A biocoagulant slow sand filtration for disinfection of Toxoplasma gondii oocysts from Mezam River in Bamenda, Cameroon
An integrated low-tech biocoagulant-sand filter drum for disinfection of oocysts of Toxoplasma gondii targeted for developing countries was evaluated. Dirty and turbid water (130.3 NTU) from Mezam River and leachates from dump sites and stagnant water in Bamenda, Cameroon, was analyzed microscopically after centrifugation for oocyst of T. gondii. Leachates from dump sites and stagnant water in Bamenda city had a very high concentration of oocyst of T. gondii too numerous to count per 10 ml while the major Mezam River had 50 oocysts per 10 ml. Considering that is widely used for various domestic chores; filtration disinfection of T. gondii was considered. A bench scale disinfection of oocysts of T. gondii with 0.2 g of powdered Moringa oleifera seeds per 10 ml of contaminated water from Mezam River showed a reduction of 50 oocysts per 10 ml to 10 oocysts in 15 min retention time. To optimize this, a pilot scale up was carried out using 120 L (120,000 ml) of water from Mezam River pretreated with 2400 g of powdered M. oleifera seeds for 15 min retention time and filtered through a sand filter drum made of fine sand, coarse sand, charcoal and gravel for 1 h filtration time. The total mean values of oocysts counts for 120 L of water to be filtered were 600,000 per 120,000 ml. The oocysts counts reduced to 10,000 after pretreatment with 2400 g of powdered seeds of M. oleifera and after a final filtration through a sand filter drum, no oocysts of T gondii was detected in the final treated water. The findings from this study suggests strongly that the application of natural coagulants and sand filtration systems could serve a simple low cost disinfection for oocysts of T gondii from water systems in resource limited countries.
Key words: Toxoplasma gondii, oocysts, disinfection, water, biocoagulant, moringa, turbidity, sand filter, drum, Cameroon.