Innovative technology makes compost
leachate come clean
It’s like magic.
That’s how Dr. Anthony Tong of Acadia University describes the result of his experiment to develop an innovative treatment method for compost leachate.
He can take wastewater that’s murky and process it using membrane bioreactor (MBR) technology to produce fluid that’s clear and clean. Like magic.
MBR is an emerging technique for wastewater and drinking water treatment. In this technique, a porous membrane is used to separate the influent and the effluent. Water molecules can permeate through the membrane, while suspended particles, microorganism and macro-organic molecules are retained in the bioreactor. Various aerobic and anaerobic bacteria thrive in the bioreactor and effectively break down all kinds of organic substances.
Dr. Tong says his job is simple: find a fast way to treat wastewater to help clean up the environment. And he has the assistance of two partners to reach that goal: E&Q Consulting and Associates Limited (E&Q), a chemical consulting and environmental chemists firm, and Northridge Farms Ltd. in Aylesford, an industrial composting facility.
Over the past number of years, E&Q has experienced significant challenge dealing with issues surrounding compost leachate. In Nova Scotia, there are 17 major composting facilities that process about 186,200 tons per year of food and yard waste from residential, commercial and industrial sources. Studies have shown that unchecked discharges of the leachate could contaminate surface and groundwater.
Wise company gets ahead of the curve
Northridge is sensitive to this issue and approached E&Q owner Jim Frazee (M.Sc., P.Chem., Marine Chemist) to do environmental water quality monitoring for them in 2000. Frazee says the Department of Environment requires quarterly reports and he collects samples, analyzes the data and writes reports on his findings.
“Right now,” he says, “Northridge is meeting all parameters that are set. However, in a few years there may be a problem, and the wise company gets ahead of the problem.”
Frazee says he talked to Northridge, he knew about Dr. Tong’s work and after consulting with both, put them together six months ago. Frazee and Dr. Tong clarified the project and Northridge asked them to formulate ideas to address any potential issue.
“We know we’ll get clean water,” Frazee says. “We wanted to design a system to handle maximum flow and were looking for a customer who had a need and was willing to explore new ideas.”
MBR technology is very new in Canada, but Frazee says it has an older history in Europe, although the systems there require much higher maintenance.
Dr. Tong’s MBR uses special porous strings as membrane filters, which are far more durable and will allow MBR systems to be more accessible and have broader applications.
“In reality,” Frazee says, “we’re using compost leachate as a starting point to expand this technology into other fields,” with applications relative to municipal systems, farming operations, pharmaceutical plants and lake water.
Dwight Horsnell is president and co-owner with his brother Robin of Northridge Farms Composting Ltd. He agreed to set up a reactor onsite because he’s very aware of the kind of environment he wants for his son, his daughter and his family.
“My family has been in the area for 200 years,” he says, “and if we can carry on in an environmentally conscious way, we can meet commitments now and in the future.”
He has no qualms either about working with people from academia. “We come from an agricultural background,” he says, “and we’ve worked with all those extensions. I hung onto grampy’s coattails growing up to learn, but over the years I’ve taken courses and worked with different people with academic backgrounds. I’m familiar with this kind of relationship.”
His company handles approximately 13-14,000 metric tons of waste annually and looks after Kings and Annapolis Counties, the Town of Windsor, the Municipality of Chester “and all the businesses in-between.”
Northridge is the only compost operation in Nova Scotia looking at this kind of technology and “if it works for us, I see it as a great benefit.”
Fully operational next summer
Dr. Tong expects to have a fully operational membrane bioreactor running at Northridge Farms by next summer. Its advantages over traditional engineered wetlands are:
- high quality effluent
- small footprint
- it runs the whole year (whereas wetlands freeze in winter and cannot be engaged until spring)
- has applications beyond compost leachate.
And once the system is established - which should take about two weeks – the clean-up after that is instantaneous. “Northridge Farms will be turning waste into product,” Dr. Tong says.
It’s a win-win in his estimation because if people don’t take steps to manage waste “it will pile up and this whole world will become a garbage can,” he says. “So we had better address the issue now than later.”
Text and photos provided by Fred Sgambati