Determination of 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\(\ell\) for all samples. The WHO guidelines for domestic water sources state that water used for domestic purposes should not   contain more than 100 CFU/m\(\ell\). Public perceptions of water quality ranged from 'unsafe' to 'highly contaminated'. 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.