MSW collection services typically represent the most expensive element of the solid waste system (Managing Municipal Solid Waste Collection Systems, SWANA, 2009).
Given this fact, MSW collection systems offer significant opportunities for communities and MSW collection firms to explore improvements and innovations that can have a dramatic impact upon the economics of providing collection services. Finding ways to increase system efficiencies is particularly important during the challenging economic times that we are currently experiencing.
The industry is evolving from a historical mindset that views the services that we provide as waste management to a more holistic resource management perspective and moving forward with the development and implementation of innovations. Consequently, collection system managers are actively engaged in identifying opportunities to improve their sustainability-to “lean” and “green” their operations (not incompatible concepts, by the way). Typical areas being analyzed include route optimization, electronic asset and operations monitoring, fuel-efficient hybrid and/or alternative fuel vehicles, increased employee and equipment efficiencies, reductions in operating costs, programs to improve customer perceptions and participation, increased value added services to their customers, and the entire service delivery chain for improved efficiencies and reduced costs.
Route optimization is an area that has historically been targeted as an area where efficiencies can be realized. Route managers realize that increased productivity and lower operational costs can be realized by focusing additional attention on how their fleets are routed. Added benefits include the potential for reducing on-route collection costs, disposal costs, vehicle maintenance, and capital costs.
Route optimization efforts can result in a reduction in the miles driven, time spent on route, reduced vehicle requirements, and overall collection operations expense.
Electronic Asset Tracking
With advances in Radio Frequency Identification (RFID) and Global Positioning System (GPS) technologies, their application to solid waste collection is increasing. Operations are employing these technologies to track everything from vehicles to waste and recycling containers. Information obtained from these devices is being analyzed to improve performance and to ensure that assets are being effectively and efficiently deployed.
In a recent news article, the city of Albuquerque investigated more than 20 incidents that involved GPS technology, “catching solid waste management garbage truck drivers acting inappropriately.”
According to the article, the city installed the GPS devices in every truck. The goal was that of increasing efficiencies and, as a result, has saved an estimated $750,000 by taking data from GPS devices and rerouting collection vehicles. Additionally, the city has also been able to curb fraud and abuse of the vehicles.
In another example, GPS tracking was installed in the city of Dallas’ garbage truck fleet at the end of 2009. And while the decision to make the relatively expensive ($700,000) technology upgrade was met with some skepticism and resistance, “the majority of city administrators believed that by monitoring sanitation workers and improving the fleet management efforts of garbage trucks, they would be able to reduce overtime and increase overall efficiency and performance of waste removal teams.” The city recently announced that, in the first year of use, it saved $677,000, or a little over $56,000 month.
RFID chips are being increasingly employed in efforts to improve service delivery and provide measurable benefits. These benefits include improving customer service through improved asset tracking and increased billing accuracy.
RFID chips (referred to as “tags”), are making their way into waste and recycling containers that are being used by individual households and commercial establishments. Their use is growing as a result of an increasing need to associate a unique collection container with each. Uses range from being able to track recycling set-outs for customers participating in a recycling rewards program or waste set-outs for customers participating in “pay for use” programs. Each container is associated with a specific customer account.
In addition to enabling the tracking of collection activity on a customer-specific basis, RFID-enabled carts make it simpler to manage container inventory, maintenance, repair and replacement and thus facilitate additional operational improvements and savings.
Hybrids and Alternative Fuels
As the price of traditional hydrocarbon fuels continues to climb, the solid waste industry is increasing its investment in hybrid and alternative fuel vehicles to conserve energy and reduce operating costs. Hybrid garbage trucks have been tested in New York, Chicago, Denver, Fort Worth, and Houston.
The stop-and-go nature of a garbage truck route makes such trucks some of the best suited to benefit from hybrid technologies. Manufacturers report that hybrid garbage collection trucks could reduce fuel consumption by as much as 20% to 35% and cut carbon dioxide emissions by a corresponding amount. While savings wouldn’t be as great on long-haul routes where there is less braking, even in those instances, manufacturers suggest hybrid technologies could allow as much as 10% savings (web source: http://www.environmentalistseveryday.org/solid-waste-management/green-environmental-health-safety-stewardship/alternative-fuels-vehicles.php).
The solid waste industry is making significant investments in alternative-fuel vehicles and their support infrastructure. Natural gas, biomethane, and biodiesel fuels are being used to replace typically diesel-fueled vehicles. Garbage trucks have become the most rapidly growing alternative fuel truck sector in the nation. Major cities in California, New York, Arizona, Texas, New Jersey, Florida, Massachusetts, and other states are using garbage trucks fueled with natural gas and other alternative fuels.
Natural gas is the most plentiful alternative fuel that we have in North America and is one of the cleanest alternative fuels available today. Using natural gas to fuel a truck may reduce greenhouse gas generation by as much as 20% to 25%, compared with petroleum-based fuels. Natural-gas trucks also are 50% to 90% quieter than their diesel counterparts, offering other quality-of-life advantages to the neighborhoods that they serve (web source: http://www.environmentalistseveryday.org/solid-waste-management/green-environmental-health-safety-stewardship/alternative-fuels-vehicles.php).
Pay-As-You-Throw and Variable Rate Systems
Variable rate or volume-based disposal fee systems are increasingly popular because they encourage recycling and waste diversion (through separate cans or collections) while discouraging or restricting the amount of MSW disposed. Under these systems, the customer pays a variable fee depending on the amount of wastes collected. The types and elements of such systems, according to the Reason Foundation, include the following:
- Variable can system-Customers are billed on the number and/or size of cans subscribed (or less commonly, set out).
- Prepaid bag system-Customers purchase special garbage bags with logos. The price of the bag includes some or all of the cost of collection and/or disposal of the waste.
- Prepaid tag or sticker-Customers purchase tags or stickers that are affixed to the wastes (or containers) set out for collection and disposal. Again, the price of the tag/sticker includes some or all of the cost of collection and disposal for a maximum amount of waste.
- “Hybrid”-A “base level” of can or bag/tag service is funded through taxes or fixed fees, with increments to that service paid through a variable rate system. The increments are usually paid through bag or tag/sticker systems. These are “hybrid” systems because they are a combination of traditional tax or flat-rate financing along with an incentive-based bag/tag/sticker systems.
- Weight-based system-Weight-based systems charge households for each pound of waste disposed.
Variable rate systems in conjunction with effective recycling and waste education programs have routinely reported between 25% and 45% reduction in waste slated for disposal. The trend toward source separated collection services has also led to changes in transfer station designs to process separate materials streams.
In the 50-odd year history and evolution of transfer stations, they have changed from simple straightforward “garbage in, garbage out” facilities to complicated industrial plants where many different materials from a variety of sources are received, processed and now directed to different markets or final disposal locations. The key to the success of the transfer station in the future is flexibility.
Many factors have influenced the evolution of transfer station design and operation, including the following:
- Population growth and increasing urbanization
- Increased zoning, building code, and emissions reduction standards
- The growth of environmental consciousness and resource conservation
- Fewer landfills close to urban areas
- Increased public involvement
The transfer station of 2020 can best be envisioned by analyzing these historic trends, identifying which ones and others that are likely to affect transfer station operations and predicting their future impact.
The trend in transfer station design and construction is to build fewer and larger facilities, with longer hauls to disposal sites. A primary factor is population growth and distribution. According to Census Bureau statistics, the US population more than doubled from 151.3 million in 1960 to 308.7 million in 2010. Coupled with urban migration, this rise in population significantly increased the need for transfer capacity in densely populated areas.
Another key factor is operational efficiency. In many collection-and-disposal systems, multiple wastestreams, including source-separated recyclables, organics, and construction-and-demolition debris, are delivered to a transfer station. Typically, floor area is needed for segregation and staging of materials for inspection, removal of unacceptable wastes, and materials segregation and recovery. These operations and staging requirements often require considerable floor space, driving the need for larger transfer stations.
Increased public awareness about recycling and the environment has increased the need to expand services for convenience for public drop-off, which has also led to larger transfer stations. In addition to providing sufficient space for customer activities, site and building layouts are often determined with an emphasis on ease of access, customer safety, and overall user friendliness.
Public engagement, increased regulations, and zoning requirements have made it challenging to site new solid waste facilities, so many owners have located compatible processes at the same site. Integrating a materials recovery facility (MRF) with a transfer station offers many benefits, including the ability to segregate materials from the MSW stream and process them in the MRF and, conversely, to deposit residue or rejected materials from the MRF directly onto the transfer station floor. The addition of a MRF processing system, tipping floor, and residue staging requires a significant amount of floor space.
Another emerging trend with comparable influence is the removal of materials from the MSW stream to prepare as feedstock for biological or thermal energy conversion technologies, thus diverting those materials from landfills for useful purposes. Transfer stations are the logical locations for segregating and processing energy conversion feedstock.
Part of this emerging trend is to add a “dirty MRF” to a transfer station. These dirty MRF systems are designed to process the MSW wastestream to do the following:
- Recover such “readily recyclable materials” as containers and cardboard
- Recover digestible organics for biological energy conversion
- Recover combustible materials for biomass fuels and for thermal energy conversion
- Recover fine fraction materials for conversion or landfill uses
As landfills close, environmental regulations become more stringent and states adopt more ambitious recycling and diversion goals. The segregation, processing and staging of various wastestream components will continue to increase accordingly. As a result, larger, more complex transfer stations will become the norm.
The recently completed Tacoma Transfer Station in Tacoma, WA, is an example of the trend towards increasing the size of a transfer station to provide the ability to recover materials from the incoming wastestream. The city’s initial intention was to build a small addition to an existing station. After examining the different wastestreams and determining that at least 10% of the material received could be recycled, the city decided to invest in a new, larger transfer station to provide space to recover materials and reduce expenditures by avoiding transportation and disposal costs. The new station was designed to accommodate installation of sorting equipment for a full MRF in the future.
Combined functions and larger facilities can benefit from economies of scale for such features as stormwater retention and treatment systems, sophisticated ventilation systems to eliminate dust and odor migration, and building shells designed to minimize sound and light pollution.
The upside of this trend is that in order to satisfy community development standards, many modern, urban transfer stations are architecturally significant facilities that enhance their neighborhood and their entire community. An example of architectural significance is the North Gateway Transfer Station and MRF in Phoenix.
Transfer station facilities are intentionally becoming models for sustainability and resource conservation. An indication of the growing commitment is the fact that many recent transfer stations have obtained or are pursuing USGBC LEED certification. Examples of this are the DeKalb Transfer Station in Georgia, the Tacoma Transfer Station in Washington, and the Shoreway Environmental Center in California.
To further promote environmental consciousness among the general public, many transfer stations have added educational centers that include viewing galleries. Visitors can observe the operations, see professional presentations and receive printed materials that promote recycling and environmental stewardship. These educational centers will continue to be incorporated into the design of new facilities, for continued education, to conduct recycling research and public outreach.
US population growth is predicted to continue, and the increases will be primarily in existing urban centers. Although the amount of solid waste disposal per capita is currently down, the likelihood is that by 2020 the overall solid waste volume in the US will be higher.
As time goes on, economic and environmental considerations will provide even more incentives to recover as many materials as possible from the wastestream and divert those materials from landfills. Transportation and disposal costs have risen significantly. On the other side of the ledger, commodity prices have fluctuated but are currently very strong. It is reasonable to predict that those trends will continue until 2020 and beyond.
Community development and environmental emissions standards are continuously being updated. Stormwater discharge and air emissions requirements will increase periodically for the foreseeable future.
To meet the demands that will arise from these factors, the prototypical transfer station of 2020 will be a large-scale, flexible facility that will receive multiple wastestreams from a variety of sources and maximize the diversion of materials from the landfill through a variety of operations. Recovered materials will include readily recyclable materials, feedstock for conversion technologies, and materials for composting, with less material going to landfills.
The transfer station of 2020 will be an important community asset that will provide a convenient location for the delivery of waste materials and the recovery of recyclables. It will be a venue for environmental education and an icon for environmental stewardship, and will support solid waste management research.
Public consultation and engagement will increasingly demand attention before beginning a project, whether in the design of drop-off/transfer facilities or solid waste collection programs. It goes without saying that the public continues to expect to have more influence in how waste is handled.
“Where” we reach the public will continue to evolve, and we must adapt to its needs. The challenge will come from the speed at which new and emerging communication channels appear and our ability to effectively make use of them before they become of little or no use.
People want to shape the products and services they spend their money on-look to the electronics industry for examples of customer-driven businesses. They will demand the same thing of government-administered solid waste programs, especially those that they have direct contact with, such as collection programs and drop-off centers.
Not only do we need to plan for effective public engagement, but also we need to be prepared to make significant changes to program design based on nontechnical, user-driven feedback.
Another real issue facing collection and transfer professionals is that of internal communication resulting from the potential for a high number of front line positions. The simplicity of one or two key spokespeople in an organization is rare, given the sheer size of some corporations as well as the ease with which communication can be broadcast in and out of a company. As it becomes more accepted (but not necessarily acceptable) for employees to broadcast their thoughts via the Internet (we had all been doing this for many years before the Internet, but the only people listening were physically in the room with us), the importance of an internal communication plan increases. The line separating internal and external communication is permeable at best; we must equip our staff with sufficient knowledge to speak about our programs.
The authors wish to give special thanks to Deb Frye of HDR Engineering for her substantial content and editorial contributions to the article.