World Trade Center Construction Uses Onsite Composting

The One World Trade Center construction project in New York (formerly called the Freedom Tower) has been using food and waste composting systems during the first phase of construction, to be completed in 2013. In line with the project goal of LEED Gold (see "WTC Going for Gold,” EBN Oct. 2006), construction practices, including waste management, are environmentally focused. According to the composting equipment manufacturer Clivus Multrum (hired by DCM Erectors, which is completing the first phase of construction), if all goes according to plan, no compostable waste material will need to be removed from the systems for the duration of the three-year phase. This plan is projected to eliminate nearly all crane time usually scheduled to remove waste from a large-scale construction site, saving energy, producing less pollution, and speeding construction.

Two sets of shipping containers have been connected and configured to house food and waste composting equipment that is raised by hydraulics as the 104-story building grows—about one floor every week or two. One set of nine connected shipping containers (each is three containers high) houses a full-service Subway restaurant, with two composting systems beneath the conditioned dining area that are used to reduce food waste. The other set houses ten waterless urinals and ten foam-flush toilets, which use only six ounces of water per flush. The mobile bathroom unit serves 150–200 construction workers a day. Fans pull air from the bathrooms into the composting spaces beneath, removing potential odors. According to Mills, workers appreciate “the vast improvement this represents over the typical [bathroom] facilities” found on construction sites.

Worms and bacteria will reduce the volume of waste in the composting units by more than 90%, according Clivus Multrum. When the first construction phase is complete, the resulting material should be usable compost; liquid waste is concentrated with evaporators. These practices eliminate the need to transport compostable waste from the site, and divert it from landfills.