In developing countries, ground water, which is contaminated with
domestic and industrial waste, is commonly used for drinking. Colour, turbidity
and microbial content affect quality of potable water. Strychnos potatorum
(Linn.) seeds are known to function as coagulants and clarify water. Our study
investigated the effect of the seed powder (10-40 mg L
$^{-1}$
) on water samples of
varying colour, turbidity and microbial content. Samples studied were of river
Yamuna, industrial effluent, a recreational pond, tap water and distilled
water. pH was maintained within ±5 units while alkalinity was
within one unit, showing that taste parameters were not affected. There was an
82-98% decrease in absorbance, denoting the seed's clarifying
effect. The reduction in heterotrophic microbial load was 99% when 10 mg L
$^{-1}$
of
seed powder was added. Ames test demonstrated non-toxicity of the seed at the
concentrations tested. This simple method can help as an effective and
affordable pre-treatment method and bring down the costs of secondary
treatment.
