nyc compost project | how
to compost | compost science | calendar | resources | search
In 2004 and 2005, the NYC Department of Sanitation (DSNY), along with its research consultants, conducted an extensive study of NYC’s residential waste stream over four seasons. In each of the four seasons, professional sorters separated 850 representative samples of residential NYC trash and recycling into material categories. The sample size and number of samples used in the study met rigorous requirements to achieve statistical significance. Final results of the Waste Characterization Study can be found on www.nyc.gov/nycwasteless.
The pie chart below shows the amount of organics found in NYC’s residential waste stream, compared to other materials. While nearly 50% of NYC’s residential waste stream is considered organic, only yard trimmings (4.22%) can be collected and composted cost effectively on a citywide scale.
2004-05 NYC Residential Waste Characterization Study |
|
 |
Other Material Suitable for Industrial Scale Composting includes textiles and rubber items; processed wood, lumber, and furniture; diapers and sanitary products; animal wastes; fines; and miscellaneous organics. Also includes gypsum scrap, an inorganic material which enhances composting. These materials could possibly be composted using machinery in an anaerobic system, but are not suitable for home composting. Other Non-Compostables include rock, brick, ceramic, plastics not designated for recycling, very small amounts of e-waste and household hazardous wastes, and miscellaneous inorganics. |
The reasons for this are simple. Unlike most other organic waste, leaves and yard waste are by their nature typically gathered and collected as a wholly separate, relatively inert and odorless material stream that can either be composted at home or set out for collection. In addition, leaves and yard waste can be composted in windrows, a low-tech, inexpensive process.
Composting other components of the residential organic waste stream is more problematic, on several fronts. First, materials such as foods scraps, fecal waste, soiled paper, and used hygienic products generate significant odor while decomposing and must be processed indoors with specialized equipment and ventilation. Such facilities are difficult to site and expensive to build. Second, even when using the most advanced composting technologies, it is difficult to produce usable compost from organic materials that are mixed with non-biodegradable waste such as plastic, glass, construction debris, and other substances. These materials can interfere with the composting process and also contaminate the finished compost, physically and chemically. Yet collecting organics separately would be prohibitively expensive and difficult to implement, especially in our dense urban setting.
The best hope for increased organic waste recycling lies in the ongoing development of technologies such as mixed waste (or MSW) processing, which employs various methods to produce compost from a mixed waste stream; or anaerobic digestion, which converts organic materials in the mixed waste stream into usable methane gas. Neither technology is as of yet foolproof and cost-effective enough to be implemented widely, but advances in these and other systems continue to be monitored.
Nonetheless, DSNY has instituted a wide range of programs to recycle those portions of the organic waste stream that can be composted at home in one’s backyard or at larger scale municipal facilities. In addition, DSNY has conducted several pilots and studies to assess the feasibility of composting mixed organic wastes with appropriate technologies. See descriptions of DSNY’s residential and municipal composting initiatives.
compost
science 1: organics in new york city’s residential waste stream
compost science 2: the decomposition process
compost science 3: how does compost happen?
compost science 4: chemical decomposers—microorganisms
compost science 5: physical decomposers—larger
organisms
nyc
compost project | how to compost |
compost science | nyc
compost resource
sitemap