By Adrian Nieoczym - Kelowna Capital News - March 30, 2008
When we flush our toilets, most of us don’t think about what happens to the material that swirls away. Out of sight, out of mind. But it doesn’t just disappear. It travels to Kelowna’s Wastewater Facility on Raymer Avenue where it is dealt with by foreman Brian McAuley and his team. Capital News photographer Sean Connor and reporter Adrian Nieoczym take you on a tour.When things go down the drain in Kelowna, Brian McAuley has to deal with it.“What you flush down the toilet is my problem,” said the foreman of Kelowna’s Wastewater Treatment Facility. More than 480 kilometres of underground pipes carry raw sewage to the plant on Raymer Avenue. Four critical marine pumps get the raw sewage circulating through the facility. Should all of them stop running at the same time, the sewage would begin backing up. It wouldn’t take long for it to start seeping into the basements of Kelowna’s homes.A couple of months ago, pump number two got plugged up. When a maintenance crew looked inside they found a plastic encased wire coil discharge hose from an RV or motor home. “Somebody lost it, and it made it’s way all the way down here and wrapped itself around the impeller and then, apart from the fact there’s wear and tear on the pump, we had to lift it out and pull off that wire that was wrapped around the impeller,” said McAuley, who speaks with a Scottish accent and has a quick wit.“Just a simple thing like that can cause a big problem…just the old oops.”
The odds of sewage backing into basements is actually quite slim. Having four pumps provides a large measure of redundancy. And in case the power goes out, the plant has a Caterpillar diesel generator as a backup, capable of generating 1.5 megawatts of power. “It can run anywhere from…some engineers say 300 homes, some say 400, so maybe they’re looking at houses in downtown Kelowna as opposed to the Mission,” said McAuley. And should it fail to kick in within seven seconds, there’s another small generator which keeps two of the pumps running while a maintenance crew gets to work fixing the problem. “We’re eliminating the chance of flooding out basements with sewage,” said McAuley. The first step in treating raw sewage is to run it through mechanical bar screens and to catch large inorganic waste, which if it went through could damage the equipment. It’s here that McAuley and his crew have to deal with the tons of materials that shouldn’t get flushed but which people send down the drain anyway. Syringes, condoms, kids toys, Q-tips, tampons and their applicators are just a few of the objects that cause problems on a daily basis. Syringes, used by diabetics to take insulin, sometimes get stuck in a pump. A worker then has to put on a wire mesh glove and stick their hand inside to get it out. Tampons and especially plastic applicators, just don’t belong in the toilet. “Industry should be the ones that are changing. Go to cardboard (applicators) and you’re not causing these problems. But they’re still using these plastic (ones),” said McAuley.
But the biggest problem are small toys that somehow get flushed. “See these free McDonald’s toys? You get a lot of those floating through.” Next to the bar screens are grease skimmers. Businesses like restaurants are required by city bylaws to have grease traps so their cooking grease doesn’t get into the sewer. But the same is not true for homes. “Grease is a big problem and we’re always telling people don’t flush grease down the toilet,” said McAuley. “We skim off the grease and it goes into this massive pit and once or twice a month, a vacuum truck comes, he sucks the grease and it goes to a special disposal. And it’s not cheap, either.” Cooking grease, from things like bacon or ground beef, should be poured off into a container and put in the regular garbage. It should not go down the drain. After it’s had large inorganic matter and grease screened out, the sewage goes into the primary clarifiers. Their blue plastic covers can be seen from the field of nearby Kelowna Secondary School. Large organic solids, which mostly come out of our bodies, sink to the bottom of the tanks. Scrappers deposit them into hoppers.
It’s this area of the plant which generates the most complaints about smell from neighbours. “But all things considered, we don’t really get a lot of complaints,” said McAuley. As part of a planned $60 million upgrade, bio-filters will soon be installed to scrub odours out of the air. When the upgrade is complete, the facility will be able to handle 60 million litres a day, up from the current capacity of 40 million litres. A the moment, the facility deals with an average of about 32 million litres every day. Where the waste water actually gets treated is in the bioreactor. “It’s called an advanced biological treatment process, because there’s no chemicals added,” said McAuley. “We do have chemicals as a backup, but there’s no chemicals normally used.” Microscopic bacteria live in the reactor. They feed on the organic material in the wastewater as well as on air pumped into the tanks. Phosphorous becomes trapped in the bacterial cells and sinks to the bottom of the tank while nitrogen gas is harmlessly released into the air. The water then goes into secondary clarifiers, to remove more solids before being put through a series of sand and coal filters to remove fine particles. The final step before the water is pumped back into Okanagan Lake, is to disinfect it by exposing it to UV lights. The lights are submerged in tanks inside a special building. “There’s numerous safety aspects to this building,” said McAuley. If water in the tanks falls below the light level, they shut off. “Less than a minute exposed to your eyes could damage your eyes and within minutes it could damage your skin.” Meanwhile, three truckloads of solids a day are transported to a facility in Winfield, where they are mixed with wood waste and turned into Ogogrow, which the city sells as compost for $3.77 a bag. Turns out there’s green sprouting from Kelowna’s brown crap.
