Microbial water quality of treated water and raw water sources in the Harare area, Zimbabwe

Abstract

Microbial water quality is an essential aspect in the provision of potable water for domestic use. The provision of adequate amounts of safe water for domestic  purposes has become difficult for most  municipalities mandated to do so in Zimbabwe. Morton-Jaffray Treatment Plant supplies potable water to  Harare City and areas surrounding Harare. This study investigated microbial water quality and the impact  of microbial water quality related disasters in the area supplied by the Morton Jaffray Treatment Plant.  Questionnaires were distributed to household owners in Harare who receive their water from the  Municipality and those who use alternate water supplies. Candidates were randomly selected from their workplace. The raw water quality of Manyame River and its tributaries was assessed.  Treated water in households was assessed for microbial quality using hydrogen sulphide test and heterotrophic bacteria plate count. Raw water sources were found to be contaminated by faecal matter. Household water sources tested negative for faecal contamination but positive for heterotrophic bacteria. CFU quantities  ranged from 1 to 452 CFU/m. for all samples. The WHO guidelines for domestic water sources state that water used for domestic purposes should not be contain than 100 CFU/m.. Public perceptions of water quality ranged from eunsafef to ehighly contaminatedf. A decrease in the level of aesthetic appeal resulted in  residents resorting to alternative sources such as wells and rivers for their domestic water. The  current state of treated water was suitable for domestic use. Pathogen monitoring of domestic water is recommended using the hydrogen sulphide test and R2A agar test.

Keywords: microbial water quality, faecal contamination, H₂S strip test, R2A agar test