The City of Fernie has received an extension to continue to discharge effluent into the Elk River. This is a regular practice during the spring months as the snow melts and the area receives rain. Effluent is sewage that is treated and ready for disposal.
“We have two processes for treatment depending on the disposal option that we choose. In both options the sewage is pre-screened, then pumped to the Sewage Treatment Lagoon Site where it is treated through a series of aeration cells that oxygenate the sewage and then allow for some settlement prior to discharge,” said Director of Operational Services for the City of Fernie Dave Cockwell,
Normally the City can manage the disposal of effluent. The typical daily average of flow is 4000m3/day and to put that in comparison, a minimum sized Olympic pool is 2,500m3.
“Under normal conditions 80 per cent of the year, the City disposes of effluent through our ground disposal system which are called Rapid Infiltration Basins. The water is absorbed into the ground and the process is complete,” said Cockwell.
The remaining 20 per cent of the time usually consists of more than double the regular volume called high inflow and infiltration periods. These irregular conditions can be caused by heavy rain and snow melting.
“Under high inflow and infiltration conditions where the City’s sewage flows can sometimes double, triple and even quadruple in volume, the ground disposal system is overwhelmed and we choose to dispose of the diluted form of sewage by sending it to the river,” said Cockwell.
According to Cockwell, the water can get into the cities disposal system a number of ways.
“Inflow and infiltration is essentially clear water that finds its way into the City’s Sanitary System. This water can get into the system through old pipes that allow ground water to enter, it can also find its way into the system through homes pumping water from their basements into the City’s sanitary system and other ways,” said Cockwell.
When the City discharges into the Elk River they further condition the effluence to minimize environmental impact.
“When we choose this option, we further treat the effluent from our aeration system by adding an alum product to the effluent which combines with phosphorus in the effluent and allows the phosphorus to settle out in another large basin,” said Cockwell. “The effluent from this basin is then directed to a UV disinfection facility to kill any fecal content and then onto the river completing the process.”
The temporary discharge period has been extended to Mar. 28.