by Kieran Hyatt and Hannah Nielsen, AP Environmental Science students
Over the past few weeks the AP Environmental Class had the opportunity to visit both a sewage treatment facility and landfill. Our first visit was to the sewage facility in Saanich where we learned how our waste is treated and filtered before it is released back in to our water ways. Our guide was very enthusiastic and extremely passionate about the facility and gave us a detailed tour as well as a detailed explanation on the process of treating our water waste.
When the waste first comes to the treatment plant it goes through a preliminary filter where waste water is passed through a 6 mm screen to remove bulk solids, these solids are then compacted and removed for disposal at the landfill. The remaining waste water then passes through to the aeration tanks where organic matter is digested by natural organisms and the primary effluent is treated and aerated. The final step to the treatment process is the secondary clarifier, this process allows for the finer solids to settle. These finer bio-solids are then sent to the Sludge Blending and holding tanks where they are eventually used as soil amendment. The water waste is now treated and the clear effluent is discharged through the outfall to the marine environment.
Our next visit was to the Hartland Landfill where we were also given a tour of the facility and a detailed look into how the plant is operated. We were very impressed with the waste reduction and management techniques at Hartland, but shocked at its 35 million dollar price tag. Before the waste gets put into the ground, the parts that can be reused or recycled are removed and sorted into a series of bins. Everything from waste wood to hazardous chemical wastes are diverted from the landfill and dealt with appropriately.
What waste actually goes into the landfill is compacted under the weight of a crushing vehicle, and then covered with a plastic sheet so as to minimize the water that is contaminated by percolating through the garbage. The water that hits the plastic runs off into the soil around the landfill while the water that comes out beneath the garbage (leachate) is collected in a special lagoon and treated before it goes into the sewer. The landfill gas (primarily methane) that comes off the garbage as it decomposes is collected from under the plastic covering and used to generate electricity that Maxim Power, an independent contractor, sells back to the BC hydro power grid.
The coolest part of the trip was by far the hawks that the landfill uses to keep seagulls away from the garbage. After seeing a Harris Hawk up close and personal, just about everyone wanted one.
On a more sober note, our guide said that the landfill has another 35 years of life in it, but that its lifespan could be greatly increased by the reduction of food waste, among other things. It was very interesting to see what happens to our garbage first hand. We are all very happy to live in a community that is conscientious of the detrimental effects its waste can have on the environment and acts accordingly to manage its waste.