Piloting a new method of diverting organics from landfill

Summary

As part of its commitment to environmental issues, the province of Quebec has mandated new targets on diverting organic waste from landfills to reduce greenhouse gas emissions and make better use of waste. To meet this challenge and contribute toward solutions, a group of municipal partners together with Investissement Québec CRIQ and Gazon Savard Inc. and supported by GMF piloted an innovative mechanobiological treatment (MBT) system that separates and processes organics from garbage in a treatment facility. Participants learned a great deal about MBT and about trialing such technology and have helpful recommendations for other municipalities exploring similar options. 

Background

Organic materials such as food waste, garden waste, and paper make up about 60 percent of the 5.8 million tonnes of waste thrown out in Quebec every year. This presents several challenges to municipalities:

• They take up valuable landfill space;
• They emit greenhouse gases as they decompose; and
• They have potential value, for instances as sources of recycled material and compost.

A novel approach to waste separation

In many jurisdictions, the solution to reduce organic waste being sent to landfills is a three-way collection system, with a separate bin for each type of household waste (landfill, recyclable, and organic).

Recently, technology has been developed for organics and garbage to be separated after collection, through a process known as mechanobiological treatment (MBT). This kind of system makes waste separation simpler for households, as it allows them to divide their waste into only two streams, one for recycling and one for garbage and organics.

By 2016, this technology was ready for testing, and from 2017 to 2019 a group of municipal partners representing more than 80 Quebec municipalities agreed to join a pilot project. The partners involved were:

• Bellechasse Regional County Municipality (RCM), with a population of about 38,000
• L’Érable RCM, with a population of about 23,000
• L’Islet RCM, with a population of about 17,000
• The Régie intermunicipale de gestion intégrée des déchets Bécancour−Nicolet-Yamaska, which includes the Bécancour and Nicolet-Yamaska RCMs, with a total population of about 44,000
• The City of Saguenay, with a population of about 145,000

The challenge

Situated in rural parts of Quebec, these communities share a common challenge in waste collection: servicing a relatively small population over a large geographic area. In addition to its other benefits, the MBT approach can address such a challenge by reducing the transportation needs of a traditional three-way system. The pilot project sought to answer two questions:

1. How well would the MBT system work in a real-life scenario?
2. Is the system a functional and financially viable option for the municipal partners participating?

Approach

During the project, partners collected more than 150 truckloads of household waste (a total of 1,860 tonnes), which was separated using the MBT approach then processed over a six-week period into compost. For the sake of comparison, the pilot also collected some waste via a three-way system.

Results

The pilot found the following:

• Partners collected more than 150 trucks of household waste (a total of 1,860 tonnes), which was separated via MBT and then processed over a six-week period into compost.
• Compostable organics made up 49 percent of the waste collected, with some slight seasonal variation.
• The MBT system was able to divert 89 percent of these organics, of which 72 percent was composted.
• The compost produced by this kind of system is rated class B, which means it is considered “good compost,” with permitted levels of trace elements and foreign matter contamination. Potential uses include in forestry, road developments and revegetation of degraded sites.
• The estimated cost to process household waste via MBT was $98 per tonne, though this does not include any potential revenue from selling the compost or other components and could be highly variable depending on labour costs, choice of site and other factors.

The organics diversion rate of the pilot was higher than that achieved by three-way collection systems, which range from about 30 to 60 percent across Canadian municipalities. This would represent a significant reduction in the amount of organic waste being sent to landfills, which would in turn reduce greenhouse gas emissions produced by decomposition and transportation and extend a landfill’s useful life.

Despite the high diversion rates achieved through this new technology, for various reasons, none of the municipal participants has yet moved forward with an MBT system. However, they found that joining this pilot project was an important step in their decision-making process. Not only did it give them an opportunity to review various options for diverting organic waste, but it gave them a better understanding of the assets they have and the ways their individual situations affect how they can best meet this challenge.

Recommendations

While MBT was ultimately not the best fit for partners in this pilot project, it could be a good option for other municipalities looking for solutions to divert their organic waste. Here are some recommendations for municipalities interested in running their own pilots to consider.

1. Look at the infrastructure you have. Potential benefits of the MBT system as opposed to other options for diverting organic waste will vary depending on a municipality’s existing infrastructure, such as whether it already has a landfill site or a network of ecocentres. This should be taken into account when examining organics diversion systems. Pilot results were not necessarily applicable to the reality of waste processing in participating municipalities. It’s important to design such studies in such a way that local situations are taken into account throughout the process.
2. Plan to be flexible. It would be ideal to have a longer and more flexible schedule both in advance of and during the project.
3. Build strong partnerships. When working with numerous organizations, priorities and perspectives often differ, and it can be helpful to take the time to define these and build relationships at the beginning of a project. One option is to have an independent participant involved to ensure a neutral approach. Should a municipality be interested in moving forward with an MBT system, there could be cost savings by partnering with nearby municipalities on this new infrastructure.
4. Understand the market. In order to make informed decisions, municipalities will need detailed cost estimates, and they should be ready to perform the relevant studies, which could affect timelines. While the compost produced can be a source of revenue, that depends on the realities of the local marketplace; it’s worthwhile to research potential buyers as part of the research process.
5. Check all the boxes. There may be regulatory barriers to transporting and processing waste in new ways. It’s best to clear the project with relevant authorities before proceeding. In addition, as the quality and composition of household waste is unpredictable and can affect the MBT process, a preliminary waste study before beginning the project would be a good idea.