Most of us flush and forget, but for District of Squamish employees who work at the Squamish Waste Water Treatment Plant, dealing with sewage is a full-time occupation. A lot of science knowledge goes into the treatment of human waste in Squamish.
In fact, to oversee the treatment facility takes almost as many years of education and training as to become a doctor, according to Scott MacIntyre, acting chief operator at the $20-million plant on Government Road.
Once the toilet is flushed, the sink is drained or the garburator silenced, the waste and water flows through an underground network of more than 105 kilometres of pipe.
Peak flow times are predictably when people are home and getting ready for the day or winding down – around 7:30 a.m. and again between 7 p.m. and 8:30 p.m., according to the district. This initial part of Squamish’s wastewater treatment is the purview of Dan Arnold, chief operator of waste water and collections for the district.
“Imagine every sewer line is an underground river,” Arnold said. The waste water moves downstream with gravity, like a river, he explained.
Household grease collecting in pipes creates a problem for district crews, Arnold said. “If you ever rinse off a plate that has grease on it, or anything like that, once it… gets into the line, it is going to stick to the edge of the pipe, wherever the water level is in that pipe, and eventually cause back-up if it doesn’t get cleaned,” he said. Crews have special equipment that is pushed through the pipes to clean out the deposits, Arnold said.
The District of Squamish processes 8 million litres of raw sewage per day, according to Bob Smith, director of operations. When the sewage first enters the Government Road plant, it goes through a screening facility where items that can’t be processed like baby wipes, paper towels, sanitary napkins, egg shells and other food waste are mechanically removed to be hauled to the landfill, Smith said. Cell phones and dentures have also been discovered in the screening process.
“The only thing that should go into the sewage system is human waste and toilet paper,” said Smith. “People think they are doing a good thing for the environment if they use a garburator, and what happens is we have to mechanically remove that… and then we haul it in a big truck to the landfill. So that should go into a compost.”
Once the sewage is screened, it is pumped to a bioreactor where microorganisms consume the biological waste. The microorganisms – or “bugs” as the operators like to call them – are in large outdoor tanks that are supplied with air to keep the bugs healthy. Once this process is complete, the remaining material and dead bugs are pumped to a Dissolved Air Flotation (DAF) in another building on site, which separates the remaining solids from the liquid. It’s like opening a pop bottle, according to MacIntyre. “All the bubbles pick up pieces of solids and bring it to the top, where the remaining solids are skimmed off,” he said.
These solids are then sent to a tank for storage prior to the final process. The last process is to pump the solids, technically called Thickened Waste Activated Sludge, to a centrifuge, where the sludge is spun to remove even more liquid. The remaining liquid goes back to the plant, and the solids are sent to a bin that Carney’s Waste Systems hauls daily to Whistler’s composting facility in the Callahan Valley.
The effluent, water from the Waste Water Treatment facility, enters the Squamish River about four kilometres south of the plant.
