Norway House Cree Nation
New Lagoon Project

Frequently Asked Questions (FAQs)

It is proposed to construct a new aerated lagoon to replace the present overloaded facultative lagoon. It is proposed to be located about 300 m (1,000 ft) east of the High Voltage Hydro line; about 300 m South of the winter road and about 1.12 km (3,600 ft) from the Highway. Some questions and concerns have been raised regarding this proposal. The following provide explanations and responses to address these concerns.

The existing lagoon is a “facultative lagoon”. It is overloaded thus does not treat sewage to current regulatory limits. An overloaded lagoon can cause high odours. The lagoon effluent discharge location is to a nearby creek which leads into the River. The existing lagoon discharge is at a location which is not preferred.

An “aerated” lagoon that continuously discharges treated, filtered and disinfected effluent to the Lake is proposed to service the community.

Facultative Lagoon: A series of stabilization ponds that are operated at generally less than 1.5 m liquid depth receive and treat waste water by allowing sewage to be naturally treated by a combination of exposure to air, sunlight, bacteria and algae. Objectionable odours can occur when the rate of oxygen transfer from the lagoon surface is less than the rate of oxygen consumption in the lower levels of the lagoon. If the waste water loading does not exceed the natural oxygen transfer rate an aerobic top layer is maintained which mitigates odour production. Biological activity within a facultative lagoon varies directly with temperature. Sewage loadings during during cold weather and ice cover will limit oxygen transfer and cause oxygen requirements to exceed waste loading rates, causing the surface to become anaerobic (without oxygen). Hydrogen sulphide, which has a rotten egg odour, is formed in wastewaters that become aerobic.

Aerated Lagoon: A holding pond usually consisting of 3 cells with a liquid operating depth of 3.5 m that receives and treats wastewater by the addition of oxygen (air) by artificial aeration which promotes the growth of aerobic bacteria which consume the waste material. A positive oxygen content is maintained at all times and during all seasons which prevent anaerobic bacteria from developing. By maintaining aeration odours are mitigated during all seasons as only aerobic bacteria are present in the waste water. Discharge occurs on a continuous basis. The wastewater is treated to a much higher quality than a facultative lagoon as the result of additional treatment
processes incorporated such as aeration, chemical addition, filtration and UV disinfection.

Q: Will all Environment and DFO (Department of Fisheries and Oceans) approvals be obtained prior to construction?

A: Yes DFO and CEAA approvals will be obtained. To obtain Federal approvals including DFO (Department of Fisheries and Oceans), applications must be given to the departments when the design of the project is 66% complete. We have not yet reached the 66% design stage.

Q: How can initial construction be started, such as clearing?

A: A site that meets all government guidelines and regulations has been identified. Studies and soils testing were done to confirm that this site would be far enough away from the nearest residents (setback distance). Clearing works will be done prior to any fish spawning in the nearby creek and no work is being done in the Creek.

Clearing is being done on First Nation land, so only local approval is required.

Q: What regard was given to the school, nearby residents and Veteran’s land?

A: Regulations and guidelines for an aerated lagoon were reviewed when considering this project. Special attention was given to setbacks requirements (minimum distances from residents and Veteran’s land). The closest point of the aerated lagoon liquid surface to the veteran’s land (Certificate of Possession) is about 725 m; to the school is about 1,300 m; to the closest resident is about 850 m. Those distances far exceed any regulatory requirement for a facultative lagoon; an aerated lagoon does not have a suggested or recommended setback distance.

Q: Will the new lagoon have an undesirable odour like the present lagoon?

A: The present lagoon is a “conventional facultative lagoon” that is sized for approximately 3,200 people based on Provincial criteria. Thus the existing lagoon is overloaded by about 60%.

The new lagoon will not give off a foul odour like the current lagoon as it will be maintained in an aerobic state. The new lagoon will have blowers and diffusers in the lagoon that will infuse air (oxygen) into the waste water in all three cells. The oxygen transfer from the air will promote the growth of bacteria under aerobic conditions that feed off the wastewater. This is called aerobic wastewater treatment. Anaerobic bacteria are less efficient in consuming organic load in wastewater than aerobic bacteria.

The existing lagoon was upgraded with surface type aeration to increase the oxygen transfer from the air however this aeration method is difficult to maintain and does not provide sufficient oxygen transfer to the wastewater. Anaerobic bacteria are present at times in the wastewater. This bacteria creates hydrogen sulphide gas, as a by product of its sewage digestion process.

Q: What are the long term affects of additional growth and more loading over time and what happens if the lagoon become overloaded like the present one?

A: The proposed lagoon will handle waste production for 20 years. The future population is determined and the lagoon is made large enough to treat the waste from this anticipated population. The growth rate used is typical for all INAC funded projects in Canada.

After the design life of 20 years has been reached, the lagoon would be assessed to see if upgrading is necessary. Upgrading can be done with larger blowers, more diffusers, more filters or more UV capacity.

The existing lagoon has already reached its maximum design life and cannot be upgraded because of its location, soil type in the area and the shallow depth that is used. To be upgraded to match the proposed loading of the aerated lagoon the existing lagoon would require more than a 3 times expansion in land area.

Q: Will future growth infringe on the setback area?

A: Regulations and guidelines do not state that an aerated lagoon requires any setback distance from the lagoon to residents. However, the design of the new lagoon incorporates a setback distance, even though it is not required. An extensive Planning Study is in the process of being completed which will identify potential development areas and their location in relation to the proposed lagoon.

The proposed lagoon will have a 450 m setback from the nearest resident, which can easily be maintained for future generations. There will be no future building activity in the vicinity because of the high voltage Hydro line and deep peat beds that do not facilitate building construction. A hospital is being proposed in the community. The setback distance from the lagoon to the hospital will be about 800 m.

The proposed lagoon will not affect development that may occur on Veterans’ land or the establishment of new subdivisions now or in the future.

Q: Will the discharge of the treated effluent by pipe into the lake add nutrients and cause lake water vegetation to grow?

A: The design process discussed below will ensure the discharge of treated effluent to the lake will not promote lake vegetation growth. To address phosphorous a chemical treatment process has been incorporated into the design to mitigate the discharge of high phosphorous effluent into the Lake. The sewage will be filtered to reduce suspended solids and will be disinfected by UV. Phosphorous is typically seen as a contaminant that can cause lake water vegetation. A facultative (present) lagoon does not address phosphorous removal thus an aerated lagoon provides enhanced treatment in comparison.

The exact location of the pipe outfall has not been determined yet as 66% design has not been completed.

Q: What happens if mechanical components break down and budgets are not available to maintain the operation?

A: Unfortunately, to treat sewage and remove phosphorous mechanical components are required. There are no feasible alternatives to treat sewage that do not use a treatment process of some kind. It is fair to say that the water treatment plant process has more components to maintain than the proposed aerated lagoon. NHCN has competent trained personnel to operate the water plant to provide potable water to the community on a daily basis; the same will have to occur for the aerated lagoon.

The present lagoon recently had surface aerators added to increase the oxygen transfer into the wastewater; most of these aerators presently are not operating. These aerators were chosen by the designer at the time to deal with the shallow depth and sludge in the lagoon bottom. Surface aerators frequently fail as they have moving parts and are exposed to all types of weather. The aeration process in an aerated lagoon is completely different in that blowers that are placed in a heated building and submerged diffusers in the cells are used. The two types of aeration processes cannot be compared in respect to maintenance and serviceability.

March 9, 2010
Prepared by J. R. Cousin Consultants Ltd.