Page 201 - Materials Chemistry, Second Edition
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CAT3525_C07.qxd  1/29/2005  9:57 AM  Page 172
                       172                       Waste Management Practices: Municipal, Hazardous, and Industrial
                       7.2.2 WEIGH STATION
                       Weighing is an obvious and necessary step for any MRF. Scales of various types are used to weigh
                       the amount of materials delivered, recovered, and removed from the facility. Scale types vary from
                       small units for weighing modest amounts brought in by individuals, to the large, platform scales
                       which are suited to handle the largest collection trucks.
                          Trucks typically are required to enter a weigh station immediately upon entry to the facility prop-
                       erty. The station often consists of a small office with series of platform scales that can handle a truck
                       of any weight (Figure 7.1). The gross weight of the truck is measured. After tipping its load at the
                       facility receiving area, the truck returns to the weigh station for final weighing and calculation of the
                       net weight of the waste. These data are used to bill the waste hauling company. Some weigh stations
                       are equipped with magnetic card readers. Vehicles may be provided with magnetic cards that are
                       inserted into the reader. Information on tonnages is thus collected and calculated automatically.
                          The weigh station provides other useful data such as the rate at which waste is processed by the
                       facility. The input tonnage is important for calculating certain facility operations, including possi-
                       ble requirements for additional storage space, greater equipment capacity, and a larger workforce.
                       The weigh station also provides data for determining the total waste production for a particular col-
                       lection area. Collection trucks may be identified by route, and the quantities of wastes delivered
                       from a particular neighborhood or town can be determined. Such data are beneficial in the planning
                       of improved collection routes or other services.

                       7.2.3 RECEIVING AREA

                       After the initial weigh-in, collection vehicles transport their loads to a receiving (tipping) area for
                       temporary storage and initial processing (Figure 7.2). The facility must be designed to create an
                       optimum flow of collection trucks. In other words, full trucks should not interfere with the prompt
                       exit of just-emptied vehicles from the tipping area.

                       7.2.4 STORAGE AREA

                       Storage of MSW at an MRF is a major practical concern, from the standpoint of both efficiency and
                       of safety. Storage encompasses sufficient space for the raw, in-coming commingled MSW as well
                       as the sorted, cleaned, baled product that is to be collected by a buyer.



























                       FIGURE 7.1 Weigh station at a materials recovery facility.
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