A comparison between Moringa oleifera and chemical coagulants in the purification of drinking water - An alternative sustainable solution for developing countries

Abstract A research project was commissioned to investigate the performance of Moringa oleifera compared with that of aluminium sulphate (Al 2 (SO 4 ) 3 ) and ferric sulphate (Fe 2 (SO 4 ) 3 ), termed alum and ferric respectively. A series of jar tests was undertaken using model water, different raw water sources and hybrid water containing a mixture of both of these types of water. The model water consisted of deionised water spiked with Escherichia coli (E. coli ) at 10 4 per 100 ml and turbidity (146 NTU) artificially created by kaolin. Results showed that M. oleifera removed 84% turbidity and 88% E. coli , whereas alum removed greater than 99% turbidity and E. coli . Low turbidity river water ( E. coli count of 605 colony forming units (cfu)/100 ml was treated with M. oleifera and ferric. Results showed an 82% and 94% reduction in E. coli for M. oleifera and ferric respectively. Tests on turbid river water of 45 NTU, with an E. coli count of 2650 cfu/100 ml, showed a removal of turbidity of 76% and E. coli reduction of 93% with M. oleifera . The equivalent reductions for alum were 91% and 98% respectively. Highly coloured reservoir water was also spiked with E. coli (10 4  cfu/100 ml) and turbidity (160 NTU) artificially created by kaolin; termed hybrid water. Under these conditions M. oleifera removed 83% colour, 97% turbidity and reduced E. coli by 66%. Corresponding removal values for alum were 88% colour, 99% turbidity and 89% E. coli , and for ferric were 93% colour, 98% turbidity and 86% E. coli . Tests on model water, using a secondary treatment stage sand filter showed maximum turbidity removal of 97% and maximum E. coli reduction of 98% using M. oleifera , compared with 100% turbidity and 97% E. coli for alum. Although not as effective as alum or ferric, M. oleifera showed sufficient removal capability to encourage its use for treatment of turbid waters in developing countries.

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