Abstract:
Attention has been rising towards natural water purifying agents as the
effect on human health and the environment of synthetic chemicals
became evident. Maerua sucordata has been used as a natural coagulant
traditionally by rural communities living around Omo River. This study
focused on the coagulation properties of Maerua subcordata powder and
its effect on bacteriological properties of water. The powder was prepared
by cutting the root into pieces, drying on sunlight, crushing by
traditional mortar and pestle, and finally ground by traditional mill and
sieved.
The optimum dose was determined by jar test using turbidities 500, 370
and 240 FTU. The workable turbidity was 370 FTU; with which further
tests were made. The powder was used to treat water with known
turbidity as a primary coagulant and also with alum. Its efficiency was
compared with alum and Moringa. The powder, when used alone
decreased the turbidity of water from 370 FTU to 8 FTU upon 1 ½ hr
settling, while Moringa achieved 9 FTU. This was much lesser compared
with alum. When used in combination with alum, 1:1 mixture reduced
the same turbidity to 6 FTU and 2:1 ratio of alum to Maerua produced 8
FTU with the same settling time. Maerua powder can give best results,
i.e. in the WHO guideline range, upon longer settling time. On the
contrary, turbidity of the water treated with Moringa powder had
regained upon longer settling times. Maerua powder was effective at
moderate turbidity.
The effect of Maerua subcordata powder on bacteriology of the water was
insignificant. Only 66.7 % reduction in fecal coliform count was
observed.
Key words- Maerua subcordata, jar test, residual turbidity, turbidity,
bacteriological quality, total coliform, fecal coliform.