VPE 511: Environment and Environmental Hygiene (2+1)

COLOUR AND TURBIDITITY

• Natural waters rarely show colours other than yellow or reddish brown, which usually indicate the presence of peat acids or , in the case of turbid water, suspended particles clay or iron oxides: occasionally algal growth is responsible for the appearance of a green or red colour.
• Few waters which can be considered satisfactory contain appreciable quantities of suspended organic matter.
• Its presence in any quantity encourages the growth of micro-organisms, renders the water difficult to filter, and frequently makes sterilization difficult. Suspended mineral matter, on the other hand , is less objectionable.
• Its presence tends to be seasonal, occurring usually after periods of heavy rain, although when in the form of hydrated oxide of iron it appears as a permanent turbidity in ferruginous waters.