AbstractsBiology & Animal Science

Small and rural communities across Canada depend on potable water sources that are collected in farm dugouts or small reservoirs. In Saskatchewan, the village of Osage and Hamlet of Benson are two communities that depend on farm dugouts for their drinking water supply. Within the last 10 years both communities implemented ozone-assisted biological filtration for water treatment; however, both plants experienced low treatment efficiency, as indicated by presence of disinfection by products and in particular trihalomethanes at concentration that exceeds Saskatchewan Drinking water standards of maximum acceptable concentration (MAC) of 100 ??g/L as a running annual average of seasonal samples. Over a 14 months period water treatment plant performance at both communities was monitored and analysed along with water quality. Water samples were collected through the treatment train every two months and analysed for a large number of water chemistry parameters. From water quality results ozone efficiency was assessed. Microbiology of the water sources at both communities in fall and early spring was analysed. Analysis of microbiology of biologically activated carbon filter media collected in fall at Village of Osage was performed. Water chemistry and performance at both plants indicates that raw water quality is the major obstacle to the efficient plant performance. High alkalinity (bicarbonate, carbonate and phenol) as well as salinity seem to inhibit / scavenge the ozone so that oxidation of organic matter is not adequate. Fluctuations in the turbidity of the water make the operation of the plant very challenging and filters requires frequent backwash. Microbiology of the dugouts suggests that salinity of the dugouts govern microbiology of the dugouts as well. Even though both dugouts have bacterial communities with identical phylum, the species richness of the each phylum is different between the two dugouts. Microbiology of the filters showed decline of drinking water pathogens through the filter except for two bacterial genera Legionella and Campylobacter. Both genera are opportunistic pathogen with potential to cause respiratory and gastro intestinal infections especially in immunocompromised (seniors, children, ill) population. Most of the pathogens identified here if not all are susceptible to disinfection, chlorination in particular. However, it is recommended that at peoples??? homes hot water tanks are keep the water temperature at or above 60 ??C and cold water tanks are set at less than 20 ??C to minimize survival of Legionella in piping and faucets. Potential improvement in design and layout of the filters is identified. Filters should be configured so that the contaminant removal from the drinking water is maximized. That can be achieved with installation of up-flow dual or multimedia roughing filter to reduce turbidity and connecting filters in series in order to maximize the contaminant removal from the drinking water. The first step in improvement of efficiency for the water treatment plants employing…