Levels and treatment options for enteric and antibiotic resistant bacteria in sewage from Sisimiut, Greenland

摘要

Sewage treatment in Arctic towns is inadequate. Sewage contains pathogenic microorganisms, parasites, antibiotic resistant bacteria, and toxic compounds. Discharging of untreated sewage can thus have a negative effect on people's health and the aquatic environment in the receiving water bodies. Conventional treatment is challenging and expensive to implement in Arctic communities due to the cold climate and scattered population. In addition, advanced removal of nutrients may in many cases be overstated due to the low population density and large receiving water bodies. In this work we investigated the presence of Total coliforms, Escherichia coli (Ecoli), enterococci, streptococci, antibiotic resistant enteric bacteria, and toxicity in sewage from two sewer outlets in Sisimiut, West-Greenland, as well as in a sub-stream from the local hospital. According to the content of streptococci and enterococci, the wastewater is very strong, suggesting a potential hygienic risk. In addition, a high fraction of antibiotic resistant bacteria and an increased toxicity in the sub-stream from the hospital, suggest that this stream contains toxic compounds, possibly antibiotic of nature that may affect the local Arctic marine environment negatively. Both peracetic acid treatment and UV-C radiation shows potential for disinfection of the wastewater after removal of solids >60μm. E-coli was most susceptible to peracetic acid treatment, while a maximum possible reduction of enterococci and coliforms of 2-3 size orders was observed. The highest reduction observed by UV-C treatment was 4 size orders for enterococci, but no maximum level was observed. UV-treatment may thus be a preferred disinfection method, in particular for a community with long transport distances to the nearest chemical supplier and access to hydropower from a local hydropower plant.