WATER

Report on a visit to the Killaloe Sewage Treatment Plant

Date of visit: Thursday, September 1, 2005

Visitors: Kevin O’Connor, Hubert Weber, Wendy Milne, John Gulland

Hosts: Senior Operator Kevin Chapeskie (756-2008); Operator/Mechanic Ugene Bloskie; Process Technologist Vanessa Newman (from the Petawawa Office), all employees of the Ontario Clean Water Agency

Report prepared by John Gulland, September 2, 2005

Summary of Findings: We were given a thorough tour of the plant, and had a chance to see the raw sewage as it arrives and right through to the water that is released into Brennan’s Creek. The raw sewage, which is over 99% water, was not pleasant to look at and had a characteristic smell. The treatment process involves aeration by bubbling air through the raw sewage to increase biological activity, then a chemical is added that crystallizes phosphorous so it can settle out; the settling chamber is next, where the sludge is separated from the water, and the final stage is where chlorine is added to the water before it is released. It takes roughly 24 hours for the water to make its way through the plant. At the end of process, the treated water was perfectly clear and had a very slight smell of chlorine. After we left the plant, the members of the delegation commented on the quality of the plant and the professionalism of its staff.

More Details: The Killaloe plant treats between about 5,000 and 20,000 cubic metres (m3) of raw sewage per month. The maximum daily flow is over 1,000 m3, but the average is less than 400 m3. There are three key indicators of the condition of raw sewage and the quality of treated water, as follows:

Suspended Solids (SS), which, as the name implies, are solid particles suspended in the water.

Phosphorous, which is a chemical often found in detergents (phosphates) and fertilizers, and which acts as a plant nutrient in bodies of water and can promote algae growth.

Biochemical Oxygen Demand (BOD), which is a technical term that I don’t pretend to understand entirely, but was explained to us as a ratio of bacteria and the organic material for the bacteria to feed on, and the oxygen available in the water to support the degradation of organic materials. This process of bio-chemical degradation is critical to the function of the plant. In fact, the staff refer to these two as “bugs” and “food”. They talk of the amount and condition of the bacteria as the extent to which the bugs are happy: “If the bugs are happy, with enough but not too much to eat, then we’re happy.” The bacteria are not introduced artificially, but are, not to get too specific, the same bugs we have in our guts for digestion, and they are the workhorses of the treatment plant.

The table below summarizes the concentrations of these three indicators in raw sewage, in the treated water, and the criteria set by the Ministry of Environment for municipal sewage plants. Figures are from the Killaloe plant for the seven months starting January 2005. All figures in milligrams per litre.

The residual sludge, in liquid form, is stored until after spring runoff and is then spread on local farm fields, one of which is directly behind the plant. The staff told us that a day or two after the sludge is spread, it is no longer detectable by look or smell.

Enforcement of Ministry Criteria: Twice each month, samples of treated water are sent to an independent accredited laboratory for testing. If a sample tests beyond the set criteria limits, the Ministry and the Municipality is notified. The point here is that a failure to comply with criteria is not a private matter between the lab and the facility in question, but is automatically a regulatory matter. In addition, the Ministry conducts an annual audit of the plant, inspecting documentation, operations and taking supplementary samples for testing.

Conclusions: To further summarize the above figures, on an average day Brennan’s Creek, and therefore Golden Lake into which it flows, receives from the Killaloe sewage treatment plant 1.74 kilograms of suspended solids, 0.06 kilograms of phosphorous and 2.37 kilograms of BOD. I don’t really know what that means in terms of effects on water quality and wildlife, but it is clear that it is well under the criteria set by the Ministry of Environment. We could follow up this study by interviewing one or more biologists to get their views on expected impacts from this effluent. At this stage we cannot draw conclusions regarding the extent to which the Killaloe plant affects water quality in Golden Lake. I think that those of us who visited the plant would agree that, from what we learned on September 1, the effluent probably does not constitute a serious threat to water quality in Golden Lake.