Solid Waste & Recycling

Feature

BioReactor

Laflèche Environmental Inc. is a waste management company that serves Eastern Ontario. The company is investing in innovative technology to augment its landfill site -- that it calls the Laflèche Environmental BioReactor -- most...


Laflèche Environmental Inc. is a waste management company that serves Eastern Ontario. The company is investing in innovative technology to augment its landfill site — that it calls the Laflèche Environmental BioReactor — most recently a new compost facility.

In 2007 Laflèche constructed an onsite wastewater treatment facility for leachate. The next year, the company began to extract methane gas from the landfill, with a view toward supplying green power into the Ontario grid via a 3 MW electric power generator. (Phase Two of the generator could see the plant generate 10 MW of power annually.)

In May of this year, the company opened a 40,000 tonnes per year (tpy) onsite compost facility, for which construction started in the summer of 2008. The compost facility consists of six channels in an enclosed building. (See opposite page.)

The BioReactor and related facilities is the vision of André Laflèche who undertook a number of environmental impact studies with then-partner BFI in selecting the current Moose Creek site and fulfilling the requirements of Ontario’s Environmental Assessment Act. This included an extensive public consultation and identification of the adjascent community as a “willing host.” The company was incorporated in 1997 and has been open to the public since 2001.

The site has the advantage of natural containment properties from clay. When waste arrives at Laflèche Environmental, it’s laid inside of an impermeable, natural clay bowl that’s lined with high-tech fabric and drainage stone. Leachate is separated into two streams; one that’s re-circulated into the waste bed (to enhance bioreaction) and another that’s pumped for treatment.

Rotating Biological Contactors (RBC) form the anaerobic system used in the wastewater treatment facility. RBC treatment consists of circular plastic discs mounted on a horizontal shaft. The rotating discs, which are partially submerged in wastewater, are covered with naturally cultivated microorganisms that metabolize the biochemical oxygen demand (BOD) into carbon dioxide. Approximately 70 per cent of the organic carbon converts to carbon dioxide, with the remainder becoming sludge.

Re-circulating the leachate encourages anaerobic reaction within the waste, accelerating waste decomposition by as much as 15 to 20 years. Waste can break down nearly three times as quickly in the BioReactor as in a traditional landfill (where decomposition takes an average of 50 years).

Benefits

Once a cell, or section, of the BioReactor is filled with waste, it’s covered with a soil cap and methane gas is captured and used to generate electricity. Over its lifetime, the company believes the BioReactor will produce enough methane to power at least 1,000 homes for more than 50 years. Heat and carbon dioxide, the two byproducts of methane production, will be used to warm onsite greenhouses and to provide an enriched carbon dioxide atmosphere (to enhance plant growth). Plans for the greenhouses include a polyculture project that would produce fish and vegetables. The company is also considering the viability of an algae farm to produce bio-diesel.

Once the anaerobic cycle is complete, it may also be possible to recover soil and recyclables. This will empty out the cells, leaving them available to take in fresh waste. Managed in this way, the landfill could continue the cycle of putting waste to work for many decades — perhaps 100 years.

Additionally, Laflèche has conducted research with two universities and received approval to used tire shreds to replace stones in the drainage layer. The Certificate of Approval allows the company to process 3.5 million tires per year (more than a quarter of all scrap tires generated annually in the province, making Laflèche the largest tire processing facility in Ontario). This project allows the facility to avoid using approximately 15,000 tpy of stone.

In addition to the BioReactor landfill, wastewater treatment and tire processing operations, Laflèche recycles hydrocarbon-impacted soil, recycles electronic waste and (most recently) composts organic materials.

Laflèche Leblanc Soil Recycling Inc. (LLSR) specializes in the biological treatment of petroleum hydrocarbon impacted soils. Through a biological treatment process, hydrocarbon contaminants are eliminated and 150,000 tonnes of clean, nutrient-rich soil is generated for reuse on agricultural, residential and industrial properties.

Laflèche Environmental is currently financing studies and working with four separate Canadian universities. The most important partnership to date is the one with the University of Ottawa. With this partnership, the students have an opportunity to experiment in real life conditions to implement their research. The major projects include algae analysis and strategy for bio-fuel, feedstock analysis and bulking agents for compost, and bioremediation of contaminated soils. Research on the BioReactor includes leachate characteristics modeling and analysis, optimized leachate recirculation, and methane oxidation in landfill cover.

The company contributes $1 per tonne of waste accepted at its site to the Township of North Stormont, to be spent at the town’s discretion. The Laflèche Environmental Trust Fund, with a planned $1.5 million, will be a key contributor to the acquisition for conservation of wetlands, such as the Alfred Bog, a high-quality bog ecosystem in southern Ontario.

Guy Crittenden is editor of this magazine. Contact Guy at gcrittenden@solidwastemag.com

The Compost Facility

Lafleche Environmental held the opening ceremony for its new compost facility on May 22, 2009. The facility is able to receive a range of different non-hazardous organic materials such as food scraps, food processing waste, biosolids, paper/cardboard, leaf-and-yard waste, and other organic materials.

The compost process uses an aerated and agitated channel arrangement contained within a primary enclosure for environmental control of moisture, air and odor. All handling areas, including channels with primary containment, are further contained within a secondary structure for protection against the elements (wind, rain, snow), containment of materials and supplementary control of air and odors.

The compost facility is constructed on a 52,000 square ft reinforced poured concrete slab and enclosed completely by a Mega Dome fabric shelter building. This structure is segregated into three sections: receiving and channel loading area; composting channels; and output area. Air is maintained throughout the facility under negative pressure and directed to an exterior biofilter system.

The process uses an agitated tunnel with forced aeration. After materials arrive at the facility and are unloaded on the tipping floor, a visual inspection is conducted. The different organic materials are then mixed in an industrial grade mixer in order to achieve a homogeneous blend with a proper Carbon to Nitrogen ratio and moisture content. The mixed materials are conveyed to the active composting area. After spending between 21 and 28 days in the composting process, the material is cured prior to use as finished compost.


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