Recommendations to DSNY regarding
2004 Residential waste characterization study categories and methods
Marjorie J. Clarke, Ph.D.
At a minimum, for this initial preliminary snapshot study, the categories should mirror the 46 categories used in the 1989-1990 study, so that comparisons can be made to show trends.
Since the original 46 were mainly recyclables (see figure below), and are therefore useful only in designing recycling programs and recycling MRFs, additional categories should be included for the purpose of designing waste prevention and reuse programs, legislation, MRFs, and incentives. However, in order to make useful recommendations for waste prevention and reuse, the sampling Must preserve the size, recognizability, and utility of the products and packaging in the waste stream. As of last week, the NYCDOS plan was to sample from the crushed remains in the back of a packer truck. This is fine if the purpose of the study is to extract information about materials for recycling (which will eventually be crushed anyway). It is inappropriate to characterize durable and nondurable products, containers and packaging, which should be the focus of waste prevention measures. For that characterization, it is necessary to know
a) the major category of durable, non-durable, or container/packaging, (e.g. furniture)
b) the subcategory (e.g., wooden desk), and
c) its condition (e.g., is it usable as is, does it require a small repair, does it require spare parts, can it be used for spare parts, or can it be recycled).
d) the weight (and/or volume) of the item
Thus, in order to achieve the purposes of determining items that can be prevented, reused, recycled or composted, the waste characterization study should be conducted as two parts. Initially, everything should be sorted according to its product or package category and subcategory. Then it should be evaluated according to the above triage system for evaluating the condition of products. Then each triage category of each product/packaging category should be weighed.
In addition, 200 pounds per sample is not very large. It is a tiny fraction of what would be in the back of one packer truck. As a percentage of the overall waste stream, it is so small, that it can’t be statistically useful predictor unless a large number of these samples are taken on a given day and for each scenario (density, borough, etc).
Once the prevention sort is complete, then the same items can be sorted into their materials. Multi-material products and packaging can be broken down into the appropriate metals, glass, plastic and paper categories.
Recommended subdivisions of Reuse Categories (i.e. durable products and subcategories)
Furniture (including tables, chairs, desks, sofas, beds, dressers, cabinets, etc)
Small appliances (including clocks, kitchen appliances, microwaves, fans, lighting)
Computer CRTs and TVs (2 categories)
Electronics (CD/DVD, tuners/receivers, VCR/cassette, other)
Computers, printers, scanners, sound system, parts, mice, keyboards, etc
White goods (refrigerators, air conditioners, stoves, dishwashers)
Clothing (usable, recyclable, not usable)
Footwear (usable, repairable, not usable)
Bicycles and parts
Batteries (lead, alkaline, rechargeable NiCad, rechargeable NiMH, Lithium, Mercury, other)
Towels, sheets, etc
Pots, pans, and silverware etc
Doors, windows, toilets, etc
Recommended Subdivisions of Nondurables Categories (and subcategories)
Fluorescent Tubes (straight, compact)
Plastic disposables (utensils, plates, cups)
Paper disposables (plates, cups, napkins, towels)
Household Hazwaste (Pesticides, solvents, paint, etc)
Unopened bulk mail
Recommended Subdivisions of Packaging Categories (and subcategories)
Paper bags (grocery, department store, other) – note whether soiled or not
Plastic bags (grocery, garbage, produce, garment, other)
Corrugated Cardboard boxes – note whether soiled or not
Grey cardboard stiffener – note whether soiled or not
(NYCDOS currently instructs residents not to put soiled papers into paper recycling, though Visy has indicated mere soiling is not a problem for its huge pulping vat.)
Other Recommended Sampling Methods
In order to get a characterization of the nature of “lost recyclables” those in garbage bags, and “contamination” non-recyclables in recycling bins/bags, it is necessary to conduct separate samples for each subcategory of recyclables / compostables and non-recyclables
- in green bins/bags
- in blue bins/bags
- in black bags/garbage bins
NYCDOS 1990 Waste Characterization study results
Pie Chart by Marjorie Clarke, Ph.D. 2004
(roughly 50% of the MSW) are targeted for recycling as of