects of wastewater are not just a few. Wastewater will directly have an effect on the fishes. Wildlife population may also be hampered. Drinking water can get contaminated. Wastewater contains various metals such as mercury, arsenic and cadmium which have chronic effects on species. It also contains decaying organic matters. This will take up the dissolved oxygen in the water bodies such as river, sea or lake and create a threat to the existence of the biotic species. Eutrophication can be caused by the nitrogen and phosphorous content and many other substances can impose threat on human life also.
There are many processes for wastewater treatment. It includes physical, biological and chemical treatment. First is the preliminary treatment. Here all the large materials are removed from wastewater. The next step is the primary treatment. The main step that is practiced here is sedimentation. Here all those elements are removed which are heavy and are settle-able. These may include both organic and inorganic materials. If the wastewater is used for irrigation, then the primary treatment is the only treatment that is required. Otherwise, the wastewater will have to go through the secondary treatment. This removes the residual organics. There are three processes that are carried on in this step. Those three processes are activated sludge process, trickling filters and rotating biological contractors. Then the tertiary treatment is carried out. This is advanced treatment. Here those constituents are removed which were not possible through primary or secondary process. After the tertiary treatment, the wastewater is put through a disinfection process.
If you study the process of wastewater treatment, you will find that different processes are aimed to remove different contents. The Grit chambers are used for grit removal, bar chambers are used to remove and grind coarse solids, Ozonation is done to control odor, and primary settling is used for BOD reduction. Oxidized particles are removed through secondary settling, decomposition of organic solids are done through anaerobic sludge digestion, sludge is disposed through sludge drying beds, phosphates are removed through chemical coagulation, nitrates are removed by ammonia stripping and colloidal materials are removed by mixed-media filtration. Disinfecting is done by UV treatment.
With the advancement of time and technology, different methods are being introduced for better wastewater treatment. So, wastewater treatment should be taken up more seriously. This will help us to have a friendly environment to live in.