A Water Treatment Process

Water is essential for humans. Hence, it is used from agriculture to industrial products. However, due to the population increases, contamination of the water systems often occurred. Contaminated water as well as wastewater has been affected in quality that is used for washing and toilet wastes. Therefore, in order to prevent the pollution problems in receiving waters, the treatment of water is proposed. As mentioned by Omran (2011), there are six steps in water treatment process includes preliminary treatment, aeration, coagulation and flocculation, sedimentation, filtration and addition of chemicals to clear water tank (exemplified in Figure 1).

Before undergoing the process of water treatment, the raw water is allowed to flow in preliminary treatment which begins with firstly, screening process. In this process, large floating materials like leaves, sticks and fish is removed to avoid the damage of plant equipment (Omran, 2011).

Secondly, the water passes through the process of aeration where the process of bringing water and air into close contact by introducing bubbles of air and letting them rise through the water (Omran, 2011). According to Omran (2011), this process is used to remove the trapped gas like hydrogen sulfide in water that can produces nasty water instead of working well in pH less than 6.5. Studied conducted by Olumuyiwa, Fred and George (2012) found that carbon dioxides that contain in water is reduced instead of decreases the solubulization of water through aeration process. This cause corrosion and leaching of plumbing materials into water.

Subsequently, after undergoes the screening, aeration and other pretreatment process, the next process which is the third is known as coagulation and flocculatio...

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...residual, and it does not cause taste or odor problems (Water supply system, 2013).

The final step of the water treatment system is pH adjustment before supplying the water to the customer. Many treatment processes such as disinfection and coagulation are pH dependent. Basically, pH is an indicator of the acid or alkaline condition of water. The pH scale ranges from 0-14; 7 indicates the neutral point. The normal pH range of drinking water is 6 - 8.5. Soda ash (sodium carbonate) and sodium hydroxide (NaOH) is added into the water system to raise or lower the pH of water to near neutral point, at the same time reduces the soda taste and increase the effectiveness of chlorination. This method also decreases the potential of pipe corrosion as water with a pH above 9 can corrode metals such as brass, copper, zinc, aluminum and iron (Adam, Wang, Loftin & Meyer, 2002).