Determination of effective combinations of selected local materials for treatment of borehole water and to compare their effeciency with municipal water treatment technology

Abstract

Use of contaminated water risks human lives hence should be treated to meet drinking water quality guidelines. The most applied technique is municipal water treatment technology (MWTT) though inaccessible in peri-urban/rural settings leading to use of untreated water like borehole waters. Desirable water treatment processes need to be developed for provision of portable water. Local materials such as Moringa oleifera seed, activated clay, activated charcoal and natural zeolite have been applied individually but are not effective in safeguarding drinking water. Therefore, there is need to determine efficacy of combinations of local materials. The objectives of this study were to determine the physico-chemical parameters and Escherichia coli of fresh and salty borehole waters and treatment effects of individual and combinations of local materials in comparison with the World Health Organisation (WHO) guidelines. The study also determined effective treatment combination for each borehole and compared their efficiency with MWTT. Water samples from each borehole were collected in triplicate. Temperature, pH, total dissolved solids, electrical conductivity, dissolved oxygen, total solids and Escherichia coli were determined before treatment. The samples were treated by passing through columns containing individual and combinations of Moringa oleifera seed water extract, activated clay, activated charcoal and natural zeolite to determine the treatment effects by comparing with data before treatment. The different combinations were calculated from permutation formulae where order was taken into account while effective treatment combinations were determined from the least summation of variance from WHO guidelines for each parameter for a particular combination. The data was analyzed by MSTATC statistical package and ANOVA (p≤0.05) was used to determine significance differences between data. Combination V (Activated charcoal → Moringa oleifera seed water extract → Activated clay → Natural zeolite) was effective for fresh borehole water and was better than all individual materials on TS, activated charcoal on pH, TDS, EC and Escherichia coli and natural zeolite on Escherichia coli. Combination U (Activated charcoal → Natural zeolite → Activated clay → Moringa oleifera seed water extract) was effective for salty borehole water and was better than activated charcoal on pH, TDS, EC and TS and natural zeolite on TS. Effective combinations also showed better treatment effects on dissolved oxygen, total solids and Escherichia coli of 34.5%, 38.7% and 99.8% for combination V and 30.7%, 54.0% and 99.6% for combination U compared to 8.1%, 31.9% and 99.2% for MWTT respectively. Combinations of local materials show potentiality in contaminated water treatment.