February 15, 2004 | General

Exploring Options For Organics Collection

Rhonda Sherman
BioCycle February 2004, Vol. 45, No. 2, p. 46
More municipal solid waste managers are focusing on household organics such as food residuals, food-soiled paper and cardboard, in addition to yard trimmings – to accelerate diversion. A variety of collection strategies are being implemented that use either carts or bags, different sizes of carts, and various collection vehicles.
What collection scheme makes sense for a particular community? “The answer is not uniform,” replies Steven Sherman, president of Applied Compost Consulting, Inc. in Oakland, California. “It depends on what will work for a particular community and its attributes. A fundamental premise is that it is best to build upon a community’s existing infrastructure.” For example, if a local government already offers yard trimmings collection and wants to add food scraps to the program, the approaches to consider depend upon climate and the existing system for picking up yard debris. “In locations with year-round yard trimmings collection, food scraps should be commingled with yard debris in a cart
to protect against vectors,” he adds. “For regions of the country that have seasonal yard trimmings collection, it is not economical nor practical to switch from loose collection to containers that commingle food scraps with yard debris. In such instances, containerizing food scraps in small bins makes more sense.”
Increasing numbers of communities in the province of Ontario, Canada have been testing collection options for household organics. Some recycling coordinators decided to use containers instead of bags for their organics collection programs. In several cities, they have tested bag and container options and found higher participation rates when hard-wall containers were provided. Many new programs are testing different sizes of containers. The following is an overview of a few of these initiatives in Ontario.
The City of Toronto, with 500,000 households, currently has a curbside organics collection program for 180,000 homes in the Scarborough and Etobicoke neighborhoods. Approximately 1,540 tons of organics are collected weekly from 95 percent of the households, averaging 8.8 pounds/household/week. In addition to food residuals and food-soiled paper products, residents can include diapers, pet waste, and sanitary products. Yard trimmings are collected curbside in plastic bags. Source separated organics and recyclables are collected one week and organics and trash the following week.
Each household was provided with a Norseman Plastics 13-gallon cart (24 inches tall by 14 inches wide by 14 inches deep) for the organics, as well as a smaller 2-gallon (7.5 liter) container that can sit on a kitchen counter or be mounted inside a cupboard. “The size of the kitchen container was selected so that the average family will need to empty it two to three times per week,” says Herb Noseworthy, of Norseman Plastics. The cost for the two containers was $20 (Canadian). A survey of residents using this collection system found 90 percent of households setting out the container weekly.
The residential organics are processed in an anaerobic digester (see “Anaerobic Digestion Operations In Ontario,” December 2003) and yard trimmings at a windrow composting facility. The digester can separate plastic bags prior to digestion using a hydropulper. Using plastic bags as liners for the kitchen containers and curbside carts is viewed as a necessary compromise to encourage participation by residents. It is expected that the city will continue to roll out the cart program to other neighborhoods.
The Region of Niagara developed an Organic Diversion Strategy that is expected to increase residential waste diversion from 30 to 60 percent by 2005. The regional government decided to allow plastic bags in addition to hard-walled containers for organics collection. Residents are able to place all food scraps (including meat) and yard trimmings in see-through plastic bags at the curb for weekly collection along with recyclables. The plastic bags may be placed directly on the curb or inside a hard-walled container that meets the size and weight limits set by the region. A two-compartment truck collects organics in one side of the vehicle and recyclables on the other side. A separate truck picks up trash the same week. A full-scale program began in three municipalities in September 2003, and the majority of the remaining areas will begin in April 2004. “We started with smaller communities so we can trouble-shoot any problems that crop up before the rest go on-line,” says Janine Ralph, manager of waste policy and planning of the Regional Niagara Public Works Department, Waste Management Division.
The goal of the new strategy is to divert an additional 18,000 to 23,000 tons of organic material per year. The net cost increase from 2002 to 2005 for residential solid waste collection is estimated at $825,000 (Canadian) -$6/household – but will avoid $1.8 million in future disposal costs ($13/household).
The region undertook a nine-month pilot program ending in March 2001 to investigate methods for source separation, cocollection and processing organic materials. The cocollection pilot evaluated organics and recyclables versus organics and trash. In one residential area, 95-gallon (360-liter) SSI Schaefer carts were used for curbside collection, while residents in the second area could choose their own container type (primarily see-through plastic bags were used). According to Ralph, both areas had a similar increase in overall diversion of organics and yard trimmings. However, in the area where see-through plastic bags were used, food residuals diversion increased to 35 percent, while in the cart-based area it only reached 19 percent. “In the end, we decided on a flexible approach to curbside collection that allows residents to use film plastics and hard-walled containers of their choice that meet our weight and size limits,” explains Ralph. “We also decided to subsidize the cost of the 13-gallon food scrap bins, like Toronto uses, by paying the manufacturer $12 and selling them to residents for $6.”
The city of Hamilton, Ontario is taking major steps to achieve its 65 percent waste diversion goal by 2008. In 2001, the city switched leaf and yard trimmings curbside collection from plastic bags to Kraft paper bags. The amount of yard trimmings collected increased by 72 percent, to over 11,000 tons compared to roughly 6,600 tons (6,000 metric tons) in the previous year. The next year they saw another 50 percent increase, to a total of 15,400 tons (14,000 metric tons).
In October 2002, a food residuals collection pilot project got underway for 2,300 homes in five areas. When city staff were considering what containers residents should use, they thought about plastic bags because some neighboring communities were using them. But some city council members pointed out the success of switching from plastic to paper bags for yard trimmings, and thought it unwise to go back to using plastic. Ultimately, it was decided to go with a cart-based collection system with no plastic bags allowed. The Green Cart Demonstration Project accepts food residuals, paper, diapers, and leaf and yard trimmings in 37-gallon (140-liter carts). A smaller kitchen collection bin was also issued to each participant. A LaBrie Expert 2000 semi-automatic side-loader split vehicle is used to cocollect trash and in-home organics. Trash is in plastic bags that are manually tossed into the truck by the driver. The organics carts are tipped by an automated lifter. Set-outs by the 2,300 households are collected during five days of the week, 500 stops per day. Recyclables are collected separately each week. Leaf and yard trimmings are so abundant during the spring and fall that they are collected separately, every other week in Kraft bags.
Between October 2002 and October 2003, participation rates were above 70 percent in two study areas and between 51 and 58 percent in the other three. The average weight of organics set out was between 220 and 330 lbs. (100 to 150 kg) in four of the five study areas – yielding an average waste diversion rate of 50 percent, up from 32 percent before the program was initiated. “The 140-liter size cart seems to be a good size for weekly collection,” says Beth Goodger, manager of waste diversion for the city of Hamilton. “When deciding on the size cart to use, we looked at pricing options, and wanted something big enough for a large family yet not oversized for small properties in densely-populated areas.”
The city has discovered the importance of lining carts during different seasons – in the summer to reduce odors and in the winter to keep food residuals from sticking to the insides of the cart. The pilot project is being expanded to five other neighborhoods, beginning this April. It is expected that it will be rolled out city-wide in 2005-06. Key to expanding the program is having a composting facility large enough to process organic materials collected from the more than 180,000 households. Hamilton has issued a request for proposals to develop an enclosed composting facility, which is expected to be operating by early 2006.
Rhonda Sherman is a free-lance writer, consultant and university faculty member in Raleigh, North Carolina.

Sign up