Comparative analysis of Moringa stenopetala seed powder and aluminum sulfate for turbidity and E. coli removal from surface water: The case of bake pond, Borana zone, Ethiopia

In rural Borana, Ethiopia, limited access to potable water and the high cost of conventional water treatment methods have led many people to rely on turbid surface water for drinking, exposing them to waterborne diseases. A study was conducted to evaluate the effectiveness of Moringa stenopetala seed powder (MSP) as a natural coagulant for reducing turbidity and Escherichia coli (E. coli) levels in pond water, compared to the conventional coagulant, aluminum sulfate (alum). Water samples were treated with MSP or alum at dosages ranging from 0 to 130 mg/L. The study assessed the effects of initial pH (1.5 to 10.5), settling time (30 to 180 min), and initial turbidity (55 to 319 NTU) on coagulation efficiency for both coagulants. Turbidity, pH, and E. coli levels in the water samples were measured before and after treatment using a portable turbidity meter, portable pH meter, and membrane filtration, respectively. A one-way ANOVA was used to assess significant differences (p < 0.05) between MSP and alum in their coagulation effectiveness. After 120 min of settling, alum (70 mg/L) reduced turbidity from 216 NTU to 1.8 NTU (99.16% removal), while MSP (80 mg/L) reduced turbidity to 4.2 NTU (98.05% removal). Both coagulants achieved turbidity levels below the World Health Organization (WHO) standard of 5 NTU, with MSP showing similar efficacy to alum. In terms of E. coli reduction, alum at 70 mg/L reduced E. coli by 29.78% (from 47 to 33 CFU/100 mL), while MSP at 80 mg/L achieved a 95.74% reduction (to 2 CFU/100 mL). Additionally, MSP did not significantly (P < 0.05) alter the pH of treated water, unlike alum, which typically lowers the pH and requires post-treatment adjustment. These results suggest that MSP is a cost-effective and sustainable alternative to alum, particularly in rural areas like Borana, where access to clean water is limited.