Our Human Practices team talked to Nicole Robinson, a Education and Community Initiatives Specialist, and Bill MacMillan a Waste and Recycling Engineer. They are both from the Waste and Recycling services of the City of Lethbridge. Nicole mainly educated us on waste diversion, while Bill also gave informative and insightful feedback.
Discussions with Nicole Robinson
Nichole informed us that there are a variety of methods when it comes to how cities deal with their food waste. In our discussion with Nichole, she described two common methods, aerobic composting and anaerobic digestion. Aerobic digestion is used on a large scale in the City of Calgary, where organic along with inorganic material is broken down, sometimes to create a biofuel. On the other hand, the City of Toronto utilizes anaerobic digestion, where organic as well as some inorganic waste is broken down through a process lacking the presence of oxygen. What’s done with the remaining product of compost also varies by the method of mitigation. Nichole explained that “cities that use aerobic composting will usually give a portion of this back to residents for free, and sell the rest to agricultural or garden companies to be used as a soil additive.” In terms of what is done with the product of anaerobic digestion, the material is sold to companies who use it as a biogas.
Another waste diversion method is curbside organics programs(green cart). Green cart programs are getting more popular across Canada, however Lethbridge is trailing behind other cities and has yet to see the implementation of a curbside composting program. Food waste is more complicated than things like yard waste. Not only are there regulations on how to deal with organics, but the large industrial scale composting system required to deal with mass amounts of food waste poses a great expense. This is one of the many reasons why citizens would oppose a curbside composting program. Other reasons include, not wanting to manage a 3rd cart on their property, not wanting a compost processing facility to create odor and dust near their residence, and even simply not caring about waste diversion and sustainability. City council will ultimately determine if Environment Lethbridge moves forward with a curbside organics program, but it is expected that there will be a curbside composting program passed in 2021 for 2022-2023 implementation. Although we don’t have any current programs to deal with food waste we do have several programs focused on managing yard waste.
The City of Lethbridge has programs such as Yard Waste Deposits, Christmas Tree/ Fall Leaf Collection and a class 2 composting facility that helps to control and combat the amount of reusable materials thrown out daily and annually. During the seasonal months from April to November, the City has three sites open where residents can deposit their leaves, branches and grass clippings instead of letting them rot away in their yard. In the month of January, residents can leave their Christmas trees out for curbside pick up, reducing the amount of trees being wasted, by turning the trees into mulch (wood chips). The mulch is then offered year round, for free, to the residents at Peenaquim Park. Reduce, reuse, recycle. The same idea is used with the fall leaf collection where residents are given two curbside pickups of paper-bagged leaf and yard waste, the city takes care of itself in small ways like collecting leaves. All compost is utilized in some way whether that be the city selling it to nearby agricultural operations, to farmers as an additive to soil, being used in parks and reclamation projects, as well as holding community compost giveaway days. All programs that the city offers provide ways for increasing waste reduction and are steps leading to our class 2 composting facility located at the Waste and Recycling Centre. A class 2 composting facility will only accept manure and things like yard waste, brush, and wood waste. All of these amazing programs are leading to better waste management and efficiency in our community as well as the city, however when it comes to waste diversion more can always be done!
Discussions with Bill MacMillan
When communicating with Bill MacMillan, a Waste and Recycling engineer for the City of Lethbridge, he brought up some concern to the uncontrolled conditions in our composting system regarding the thermostability. He said "It could have a big impact if your project can be developed to control the compost environment so that it remains ideal for its intended purpose.” However, rather than controlling the compost environment we are going to work towards making our system more resilient to the varying temperatures present in a compost environment.
Taking his words into consideration, we understood that we needed to create a system that could withstand the high temperatures that compost can often reach. For this we are planning to use a protocol to design thermostable variants which can be tested with molecular dynamics.