Water is very good at dissolving substances. As water from rain and snow flows over rocks and through soil, it dissolves minerals. The freshwater we drink or use for our daily life processes is a dilute solution containing a number of minerals. When these minerals are in suficient concentration, water becomes unfit for human use. Many human activities also pollute the surface and groundwater. Human activities such as household waste, agricultural waste, Hill leaks, detergents, septic tankil discuss household tural s livestock waste result in contamination of water bodies. We waite in higher grabeld waste and Industrial waste in this unit. You will learn about other types of waste in higher grades.
Household wastes include human wastes, livestock wastes, soaps and detergents, paints and oil, food, vegetable wastes, garbage, etc. Although detergents have stronger cleansing action than soap, they remain in the water for a long time and make water unfit for aquatic life. When household water containing detergents is discharged into lakes, ponds, rivers, etc. it causes the death of aquatic life. Chemical and bacterial contents in household water can contaminate surface and underground water. Bacterial contents present in water may cause infectious diseases such as cholera, jaundice, hepatitis, typhoid, dysentery, etc.
Water treatment is essential for many reasons.