Goals of transfer station  design should include:

• efficient waste handling

• equipment and building durability

• simple operating scheme

• flexibility to modify facility.

Transfer Station Design Considerations

  This section discusses factors that should be considered during station design.

In general, these factors were developed for designing large stations, but

many also apply to smaller transfer stations.

  The main objective in designing a transfer station should be to facilitate

efficient operations. The operating scheme should be as simple as possible; it

should require a minimum of waste handling, while offering the flexibility to

modify the facility when needed. Equipment and building durability are essential

to ensure reliability and minimize maintenance costs. With modification,

the facility should be capable of handling all types of wastes.

Site Location and Design Criteria

Local residents are most likely to accept the facility if the site is carefully

selected, the buildings are designed appropriately for the site, and landscaping

and other appropriate site improvements are made. These design features

should be accompanied by a thorough plan of operations. When selecting a

site, municipalities should consider the following factors:

• Proximity to waste collection area: Proximity to the collection area

helps to maximize savings from reduced hauling time and distance.

• Accessibility of haul routes to disposal facilities: It should be easy for

transfer trucks to enter expressways or other major truck routes, which

reduces haul times and potential impacts on nearby residences and

businesses. When considering sites, determine if local road improvements

will be necessary, and if so, whether they will be economically and

technically feasible. Accessibility to rail lines and waterways may allow

use of rail cars or barges for transfer to disposal facilities.

• Visual impacts: The transfer station should be oriented so that transfer

operations and vehicle traffic are not readily visible to area residents. To

a great extent, visibility can be restricted if the site is large enough. The

area required will depend on vehicle traffic and storage needs, necessary

buffer areas, and station layout and capacity.

• Site zoning and design requirements: Municipalities should confirm

that the proposed use meets the site zoning requirements. In addition,

the local site plan ordinance should be reviewed to identify restrictions

that could affect design, such as building height and setback, and

required parking spaces.

• Proximity to utility tie-­ins: The transfer station may require the following

utility services: electricity and gas, water (for domestic use and fire

fighting), telephone, and sanitary and storm sewers. Station designers

should determine the cost of connecting to these utilities and the continuing

service charges associated with them.

In some cases, municipalities may wish to consider the construction of more

than one transfer station. For example, two transfer stations may be economically

preferable if travel times from one side of the city to the other are excessive.

One of the most time­-consuming aspects of transfer facility design is site

permitting. The permitting process should, therefore, be started as soon as a

suitable site is selected. States usually require permits, and some local governments may require them as well. The project team should work closely with regulatory agency

staff to determine design and operating requirements, and to be sure that all

submittal requirements and review processes are understood. Table 4­6 summarizes

additional considerations for site design.

Building Design

Whenever putrescible wastes are being handled, larger transfer stations

should be enclosed. Typically, transfer station buildings are constructed of

concrete, masonry or metal. Wood is not generally desirable because it is difficult

to clean, is less durable, and is more susceptible to fire damage. Key considerations

in building design include durability of construction, adequate size for tipping and processing requirements, minimization of column and overhead obstructions to trucks, and flexibility and expandability of layout.

Office Facilities

• Space should be adequate for files, employee records, and operation and maintenance information.

• Office may be in same or different building than transfer operation.

• Additional space needed if collection and transfer billing services included.

Employee Facilities

• Facilities including lunchroom, lockers, and showers should be considered for both transfer station and vehicle personnel.

Weighing Station

• Scales should be provided to weigh inbound and outbound collection vehicles and transfer vehicles as they are being loaded or after loading.

• Number of scales depends on traffic volume. Volume handled by one scale depends on administrative transaction time, type of equipment installed, and efficiency of personnel. A rough rule ­of ­thumb estimate for collection vehicle scales is about 500 tons/day.

Another estimate that can be used for design purposes is a weighing time of 60 to 90 seconds/vehicle.

• Length and capacity of scales should be adequate for longest, heaviest vehicle. Different scales can be used for collection and transfer vehicles. Typical scale lengths are 60 to 70 feet. Typical capacities are 120,000 to 140,000 pounds.

• Computerized scale controls and data­ recording packages are becoming increasingly common. Computerized weighing systems record tare weight of vehicle and all necessary billing information.

On­site Roads and Vehicle Staging

• If the public will use the site, separate the associated car traffic from the collection and transfer truck traffic

• Site roads should be designed to accommodate vehicle speed and turning characteristics. For example, pavement should be wider on curves than in straight lanes and have bypass provision on operational areas.

• Ramp slopes should be less than 10 percent (preferably 6 percent max. for up­ramp) and have provisions for de-­icing, if necessary.

• The road surface should be designed for heavy traffic.

• Minimize intersections and cross ­traffic. Use one­ way traffic flow where possible.

• Assure adequate queue space. For design purposes, assume that 25 to 30 percent of vehicles will arrive during each of two peak hours, but check against observed traffic data for existing facilities.

Site Drainage and Earth Retaining Structures

• Drainage structures should be sized to handle peak flow with no disruption in station operation.

• Provide reliable drainage at bottom of depressed ramps.

• For most transfer station designs, earth retaining structures will be required. Elevation differences will vary depending on station design.

Site Access Control

• A chain­link fence, often with barbed wire strands on top, is usually required for security and litter control.

• Consider installing remote video cameras and monitoring screens to watch access gates.

• A single gate is best for controlling security and site access.

• Signs stating facility name, materials accepted, rates, and hours of operation are usually desirable and often required.

Ordinances may specify the size of such signs.

Buffer and Landscaping Areas

• Landscaped barriers (berms or shrub buffers) provide noise and visual buffers, and are often required by local ordinance.

• Fast­-growing trees that require minimal maintenance are the best choice. Evergreens provide screening throughout the year.

Design berms and plantings to meet site­ specific screening requirements.

Fuel Supply Facilities

• Fuel storage and dispensing facilities are often located at transfer stations.

• Adequate space to accommodate transfer vehicles is very important.

Water Supply and Sanitary Sewer Facilities

• Water must generally be supplied to meet the following needs: fire protection, dust control, potable water, sanitary facilities use, irrigation for landscaping.

• Fire protection needs usually determine the maximum flow.

• Sanitary sewer services are usually required for sanitary facilities and wash­down water.

• A sump or trap may be required to remove large solids from wash­down water.

.Electricity and Natural Gas

• Electricity is necessary to operate maintenance shop, process and other auxiliary equipment and provide building and yard lighting.

• Natural gas is often required for building heat.

Source: Waste Transfer Stations: A Manual for Decision-Making. United States Environmental Protection Agency (US EPA), 2002.