Weight-Based Faces An Up-Lifting Future

Lisa A. Skumatz and Hans P. Van Dusen

Under the careful scrutiny of municipalities and private haulers alike, weight-based rate systems have gradually matured over the past few years. Progress has been made on three fronts: commercial front-loaders, semi-automated residential tipping systems and fully automated residential systems. Today, several certified systems are available and implementation slowly is gaining ground, according to a recent survey by Skumatz Economic Research Associates Inc. (SERA), Seattle.

Following are summaries of the basic certified equipment systems: * Commercial front loaders. Scale companies are adapting front loaders' standard dumpster tipping arms with load cells used on fork lifts in freight yards. Because the units weigh during tipping, no operational or efficiency changes result.

* Semi-automated residential tipping systems. Standard cart tippers have been mounted on load cells to overcome the initial challenges to national certification. Both in-motion and stop-cycle systems have been certified. These technologies reportedly slow cycles for four to nine seconds; manufacturers estimate the impacts on a full-day, real-world route to be approximately 15 minutes per day.

* Fully automated residential systems. After some delay in developing reliable systems, one successful design includes a hopper to weigh each customer's waste before dumping into the truck body. This design aims to avoid dynamic and indirect arm movement problems. These systems reportedly do not change procedures, time or efficiency since the hopper is weighed while the arm is returning the cart.

The price, reliability and convenience of data-downloading and radio frequency identification (RFID) systems have improved greatly, according to the survey.

In addition, turnkey systems are now available, which include the truck equipment and retrofit, real-time radio-downloaded data transfer and billing and financial reporting software in one package. This integrated approach is most accessible for communities that prefer not to piece together and tweak a system. Turnkey systems also minimize operational and staff changes. The crew's job remains the same - to collect the garbage - since weight-based billing requires no special procedures.

Certified equipment, including equipment for off-level weighing, has been available since spring 1994. Currently, certified systems are available from Toter (dynamic semi-automated residential systems); Mobile Computing Corp. (stop-cycle semi-automated and fully automated residential and commercial systems, all of which include turnkey integrated systems and software) and Cardinal (stop-cycle semi-automated and commercial systems).

SERA's survey identified several other firms who report that their equipment has been pilot-tested and will be submitted for certification soon.

Slow Going Although many municipalities are sending out "feelers" to learn more about weight-based systems, few have actually followed through. Vendors have spent considerable time talking to communities and preparing bids, according to SERA's survey, but no fully implemented, city-wide systems are yet in place. Those projects that have come closest to implementation have failed for several reasons, including negative reactions from citizens and newly elected officials who require a time-consuming education process.

Ironically, in virtually every community where these systems have been tested, participation has been overwhelmingly positive. At first, some customers fear they'll have to foot the bill for others who dump trash in their container. However, customers react very positively to knowing what they'll be charged and to the equity of the new system.

For now, the residential market is still very fragmented. Consequently, manufacturers are focusing on two areas for the near to medium term: the recycling market and commercial haulers (front loader systems).

On the recycling front, strong markets have compelled some haulers to weigh recovered paper and to provide customers with vouchers to pay for the materials.

For their part, commercial haulers can use weight-based systems to establish more efficient routes; to avoid overweight truck problems; to segment customers to determine cost-related rates and improve equity; to identify desirable and less desirable customers; to help determine customer service needs; to track the collection staff's efficiency; and to improve overall efficiency and the bottom line.

One manufacturer related a dramatic example of how commercial haulers can benefit from the system. The hauler purchased a weighing system for its front loader operations, figuring on an 18-month payback if 10 to 15 percent of their commercial customers' loads were significantly larger than their "back of the envelope" volume-to-weight calculations indicated. In fact, payback reportedly occurred within six weeks because many customers' rates did not accurately reflect the hauler's costs to service the accounts.

Because the system was not certified, the hauler used three-month weight averages to determine the amount of waste in a customer's container. Representatives then worked with the customer to adjust service fees when weights were significantly higher than expected.

By addressing the situation in a professional manner, the hauler reportedly retained approximately 90 percent of its customers. Generally, those customers who objected to the new rates and switched to another hauler had been the least profitable customers, according to the manufacturer.

Furthermore, Oakland Park, Fla., currently is completing a six-month pilot for 150 commercial dumpster customers with two- to eight-cubic-yard containers.

The equipment, including scale, RFID and downloading computer and software, reportedly has performed smoothly with one miss in 5,700 reads and no significant changes in operational procedures or efficiencies. The truck, whose front loading arms were modified for weighing, has received state certification and reportedly is ready for full implementation after the pilot is completed in November.

So far, the pilot study has found that restaurants and manufacturing customers tend to dump heavier loads than multi-family, retail and office customers with similar sized containers. Gerry Alfono, Oakland Park's solid waste/recycling director, believes that the equity of the new system will convince the city council and commercial customers to approve the program in November. "When customers find out [that] they are subsidizing the disposal costs of others under the current volume-based rate structure, they will insist on the new weight-based system," he said.

If accepted, the new rates would include a "drive-by" fee reflecting operational costs and a per-pound fee reflecting the city's per-ton disposal costs. Alfono also believes that single-family residences will push for a weight-based system when they see the improved fairness in billing among commercial customers.

Alfono is not alone in his hopes of adopting a residential system. Despite the wide-spread inertia among municipalities, several have field-tested residential systems, according to Garbage by the Pound: On the Streets, a study recently released by SERA and published by the Reason Foundation. These include:

Victoria, British Columbia. One of the most extensive pilot tests for weighing residential waste recently took place in Oak Bay, a municipality in the Capital Regional District (CRD) of Victoria, B.C. The CRD considered weight-based billing as one method to push residents toward a 1995 diversion goal of 50 percent. For the pilot, the collection staff tested prototype equipment that simultaneously weighed and collected three different residential waste streams in one stop. The materials were refuse, non-glass recyclables and organics.

The city used a triple-packer truck with three packing bins and three tipping arms, each of which was modified with load cell weighing technology and a RFID system. All Oak Bay citizens were encouraged to volunteer for the program; 65 percent opted to participate and received special carts with RFID tags.

At each stop, the system recorded the content's weight, the material type and the generator's name and address; this information was then remotely downloaded through a radio system to a computer at the downtown headquarters.

The district hopes to implement the system throughout the CRD within three to five years.

Hampton, Va. Hampton, Va., recently began a pilot test for residential waste using a new hopper weighing system for fully automated collection. The city encountered several technological obstacles but was able to overcome these with support from its Solid Waste Advisory Committee and city administrators. The system has achieved necessary state certification and officials currently are smoothing out software glitches.

The pilot test's system includes a weighing modification to Hampton's fully automated truck and complete software programming for downloading and processing data from 300 customers. Officials hope to implement the system for all customers by October 1996. Half of the solid waste revenues are generated from general fund and half from weight-based billing, estimated to be approximately $0.03 to $0.04 per pound.

The city has learned much from its experiences with the pilot test. "Developing a new system requires full commitment from above and below to overcome obstacles," said Kevin Gallager, Hampton's recycling manager. "A full, multi-disciplinary project team must be established ... [with the expertise needed to cover] collection, billing and customer relations."

Columbia, S.C. This spring, Columbia, S.C. conducted a pilot weight-based program for 500 households; billing data was collected for approximately 165 households. The system used a modified semi-automated rear loader with a 25-cubic-yard body. A RFID tag attached to the cart dumper reads the RF tags just below the roll carts' upper lip. A computer in the truck's cab maintained the data. Productivity (stops collected per hour) during the pilot reportedly has kept pace with pre-pilot rates.

Milwaukee. Milwaukee's pilot test with retrofitted semi-automated tippers is unique because, rather than identifying the carts via RFID, Milwaukee is using a computerized routing system. The stops are entered, in order, into the computer, which then displays the next house's address after each stop.

Durham, N.C. During a six-month field test in 1991, Durham focused on producing a certified scale modification to their semi-automated side-loading tippers; a customer identification system will be pursued later. The scale system reportedly performed well but refinements to pass certification (especially in off-level conditions) took considerable time. City staff, vexed by time requirements, gave up trying to obtain approval from the council for a variable-rate system.

Seattle. Between 1989 and 1990, the authors conducted a two-phase pilot test of 1,500 Seattle households using two systems, with financing from EPA. The first test system involved a manual process (bar codes) using available technology to produce data for mock bills and to solicit feedback. The second phase tested an early semi-automated tipper scale and radio frequency tags, which were successful in identifying carts and weights.

Seattle's mock bills charged a customer drive-by fee and $0.08 per pound for the first 25 pounds, with a higher rate for cans weighing more than 25 pounds. The city found that customers reduced their set-out weights by 15 percent in response to the bills and were supportive of the weight-based concept, with a large share preferring it to the volume-based system.

Seattle will not be considering any full-scale changes to their collection systems until long-term collection contracts are renewed in 1996 or 1998. The city has operated a volume-based rate system for 14 years.

Farmington, Minn. Farmington wanted to become the first municipality to implement weight-based rates, but technological setbacks and unsuccessful redesigns ultimately led to the demise of the program (see World Wastes, December 1994).

Farmington conducted field tests using various component combinations with its modified, fully automated collection truck. At least one test was fairly successful, aside from the electrical problems incurred by abusive field conditions. The system's static weighing mechanism required a two-second pause in tipping cycle.

As with Seattle's earlier test, two types of identification and data storage were tested: RF cart identification and a fixed barcode scanner reading an on-board route sheet. Ultimately, the equipment design did not meet certification during the pilot. In addition, Farmington experienced retraining difficulties and opposition from collection personnel.

Minneapolis. Minneapolis ran a small pilot test of a weight-based system in spring and summer 1993. Operators installed load cells on two semi-automated lifters and used RFID for can identification, to be read by an antenna. The system weighed before and after dumping, storing the information on an on-board computer and downloading it in the evenings.

Although officials found the system to be reliable and accurate, they felt the trial did not last long enough to determine the system's ultimate success. They were concerned that variables such as continuous movement, the angle of collection, wind speed, dump speed and relative amounts of refuse would affect performance. In addition, fears of customer complaints also has caused the city to abandon its plans to implement the system at this time.

A Ripple Effect Current trends demonstrate that widespread implementation of weight-based systems will likely start with commercial haulers. As technological and operational barriers are overcome and the systems' equity is more widely understood, municipalities and residential customers will follow suit.

Of course, a chance for parallel adoption exists. For volume-based rate systems, the most frequently cited source for information prior to adopting a new system, according to SERA, is a "neighboring community" with a successful implementation. This results in a ripple effect in the region and weight-based rate systems probably will experience a similar pattern. It takes time, however, and, despite current significant marketing efforts, the impetus may have to originate within the communities themselves.

Developing realistic information on the cost, efficiencies and benefits of incentive rate programs is crucial to determining payback estimates for communities and haulers.

Payback estimates vary based on avoided cash scenarios, current efficiency and rate information, equipment alternatives, billing systems and diversion alternatives. Other factors to consider include equipment costs and operations alternatives, as well as the impacts on and benefits to customers.

Often, communities and haulers seek information from their peers and from consulting firms in assessing the feasibility of weight- or volume-based rate systems.

For fully automated residential collection, several difficulties were encountered in developing reliable, certifiable systems. The problems included weighing accurately in motion and withstanding vibration.

In addition, accuracy suffered because weighing the containers at the end of the arm required an indirect measurement - including using the "moment" - rather than a direct scale measurement. Introducing a "hopper" into the system solved that problem. The certified systems avoid this "arm" issue by dumping waste into a scale and "hopper" system and weighing the hopper when empty and full.

The National Type Evaluation Program (NTEP) has deemed that Class III certification is required for all on-board weighing systems. This requires an accuracy of 0.1 percent.

NTEP conducts tests according to the specifications outlined by the National Institute for Standards Technology. Certification requires two key phases of testing.

For example, certifying an in-motion, semi-automated system requires field permanence tests. Each dumper undergoes four rounds of tests using eight to 10 various bag configurations and weights ranging from 25 to 500 pounds. The following stages of weighing are tested: * static (with a stop in the cycle);

* in-motion, on-level; and

* in-motion, out-of-level. with

four options: three degrees pitch on each side and three degrees roll in both directions.

After the system passes the initial round of field permanence tests, it must field-operate for 21 days with no adjustments allowed. Next, the tests are repeated to re-check that accuracy falls within Class III.

Finally, influence factor tests check whether the load cells and electronic components can physically function in low, medium and high temperatures (-10 to +40 degrees Celsius). After passing these tests, Class III certification is granted.