With reference to water treatment: (a) state the treatment required for fresh water taken on from ashore; (2) (b) state FOUR properties required for water used for domestic purposes, describing how this may be achieved in EACH case.(8)
(a) Treatment of fresh water taken on from ashore (2 marks)
Chlorination – to kill bacteria and provide residual sterilising effect.
Filtration or UV treatment – to ensure removal/inactivation of any remaining impurities or microorganisms.
(b) Properties required for domestic fresh water & how achieved (8 marks)
Free from harmful bacteria (Sterility)
Achieved by chlorination, UV treatment, or silver ion dosing.
Correct pH / non-corrosive
Adjusted by adding hydrated lime to raise alkalinity, preventing corrosion of tanks and pipework.
Pleasant taste and appearance
Achieved by re-mineralisation (adding small amounts of calcium salts or lime) and maintaining proper storage/clean tanks.
Free from turbidity and suspended solids
Ensured by filtration during treatment and keeping storage tanks clean to avoid sediment build-up.
