Performance of municipal waste stabilization ponds in the Canadian Arctic

Wastewater treatment and public health in Nunavut: a microbial risk assessment framework for the Canadian Arctic

“…In one Nunavut community, wastewater is discharged directly to a marine outfall without passing through a wetland. Passive treatment systems can reduce contaminant concentrations in an arctic climate (Chouinard et al 2014;Doku and Heinke 1995;Hayward et al 2014;Ragush et al 2015;Schmidt et al 2016;Yates et al 2012). As noted by Hayward et al (2014) and Yates et al (2012), however, E. coli concentrations in the wetlands are highly variable over the treatment season.…”

“…Engineering assessments show that passive wastewater treatment systems are capable of reducing the level of Escherichia coli (used as a regulatory indicator of the presence of pathogenic organisms) in an arctic climate, but generally not to levels typically achieved with conventional 5 wastewater disinfection systems (Hayward et al 2014;Krkosek et al 2012;Krumhansl et al 2015;Ragush et al 2015;Yates et al 2012). However, these assessments do not explicitly consider possible human exposures and potential risks to public health.…”

“…QMRA can serve as a suitable exploratory tool for early or screening-level assessment of health risks, prior to more detailed studies, environmental monitoring or public health surveillance (Ashbolt et al 2013; Sales-Ortells and Medema 2014). For the Arctic communities described in this paper, the pathogen removal capability of typical wastewater treatment systems has recently been characterized (Hayward et al 2014;Huang et al 2014;Ragush et al 2015;Yates et al 2012) and serves as a starting point, allowing the corresponding range of risks of infection to be estimated for assumed exposures.…”

“…Wastewater is continuously deposited into the ponds, where it remains frozen for the winter which lasts from approximately September to June. In June, as conditions warm, the wastewater influent begins to melt and a period of natural treatment occurs for two to four months depending on the location of the community (Ragush et al 2015). These passive treatment systems result in sedimentation and microbial decomposition as well as some pathogen inactivation due to ultra violet irradiation during the arctic daylight hours (Smith 1996).…”

بهبود کیفیت پساب خروجی از برکه ی تثبیت تصفیه خانه های فاضلاب به کمک عدسک آبی

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