Englobe leading the way on the road to zero waste composting
Density separation among strategies used by Quebec composter in efforts to reach ultimate end goal in composting
Englobe Corporation, with headquarters in Quebec City, was established in Canada close to 60 years ago and is one of the country's largest firms specializing in soil remediation, composting and environmental engineering.
Englobe runs three static pile composting sites in Quebec. Lachute (near Montreal) and Bury (near Sherbrooke) have been in operation for approximately 20 years, while their Saint-Henri de Lévis site, on the south shore of Quebec City, celebrated 40 years in operation in 2019.
According to Benoit Lamarche, Eng., their overall goal is to deliver quality compost and commercial topsoil to customers.
"In French, we say eco produits [eco products], which we manufacture from the organic fraction of the waste we receive."
Englobe's main composting operations use large, static piles, all outdoors, turned with mechanical shovels or excavators and moved with front end loaders at screening and other delivery stages. They also have a great deal of experience with aerated static piles, soil treatment applications and bioremediation, as well as biosolids processing.
"We have one installation in Saint-Henri which is fitted with an aerated static pile, which we've run for a couple years," explains Lamarche. "But when we look at operating costs, from our perspective, it's more productive to run big static piles."
"We have our composting sites, and then we have our land application contracts for processed biosolids, which is a different business," explains Lamarche. "We have a team of about 10 dealing with land application. For biosolids and paper mill waste, or sludges, our team delivers quality product, basically a lime equivalent, for spreading on farmlands. It's another stream of our business which is very important."
Lamarche adds that they have also looked at anaerobic digestion in depth, but the business case for a private company has not yet proved to be the best way to go, based on the current stream of feedstock. The capital cost up front is one of the barriers. "The stars are not well aligned for anaerobic digestion for us," he says. "For public utilities and cities, maybe, but not for us."
A Long history in composting
Englobe's first composting site was established in Saint-Henri in 1979.
"It started as a pig farm and the original owner began composting pig manure together with paper mill sludge," says Lamarche. Since then, it has evolved greatly.
Lamarche says they now receive about 75,000 tons per year of mixed green waste, as well as food waste and some biosolids. The other two sites receive about 50,000 tons per year of mostly green waste and food waste, with some biosolids, but a lesser amount compared to the Saint-Henri site.
"We do screen and manufacture end products at all three locations," says Lamarche. "Our market is 100 percent bulk, so you won't find any of our products at Canadian Tire or Walmart. We do sell to businesses which have packaging lines, and we used to have one, but we quit that business about 10 years ago to focus on bulk only."
He says the agriculture industry is an emerging market for them.
"Farmers are not our traditional customers for compost," he explains. "Farmers don't want to pay for compost. What is the value for a farmer to bring in compost? From an N-P-K standpoint (nitrogen, phosphorous, potassium), compost brings very little contribution to plant needs. Value would be to add carbon (organic matter) to the soil. But until now, value based only on adding carbon to the soil is not enough to convince clients to pay for it. We need to work on demonstrating the benefits for farmers."
Lamarche says he has been working with Glenn Munroe and Susan Antler from the Compost Council of Canada in depth on end market development, and that farmers in general increasingly recognize that there is enough value in using compost on farmlands.
"We are involved with the Living Soils Symposium events and are trying to promote the use of compost, but we're still quite far from being able to deliver large amounts of compost to farmers for a return," says Lamarche. "Our end markets are currently more landscape contractors and cities, which will buy back our products for their landscaping needs."
When asked about the importance of their compost being certified, Lamarche says it is absolutely critical. In the province of Quebec compost is certified by either by BNQ (Bureau de Normalisation du Québec) or CQA (Compost Quality Alliance.)
"We have both of these certifications for our end products," says Lamarche. "It allows the buyer, the user of our compost to be able to receive it without having any kind of special permission from the Ministry of Environment.
"The main thing with being certified BNQ or CQA is to guarantee that we deliver quality products to our customers," he continues. "This is one area of our work that requires lots of energy.
"What society wants and needs is to divert organics from landfills. So we need to make our compost as per the protocol described in the compost quality certifications."
Learning from experience
Lamarche says he has travelled extensively to visit sites in the U.S., Europe and Canada, to see methods used by other composters, and they also have learned a lot at Compost Council of Canada events in recent years.
"Last year, the Compost Council event was in Guelph, Ontario," he says. "We went to visit several composting sites there, and confirmed that we are basically doing the same thing. We balance our carbon to nitrogen ratio (C/N). We aim for a C/N of 30, but end up usually just below that. We'd like our process to be under the 18-month target, but we probably take a bit longer than that in real life, when taking into account seasonal effects due to winter, but that's compost. It's like growing a plant; there's no way you can cut corners to make it grow faster, when you want quality, finished compost."
One of the single most important elements of creating quality compost, he adds, is to closely monitor oxygen levels in the piles. When they get below about five percent oxygen, they reopen the pile and let fresh air flow.
"Big piles tend to settle," he explains. And then you can get anaerobic zones (without oxygen) developed at the base of the pile, which is not what we want.
"We have learned to constantly turn the pile, using big machines, excavators, and we do it very quickly. Turning 10,000 cubic yards, which is just one pile on our site, is done in a couple of days."
One key initiative Englobe is working on is to become a full zero-waste company. Part of that effort is the implementation of density separation technology.
"We use density separation to deal with overs and rejects from our compost screening operations," explains Lamarche. The technology uses a set of dual air blowers which create an adjustable high-velocity air stream known as air knives. The process separates heavies (rocks), lights (wood) and ultra-light particles (plastic and film) and is coupled with an overband magnet separator for metals.
"When particles come into contact with the high-velocity air stream, light particles will tend to fly up, and more dense particles will drop into the accumulating zones underneath. We are thrilled to be moving toward zero waste, and our density separator is playing a big part in that," he says.Englobe's density separator was built in Quebec by Vibrotech, under license by General Kinematics, and is installed at their Saint-Henri site.
"They call it a Destoner," says Lamarche. "This is one area that we have put lots of focus on," he continues. "We don't run the whole compost pile through it, only the rejects. So our main screening operation is still done with trommels.
"Rejects tend to be considered as waste, but when you do a full characterization of the material, you realize you have valuable stones and aggregate, wood, plastic and tiny bits of metals. When you find a way to separate all this and still have very good quality compost from the static piles, this is ideal."
Englobe uses recovered stone for building sub-base infrastructure or for parking lots, etc., on their site. Any wood captured (in addition to purchased wood fibres) is used as carbon input for their compost. For plastic, they send it to co-generation or to cement kiln operators for fuel, and metals go to local scrap recyclers.
"We're still learning how to use density separation properly in the compost industry, because our material, at times, tends to be sticky with oversized bits," he says.
"After some trials and growing pains at the start, we reinstalled the equipment in a new configuration, and are quite thrilled by the results so far."It's important to know when to use this technology, because if it's frozen, or if it's too sticky due to moisture content or weather, then it may not work at all," continues Lamarche. "It pretty much behaves like a combine harvester. We seem to have found the right timing of the year to use it.
"We have put in tremendous effort, and have been subsidized in part by Recyc-Quebec from the Quebec government to implement our Density Separation technology," he says. "We are almost ready to present detailed results. We plan to disclose our findings to the composting community when we are able to have our next event with the Compost Council."
Key Heavy plant
With respect to other key equipment in use at Englobe's sites, Lamarche says they run a straightforward operation, technically. "We're using large-scale, 30-tonne excavators, and front-end loaders with 7- to 8-cubic-yard buckets.
"We don't have any preferred equipment suppliers," he says. "We mainly look at the kind of after-sale service we can obtain locally. We're quite far between our sites in Sherbrooke, Lachute and Quebec City. From Saint-Henri to Lachute, with a large truck, it's a four-and-a-half-hour drive."
For wood waste grinding, Lamarche says they hire contractors to come to their sites. They create large stockpiles, from a few hundred to a few thousand tons of wood. "When we have a pile big enough, we call in the contractor and he comes with his huge machine to do the grinding."
Besides wheel loaders and excavators, the main heavy plant on site at Englobe's operations are their mobile trommel screens.
"We have six in total," he says. "We prefer screens that are longer, and so far, we've really liked the 28-foot versions."He explains that basically, with as long as possible retention time in the trommel, and the optimal rotating speed, they can obtain the best screening efficiency (with minimum compost ending up as rejects). "Our guys tend to find their sweet spot at running these machines," he says.
"This is partly why when we run with front end loaders. They supply bucketloads of feedstock and then go back to get another bucket, leaving just enough time for the hopper to empty into the trommel, and then they can feed another bucket. Our guys have found a way to have a circulation path that is proportional to the speed of the trommel. It's been running like this for 40 years in Saint-Henri, and 20 in Bury. It's quite a mature process."
He adds that all their working trommels currently are supplied by Peterborough, Ontario-based McCloskey. "I am a fan of our McCloskey machines," he says. "We benchmark each of our screens almost every second year. We maintain good relationships with a number of vendors in the market. We're willing to pay for freight to get machines to us so we can test them and figure out if they are working better than what we have, and we assess the pros and cons of each machine."
Composting during COVID-19
In the current age of COVID-19, composting, along with other recycling and waste management activities, has quite quickly been deemed an essential service to society.
For Englobe, they continue to receive brown bins from all over the province. (Brown bins are used by residents in Quebec at the curbside to collect food waste and green waste.)
"We have had to implement very stringent operating procedures for making sure we abide by and respect our public health directors," says Lamarche. "We are most concerned by incoming biosolids. There seems to be some evidence that biosolids can be a vector for the coronavirus, so it could be present there.
"But at the same time, we are used to dealing with asbestos contamination in soil and so, for example, our loaders and excavators are fitted with state-of-the-art positive pressure filtration for operators in the cab. Health and safety of our people is top priority.
"If it does become unsafe, we would unfortunately need to shut down operations and find a way to resume in a safer manner. We're coping with the situation. The toughest thing so far has been a few of our guys, who were on spring break and had to spend time in isolation."
He adds, "Now, in the context of having our current government borrowing huge amounts of money to establish support plans for everyone who is losing their jobs, due to COVID-19, I'm concerned that if they choose to back anaerobic digestion as the main technology to treat organic feedstock, we'll end up having a major cash flow issue."
Composting to offset carbon
Lamarche is a firm believer that the composting industry and those businesses that use finished compost should become approved as a carbon offset activity and be recognized under a carbon credit program. He points out that one tonne of compost used once equals one tonne of CO2 captured per year for the next 20 years. This has been scientifically proven by top researchers, including Dr. Johnson at the University of New Mexico and the research team at Marin County California where they are currently carbon farming.
"With Quebec still being a member of the WCI (Western Climate Initiative), along with California, I don't see why a landfill-generated CH4 molecule (methane) can get renewable carbon credit and compost does not," states Lamarche.
"There's a stock market for carbon, and I'm puzzled by the fact that we call methane from landfill renewable, but not compost. But that's the way it is and this needs to change.
"It bothers me and motivates me to speak up and ask for things to change. As a society, we need to make sure that we support the composting industry in an efficient way."
He continues, "I want to become a voice in Quebec for this change. We should promote the fact that using compost on rangelands and farmlands can become a carbon farming activity [carbon sequestration] that is profitable, and that is good for the earth. It will allow crops to grow healthier and better.
"While farmers are not our typical end market, I believe they should be," he says. "It would build our end markets, put carbon from compost back into farmland and support growing more and better food in the future."
In the years to come, Lamarche says Englobe is looking at creating other sites to serve different municipalities in Quebec. "There's a roadmap in front of us to capture millions of tons of organics in the coming years," he says, adding that they are constantly contacted by municipalities who wish to initiate brown bin programs, collecting green waste and food waste at the curb.
"I think there will be, in a short period of time, a huge scaling up of our industry. We need to be prepared for that, we need to continue to deliver quality products, and we need to build confidence with the public about our products and operations.
He adds that it's actually easy to admit the wrong feedstock to a composting site at the wrong time of year, and then you can get into big trouble with foul odours.
"We've been there, unfortunately," he continues. "So we learn from our mistakes and we continue to focus on trying to build good relationships with our neighbours. We speak with them, we get them involved in a constant monitoring mode of our operations. If there's a slight smell coming their way, they will let us know. We'll adapt our hours of operation, things like that. It is part of our ‘social acceptability.'
"If the public sees that we are doing the right thing, that we are not managing the issues that cause odours or other problems in the community, then we will lower the ‘not in my backyard syndrome' for establishing new sites," concludes Lamarche.
"When a composting site is run well, with knowledge and the right technology, it's not difficult to do it the right way." RPN
This article was originally published in the April 2020 edition of Recycling Product News, Volume 28, Number 3.