The Province of Nova Scotia, a world leader in recycling and composting, has a population of about one million. Its waste diversion strategy and results are well documented: there are now about 18 composting facilities across the province that have the capacity to handle 120,000 tonnes of material every year. All municipalities with an organic collection program chose to use an organic cart (bin) system. While they all used a detailed selection process to choose their collection system, none was as detailed as that of the City of Halifax.
In 1996, Halifax Regional Municipality (HRM) issued a request for proposals (RFP) for containers to collect source separated organics. The proposal didn’t mention any specific technology (bags or bins). They could be rigid or flexible (paper, plastic or metal). Four suppliers responded — three cart manufacturers, one plastic and one paper bag manufacturer. HRM then completed an economic analysis of plastic bags vs. plastic carts.
The economic analysis concluded that in six years the average household would spend the same on plastic or paper bags as they would on a residential cart. Additional features were also attractive. Using bags, they would have to separate over 100,000 bags per week from the organic material to send to the landfill. They were also concerned with organic material going anaerobic in the bags with a biweekly collection program. The only benefit of using a bag-based program, according to Halifax, was that it didn’t have any capital outlay for residential collection. With a cart program they had to borrow millions more.
Based on their analysis, the municipality chose the cart-based program. That program is now the same throughout the 75 per cent of the province that has full organic collection. Every household has been given a 64-gallon size cart and a household mini-bin. The SSI Schaefer cart and the Rehrig Pacific cart are the two of choice for the province. Both come with a multi-year warranty. In Halifax, it’s a ten-year warranty — long past the payback period on the use of bags.
Municipalities delivered these carts to most single-family dwelling, duplex, and apartment building up to six units (the number of units sometimes varied between municipalities). Costs per cart range from $75 to $90 per cart (including the kitchen mini-bin). Cost for collection averages $67 per household for all three streams (recyclables, organics and waste). This is 15 per cent to 30 per cent higher than those areas with only two-stream collection (recyclables and waste).
The same survey shows composting processing costs at $80 per tonne. Landfilling costs the same. It’s expected that as compost revenues increase, composting costs will drop. And, if the cost of perpetual care of landfills and the costs of the environmental footprint are added, the differences between landfilling and composting costs are even higher.
These are some issues associated with any cart-based organic program: contamination; odour, flies and maggots; biweekly collection; biodegradeable bags; and, contamination.
Participation rates now are usually 80 per cent and 90 per cent and can easily reach that level in a matter of months, but public education about how to control contamination is still required.
Lunenburg, Nova Scotia provides one of the best examples of what needed to be done. Once its program was up and running the municipality decided that education and awareness was no longer necessary. This led to a dramatic decrease in the quality of feedstock and a decrease in participation. Contamination levels at 50 per cent led to the inability to make good compost. Lunenburg promptly began a new education and enforcement program. They produced flyers, handouts, radio and newspaper advertisements. Rejecting contaminated carts for pickup was one of the most effective ways to get the message through to residents.
With regard to odour, flies and maggots, while biweekly collection keeps costs low, it results in some organic material sitting in a cart for two weeks. During hot and humid summer months this can result in obnoxious odours and can attract insects such as fruit flies and houseflies. But there are solutions. Residents are asked to keep organic containers in the household emptied frequently and to keep fish and meats covered. Some residents have reacted negatively to these problems by not participating, but fortunately they are relatively few.
To encourage participation, most municipalities have undertaken extensive education and awareness programs during summer months. In addition, a couple of smaller municipalities have implemented weekly collection. Halifax is conducting a pilot program on weekly collection this summer.
One of the hottest and most widely debated issues has been the acceptance of biodegradeable bags in the composting stream. Biodegradeable bags are acceptable in half of the municipal composting streams while other municipalities won’t allow them, even from the IC&I sector.
There are pros and cons to biodegradeable bags. From a municipal perspective the answer is clear: if using a bin-based system, why have a bag inside the bin? However, there are many arguments from the proponents of bags who suggest higher participation rates and better hygiene.
Probably the biggest issue that municipalities fear is that consumers will interchange biodegradeable bags with regular plastic bags. Given that the plastic bag industry has been slow to develop an effective recycling process, municipalities are reluctant to give credence to new bag manufacturers. Perhaps when compostable packaging materials are more commonplace and the plastics industry solves its other problems there may be more acceptance. The hope is that new technology will improve the cart based organic collection program and provide more benefits to its successful solid waste-resource program. (Also see “Halifax’s Organic Cart System” in the June/July 1999 edition.)
Barry Friesen, P. Eng., is the solid waste-resource manager for the Nova Scotia Department of the Environment. Barry would also like to acknowledge the help of: Bob Kenney, Mark Norton, Lunenburg and Halifax Regional Municipality E-mail Barry at email@example.com