space
About UNEP
space
space
United Nations Environment Programme
Division of Technology, Industry and Economics
top image
space
space space space
space
space
Newsletter and Technical Publications
<Municipal Solid Waste Management>

Sound Practices
Collection and transfer

1.3.3 Sound technical options - transfer

Transfer stations and transfer points

Transfer stations are centralized facilities where waste is unloaded from smaller collection vehicles and re-loaded into larger vehicles (including in some instances barges or railroads) for transport to a disposal or processing site. This transfer of waste is frequentlyaccompanied by some removal, separation, or handling of waste. In areas where wastes are not already dense, they may be compacted at a transfer station.

Transfer stations represent sound practice when there is a need for vehicles servicing a collection route to travel a shorter distance, unload, and return quickly to their primary task of collecting the waste.

In industrialized countries, and for waste from large urban areas in developing countries, larger, new landfills, incinerators, and composting facilities are increasingly designed to serve a number of communities or an entire region, with the result that they are sited at a considerable distance from the collection service areas. In this circumstance, since transporting waste from the route to the facility takes longer and uses more fuel, transfer stations can be very attractive.

Transfer trailers or compacting vehicles can carry larger volumes of MSW than regular collection trucks, which allows them to travel longer distances carrying more waste. This lowers fuel costs, increases labor productivity, and saves on vehicle wear.

Drawbacks to transfer stations include the additional capital costs of purchasing trailers and building transfer stations, and the extra time, labor, and energy needed for transferring waste from collection trucks to transfer trailers.

Some developing countries have transfer stations of the type described above, but there are also unmechanized, local transfer points that serve the special needs of particular collection service areas. A micro-collection vehicle designed to service a hilly area or a densely populated area with narrow or congested streets can transfer its load to a larger vehicle or a stationary container at such a transfer point. This can make it possible to service collection areas that a truck could not enter. Such transfer points may also degenerate into unregulated dumps in the absence of institutional commitment and managerial capacity to ensure their efficient operation.

Elements of transfer

Siting
Sound practice for the siting of transfer points and transfer stations includes the choice of a site accessible to collection vehicles and positioned for staging of the larger trucks that will haul away the waste. Sound practices for siting transfer points include the following:

  • the neighborhood must be willing to accept the transfer point as designed and located;
  • agreements made with the surrounding community must be taken seriously and honored by the relevant authorities; and
  • odors, noise, leachate, and increased traffic must be minimized.

Larger-scale transfer stations should in general be sited:

  • far enough from residential areas that odors, noise, leachate, and traffic are not acute issues;
  • close enough to the collection area that collection vehicles can quickly return to the area;
  • at sites that are zoned for commercial or industrial use;
  • where there is easy access to major roads;
  • on the site of a closed landfill, since the existing land uses and road network around the landfill are already suitable for transfer stations; and
  • where road restrictions (weight, noise, speed, surface, axle weight, truck length) do not conflict with the expected usage related to transfer.

In some large or heavily populated areas, or in regions with dispersed population centers separated by relatively sparsely populated areas, more than one transfer station may be desirable. The appropriate number of transfer stations depends primarily on the number and size of service areas covered by the MSWM system, the distance between the areas, the volume of MSW generated, the distance to disposal, the types of vehicles in use in primary collection, and the size and type of transfer stations selected.

Transfer vehicles
A number of truck types are currently used for transporting wastes from transfer points. At large transfer stations, large transfer trailers are used for bulk transport of compacted waste to more remote disposal facilities. These can be either open-top (usually a cover is required during waste transport) or enclosed.

Large-scale transfer station design
Transfer station design in industrialized countries generally includes a tipping floor serviced by bulldozers for pushing waste into transfer trailers or a compactor blade for packing waste into trailers. Recyclables and special wastes are increasingly being sorted and processed at transfer stations. There are three common types of transfer station that represent sound practice.

Open tipping floor. In the open tipping floor design, collection trucks unload uncompacted waste onto the tipping floor, and bulldozers organize the waste and place it in open-top trailers.

Often the most appropriate choice for developing countries, this type of facility:

  • is more efficient for small volumes of waste than for large;
  • can serve to transfer different materials at different times or into different vehicles;
  • can easily accommodate recovery of bulky wastes or of materials such as cardboard;
  • allows for waste picking at the transfer station; and
  • maximizes the possibility of spreading the waste, ideally on concrete platforms, in order to pre-dry or pre-compost it for a day or two before transfer to a landfill or processing facility.

Open pit design. An open pit transfer station has the collection trucks dump waste into an open pit, where bulldozers organize the waste and load it into open-top trailers. Alternatively, the waste is compacted and loaded into enclosed trailers. This design:

  • allows multiple collection vehicles to unload at the same time that loading and transfer operations are in process;
  • can accommodate larger vehicles than an open tipping floor design;
  • has higher capital and operating costs than an open tipping floor;
  • is not ideal for pre-processing or separation of recoverable materials, although this can be accommodated;
  • is vulnerable to breakdown of compaction units, if they are used; and
  • can incorporate waste picking only with difficulty, since the open pit is hazardous.

Direct dumping transfer stations. In direct dumping, collection trucks unload through hoppers directly into either open-top trailers or compactors. This system:

  • has no intermediate handling, which increases efficiency and decreases labor;
  • does not permit waste picking or any other type of intermediate handling, and therefore effectively prevents recovery;
  • requires an intermediate level of capital investment in the facility, but a significant investment in the transfer trailers themselves;
  • can be rapidly constructed and/or moved, since most of the capital investment is in the vehicles, not in the facility itself;
  • requires an abundance of extra trailers;
  • is vulnerable to a shortage of trailers, since there is no buffer when there are insufficient trailers available to load the waste; and therefore
  • is a poor choice when equipment maintenance, repair, or replacement represent significant difficulties within the system.

Some of the drawbacks to direct dumping can be solved in hybrid systems, where vehicles discharge onto a tipping apron which allows brief access to the waste before it is pushed by loaders or dozers into the hoppers that feed the transfer trailers.

Distance to processing or final disposal. Since one of the main reasons for including transfer in a waste system is to increase the efficiency of hauling to disposal or processing, sound practice must include an assessment of the distance from the collection service areas to these facilities in comparison to direct haul to the disposal facility.

Health and environmental considerations of transfer
Environmental benefits of transfer. From a system-wide perspective, transfer operations have the potential for environmental and health benefit, in the following ways:

  • They can reduce air emissions and fuel consumption because of increased collection and transport efficiency and reduced energy use.
  • Access to the materials for pre-processing, waste picking, or materials recovery, together with removal of bulky or hazardous items, reduces fuel use and increases recovery.
  • Design for safe pre-processing and waste picking can improve the health and working conditions of waste pickers who would otherwise be salvaging materials from the landfill or open dump.
  • The availability of transfer in a collection system means that landfill siting becomes less dependent on considerations of accessibility for carts and short-distance vehicles. Landfills can therefore be sited with more consideration for public health and environmental factors such as hydro-geological conditions, the containment of leachate and landfill gases, and physical isolation of the facility to minimize the threat from disease vectors such as rodents.

Environmental problems related to transfer. Transfer stations and transfer points can also cause problems for human health and the environment.

  • Negative neighborhood impacts can include noise, air emissions, and leachate, and oil emissions from the collection and transfer vehicles, and from truck maintenance facilities.
  • Like other MSWM facilities, transfer stations and transfer points have potential odor, litter, and disease vector problems. But, since they facilitate greater and more timely collection, they often on balance alleviate such problems.
  • A lack of control can result in a neighborhood transfer point serving as a place for uncontrolled dumping.

Summary of selection factors for transfer stations and transfer points

The following design and selection factors for transfer stations and transfer points are associated with sound practice:

  • Choose a transfer system that can accommodate the full range of collection vehicles already in use or planned (even when the long-term desire might be to phase out certain types).
  • Site transfer stations and transfer points to minimize odor and noise and to allow waste to be accumulated, if necessary, prior to long-haul transport.
  • Respect and abide by agreements with the neighborhood in which a transfer point is sited.
  • Select and design transfer systems that allow access to the waste for pre-processing and removal of recyclables, compostables, or problem materials, unless there is a compelling reason to do otherwise.
  • For large-scale transfer stations, select locally made equipment, local designs, and local expertise whenever possible, supplemented if necessary by assistance from national or international experts.

 

      Table of Contents

  • Brochure
  • IETC Brochure


  • International Year of Forests
  • International Year of Forests


  • World Environment Day
  • ??????


  • UNEP Campaign
  • UNite to Combat Climate Change