The City of Regina has historically received hauled wastewater at a temporary receiving station in the corner of a lagoon at its wastewater treatment plant. Over time, the city encountered many limitations with this approach, including difficulty removing solids from the lagoon, risk of inadequate treatment prior to discharge, lack of source control, lack of hauler tracking, and no automated billing capabilities. With plans to upgrade its wastewater treatment plant, the city saw the need to develop a new hauled wastewater receiving station to protect the new treatment plant. The facility would also accept and process heavy grit loads generated by sewer cleaning activities.
In 2014, the city engaged Associated Engineering to complete the preliminary and detailed design and provide construction services for the new facility. Project Manager, Cory Wihlidal tells us, “As part of the preliminary design, we toured eight septage receiving stations in Alberta and British Columbia with city staff. Some of the takeaways from the tours included a preference for manhole-style dump stations, automated receipt and tracking systems, and automated sampling systems.”
Characterization of the incoming material presented a challenge to designers, due to limited data. Wastewater Treatment Specialist, Mike Whalley advises, “We characterized the quantity and quality of waste based on a combination of laboratory analysis of incoming material, truck counts, and interviews of septage haulers at the previous receiving station. This helped us establish design criteria and treatment processes.”
The new facility features separate entry and exit gates for domestic septage with low (less than 3% by weight) solids content (Stream A) and materials with high (greater than 3% by weight) solids content (Stream B). Three dumping stations were constructed for Stream A and one for Stream B.
Each dumping station for Stream A includes a billing kiosk and receiving manhole. Haulers are required to enter information into the kiosk before dumping. A glycol hydronic system provides heat to a concrete pad at the Stream A receiving stations. Stream A material flows to the process building via buried heat-traced, 200 mm diameter stainless steel conveyance pipes. Conductivity probes, pH sensors and acoustic sensors are fitted to each conveyance pipe. Magnetic flowmeters measure the volume of material dumped. Refrigerated automatic samplers extract random samples, and identify abnormal conductivity, pH or sound readings. Stream A materials are processed through combined 6 mm screens and grit removal units.
Stream B materials are deposited in a receiving tank accessed through an overhead door. Processing includes 10 mm screening and grit removal.
Waste liquid from processing is stored in equalization tanks and then pumped into the city’s wastewater forcemain to the wastewater treatment plant. The equalization tanks are aerated and mixed.
Cory says, “The facility has to provide sufficient treatment to meet criteria for incoming wastes into the new wastewater treatment plant.” EPCOR Water Prairies Inc. operates the Hauled Wastewater Receiving Station, and will operate the new wastewater treatment plant.”
Screenings from Streams A and B are conveyed to a trailer for regular disposal to landfill. Grit is discharged to a disposal bay outside of the building. Cleaned grit has potential for reuse.
The site has strict requirements for odour and noise control. Ionizer modules on the building’s make-up air units treat odour inside the facility. Exhaust fans blow air through activated carbon scrubbers located outside the building to meet odour discharge criteria.
Commissioned in January 2018, Regina’s new modern Hauled Wastewater Receiving Station includes automated entry and exit gates for haulers, activated by card readers, to meet the city’s goals for hauler tracking. The facility also meets requirements for full cost recovery, source control, treatment, and protection of the new wastewater treatment plant.
Key project staff include Cory Wihlidal, Mike Whalley, Stan Torgunrud, Richard Zepick, Chris Reese, David Shymko, Geoff Sarazin, and Micheal Claassen.