Drinking water quality monitoring

• Main Author: Kilungo, Aminata P
• Format: Dissertation
• Language: English
• Subjects: environmental science; microbiology
• ISBN: 9781303398193; 1303398192

This dissertation involves two different studies. The first concerns the real-time detection of microbial contamination in drinking water using intrinsic fluorescence of the microorganisms. The prototype, "Blinky", uses LEDs that emit light at 365nm, 590nm, and 635nm for ultraviolet, amber, and red light, respectively. The instrument was modified by replacing existing LEDs with LEDs that had 50% more intensity. Two more LEDs were added for amber and red light and were positioned closer to the photomultiplier tube to increase sensitivity. The detection limit of the viable bacteria was ∼50 live bacteria/L. No change in the intrinsic fluorescence below the concentration of ∼10 8 dead bacteria/L was observed. The results for spore measurements suggested that most of the spores had germinated and could not be detected. The instrument was successful in detection of viable bacteria and differentiating viable and non-viable bacteria.
The second study was designed to assess the water quality of well construction in southeastern Tanzania. Three designs were tested: Msabi rope pump (lined borehole and covered), an open well converted into a closed well (uncovered well into a covered and lined), and an open well (uncovered). The study looked at microbial and chemical water quality, as well as turbidity. The survey included 97 water collection points. For microbial analysis, heterotrophic plate count (HPC), total coliforms and E. coli tests were performed. Fifteen of these wells were further analyzed for microflora and diversity for wells comparison purposes, using culture methods, followed by polymerase chain reaction (PCR) and genome sequencing. Ten wells were analyzed for calcium, potassium, nitrates, nitrites, chloride, fluoride, bromide, sulfate, iron, and arsenic. Two water points were selected for organic compound analysis (gasoline components). The results of this study showed that the open wells performed poorly in microbial water quality and turbidity. There was a statistical difference in HPC, total coliforms, E. coli numbers and turbidity in open wells compared to closed wells and the Msabi rope pumps. There was no statistical difference in HPC, total coliforms and E.coli numbers between the closed wells and Msabi rope pumps. Msabi rope pumps performed better in turbidity and had low bacteria diversity.