An assessment should be made of the physical plant. Cold water storage tanks are a possible source of contamination, particularly where there is insufficient turnover at all times of the year.

The design of tanks should be checked to make sure that the inlet and outlet points are not so close together that stagnant water can build up in the tank. All tanks should be covered and any openings should be designed to prevent contamination from airborne particles, birds and rodents.

Domestic hot water storage tanks should also be checked to make sure that there is sufficient turnover. Water temperatures should be checked to ensure that bacteria, an assessment should be made of the physical plant.

Cold water storage tanks are a possible source of contamination, particularly where there is insuffi­cient turnover at all times of the year. The design of tanks should be checked to make sure that the inlet and outlet points are not so close together that stagnant water such as regionally pneumophilia cannot survive and multiply.

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The water distribution system should be inspected to ensure that contamina­tion cannot take place and that harmful bacteria cannot breed in the pipe work and contaminate the water.

For example, there should be strict isolaton of domes­tic hot water supplies from any other non-domestic systems, which may not oper­ate with the same quality of water as domestic systems. There should be no possi­bility of back siphon age from other systems.

Where there is a possibility, vacuum- breakers will need to be installed. Any redundant pipe work, which will allow the build-up of stagnant water, should be isolated from the distribution system.

All kitchen drains should be fitted with grease traps. Any non-potable water supplies for cleaning, irrigation, etc. should be locked (or isolated in some other way) if they are accessible to guests or employees.

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Water softening treatment is to be given to water for the removal of permanent hardness.

Purification of water:

Removal of volatile & oxidizable impurities.

Organic matter

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Natural aeration

Artificial aeration – Fountain spray

(i) Removal of sulfides, chlorine.

(ii) Removal of suspended impurities Settling coagulating & settling taut.

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Coagulation

Filtration – filtration tank.

(iii) Removal of soluble impurities – hardness;

(iv) Removal of Bacteria microorganisms & portability of water. Sterilization with bleaching powder. High test hypo chlorine chlorimiozon ultraviolet rays.

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(v) Removal of slime and algal Screening Prechlorination

(vi) Removal of oil.

(vii) Removal of nitrites.

Flourines

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Magnense

Sulfate

Hard Water:

Water which does not produce lather with soap solution is called hard water Units of hardness

(i) Part per million is the parts of calcium carbonate equivalent hardness per 106 part of water.

(ii)‘ Milligram per liter is the number of milligrams of calcium carbonate equivalent hardness present per liter of water. Calcium & magnesium salt can create water hardness problem.

Acid entrained oxygen on CO, can cause water pH.

Iron & manganese can create fixture discoloration problem organic matters silt or suspended matter can create poor taste, bad water odor or turbidity. Effects of hard water:-

(a) Performance & life oancy of mechanical equipment, scale, hot water corrosion. Incrustation.

(b) Water unpleasant for human consumption, drum formation of stone or Callus.

(c) Create Laundry problem, more consumption of soap sticky precipitate adheres. On cloth, giving spots & arches straining of cloth.

(d) Fuel cost increased, been pea do not cook.

(e) Tea and coffee unpleasant in taste, muddy looking.

(f) Food tasfelan tough rubber

(g) Overheating of utensils.

(h) Bath soap is wasted skin dry & dark,

The hardness is of two types –

(a) Temporary/Carbonate hardness- due to the presence to bicarbonates / calcium and magnesium. It can be removed by boiling or by adding lime to the water.

(b) Permanent Hardness – due to the presence of sulfates, chlorides and pirates of calcium and magnesium.