Materials Collection Comes Of Age

Marc J. Rogoff and John F. WIlliams

In the early days of recycling programs, before significant government involvement, residents and businesses had to locate buyers for their recyclables, transport the materials to a buyback center or rely on collections by volunteer groups.

Today, to encourage greater recycling participation rates, counties and municipalities across the county are providing curbside materials collection. Most programs reportedly achieve a 40 to 60 percent participation, on average.

During collection, materials are source separated, picked up and hauled to a processing facility or end market. The collection fleet and the processing facility design determine the amount of source separation needed.

Residents can use three-bin containers, single bins or plastic bags to sort their recyclable materials. Each curbside collection system has advantages and disadvantages (see "Curbside Recycling" chart).

Both multi-family and commercial units require different collection approaches than most residential homes. A densely populated high-rise unit, for example, requires a different collection method than an apartment complex or a two-story condominium.

Generally, property managers are required to provide storage space for recyclable materials. In New York City's multi-family collection program, each building receives a 2-cubic-yard, front-loading container that is emptied every week.

Due to communication barriers and high turnover rates in apartment complexes, many cities have been reluctant to expand multi-family recycling collection programs.

Source separation, with specialized collection trucks, usually provides high-quality material - but it is a labor-intensive method. Participation tends to be lower than other approaches because it takes more effort and space to separate the materials. This concern increases with the number of materials recycled.

Separate yard waste collection poses unique problems depending on the existing collection equipment, the composition of materials deposited at curbside and the frequency of curbside collection pickups.

In northern climates, yard wastes are raked into the street in the fall and collected with mechanical-claw or vacuum leaf-collector trucks. With loose yard waste collection, extraneous materials in the waste make contamination, safety, aesthetics and stormwater major concerns. Specialized equipment such as street sweepers may even be needed.

In other communities, standard plastic garbage cans or wheeled 60- or 90-gallon containers are used to collect yard waste. This system minimizes blowing leaves and grass, works under any weather conditions and keeps contaminants out. Containers eliminate the cost of manually debagging the waste, but start-up costs can be high if the community purchases the containers and modifies its existing collection fleet with "flippers" to lift them.

Most communities ask residents to use standard, plastic garbage bags or biodegradable kraft paper bags to minimize capital costs. These are easy to purchase and let collection crews examine the contents for contaminants, but they interfere with composting or mulching equipment.

Communities often have to decide whether to reduce collection efficiency and debag during curbside pickups, or to install bag-separation equipment or have additional employees at the composting facility to manually remove the bags before the waste enters the tub grinder. Removing the plastic bags is essential if the compost products are going to an end market.

Biodegradable bags may save debagging time, but some communities have complained that they do not break down as expected.

With curb sorting, residents place all recyclables into a single bin at the curb. The collector sorts the recyclables into separate compartments in the collection truck. Both material quality and participation rates reportedly are high using this approach because the single bins are convenient and the sorters can reject non-recyclables.

Some studies have shown that curbside sorting can be highly efficient, but it's labor intensive and only a limited number of homes can be collected economically. The curb sort approach generally applies only to the single-family, residential waste stream, but small and medium-sized communities that lack money for processing facilities should also consider this option.

In commingled collection, residents put recyclables in a single bin at the curb, where they are collected with a single- or dual-compartment truck to maximize the truck's capacity. The commingled recyclables are then separated at a material recovery facility (MRF), which adds another expense to the total recycling program budget. Collecting commingled recyclables saves time and extends the route size, but the processing time is increased since the collected materials have to be separated, cleaned, baled, shredded or otherwise prepared to enter the market.

With the combined collection approach, residents or businesses set out commingled recyclables in a separate, easily identifiable, translucent bag. The recyclables (newspapers, glass containers, HDPE, PET, steel, bimetal and aluminum cans) are then collected in packer trucks, either alone or with the mixed waste. Collected materials are delivered to a facility for separation, recyclables are directed to a processing facility and waste goes to a disposal facility. The combined collection alternative helps communities provide more cost-effective curbside recycling programs.

Using ordinary packer trucks, many communities are collecting commingled, compacted recyclables in blue, 13-gallon plastic bags. Here, collection service only must be modified to accommodate recycling. Collection service is usually changed from twice-weekly, mixed-waste collection to weekly mixed-waste and recyclables collection. This approach involves no additional collection costs, which typically represent 50 to 75 percent of the costs of a curbside recycling program.

Permanent Collection Centers Although many communities have launched extensive curbside recycling programs in the last decade, others have backed away due to high operating costs and low prices paid for recyclables. These communities have replaced curbside collection programs with permanent collection centers, which require residents to separate the recyclables.

Although drop-off centers divert between 1 to 10 percent of the residential waste stream, they are a good place to start a comprehensive recycling program. They also can serve homeowners who miss scheduled pickups or need to remove materials immediately, and help residents in multi-family housing and businesses participate in a recycling program if they do not receive curbside service.

Drop-off centers may collect a broad range of materials, including aluminum, glass, newspaper, old corrugated containers and high-grade office paper. To save money, drop-off centers are often located on free property such as municipal lots, schools, churches and shopping center parking lots. Permanent collection centers can range from a few collection bins to a large processing center located at disposal sites.

Centers may be open 24 hours a day, with or without an attendant on duty. The centers must be well-lit and located near roads and other public facilities to avoid vandalism or illegal dumping.

If drop-off centers provide material processing for volume reduction or improved marketability, additional equipment is required. For example, sorting tables, balers, conveyors, shredders, magnetic separators, can flatteners, glass crushers and fork-lift trucks are usually included in addition to weigh scales and storage containers.

The quantity of materials recovered at a drop-off center program depends on:

* Program promotion;

* Local waste composition;

* Types of materials collected;

* Number of centers in a given geographic area;

* Site maintenance;

* Site security; and

* Access to the centers.

The amount of material recovered in U.S. drop-off centers ranges from seven to 53 pounds per capita per year. Most communities have participation rates between 5 and 20 percent. Although publicity and promotional campaigns normally increase public awareness and participation, facility convenience, cleanliness, accessibility, operational hours and market preparation requirements are the major factors that affect participation levels.

Permanent collection centers can be effective, especially in rural or low population areas where curbside collection or buy-back centers may not be cost efficient. These centers also can be used to collect special wastes such as automobile or household batteries, used oil and household hazardous wastes.

Buy-back centers provide economic motivation by paying cash for recyclables. Since citizens may be willing to travel farther for money, buy-back centers usually have a larger service area than drop-off centers.

Complex centers purchase a wide variety of materials and often process materials through glass crushing, aluminum densifying and waste paper baling. Like drop-off centers, buy-back centers may require special equipment and several employees.

A simple buy-back center with limited processing capability can be started with scales and storage areas or containers and can be inexpensive if the land and equipment are donated. Cash must be on hand to purchase materials from the public until a sufficient quantity is accumulated.

Many recyclers and end purchasers have attempted to reduce the costs of constructing and operating buy-back centers by installing automated facilities with reverse-type vending machines. Installed in convenient locations, reverse-type vending machines accept and process beverage containers made of aluminum, steel, glass and plastic.

Reverse-type vending machines pay customers based on the weight and current value of the materials deposited. Some have also used coupons and prizes to encourage public participation. The machines currently account for an estimated one-fifth of the 50 percent aluminum recovery rate.

The machines have been touted as a way to reduce high labor costs, but manufacturers have seen relatively little sales growth in the past five years. Many recyclers avoid the machines because of their high initial purchase costs ($5,000 to $25,000) and service requirements, but less expensive models are becoming available.

For periodic collection programs, the public delivers specific recyclables to a designated location at a particular time. Newspaper or aluminum can drives sponsored by volunteer civic groups and churches are examples of periodic collection programs, but municipalities sometimes sponsor these programs as well.

Other Recyclables Surveys show that offices generate approximately half a pound of recyclable waste paper per employee per day. Typically, offices with the highest employee concentrations usually initiate an office paper recycling program.

Convenience is the key factor in designing a successful office paper recycling program. The number of employees per building or office determines how many individual and main storage containers are needed.

Separating recyclable waste paper from an employee's desk is only the first step. Investigate the janitorial staff's existing disposal procedures to determine the collection and location of main storage containers; otherwise, the separated paper may still end up in the waste stream or create a nuisance.

Appoint a coordinator and designate recycling liaisons to answer employee questions or problems. To encourage recycling, use seminars, recycling posters and periodic memos on the current recycling rate or status toward a goal. Each office paper recycling program is limited only by the energy and imagination of the individuals managing the program.

In addition to residential and commercial solid waste, every community produces construction and demolition (C&D) debris, comprised of bulky, difficult-to-process material like wood, tires, concrete, rugs and carpets, corrugated containers, wire and strapping metal, rocks and dirt. C&D haulers usually perform a limited amount of processing to recover the materials they can easily market.

When processing C&D waste to recover recyclables, the major goal is to reduce the volume of waste that must be collected, transported and disposed. Some vendors claim that processing can create a nine-to-one reduction rate. Processing begins with crushing the oversized material, then hand-picking the "unders" for recoverable material. The remaining waste is shredded and/or composted. C&D processing equipment includes balers, grapples, trommels, hammermills, vibrating screens and dust control systems.

Industrial And Commercial In general, there is more corrugated cardboard and office and computer paper in the commercial waste stream. Waste composition is also industry-specific; for instance, restaurant waste is completely different from the waste generated by a newspaper publisher.

Commercial and industrial recycling collection programs are best administered by the business involved. Utility and service companies often have portions of their paper waste delivered to a broker and shredded for confidential reasons, so this type of solid waste never becomes part of the municipal waste stream.

A wide range of businesses can recover office paper, as much as five pounds of wire ledger paper per employee per month. Bars and restaurants can be targeted with glass and beverage container recovery programs. Grocery stores, warehouses and supply businesses usually recover corrugated.

In order to be successfully implemented, these recovery programs must demonstrate corporate support, economic viability, a sufficient amount of quality material and in-house adaptability. Items to consider include in-house collection procedures, labor requirements, storage facilities, employee educational programs, materials purchase contracts and performance evaluations.

In a passive or active industrial waste exchange, the by-products or waste products of a particular industrial process are reused by another industry. A passive waste exchange, generally operated by a non-profit association, trade group, government agency or university, acts as an information clearinghouse. An active exchange is typically operated by a for-profit business and becomes involved in materials handling. Generators list available wastes in a catalog or brochure.

Recycling collection programs have come a long way to meet the needs of the communities they serve. As recycling gains strength as a solid waste management option, the systems, equipment and labor force will continue to evolve.