Fresh-Water Treatment

Step 1- Raw water storage

Fresh-water is taken from the source i.e. from river or ground water and stored in storage location (tanks or lagoon)


Step 2- Raw Fresh-water screening

Large items such as logs, fish and plants are screened out from river water at the intake by large filters called bar screen.

Step 3- Clarification

Clarification by adding chemicals and sedimentation

• Special chemicals are added to the water
• The chemicals start to form tiny particles from the exist
  contaminants
• The small particles start to stick together and form larger
  particles
• Finally the particles settle to the bottom and are removed
  from the water by sedimentation process

There are always a few particles which do not get removed from step 3, so the water flows through filters made of sand and gravel. Bacteria are so small that they would go straight through the spaces between the sand grains but because they are caught up in the particles the sand can remove them.Also the top carbon layer in the filter removing any bad smell came along from water source.


Step 5- Disinfection

A small amount of chlorine is always added to the water to kill any remaining germs and to keep the water safe as it travels through the water pipes to the tap. Chlorine has been used as a disinfectant in water for over a hundred years

Water gets from the treatment plant to houses and factories through the Distribution System. The Distribution System usually goes from the treatment plant into large water piping.

The pipes keep branching out and becoming smaller until by the time theyreach a house they may be as small as 25 mm size.water treatment plant usually produce water at a steady rate even though people use different amounts of water at different times. For example, people use a lot of water in the mornings and early evening.Distribution systems contain very large covered tanks called Storage reservoirs. These fill up at night when people are not using much water and allow it to be used at a much faster rate during the peak periods.The water pipes are usually made of fiberglass, PVC(poly vinyl chloride) or iron, sometimes lined with plastic or cement.


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