The Effects of Native Plant Species Vegetated in Constructed Wetland on Removal of Selected Pollutants in Water of Bomachoge Sub County in Kisii County-Kenya

Abstract

The relationship between water quality and health should be appreciated by engineers and researchers so that water resources users can be sensitive to water contamination and associated health impacts. It’s against this background that this study was carried out to establish the quality of water before and after passing through vegetated constructed wetlands. This is presumably a less costly method of naturally reducing pollutant load in water sources. This study evaluated the levels of microbial and chemical parameters of water in surface flow through constructed wetlands vegetated with Colocasia esculenta, Cyperus esculentus and their combination to determine the efficacy of plant species in removal of these parameters. The study was conducted from August 2015 to February 2016 at Bomachoge Sub County of Kisii County, Kenya. Measurements and laboratory examinations of water samples was carefully done and results revealed that there was significant (p<0.005) removal of all selected parameters, whereby Colocasia esculenta was more effective than Cyperus esculentus and their mixture. C. esculenta (A), C.esculentus (B) and their combination (AB) removed selected  bacteriological parameters such as faecal coliforms by (A 98%, B 16%, AB 36%), faecal Streptococcus (A 100%, B 13%, AB 15%), total coliforms (A 98%, B 18%, AB 26%) and Escherechia coli (A 97%, B 11%, AB 34%) and physico-chemical parameters such as, dissolved oxygen increased by (A-244%, B-318%, AB -107%) conductivity removed by (A 65%, B 41%, AB -28%), phosphates (A 95%, B -20%, AB 37%), nitrates (A 86%, B -38%, AB 40%) and turbidity (A 65%, B 67% AB -19%)  from the result DO increased significantly. These results show that C. esculenta performance was higher compared to C.esculentus and the mixture of both plants, however, the combination of two plant species performed better than C. esculentus. Statistica statistical program was used to compare the overall, among and within samples. From the findings it shows that both plant species significantly removed pollutants from water. It was recommended that C.esculenta and C.esculentus plant species to be conserved and more studies to be done on other native species in other places of kisii county to ascertain their efficacy in water purification.

Keywords: Faecal, Contamination, Anova, Parameters, Coliforms, Wetland, Bacteriological.