Solid Waste & Recycling

Feature

An Investment in Technology

Plans to introduce a region-wide kitchen organics program, the desire to improve collection efficiencies, and mounting pressures to continue increasing its waste diversion rate provided the impetus fo...


Plans to introduce a region-wide kitchen organics program, the desire to improve collection efficiencies, and mounting pressures to continue increasing its waste diversion rate provided the impetus for the construction of an integrated waste management facility and the switch to single-stream recycling in the Region of Peel, Ontario.

Peel anticipates positive returns on its investment in this innovative facility. With the ability to process various waste streams with advanced technology, the region can implement new and enhanced collection programs to increase its diversion rate. In addition to increased collection efficiencies plus lower collection and processing costs, Peel will attain higher revenues from marketed materials and, ultimately, lower disposal costs.

Located on a 41-acre region-owned site in Brampton, Peel’s Integrated Waste Management Facility (IWMF) includes a single-stream Material Recovery Facility (MRF), a waste transfer station and an organics composting plant.

“The development of Peel’s Integrated Waste Management Facility represents a major step forward in our Long Term Waste Resource Management Strategy,” says Mitch Zamojc, the region’s public works commissioner. “It provides recycling and organic processing, as well as waste transfer capacity to accommodate Peel’s future waste management needs.”

Waste Management of Canada (WM) designed and built Peel’s IWMF at a cost of $35 million (excluding the composting system). MacViro Consultants Inc. conducted the initial integrated facility planning study to define its needs, prepared the RFP including design-build specifications, conducted evaluations and is providing contract administration on behalf of the Region. The 16,000m2 building houses an 8,000m2 MRF, a 3,800m2 waste transfer station and a 3,300m2 organics composting plant. With maintenance areas and office accommodations taking up the remaining space, the region boasts the largest facility of its kind in Canada.

“This new site will allow us to continue providing Peel residents with efficient and cost effective waste management services,” says Andrew Pollock, the region’s director of waste management. “Bringing complimentary processing and transfer facilities under one roof provides a significant savings for taxpayers.”

The recently commissioned MRF and transfer station are now fully operational. WM is also contracted to operate and maintain the MRF, as well as market all fibre material for a five-year period. Maple Reinders Constructors Ltd. is currently completing construction of the $8.3 million dollar organics composting system and commissioning of the system is expected to be completed later this spring. Regional staff are responsible for the operation of the waste transfer station and the organics composting plant, after commissioning.

Material Recovery Facility

The MRF has a capacity to process 35 tonnes of recyclables per hour, which equates to roughly 130,000 tonnes per year. Up to four collection vehicles can dump loads in the receiving area, which is designed to accommodate approximately 1,000 to 1,200 tonnes of material (two days storage).

The processing system moves recyclable material onto two inclined feed conveyors to a pre-sort area. At this point sorters return bagged material to an automatic bag breaker, remove plastic film to a film baler, sort polystyrene to a storage bunker and remove and separate residual waste into two compactors. Spare pre-sort stations are designated for program growth.

The remaining material is then conveyed to corrugated cardboard screens where corrugated cardboard is removed to a walking floor storage bunker. Smaller material passing through the corrugated cardboard screens is conveyed to parallel newspaper screens. Newspaper is conveyed to a double deck fibre sorting station.

Material passing through the newspaper screens is conveyed to a single, state-of-the-art “V” screen which then separates any remaining fibres (that were not removed by the newspaper screens) from the container stream. Much of the plant’s mixed broken glass is captured below the newspaper screens and conveyed directly to a bunker.

Containers are conveyed from the “V” screen to a combined trommel/magnetic separator (Trom-mag). The trommel “unders” are directed to a glass sortation conveyor. The trommel “overs” fall off of the end, where a magnet captures the ferrous material. The remaining “overs” are directed to an air classifier, where the light fraction is removed and sent to the container sort line. The heavy fraction is directed to the glass sorting line, where clear and coloured glass are separated. Any remaining glass is conveyed to a mixed glass bunker.

The container sort station includes HDPE, PET, mixed plastics (tubs and lids), gable top and aseptic container sorts. A dual eddy current captures aluminum at the end of the container sort line. All container grades are stored in dedicated sloped-bottom cages.

The MRF is equipped with two balers, one for fibre baling and another for container baling. The walking floor silos direct the fibre material to the fibre baler feed conveyor. Containers are removed by gravity from their storage cages onto the container feed conveyor. The system is designed to allow fibres or containers to be conveyed to either baler if necessary.

Modular processing equipment throughout the MRF allows for technical modifications.

Peel Region currently collects approximately 100,000 tonnes of recyclable material each year. The region plans to process additional recyclable material from nearby municipal and private sources to maximize the capacity of the facility, decrease per tonne processing costs and increase market revenues. As the population grows, the excess capacity will be used for its rising tonnages.

To coincide with the opening of the MRF, Peel will launch its single-stream recycling program to more than 355,000 households across the region. By making recycling easier, the region hopes to boost resident participation and material capture rates.

Waste Transfer station

The new transfer station is licensed to transfer up to 299 tonnes of waste per day. Garbage on the tipping floor is loaded into long-haul transfer trailers using two front-end loaders. The transfer station is equipped with one dedicated rear compactor transfer bay and one top-loading transfer bay. A third transfer bay is capable of both top-loading and rear-compaction loading of the transfer trailers.

Organics composting plant

The organics composting system, expected to be completed later this spring, will have the capacity to process 60,000 tonnes of organic material annually. Equipped with six 30-metre long aerated static tunnels, this facility will initially process yard waste collected from Brampton and Mississauga. Once the region-wide kitchen organics program is launched in spring 2007, all collected kitchen organic material will be delivered to this site for processing. In the interim, other municipal sources of organic waste will be solicited to maximize the processing capacity. (See the article on Hamilton’s similar new organics plant, page 16.)

Annette Geldbert is public affairs associate for the Waste Management Division at the Region of Peel, Ontario. Contact Annette at annette.geldbert@peelregion.ca

Hamilton’s New Compost Plant

The City of Hamilton is currently constructing a state-of-the-art in-vessel aerobic composting facility that will process 60,000 metric tonnes (with a peak capacity of 90,000 metric tonnes) of organic waste per year collected from households via the new city-wide Green Cart Program, starting this spring. This program is being implemented as part of the city’s goal to divert 65 per cent of waste from landfill by 2008. Once facility construction is complete, source separated organic (SSO) waste and leaf and yard waste will be processed into a nutrient-rich

stable compost material that can be sent to markets. The construction of the facility is part of an envisioned integrated waste management system capable of handling residential wastes in an economically, environmentally, and socially-responsible way.

The technology employed was developed by the Christiaens Group in the Kingdom of the Netherlands and is currently being used in approximately 30 facilities in Europe, South Africa, Australia and Canada for composting of agricultural wastes, sewage sludge, and municipal organic wastes. (See article on Peel Region, page 14.) Hamilton’s central composting facility is being constructed under a design, build, operate contract with Maple Reinders Constructors Limited of Mississauga, Ontario.

The facility utilizes 16 closed aerated concrete tunnels to process organic waste into compost. This technology utilizes a three-phase composting approach designed to efficiently process organic material. As the organic waste enters the site, it’s unloaded on the receiving floor prior to being shredded and conveyed to a selected phase-one compost tunnel. The tunnels are filled using an automated filling cassette which travels the length of the tunnel (to ensure an even distribution of materials). The cassette can also fill the tunnel to capacity on subsequent days without compacting or disturbing any of the previously placed material (i.e., without creating anaerobic pockets or zones). Once the tunnel is filled, the in-vessel climate control program creates an optimal aerobic environment for the composting process. It controls temperature, moisture and oxygen levels.

After seven to ten days, the material undergoes a 20 per cent volume reduction and is moved from the phase-one tunnels to the phase-two tunnels (via a front-end loader) for a second round of composting. The purpose of the second composting period is to ensure that any pockets of material that were too dense to allow aerobic decomposition are broken apart and are fully composted. Phase-two composting takes an additional seven to ten days and volume is reduced a further 15 per cent. Pathogens are destroyed.

Once the process is complete, a loader removes the compost from the phase-two tunnels to a segregated screening area that ensures there’s no cross-contamination between the finished compost and raw materials. At this stage the compost material is screened to remove contamination and particle sizes greater than 10 mm. After screening, the finished compost is conveyed to the third and final phase: curing. Curing takes place in a dedicated enclosed building where it’s stored for a final maturation period of 20 to 30 days.

The facility houses a sophisticated centralized computer controlled air handling system to control oxygen levels in the tunnels as well as odor management for the facility. All exhausted process air from the tunnels (and internal air located within the tipping/receiving area) is directed to the onsite scrubber before proceeding to a large bio-filter. Within the scrubber, odorous air is cooled and humidified using potable water which is then collected and recycled back into the compost tunnels. This maintains ideal moisture levels in the composting process. The humidified exhaust air then flows to the bio-filter where active bio-media cleans the it (by breaking down the odorous compounds). Temperature, moisture and oxygen levels are monitored within the odor control system to ensure optimal performance at all times. Additionally, the entire facility has been designed with internal negative air pressure to combat fugitive odor emissions.


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