1. 2 nd presentation by Patricia REVERSE OSOMOSIS :the possible solution for water hardness.

2. DEFINITION Reverse Osmosis is a type of water filtration process that involves the use of osmotic pressure to remove a certain element or elements from water. Although there are reverse osmosis water filtration systems designed for purifying a home's water, it's most common use is to remove salt from ocean or salt water to make it drinkable. Reverse osmosis Liquid filtering process in which a contaminated (more concentrated) liquid is forced to pass through a semi-permeable membrane that block most dissolved or suspended contaminants. It is called 'reverse' because in normal osmosis a less-concentrated liquid passes into a more concentrated one. It is (reverse osmosis) a process in which pure water is produced by forcing waste or saline water through a semipermeable membrane. Reverse osmosis is considered a highly effective water purifying process. It is the movement of freshwater through a semipermeable membrane when pressure is applied to a solution (as seawater) on one side of it.

3. Reverse osmosis- how it work ! Reverse osmosis is sometimes referred to as ultrafiltration because it involves the movement of water through a membrane. The membrane has microscopic openings that allow water molecules, but not larger compounds, to pass through. Some RO membranes also have an electrical charge that helps in rejecting some chemicals at the membrane surface. Proper maintenance is essential to retain effectiveness over time. Some units are equipped with automatic membrane washing the membrane.

4. MATERIAL NEEDED  Pressure switch  Flow restrictor  Solenoid valve  Electric wires  Storage tank  Pump

5. PROCEDURE PROCEDURE You need to remove the existing auto-shut- off valve, the devise look like a square block for a disc shape that has four tubing connect to it. Once you remove the auto-shut-off valve, you will have four loose tubing. The four tubing will be connected to the solenoid valve and the pressure switch. Two tubing for the solenoid valve and two tubing for the pressure switch. Connect the solenoid valve (ESO) first. After the third stage filter, the tubing is connected to the inlet of the solenoid valve, then the outlet of the solenoid valve is connected to the input side of the 4th stage membrane filter (the 4th stage membrane filter is the larger filter on top laying horizontally. The input side is the side with only one connection or where the membrane cap is located) Then the other two remaining tubing belongs to the pressure switch. The pump would be connected to the water input and the first stage filter, (make sure the arrow on the pump is pointing to the direction of flow) Connect the electric wires, and then plug in to electrical outlet

6. EXPECTED RESULT After the overall procedure, clean water will be obtain from the storage tank.

7. REFERENCES Agriculture and Agri-Food Canada. 2003. Reverse osmosis: enjoy cleaner water. http://www.agr.gc.ca/pfra/flash/osmosis/en/revosmosistxt_e.htm. Canada Mortgage and Housing Corporation. 2007. About Your House: Reverse Osmosis Water Treatment. http://www.cmhc-schl.gc.ca/en/co/maho/wawa/wawa_001.cfm. Canadian Broadcasting