Applicability of energy-positive net-zero water management in Alaska: technology status and case study

Abstract

Challenges of water and wastewater management in Alaska include the potential need for above-grade and freeze-protected piping, high unit energy costs and, in many rural areas, low population density and median annual income. However, recently developed net-zero water (NZW), i.e., nearly closed-loop, direct potable water reuse systems, can retain the thermal energy in municipal wastewater, producing warm treated potable water without the need for substantial water re-heating, heat pumping or transfer, or additional energy conversion. Consequently, these systems are projected to be capable of saving more energy than they use in water treatment and conveyance, in the temperate USA. In this paper, NZW technology is reviewed in terms of potential applicability in Alaska by performing a hypothetical case study for the city of Fairbanks, Alaska. Results of this paper study indicate that in municipalities of Alaska with local engineering and road access, the use of NZW systems may provide an energy-efficient water service option. In particular, case study modeling suggests hot water energy savings are equivalent to five times the energy used for treatment, much greater savings than in mid-latitudes, due largely to the substantially higher energy needed for heating water from a conventional treatment system and lack of need for freeze-protected piping. Further study of the applicability of NZW technology in cold regions, with expanded evaluation in terms of system-wide lifecycle cost, is recommended.

Identifying the Built, Natural, and Social Factors of Successful and Failed Rural Alaskan Water Projects: Perspectives from State and Regional Professionals

“…Beyond technology needed for water infrastructure, an interviewed geophysicist speculated how improving transportation infrastructure to a condition similar to that in rural communities in Nordic countries would reduce the issues caused by geographic remoteness. In more remote areas of Alaska, the geographic remoteness lowers the reliability of a water supply due to location and heightened transportation costs . Although the investment needed for the described transportation infrastructure is unlikely due to financial restraints and habitat impacts, increased connectivity could assist in the transfer of resources between communities that has previously been found to help rural water systems in the United States during emergencies such as the COVID-19 pandemic …”

“…As one facilities manager described, scenarios where it is difficult to generate revenue often lead to situations where “the operator and the community give it their best to keep the system running, and the system [would] usually stay running until something catastrophic happens” due to the lack of proper maintenance. Shortcomings within built system factors, further impacted by social and natural system factors, have led to troubling issues influencing communities’ access to clean drinking water, as demonstrated by the American Society of Civil Engineers’ “D” rating for drinking water infrastructure in Alaska . Like successful drinking water projects, the interactions between the different system factors can contribute to apparent failure.…”

“…In more remote areas of Alaska, the geographic remoteness lowers the reliability of a water supply due to location and heightened transportation costs. 41 Although the investment needed for the described transportation infrastructure is unlikely due to financial restraints and habitat impacts, increased connectivity could assist in the transfer of resources between communities that has previously been found to help rural water systems in the United States during emergencies such as the COVID-19 pandemic. 42 The interviewees additionally recognized the financial need (i.e., social system factor) required for an improved built system.…”

“…Shortcomings within built system factors, further impacted by social and natural system factors, have led to troubling issues influencing communities' access to clean drinking water, as demonstrated by the American Society of Civil Engineers' "D" rating for drinking water infrastructure in Alaska. 41 Like successful drinking water projects, the interactions between the different system factors can contribute to apparent failure.…”

Wastewater Treatment in Remote Arctic Settlements

“…This scheme proved to be quite competitive. The cost of its implementation was $ 3 per 1 m 3 of water, which was only 13% higher than traditional schemes [15].…”