Water filtration is mainly a physical water purification method. It's termed as so because it does not alter the chemical composition of a sample of water. Filtration involves removing solid impurities from water using techniques such as screens, sand filtration and cross-flow filtration methods. The first two are elementary methods of filtration. On the other hand, cross-flow filtration methods are more complex and are able to remove dissolved salts, microscopic material and other organic matter.
Water pH is the measure of the basic or acidic levels of water. Most water supplies in cities have slightly basic pH levels. However, depending on the water's use, pH levels can be increased or decreased using stable alkalis and acids such as diluted di-potassium phosphate and diluted phosphoric acid, respectively. PH levels above 7 on the pH level scale are basic levels, while those below that are acidic. Pure water is exactly at pH 7, meaning it is neutral in nature.
Flocculation and coagulation are processes of removing any color impurities in water to make it clear. This water purification method involves causing the impurities in water to coagulate into solid particles that are later removed through physical means such as filtration. Coagulation and flocculation involves the use of chemical agents such as aluminium sulfate and aluminium hydroxide, respectively.
Disinfection is a water purification method used to kill microorganisms and pathogens in water that are harmful to consumers. The most common method of water disinfection is the use of chlorine and some of its compounds such as chloramines and chlorine dioxide. Other disinfection methods include ozone disinfection that uses O3 properties to kill microorganisms, and the use of hydrogen peroxide.