The City of Castlegar is making some changes at its sewer treatment facilities after a series of inspections found several issues at the South Sewage Treatment Plant (SSTP) and the North Lagoons.
Four regulatory inspections have been completed at the plants by federal and provincial authorities over the last year. An inspection on Oct. 14, 2021 at the SSTP was prompted by a complaint, but the rest were routine regular inspections.
“By no means has any of this been purposely or intentionally kept away from the public,” said Mayor Kirk Duff at the Sept. 6 committee meeting where the inspections were brought before council and the public. “It doesn’t mean mistakes aren’t made, but it’s not malicious. It’s accidental or unintentional and it’s fixable.”
The city has contracted Urban Systems consultants to assist in developing and implementing a plan for corrective actions at the plants.
Issues and corrections
Four issues were flagged at the first inspection at the SSTP. The city received a warning letter in June and was given 30 days to respond with an action plan.
• No effluent flow meter
Joanne Quarmby from Urban Systems explained to city council that when the SSTP was designed, effluent flow meters were not required. Since that time, standards have changed and the MOE is now requiring the meters.
An effluent flow meter that will work at the facility has been located and will be installed by the end of 2022.
• Two exceedences of authorized discharge allowances and failure to report
Quarmby said this item is something that is very common on ministry reports and was of “low concern.”
“Out of all the data from the time period (about 18 months) there was a total of 88 data points and there were three non-compliances. That is a very low threshold when looking at compliance history,” explained Quarmby.
She also said that there are several reasons samples could fail outside of failures at the plant including sample contamination and limitations with testing.
“It wasn’t necessarily a problem with your plant,” said Quarmby.
• Inadequate storage of biosolids
Chris Hallam, the city’s director of municipal services, said this is a problem the city was already aware of and has been working on a solution for some time.
The city has published a request for proposals for a biosolids reuse program that has a closing date of Sept. 22.
Hallam said he hopes to bring the winning proposal before council soon and the problem should be solved by the end of the year.
• No annual reports for the inspection period of Sept. 1, 2020 through May 31, 2022.
Hallam said staff turnover in the department was primarily to blame for the missing reports and that it was not a chronic or long-term problem.
The missing annual reports have now been filed.
Even though residents in the area of the SSTP have been complaining about odours from the plant for years, on the day the inspections took place, the plant was in compliance with regulations.
However, Hallam noted that the smells come and go and the inspection was just on one single day.
June 7 inspections
These inspections by Environment Canada listed four areas of concern at the SSTP. A corrective action plan was due by Aug. 1 with the work completed by Dec. 1.
• Sludge drying bed freeboard at SSTP
Freeboard refers to the difference between the height of the berm and the top of the water in the pool and the inspector thought the pool appeared too full.
The concerns will be addressed by installing visual gauges and checks of the gauges will become part of regular operating procedures.
• Inadequate storage of biosolids
This is already being addressed as previously stated.
• Inadequate site drainage and erosion at SSTP
Matthew Smith with Urban Systems says they will be finalizing a plan to address these issues by the end of September. Drainage improvements including things like cleaning out rock pits and catch basins will be utilized as well as grading.
• Foaming and spill over of south train at SSTP
The inspector was concerned that the spill over was near a catch basin that could potentially flow to the river.
Smith said the city has confirmed that the catch basin in question flows to a rock pit on site, not the river.
More samples of the foam are being collected as it appears periodically and Urban Systems researchers will be looking at it more closely under the microscope to determine what is actually causing it.
Two concerns at the North Lagoons were noted by the inspector.
• Lagoon freeboard
The city will maintain a 600 millimetre freeboard and ensure regular maintenance of control structures.
• Improper de-chlorination system
Smith explained that according to the city’s treatment plant permit, it is required to disinfect by chlorine at a residual level that is greater than the maximum level that is currently allowed by newer federal regulations.
“You are in a bit of a catch-22 there,” said Smith. “Nevertheless, you are required to chlorinate by the federal regulation.”
He said an ad-hoc system developed by operators is working, but could use some improvements. Engineers are working on ways to improve the system as well as exploring treatment by UV light as an alternative.
Smith also said the federal chlorine residual regulation level (.02 parts per million ) was difficult to achieve and measure, and that trying to install an online system at the facility was not really feasible.
Hallam said finding a reliable solution was a priority to ensure that at any moment of time the plant is always in compliance.
“It is an old system and not one that we would design and use today,” added Smith. “With some tweaks we should be able to make it more reliable.”
July 28 inspection
Hallam said the MOE inspection on July 28 did not identify any areas of immediate concern, but the city is still awaiting the inspector’s final report.
He thinks the corrective actions needed at the sites can be done within the city’s current budget.
The remedies are expected to see the city through for five to ten years.
However, the city will be working on a long-term liquid waste management plan over the next few years that will likely include some major changes.
Smith said Castlegar is now at a point where it will have to make a once-in-a-generation decision about its treatment plants.
Mayor Duff said dealing with the city’s aging sewage plants will be one of the most expensive things the city will face in the coming years.
The report and council conversation related to the inspections can be found on the the video from the Sept. 6 committee of the whole meeting at castlegar.ca.