The search for lower cost water in the far north

The search for lower cost water in the far north

By Ken Johnson, Stantec

Water point in Chefornak, Alaska

A search continues for technology with lower costs for water systems in the far north. One of the primary areas of this search is decentralized wastewater technology and water reuse technology. The use of decentralized wastewater treatment is not new, and in fact it has provided a low cost way of treating wastewater for rural homes houses in the south since the 1940's. Technical innovations of the past 20 years have facilitated an expanding use of decentralized water systems, and water reuse systems, and even advanced the use of this technology into the urban environment.

In the context of the Canadian far north, the climate, ground conditions, and community isolation create expensive problems for piped residential servicing. In the City of Yellowknife, development costs, including roads and drainage, are over $120,000 per lot. A study over 15 years ago suggested that a comparable development cost for a water reuse system could be less than $70,000 per lot.

In consideration that approximately 55 percent or 10,000 litres of the water used in a typical Yellowknife household each month goes to the toilet or the laundry, there is substantial opportunity to save money on water use by treating it, and recycling it for the same use.

The Yellowknife study compared the cost for a typical residential piped water and sewer system, and a water reuse system over a 20 year period. It concluded that water reuse could save approximately 40 percent in the overall cost, with the most significant part of this cost reduction associated with the elimination of pipes in the ground.

The typical unit processes of the water reuse system considered for Yellowknife included a septic tank for primary treatment, a bio-filter followed by a slow sand filter for secondary treatment, and ozonation for disinfection of the water before it is reused. The application of water reuse in

a house would incorporate changes to the plumbing system, the electrical system, and the building structure. The most important part of the system is the plumbing, which must ensure a separation of the drinking and non-drinking water supply systems.

Unfortunately, the Yellowknife initiative did not advance beyond the conceptual design phase.

In the State of Alaska, more than 4,700 rural Alaska homes lack running water and sewage systems. The palette of existing water and sanitation systems includes washeterias, and central water points, individual well and in ground systems, water and sewer truck or trailer haul systems, and piped water and sewer systems. All of these systems operate on a user pay principle with no operating subsidies, which is contrary to the considerable operating subsidies provided to water and sanitation systems in the Canadian north.

Decentralized systems are used in Alaska applying individual wells and septic systems, which make use of the favourable in-situ soil conditions. Trailer haul systems are also used, which are a scaled down version of northern Canadian truck haul system. These systems utilize 4 wheel all terrain vehicles (summer) and snowmobiles (winter) to pull specially designed trailer mounted water or sewage containers.

Conventional, community-wide piped systems in Alaska are increasingly expensive to construct, maintain and replace. The available capital funding cannot meet the demand for new systems and rehabilitation of aging systems, which has an estimated capital budget of close to a billion dollars (CDN$). As well, many communities cannot afford the high operation and maintenance costs associated with piped or haul systems.

These emerging realities prompted Alaska to embark on a significant program in 2013 to retain consortiums to develop and implement decentralized water and water reuse systems. This program has advanced under the name of the Alaska Water and Sewer Challenge.

The competition for the prospective companies was unusual because it did not employ the typical request for proposals, but rather an expression of interest, which includes funding for the research and ultimately the development of a technology to the tune of nearly $30 million (CDN$). Six companies, out of an initial 18 that applied in the initial phase, advanced to the competition's second phase, which ended with proposal presentations late 2015.

A phase three of the project is underway with the top three proposals from the second phase being funded for testing and product development. From these final three, a “winner� will be chosen, and the system is expected to advance to manufacturing in the next four to six years.

The program's ultimate goal is a secure, safe source of at least 55 litres of running water per person, per day, that will cost no more than $175 (CDN$) per month for a home to run and maintain. Wastewater management is an integral part of the Alaska system design, along with integration into existing housing units.

In Canada, there is a cautious optimism about the successful outcome of the Alaska water and sewer challenge. Certainly the successful technology may have applications in northern and remote regions of Canada. Time will tell.