Lynn Katz

Providing water services in rural communities is a complex endeavor. Intertwined environmental, economic, and social factors can create barriers to reliable water services in communities. For instance, melting permafrost can threaten the structural integrity of infrastructure, or a lack of trained workforce can lead to system neglect. Geographic isolation of communities can lead to extreme challenges for construction and maintenance. As a result, water utilities serving these communities often incur violations either due to water quality or insufficient monitoring. Thousands of homes in rural Alaska still today do not have piped drinking water to their homes. In many cases, water haulers deliver water to home storage tanks in one to four week intervals. Moreover, the aesthetic quality of the water (brown colored with chlorine odor) delivered to these communities has been challenged, and many residents choose to drink from alternative water sources (i.e., rainwater, bottled water, snowpack). Utilities also struggle to recruit and retain qualified staff to operate treatment processes that require higher levels of certification such as oxidation and greensand filtration.

The most common method of iron and manganese removal in Alaska is a continuous regeneration manganese greensand process. Greensand consists of a manganese oxide coating on glauconite, an iron rich member of the illite clay mineral group. The greensand filtration process often operates in a continuous regeneration mode using permanganate to oxidize soluble iron and manganese to insoluble species (MnOx(s) and Fe(OH)3(s)) that are removed by greensand media alone or by a combination of anthracite and greensand. While greensand filtration processes can be effective at removing iron, manganese and arsenic, optimization of the process is challenging due to the complex interactions associated with near simultaneous oxidation, adsorption and precipitation processes. For example, iron oxidation leads to formation of amorphous iron hydroxide solids which can either co-precipitate or adsorb co-oxidized arsenic species. The presence of arsenic, in turn, can impact the structure and morphology of the iron hydroxide solids formed as well as overall process efficiency. Thus, while the process may seem relatively straight-forward, there is a need to develop a more complete understanding of the process and controlling mechanisms to establish clear operational guidelines for remote communities.

This presentation focuses on water quality results from a recent study of drinking water in homes that receive hauled water from a groundwater sourced water treatment system in the Yukon-Kuskokwim region of Alaska. The first part of the talk will address the challenges associated with operating and delivering water in these remote communities, the water quality challenges experienced, and the performance of the drinking water processes. The second part of the talk will explore mechanisms associated with contaminant removal in precipitating systems. Finally, the presentation will explore the role of climate change in delivering infrastructure in the Arctic and what climate adaptation looks like in communities that are on the melting tundra with regard to water delivery.