By Shreya Shah
Surface waters necessitate water treatment before consumption to guarantee no health risk is present to the user. Poor quality water which consists of dissolved and suspended particles, can impact and cause health risks to consumers. The most important contamination is the microbiological contamination as it leads to infectious diseases (Water Treatment, 1994). Chemicals such as nitrates and cyanide when contaminate the water cause long-term health risk such as cancer, kidney and liver damages. Physical contamination may also cause a health risk such as eczema as it extends microbial survival (Drinking Water Treatment Chemicals, 2001).
The water treatment system is designed to remove the contamination, which includes the suspensions of solids from the water. During the treatment the final process used is disinfection where many types of disinfectants are used, however ultraviolet radiation and chlorination are the most common types used. Chlorination is believed to be a more suitable process compared to ultraviolet radiation. However, ultraviolet radiation also has many positive processes to produce germ-free water.
The treatment process involves the removal of contaminants through a number of stages which include: pre- water treatment, suspension, coagulation and flocculation, sedimentation, filtration, and disinfection which include either chlorination or ultraviolet radiation. This is called the multiple barrier principle (Water Treatment, 1994).
Figure 1: This shows large objects in the surface water being removed as it is passing through the screen. The flow of water is indicated by the direction of the black arrows. http://www.chemistry.wustl.edu/~edudev/LabTutorials/Water/PublicWaterSupply/PublicWaterSupply.html
Figure 1: This shows large objects in the surface water being removed as it is passing through the screen. The flow of water is indicated by the
Bibliography: Water Treatment, 1994, United Nations, n.p , viewed 12 April 2012, <http://www.who.int/water_sanitation_health/dwq/S12.pdf>. Diagrams: