Incineration is a political hot potato in Canada to the extent that in some provinces (such as Ontario) it’s currently hard to imagine a new facility being approved. Yet an operation on the West Coast demonstrates that waste-to-energy is an effective means of waste disposal that can co-exist with successful recycling programs. In progressive British Columbia, it appears not to even be controversial. We invited senior staff from the facility to describe it to readers. — ed.
The Greater Vancouver Regional District’s (GVRD) energy-from-waste (EFW) facility is an integral part of a solid waste management system which provides disposal services to 21 municipalities and one electoral area in the Greater Vancouver area. This represents a total serviced population of approximately two million people who generate 2.5 million tonnes of municipal solid waste per year. With a recycling efficiency of 50 per cent, the net disposal rate is 1.25 million tonnes per year.
The solid waste management system is comprised of seven transfer stations, two landfills, and one EFW facility. A single regional tip fee of $65 per tonne applies at all facilities in the GVRD system. This fee includes the provision of 3R services, debt retirement, and operation of all facilities. There has been no rate increase since 1991.
Since it commenced operation in 1988, the EFW facility has disposed of 250,000 tonnes annually — about 20 per cent of the total municipal waste disposed in the Greater Vancouver area. The facility is designed to attain a minimum 85 per cent availability and has exceeded this expectation with an average availability of 94 per cent.
The facility has three identical mass burn processing lines; each incinerates 10 tonnes of waste per hour and produces over three tonnes of steam for every tonne of refuse. This produces the equivalent of 175,000 MWh of energy each year. It also has state-of-the-art pollution control technology and has enjoyed many “first” successes in its industry. For example: it was the first in North America to implement a treatment system for mercury reduction; first in Canada to install an aqua-ammonia injection system for NOx reduction; first in Canada to be certified by the International Standards Organization for Environmental Management Systems (ISO 14001); and, it’s is the first of its kind in this country to sell both steam and electricity from the combustion of municipal solid waste.
Operations & pollution control
Municipal solid waste is gravity fed onto a grate and burned for a minimum of 30 minutes reaching temperatures of more than 1,000 Celsius. No additional fuel is required to burn garbage during normal operations. The facility is a “zero liquid discharge” operation which means that all the water is reused and no liquid (other than from the washroom facilities) goes to the domestic sewer.
The unburned residue (bottom ash) amounts to about 17 per cent of the incoming waste (or 42,000 tonnes per year). Magnets remove over 8,000 tonnes of ferrous metal annually for sale to a recycling company. Bottom ash is used as a road base material and landfill cover at a local landfill (i.e., to displace the use of other materials).
Fly ash, the airborne particulate captured in the air pollution control plant, is treated and disposed of as regular municipal solid waste at landfill at a rate of 9,000 tonnes per year.
Specific air emission limits for the plant are set and regulated by the B.C.’s Ministry of Water, Land and Air Protection. Parameters such as acid gases, particulate matter, metals and organic compounds are measured continuously or through manual stack tests by an independent tester. All actual emission levels are well within the set limits.
In addition to the monitoring of stack emissions at this facility, the GVRD monitors the ambient air environment at 30 sites throughout the Lower Mainland. Of these, three were specifically chosen as key locations to measure the impact of emissions from the EFW facility. To date, no environmental impact has been recorded.
The process produces steam during the waste combustion process. The heat generated by burning the garbage is recovered by converting water in boilers to steam. An early environmental and revenue-generating strategy was to sell this steam to a nearby paper recycling mill. This mill historically utilized up to 66 per cent of the steam. This replaced steam that that the mill would otherwise have had to generate burning fuel.
Poor paper markets and an aging paper mill resulted in the closure of two of the three paper machines by July 2000. This resulted in a reduction of the steam utilized (to 40 per cent of the steam produced by the EFW facility).
The right conditions were created for the next phase of eco-innovation: the installation of a turbo generator to create electricity from the steam. This presented an opportunity to achieve three goals: create up to 25 MW of electricity with little to no additional impact on the environment; revenue to minimize the cost of waste disposal in the Greater Vancouver area; and, reduce emissions to the airshed by displacing energy that may have otherwise been created through the burning of fossil fuels.
In fact, even though the greenhouse gases are inherently created with any disposal method, greenhouse gas offsets from the energy recovery at the facility are greater than the greenhouse gas emissions from it, so there is a net positive impact on the airshed in that respect.
In 2003, the Association of Professional Engineers and Geoscientists of B.C. presented its first annual Sustainability Award to the GVRD, in part for the installation of the turbogenerator. In addition, in 2004 the facility has won a Power Smart Excellence Award for Energy Efficiency from B.C. Hydro, the Federation of Canadian Municipalities Sustainable Community Award (in the energy category) and the American Society of Mechanical Engineers Best Large Waste-to-Energy Facility Award.
Management is currently exploring opportunities for further eco-efficiency strategies at the plant in support of the GVRD’s vision of sustainability in the region. One possibility is to use residual energy from the process to heat a nearby industrial development. Other potential future projects include recovering CO2 from the stack emissions for industrial use and enhancing the heat recovery already incurring in the plant.
Chantal Babensee, P.Eng., is a senior project engineer with the Greater Vancouver Regional District in Burnaby, British Columbia. Contact Chantal at firstname.lastname@example.org