Essay by alexswanHigh School, 12th gradeA+, October 2008

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SECTION 1:Water is one of the most vital substances for human survival. However, if water is unsanitary or untreated it can transfer disease and cause potentially dangerous water borne diseases in the human body. Water needs to be disinfected in order to kill any pathogens and to destroy or prevent them from reforming in other environments.

There are many methods in cleaning and disinfecting water. Treating water involves a few steps in order to produce a cleaner, filtered and disinfected substance.

–Primary TreatmentThis is where large particles are removed from the water in order to remove most of the physical contaminants.

Screening- is where large bars with screens between them are raked through the water and removes the majority of the large particles and debris.

De-gritting – is where the water is put through an even finer filter to remove more of the finer particles from the water and reduce or eliminate the grit in the water depending on the size of the filter holes.

Flocculation – chemicals are mixed rapidly of the water which makes particles become suspended in the water, these particles may contain thousands of harmful and beneficial microbes.

Sedimentation- is where the suspended particles are given time to settle with the microbes to the bottom of the tank.

Sludge processing – the sediment that is in the bottom of the tanks is removed, collected and processed to remove any harmful chemicals for disposal.

–Secondary Treatment:•Membrane Filtration – Any remaining microbes or particles in the water are removed in this step. The water is forced through a membrane with tiny holes that filter out any small particles; if the size of these pores are smaller the water is filtered more. This method is used widely through out Australia as it is very effective, it is easy...