Blue planet, green ideas | Compost on site rather than waiting for collection

Managing organic matter is a challenge for large establishments. Rather than finding a supplier to recycle them at an external site, the Hull hospital decided to compost them itself, on site. A simple, inexpensive and ecological solution.

Jean-Thomas Léveillé
The Press

(Gatineau) As soon as the meals are over, employees of the food service at the Hull hospital begin to “clear” the 300 trays that come back. Dishes on one side, garbage in the trash and, since last summer, table scraps and other organic matter in a bin.

When the tank is full, it is emptied into an “aerobic digester” installed in the same room.

Total distance traveled by organic matter before being “composted”: about two meters.

Organic materials from the adjacent kitchen, such as vegetable peelings, are also sent there.

“We opted for this new technology for convenience,” explains Éric Ndandji, executive advisor in sustainable development and performance in the technical services and logistics department of the Integrated Health and Social Services Center (CISSS) of the Outaouais. Other solutions would have required costly redevelopments of the building or would have imposed logistical constraints, he says.

With enzymes and oxygen – hence the term “aerobic” – the device transforms organic matter into a digestate resembling dry earth in 24 hours, which could be used as fertilizer (see box).

“It works continuously, it can be open continuously,” explains Éric Ndandji.

This system, widespread in Europe and the United States, but used for the first time in Canada, avoids slowing down the disposal operation, underlines Lucie-Anne Derome, head of the hospital’s food service.

“Before it took 45 minutes, now it’s another 45 minutes,” she says.

Reduce GHGs and injuries

Recovering organic materials, rather than sending them to landfill, will allow the hospital to avoid the annual emission of 167 tonnes of greenhouse gases (GHGs), according to Synergie Santé Environnement, which accompanied the CISSS in the Outaouais in its efforts.

This is the equivalent of the emissions of a car that would drive more than 800,000 km, calculated the organization (based on a consumption of 9 L/100 km).

By reducing the amount of organic matter it generates by 200 to 40 kg per day, the hospital has also reduced injuries to its maintenance employees.

“Have you thought about the tonnage we were throwing away? “says Yves Marinier, who appreciates the reduction in the weight of the waste that he and his colleagues transport.

But the most noticeable effect will have been the reduction in bad odors from garbage bags, he says, an observation that Éric Ndandji also makes.

Installed in the spring of 2021 and fully functional since the summer, the Hull hospital digester has therefore entered the daily lives of employees without too much difficulty.

The redistribution of tasks “required a little getting used to,” but the adaptation was quick, says Marie-Ève ​​Laroche, who has worked for two years in the food service. Throwing away food distressed her, but composting it comforts her now.

Diverting organic materials from landfill also reduces waste management costs – the savings are difficult to quantify for the Hull hospital, however, since organic materials represent only a small fraction of the total. of its waste, explains Éric Ndandji.

Model for large generators

The Hull hospital’s approach demonstrates a solution to the challenge of organic matter management for large generators, while the Quebec government’s organic matter recovery strategy provides that industries, businesses and institutions (ICI) will have to recover them by 2025.

The success is such that the CISSS de l’Outaouais has ordered a dozen additional digesters for its other establishments. It will implement the collection of materials where the installation of a device is not possible or not optimal.

“We wonder why we didn’t do it sooner,” exclaims Éric Ndandji, who believes that any establishment that generates more than 100 kg of organic matter per day would benefit from having such a system, citing the example of grocery stores.

Inspired by the Gatineau experience, six hospitals in the Montreal region will also install a digester soon, starting with the Maisonneuve-Rosemont hospital in April.

Pending Ministry of Environment approval

The digestate produced by the Hull Hospital digester must be recognized as “fertilizing organic matter” by the Quebec Ministry of the Environment and the Fight against Climate Change (MELCC) before it can be distributed. So the hospital must for the moment throw it away or send it to a composting center. It is only a matter of time before the authorization arrives, believes Éric Ndandji, senior advisor in sustainable development and performance in the technical services and logistics department of the CISSS de l’Outaouais, who would like to give this matter to the residents of Gatineau. A research project for its use in the agricultural sector is also underway. The MELCC affirms that “no data or information [lui] has been transmitted which would make it possible to decide on the recyclability of this type of output”, indicated to The Press its spokesperson, Caroline Cloutier.