City of Red Deer Wastewater Utility

Making it clear┬áThe City of Red DeerÔÇÖs Wastewater Treatment Plant is undergoing major upgrades to become a regional facility, wastewater superintendent Geoff Stewardson explains to Gary Toushek. The City of Red Deer, Alberta, about halfway between Calgary and Edmonton, has a population of 90,000 and counting and is located on the Red Deer River, which begins in the Rocky Mountains at Banff and flows into Saskatchewan.┬áAlberta Environment, the environmental agency of the provincial government, has mandated that communities on the river upstream from the City of Red Deer will no longer be allowed to treat and discharge their wastewater into the river. In concept, it will be carried from those communities via pipelines yet to be constructed, to Red DeerÔÇÖs Wastewater Treatment Plant, which would be expanded and upgraded to become a regional facility. The proposals of cost sharing, timelines and infrastructure requirements are currently in discussion between the City and governmental agencies and have yet to be determined.The project coincides with the CityÔÇÖs 25-year Master PlanÔÇöto 2031ÔÇöwhich forecasts a population of 300,000. Stantec Consulting Ltd. has been involved in completing the Master Plan and is currently implementing the on-schedule and on-budget Phase III of the upgrade program along with Graham Industrial Services. ÔÇ£This is a massive project for us,ÔÇØ says the CityÔÇÖs wastewater superintendent, Geoff Stewardson. ÔÇ£ThereÔÇÖs a timeline [up and running by 2013], a budget [likely exceeding $283 million] thatÔÇÖs still in the process of being funded, and a lot of coordination between City and Provincial departments.ÔÇØ He manages a staff of about 38 who perform the day-to-day operations of the Wastewater Utility, including the collection system and the treatment plant, as well as the storm water system (which is not part of the utility itself). In order to appreciate the upgrades, itÔÇÖs worth a look at the CityÔÇÖs current wastewater treatment system. Wastewater from residences, commercial and industrial buildings goes into a collection system of about 430 kilometers (267 miles) of pipelinesÔÇömostly gravity-fed, with one elevated liftÔÇöwhich is pumped into the ÔÇ£headworksÔÇØ area of the Wastewater Treatment Plant, to screen out larger materials. The next treatment stage at the plant is a process called primary clarification, a series of calm water pools. Materials like oil and grease float on the surface to be removed, while sand and gravel sink, and the remaining wastewater goes into a Biological Nutrient Removal (BNR) system, a huge aeration tank that provides oxygen for the bacteria to break down chemical components, especially ammonia. Promoting bacterial growth with the BNR process creates a lot of solids too, which also must in part be eliminated. ÔÇ£We intensify that mixture of solids in a fermenter, which produces volatile fatty acids that we pump back into the BNR section of the plant,ÔÇØ Stewardson says, ÔÇ£and the biological process removes phosphorus from the wastewater. Phosphorus is a nutrient used in the production of fertilizers, but we donÔÇÖt want to release it into the river, since it can spawn algae blooms, which use up oxygen meant for fish, and the fish die.ÔÇØ Solids removed through the process are run through a Dissolved Air Flotation (DAF) process, which allows compressed air to bubble through the wastewater. The bubbles attach to solid particles and ride them to the surface, where theyÔÇÖre skimmed off. At the end of the wastewater treatment process are secondary clarifiers, which allow for a final solids settling, then the clear, treated water is piped into the Red Deer River. ÔÇ£The purpose of the Wastewater Treatment Plant is to separate the solids from the water and treat both so that theyÔÇÖre safe going out. The solids are deposited into bio-solids lagoons and used as fertilizer for farmland.ÔÇØ Until now the treated wastewater has easily met Alberta EnvironmentÔÇÖs standards for discharging into the river. With new, tougher standards issued a year ago that include E. coli levels in wastewater effluent, the Phase III upgrade is in the process of installing ultraviolet (UV) disinfection technology to meet the stricter criteria. ÔÇ£We have an approval to operate from the provincial government, which sets out criteria and stipulations, based on current and future health and environmental factors,ÔÇØ Stewardson says. ÔÇ£Soon weÔÇÖll potentially be taking on the added wastewater from surrounding communities and when necessary scaling up our UV system with banks of ultraviolet lights. Then the effluent from the secondary clarifiers will be treated with a final step of ultraviolet light to deactivate most harmful microorganisms such as E. coli before being safely released into the river.ÔÇØ This Phase III upgrade is based on hydraulic capacity, because the plant is currently taking in more wastewater than it is designed to treat, so he doesnÔÇÖt want it flowing through the plant too quickly. HeÔÇÖs also adding a bioreactor to the BNR section, as well as another secondary clarifier.┬á┬áIdeally and in concept, the infrastructure for the regional pipelines, under the auspices of Alberta Infrastructure and Transportation, the south leg will come online first, in 2011, in the form of an 80-kilometer pipeline to bring wastewater south of Red Deer to the City. Funding is approved, and construction will begin soon. The west leg (63 km) and the north leg (19 km) are still unfunded. Alberta Environment expects the entire system to be operational in 2013. Upgrades to the Red Deer plant just to accept the capacity of the south leg will likely exceed $68 million.The challenges seem obvious. The facility first needs to be upgraded to properly handle its current daily influent flow average of 43 million liters, compared to its design flow of 32 million liters, which means it is now operating at 134 percent of its capacity. The new bioreactor will soon bring it to 97 percent. ÔÇ£ThereÔÇÖs also a peaking factor to consider,ÔÇØ Stewardson says, ÔÇ£that allows us to push the plant beyond its design capacity for a limited time during the day, since wastewater flows increase in the morning and evening and are lower at other times of day, so weÔÇÖre still meeting the provinceÔÇÖs approval criteria.ÔÇØ He hopes the slowdown in the economy in Alberta will get the City better pricing for upgrading the plant. In the Phase III upgrade, ÔÇ£the UV system, the bioreactor and the additional secondary clarifier will be an estimated $35 million, and when we put the project out for tender, we got only one bid.ÔÇØ Previously, wastewater was under the jurisdiction of Public Works, but today itÔÇÖs under the newly created Department of Environmental Services, a sign of the times. And since the City has a number of environmental projects on the books right now, Jeff Miller, the CityÔÇÖs environmental planning superintendent, will lead a team of engineers to manage those projects as well as upgrades to the Wastewater Treatment Plant. ÔÇ£WeÔÇÖre proceeding in stages. If you build a plant thatÔÇÖs larger than what you need, it doesnÔÇÖt work effectively,ÔÇØ says Stewardson. ÔÇô Editorial research by Michael Fretwell┬á