Another perspective on Dawson’s wastewater treatment option

Another perspective on Dawson's wastewater treatment option I'd like to take the opportunity to address some of the errors in the April 24th article concerning a proposed technology for Dawson City's wastewater treatment facility. It is not my intentio

I’d like to take the opportunity to address some of the errors in the April 24th article concerning a proposed technology for Dawson City’s wastewater treatment facility.

It is not my intention to advocate for any particular wastewater treatment process or technology, but it is my responsibility to ensure your readers are not left with the mistaken impression that the citizens of Dawson will be presented with an unsuitable or inappropriate solution to their wastewater needs.

Given the high cost of wastewater treatment, a detailed technical analysis of each bid package received for this project was undertaken by a team of experts in engineering, financial analysis and wastewater treatment.

Team members, individually and collectively, evaluated the merits of each submission. As a result of this evaluation process, only one bidder qualified for the next step of the review process where the bid price was revealed.

The article correctly notes the wastewater treatment technology proposed by the lead proponent is provided by Noram.

Unfortunately, the article then inaccurately reported on technology and financial issues. I would like to identify, and hopefully clarify, these inaccuracies.

Contrary to comments provided by the Yukon News, there are numerous “deep shaft” wastewater treatment systems in operation in Canada and other countries. One of the attractive features of this technology is that it has been tested and utilized in cold regions and also in municipalities with larger and smaller populations than Dawson City.

Quotes in the article attributed to Virden, Manitoba’s manager of works and utilities on some technical measures of wastewater purity appear to be in error, or are at least using some unknown unit of measure.

One quote reads: “the total fecal coliform count should be around 30 É Virden’s is at 9,000 É”. In this area, the public should be informed the current regulatory limits are 20,000 MPN/100 millilitres (MPN refers to “most probable number”). In addition, the quote, “total suspended solids is even worse É the average is 40 to 60, we’re at 110,000,” is difficult to interpret.

Dawson City’s current outgoing effluent, which receives only preliminary screening treatment, averages about 20 mg/L of total suspended solids (TSS), and peaks at about 36 mg/L in the summer. It is difficult to conceive of a system that would increase TSS. Any facility constructed in Dawson will meet the new TSS requirements established by the Canadian Council of the Ministers of the Environment, which is 25 mg/L.

The article quotes Homer, Alaska officials who state: “It works very well” and “It meets our fecal and total suspended solids (standards) easily.” The deep shaft wastewater treatment system in Homer was quoted as costing the municipality $524,000 last year.

This figure should not be assumed to be comparable to what Dawson’s facility will cost, as there are important differences between the two locations, including population sizes, the distribution systems that are part of the wastewater infrastructure and how water and wastewater treatment costs are combined.

The project team includes staff from Dawson City and the Yukon government and has kept an open mind in assessing potential mechanical and lagoon solutions for Dawson. Our objective is to ensure a sustainable and appropriate solution for Dawson is put in place as expediently as possible and we’re confident both Yukon and Dawson taxpayers will be satisfied with the outcome.

We have not yet signed a contract with any proponent for the construction of a wastewater treatment facility and will provide further information concerning project progress at additional public meetings in Dawson in May.

Updated information can always be found on the project website: www.dawsonwastewater.ca.

Catherine Harwood, engineer and project manager

Whitehorse