Microbes in Water

In this section students were asked to  presents two different methods used in different countries that reduce the microbes in water.  One is the Hong Kong water treatment method and the other is Western Australia water treatment method. The report gives a comparison between the two methods and how effective the water treatments are. Where both the method official links are hyper linked on the right to allow easier access. 

 How can diseases caused by microbes in water be reduced?

Hong Kong method used to reduce microbes in Water (Sedimentation, Coagulation and Flocculation)

To reduce Safety waters in Hong Kong, Hong Kong had ensure their water sources is safe and ensure that the water is possessed before going onto people’s house’s tab. The Hong Kong Government import raw water from Dongjiang, also known as the East River. Hong Kong uses a standard water treatment process to ensure that the water is safe to use and reduce the microbes in water. The raw untreated water is mixed with chemicals for coagulation and flocculation and then it passes to clarifiers where it allows the water to settle and impurities. Coagulation is a well known method why by using the addition of electrolyte, where the charged particulates in water combine with ions neutralizing the charges. The neutral particulates combine to form even larger particles and finally settle down. Where flocculate uses high molecular weight material to trap the particulates that is not needed and settle down together. The clarified water will then passes through filters of sand and anthracite for removal of divided particles. The water then will pass on into tanks where hydrated lime, fluorine and chlorine are added into the water to kills off the bacteria and control the pH of the water. In which a little amount of chlorine is left in the water in order to allow the chlorine to kill off any bacteria through the process of passing the water through pipes to the public. Below is a diagram of Hong Kong water treatment process. The Water Supplies Department in Hong Kong also continuously monitor and check the levels of Dongjiang water which transfers to Hong Kong. The department will also take regular samples in the supply water system to check the substances in the water. Hong Kong government had also prohibited the use of unlined galvanized steel pipe for water transportation to avoid corrosion of pipes to avoid any bacteria or substance in the corroded pipes to infect and grow in the water. 

Another Method Used (Australia: Adsorption, Water stabilization and disinfection) 

The Australia uses the most common water treatment process like Hong Kong, the sedimentation, coagulation and flocculation. However, they also use adsorption, water stabilization and disinfection for the water treatment process. Absorption is a form of chemical filtration that involves dissolved substances to filter material. Absorption uses carbon and ion exchange resins that could use to remove a range of soluble contaminants from water. It is when chemical bonds are formed between species. The use of charcoal can also remove the unwanted substance in the water, through using charcoal, sand and charred vegetation for the filtration of water. Water stabilization is to chemically stabilize the water to a particular pH level, which means to decide which the water is acidic or alkaline, which this could be done by adding more lime and carbon dioxide. This could alter the amount of microbe’s presents in the water as water which is more acidic will allows the bacteria to stay and grow inside the water. The use of disinfection is to prevent the water from bacteria to grow in the distribution system. The most common methods that use to kill microorganism through using disinfection is water supply are oxidation with chemicals such as ozone and radiation with ultra-violet radiation.