The City of Fernie held an open house regarding their Liquid Waste Management Plan at the Aquatic Centre on May 1. The public was asked to complete a survey in response to a study commissioned to explore the various options related to Fernie’s most significant liquid waste management challenges, inflow and infiltration (I&I).
Inflow refers to water getting into the sewer system through above ground means, including runoff or through manholes after rain or snow melt. Infiltration refers to water that seeps into the system through cracked or leaky pipes, poor fitting joints or sump pumps that are connected to the system.
Currently, high I&I leaves the city at risk of not being able to adequately discharge all the effluent generated by the sewage treatment system or adequately control the effluent quality.
The options that resulted from this study include:
Option 1: Stop rainwater from entering the system by replacing the old a leaky pipes as soon as is practically possible (within five years). Estimated cost would be $16.5 million.
Option 2: Let rainwater continue to enter the system as it is now, while treating the effluent to a much higher quality to provide other discharge options. Estimated cost is $200,000 plus any costs required to upgrade the sewage treatment plant.
Option 3: Combine options one and two. This option recognizes that removing I&I at the source is preferable if done in a more cost effective manner. This solution would replace the old and leaky pipes over a longer period of time. Estimated $16.5 million over 20 to 30 years. At the same time, the effluent would be treated to a much higher quality to provide other discharge options in the short-term. Estimated $200,000 plus any costs required to upgrade the sewage treatment plant.
The City believes that option three is in the best interest of the community.
“Option three is the best way to go because it’s a combination of options one and two,” said Dave Cockwell, City of Fernie Director of Operational Services. “Option three is the best of both worlds so we don’t have a high price to deal with all at one time.”
The study also looked at other possibilities for managing the excess effluent during peak weather periods
Option 1: Release all effluent to the ground.
Option 2: Improve effluent quality to a level acceptable for effluent reuse.
Option 3: Improve effluent quality to a level acceptable for release to the Elk River.
Option three proved to be feasible. The study showed that if substance concentrations in the treated effluent are maintained at the provincial and government required levels, the City would be assured that releasing excess effluent would pose little to no risk to the environment or public health.
“We will still discharge to the ground whenever we can,” said Cockwell. “But there will be times that we have to discharge to the river.”
To ensure that the treated wastewater meets the high standards required for release to the Elk River, the City is required to improve its sewage treatment process. The City studied two options for improving treatment.
Option 1: Lagoon option – The City would continue to use the existing sewage treatment lagoons but upgrade them with specialized technology to provide phosphorus reduction and ultra violet (UV) light disinfection. The cost of the lagoon upgrades would be approximately $1.2 million.
Option 2: Mechanical option – The City would continue using one of the existing lagoons, but would need to also build four biological treatment tanks to remove substances and then provide ultraviolet light disinfection. The cost of the mechanical option would be approximately $8 million.
The City believes that the lagoon option is in the best interest of the community.
“We are going to build a lagoon system that will handle the flow that we have now, we will not let anymore storm water get in,” said Cockwell. “In fact we will start to reduce that storm water getting in by replacing pipes over the next 10 or 20 years.”