- New Yorkers are putting less material on the curb even as their population numbers grow, according to a new 2017 waste characterization study from the Department of Sanitation (DSNY). The agency noted a drop in aggregate annual weight per household (now 0.994 tons) from 2013 (1 ton), largely due to a decline in refuse.
- Based on this study, conducted by MSW Consultants and Cascadia Consulting, organics account for the largest portion of DSNY's residential material stream at 34%. Curbside recyclables account for another 34%, followed by 9% of other "divertable" material such as textiles, plastic shopping bags, e-waste and household hazardous waste. That puts DSNY's theoretical maximum diversion rate at 68%, or 77% when factoring in drop-off or specialized collection options, under its current system.
- The study also found increasing contamination rates for both of DSNY's two recycling streams. The contamination rate for paper was 8.9%, up from 7.3% in 2013. For the metal/glass/plastic stream it was 19.5%, which stayed flat from 2013 when factoring in the addition of rigid plastics since. Some of this contamination resulted from misplaced material in opposite categories.
This is the fourth waste characterization study of its kind (following 1990, 2005 and 2013) and is considered directly comparable to the previous one, factoring in the addition of both rigid plastic and organics collection since then. In total, the consulting team assessed 810 samples across three seasons with 70 main sort categories.
One notable change in 2017 was the study of material from both public schools and the New York City Housing Authority (NYCHA). Takeaways include high recycling contamination rates in schools, but also high potential for capturing organic material which comprises more than half of the stream. NYCHA's waste stream was similar to other residential data, and also showed high potential for recycling.
Overall, DSNY collected 3.1 million tons of residential material last year. 2.5 million tons of that ended up being disposed in landfills or waste-to-energy facilities. Those totals do present a decline in disposal, especially when factoring in how the city's population grew from 8.2 million to 8.5 million since the last study, but also show how much farther there is to go toward the goal of "zero waste" by 2030.
Based on this new composition, DSNY is still collecting 23% of material "for which there are no or very limited options for beneficial use at this time." This includes small-scale construction and demolition debris, furniture, treated wood and lumber, carpet, plastic film, foam, diapers, animal byproducts and other assorted items.
While the agency has already recognized that "zero waste" may be more of a cultural aspiration than a hard target that doesn't mean it can't make significant progress from the current 17% residential diversion rate. Other findings from the study show areas that have been or could be affected by policy changes, shifts in consumer behavior and new opportunities for focus.
For example, e-waste tonnage dropped by nearly two-thirds since New York enacted a state disposal ban in 2015. Curbside organics collection, which is still being expanded throughout the city this year, yielded low tonnage but also had low contamination rates. The average household discarded more textiles, and non-clothing textiles saw a slight uptick. Plastic bags, a hot button policy issue in the state, are being discarded in smaller numbers, perhaps due to drop-off options.
In the dual-stream curbside system, cardboard had the highest capture rate while aluminum had one of the lowest. A potential factor here is that aluminum cans are a popular target for informal recyclers that often get to the material before DSNY collection crews.
Parsing through what all of this means for future policy decision will take time, and the New York City Council's sanitation committee has scheduled an oversight hearing for April 24. Key things to watch will be whether DSNY believes it can keep contamination rates in check with an expected switch to single-stream by 2020, how this data could influence ongoing "save-as-you-throw" planning and whether this changes any expectations about the viability of reaching "zero waste" in the next 12 years.