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Treatment of Water
Transcript of Treatment of Water
Gather, process and analyze information from secondary sources to describe how drinking water can be treated. Use available evidence to explain how these methods reduce the risk of infection from pathogens. Assess the impact of these methods on society and the environment.
The most common method of water
treatment contains 4 processes.
Coagulation removes dirt and other particles from in water by creating a solid mass. This is done by adding Alum or other chemicals to create Tiny sticky particles called "floc” that are attracted to the dirt particles. The water flows into a tank with paddles that provide slow mixing, bringing the small particles together. This forms larger particles that more easily removed.
COAGULATION / FLOCCULATION
The water flows to a tank called a sedimentation basin. It is here where the floc sinks to the bottom due to the combined weight of the alum and dirt particles. This is called sedimentation. Floc which collects on the bottom of the basin is called sludge, and is piped to drying lagoons or a sludge pit. The remaining water without the floc, moves on to the next stage.
With most of the particles removed during sedimentation, the clarified water moves to the filtration step where remaining finer particles are removed. The filter device is a concrete box that contains sand, gravel and an underdrain.
The sand becomes clogged with particles and must be backwashed after a period of operation and are then flushed from the system.
The last process of water treatment is disinfection. Water disinfection means the removal, deactivation or killing of pathogenic microorganism. This involves the addition of chemicals in order to destroy pathogens habiting in the water. These pathogens include bacterial, viral and protozoan pathogens. Due to being large in size, protozoan pathogens have been removed with other particles during the previous way of treatment. The disinfectant chlorine is added to the water for exterminating the remaining bacteria and viruses. An adequate amount of chlorine is added to the water , allowing the public to be protected once the water leaves the plant.
This process is specifically called flocculation.
Besides chlorine, other chemicals like lime, carbon dioxide, sodium hydroxide and sulphuric acid may be added in small amounts.
This improves the safety, pH and .
As required by NSW law, fluoride is also added to help prevent tooth decay.
The water is taken from a reservoir.
eg. river, lake
and is then transported to a water treatment plant where these processes occur.
Safe and clean water is a vital component for every day life. Water is essential for hygiene, health and the productivity of our community.
The water treatment process may vary slightly, depending on the technology of the plant and the amounts of water needing to be processed. This is varied at different locations but the basic principles are mostly the same.
After the water is treated, it is stored; ready to be supplied to households within the community.
A pathogen is a biological agent that causes disease or illness to its host. Pathogens in drinking water pose the greatest potential threat to human health.
How do these methods of treating water reduce the risk of infection from pathogens.
There are several pathogens that can be found in untreated water. The two most common pathogens are Giardia and Crytosporidium. These are categorized as protozoan pathogens which can survive for long periods and are difficult to deactivate. Others include Legionella, E Coli, Campylobacter, and Enteroviruses. Several diseases and infections have been linked to drinking dirty water that contains these pathogens. These include diarrhoea, chloera, typhoid and internal worms. Pathogens can be removed from water through physical or chemical processes. Previously discussed treatment methods of coagulation, sedimentation, filtration and disinfection can remove a large percentage of bacteria and other microorganisms from the water. Storage can also kill a portion of the disease-causing bacteria in water. The use of these methods therefore results in a reduction of water-borne illnesses as the pathogens are the cause of disease.
HOW DO THE TREATMENT METHODS IMPACT ON:
Methods of treating drinking water can have a substantial impact on the environment. This impact can either be positive or negative, resulting in various changes to ecosystems.
An example of this impact is the loss of habitat caused by the plants these methods are used within. The use of a water treatment plant results in deforestation of land, reduction in population of flora and fauna and less land for various organisms. Flora and fauna are also effected by the use of sludge pits and drying lagoons, which take up more space within their environment.
The remaining sludge from the sedimentation process effects the environment as it has to be placed in landfill, increasing the area taken up by waste.
A disadvantage to the treatment of water for drinking is the amount of pollution produced and electricity used by the plants. This damages the environment, impacting on the long term sustainability of earth.
The treatment of water can also cause a positive influence on the environment, as other organisms can consume the clean water that is produced.
The treating of drinking water cannot only have an effect on the surrounding environment, but it can also have an immense impact on society.
Where the water is treated, people are less susceptible to disease. This is due to the lack of pathogens and the overall cleanliness of the water. This creates a better standard of living and a healthy lifestyle for members of society.
People experience stronger and healthier teeth as the chemical fluoride may be added during these methods.
These methods increase availability and accessibility of clean water.
Less money for the community as there is expenditure going towards the plants and technologies of these methods.
People of the community are provided with jobs
Less strain on health system due to less people with illness.
To ensure that pathogens do not pose a health risk to the community, water supplies are treated in various ways before being distributed within a community for drinking purposes.