Types Of Wastewater Treatment And Its Importance

Types of Wastewater Treatment

Water pollution can be defined as the contamination of water bodies such as oceans, sea, lakes, river, groundwater and aquifers mostly caused by human beings (Pal et al. 2014). Waste water treatment is a procedure of converting waste water into water that can be used again. Waste water can be formed through various activities such as bathing, washing or even using toilet (Von Sperling and de Lemos Chernicharo 2017). While the waste water contents various contaminants including chemicals, bacteria and other toxic particles. The treatment of waste water aims to produce water from the waste water that will have reduced contaminant to the extent when it can scientifically be called safe. Waste water treatment is also known as sewage treatment (Loos et al 2013). It is removal of impurities from sewage or waste water before the waste water reaches the natural water bodies. The water bodies content water that is naturally found in the lakes and rivers. Any polluted water in the aquifer will disturb the natural balance of the components present in the water. Since there is less pure water available, the difference between the uncontaminated water and contaminated water highly relies on the form and concentration of impurities that are found in the water. Considering the broader meaning, water is said to be polluted when it contains adequate impurities in order to make the water unsuitable for drinking, fishing as well as swimming. Even though quality of water is said to be impacted by natural conditions, the word pollution usually implies the human activity as the main cause of water pollution. Hence, the prime cause of water pollution is caused by the drainage of contaminated wastewater into groundwater or the surface of water. Wastewater is one of the main causes of water pollution. Fig: 1 illustrates the process through which sewage treatment, a process of water treatment takes place.

Waste water is any kind of water that is impacted by human use. Any form of used water that is in combination of domestic, industrial, commercial or agricultural activities, storm water, or any sewer water is under the category of wastewater (Campbell and Corley 2015). This wastewater is unsafe for drinking purpose however they can be used by human in many ways. The water changes the chemical properties and changes their nature by making them unsuitable for human, plant and animals. Every particle that can be either organic or inorganic determines the quality of water, chemical and biological. This particle includes microbes, viruses, bacteria, fungi and many more (Rezania et al. 2015). However, the wastewater can be treated before they are released into the water bodies. There are several ways the water treatment is performed.

There are treatment plants for wastewater, chemical or physical and biological. The biological waste treatment plants utilize biological matters as well as bacteria that help in breaking down the waste materials. Hence, biological treatment systems are ideal when household waste water needs to be treated The water contents are compared with the standards set against what is indeed achieved through treatment of water scientifically (Stringfellow et al. 2014)..

Effluent treatment plants

The procedure of cleaning the waste water is to expel the pollutants from the household and water sewages. The three subdivisions can be created when the waste wastewater treatment strategies are arranged. The three kinds of wastewater treatment process are as follows.

These plants are mostly used by the large industrial organizations and the pharmaceutical. These plants are engaged more synthetically. The organizations that use these plants are mostly prone to chemical spill over, therefore, effluent treatment plants are used for they are likely to cleanse water to help ensure the environment. These facilities use evaporation and various other drying techniques as well as additionally microscopic filtration so the chemical processing is spurred (Rizzo et al. 2013).

Sewage treatment plants: the sewage treatment is known as the process in which contaminants from family unit sewage and wastewater are expelled on large scale. Through incorporation of physical, biological and chemical methods chemical, physical and biological contaminants are evacuated.  To create a waste stream is the main goal of this process. It also includes treatment of profluent and a solid waste to make it safe for reuse as well as release into the environment. The first method, pre-treatment evacuates materials that are collected from the raw wastewater for the prevention of damage or any clogging up of pumps as well as pipes.  The influent sewage water is checked and filtered to expel each substantial object that is carried in the sewage stream. Today plans that are serving extensive populaces are most likely to be done with an automated mechanically rounded bar screen. For the smaller or plants that are less modern manual cleaning is utilized. The solids which get collected are arranged later in a landfill and burned. Grit evacuation might be incorporated in the pre-treatment that involves a sand or coarseness channel or chamber. In these, the speed of the approaching wastewater is made to permit sand, stones, and grit in order to settle (Michael et al. 2013).

Small-scale industries usually lack sufficient energy, space or funds to set up any treatment framework by themselves. Therefore, they are highly depended on a consolidated networking system arrangement of plants for the purpose of wiping out wastewater (Bharagava and Mishra 2018.). In order to combat the reach of these organization’s belongings, in industrial centers who releases high amount of contamination the combined effluent treatment is frequently used. The septic tank of house is not only the basic tool for cleaning home but also for keeping the environment clean (Luo et al. 2014).

Traditional wastewater treatment plants are the large outdoor facilities. It cleans the water as well as leaves the water with several qualities. a process used for cleansing water.

The traditional process of waste water treatment included only the basic and required process:

• Screening: screening removes large objects such as nappies, sanitary items, diapers and many more.
• Primary treatment: this process involves separating organic matters or human waste. This process removes the dirt by letting it settle in a large tank.
• Secondary treatment: this method involves cleaning the water again approximately applying the same methods in more intense form.
• Final treatment: final treatment is removing the harmful substances. This process is done by letting the water filter through a bed of sand and after this process, the water is released into the environment.

Water pollution that is caused by sewage water is mostly found in the cities. It is one of the main difficulties in the urban areas. Sewage water flows into the rivers, lakes and water bodies without being treated. The disposal of water without much care creates a long chain of problems. Issues such as speeding diseases, increase in biological oxygen demand, eutrophication and many more are the result of the careless act performed by human (Guerrero, Maas and Hogland 2013).

Process of Treating Waste Water (Hejab)

Wastewater treatment is a performed through a process. Figure 3 illustrates process of treating waste water stage by stage. The stages of waste water treatment are as follows:

1. Wastewater collection: The initial step of wastewater treatment is the gathering of the waste water. Collection systems are placed as per the sewage water areas. These collection systems are placed in households as well as the responsible administration. The water id directed to the treatment pants with the help of underground drainage systems (Qasim 2017). It is important to transfer the wastewater under hygienic conditions. The pipes used in the process should be free from any leakage and the people involved in the process should wear protective clothing as well (Hedgespeth et al. 2012).
2. Odor control: odor control is very important while treating the wastewater. For the presence of dirt and contaminated particles, the wastewater develops a foul smell over the time. This process includes processes of removing the foul smell that is developed over the time through odor treatment plants. The bad smell producing elements are controlled and treated using various chemicals to neutralize. Since it is the initial wastewater treatment plant process it is a crucial stage (Yang, Zhang and Wang 2015).
3. Screening: screening is the following step of the treatment process. This process includes elimination of big objects such as diapers, plastic bottles, face wipes and other non-degradable objects. It is one of the crucial step for any ignorance in this process will lead to constant machine problem or equipment issues. The specially designed machine operates to separate the grit that commonly washed down into the sewer lines by rainwater. The solid wastes are disposed in the landfills separated from the water (Czekalski et al. 2012).
4. Primary treatment: the primary treatment process involves the first macroscopic particle separation. The separation of macrobiotics solid matter from the wastewater. This treatment is done by pouring wastewater into the big tank and let the solid particles settle down at the lowest surface. Then with the help of a large scrapper the solid waste and sludge is removed. It pushes the wastes into the center of the cylindrical tanks which is treated later by pumping it out. The water that remains are pumped for the secondary treatment (Razzak et al. 2013).
5. Secondary treatment: this process is also called as the activated sludge process. This process involves adding seed sludge to the waste water to make sure it is broken to the furthest level. Air is pumped into huge aeration tanks, which encourages the growth of bacteria that uses oxygen. The remaining growth of other microorganisms that consume rest of the organic matter. The large particles settle down in the tank’s bottom. The large tanks are passed through the wastewater for a period of 3- 6 hours (Yang, Zhang and Wang 2015).
6. Bio-solid handling:  the solid matter after settling down of primary and secondary treatment stages are directed to digesters. These digesters are bringing into heat at a room temperature. The solid waste that are collected are then treated for a month and during the process they undergo anaerobic digestion (Czekalski et al. 2012). Methane gases are produced while this process takes place and nutrient rich bio-solids is also formed. These are recycled as well as dewatered into the local firms. The methane gas produced can used as a source of energy for the treatment of plants. The gas can be used to form electricity in machines or even for driving plant equipment (Hedgespeth et al. 2012).
7. Tertiary treatment: similar to clean raw water for drinking purpose the tertiary treatment is capable of removing 99 per cent of impurities from wastewater. The process makes the water close to drinking water quality. However, this process inexpensive and cannot be afforded by everyone (Hedgespeth et al. 2012). This process is well trained and high skilled equipment operators, chemicals and steady energy supply is required. These requirements are not easily found.
8. Disinfection: there are still some of the diseases causing organisms. This process is helpful in eliminating these particles from the wastewater. Around 20- 25 minutes in tank is needed in order to treat the wastewater and disinfect them. This is an important part of the process. In the tank chlorine and sodium hypochlorite is used. After this process the effluent is released into the environment through local water ways (Czekalski et al. 2012).
9. Sludge treatment: the sludge treatment is the process where the produced sludge that is collected during the primary and secondary treatment needs thickening and concentration to enable further processing (Kelessidis and Stasinakis 2012). The collected materials are put into thickening tanks and let it settle down. Later, the settled particles are separated from the water. This particular process can last for 24 hours. The remaining water is gathered and treated in the aeration tank. The sludge that remains is safe for any other purpose in environment such as agriculture. The waste water treatment has several benefits and these benefits should be utilized as well (Yang, Zhang and Wang 2015).

References

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