The companies that collect garbage and recyclables will provide carts and/or bins to hold those materials prior to collection. The size and number of these containers will depend on the size of the project and possibly on the frequency of collection, as well as the types of containers used by the collection company.
The most common collection containers are carts with 20, 32, 64 or 96 gallons of capacity; and bins (“dumpsters”) with 1 to 7 cubic yards of capacity. For very high volume customers, most collection companies can provide truck-size “rolloff boxes” that are typically 15 to 40 cubic yards in size. These require special design considerations that go beyond the scope of this document.
In a multifamily setting, for once-a-week collection (the norm), a reasonable rule of thumb is to provide 50 gallons or ¼ cubic yard (cy) of container capacity for every three residents. This would be the sum of the volumes of refuse, recycling and organics carts (or bins), with volumes in the proportions of 40% for refuse, 40% for recyclables, and 20% for organics. This does not include plant debris from landscape maintenance at the site; that volume is site-specific and will need to be estimated separately and added, unless the landscapers remove all of the solid waste that they generate.
For example, a 60-unit multifamily complex with average occupancy of three people per unit would require 15 cubic yards of total capacity (1/4 cy x 60), which, following the 40-40-20 rule, equates to 6 cubic yards each for refuse and recycling and 3 cubic yards of organics. If the collection company uses 6-cubic-yard bins for refuse, 96-gallon carts for recyclables, and 64-gallon carts for organics, this could be served by one refuse bin, 12 recycling carts and nine organics carts, if all collection takes place once a week. Alternatively, twice-a-week service (if available) could reduce the on-site storage volume significantly, but could cost more due to the need for more truck trips per week.
Another approach is to estimate the number of occupants by multiplying the number of bedrooms by 2, and allowing 15 to 18 gallons per occupant, then applying the 40% - 40% - 20% proportions cited above.
It is good practice to provide 20% to 35% excess capacity for seasonal variation and other surges in volume.
Occupants’ convenience and the area needed for grouped containers should also be considered. As an example, if convenience dictates that four groups of containers should be used, our multifamily example would use clusters that each comprise a 2 cubic-yard refuse bin, three to four recycling carts, and three organics carts.
In a commercial setting, there is no rule of thumb for container volume; different types of commercial activities generate very different volumes of solid waste. The relative amounts of each stream (recyclables, organics and refuse) vary as well.
At the state level, in 2005 CalRecycle researched the volumes and types of materials in wastes disposed by many kinds of businesses, and this can provide some indication of how services should be apportioned. Obviously, one can expect retail establishments to produce a significant amount of cardboard boxes, and restaurants will likely require at least 50% of their volume to be organics service. Less obviously, churches and schools with active kitchens (but not all schools, or churches) can also require a substantial amount of organics service; and many health care facilities discard very little office paper, because they use electronic medical records and send discarded documents to a shredding service. For a more accurate estimate, an owner or designer can consider the type of occupants that they are expecting, and look into service levels at comparable locations, keeping in mind that these “comps” may not be fully diverting recyclables and organics from their refuse stream.