Waste Composition Study (Mecklenburg County, North Carolina)
The GBB Project Team performed a waste composition study to ascertain the current breakdown of the Mecklenburg County’s residential and institutional waste by material types. The information was gathered, in part, to gauge the effectiveness of waste diversion programs, and to gain an understanding of the quantities and types of materials in the waste stream that were being landfilled.
The waste characterization study used a unique approach that relied on a combination of both hand-sorting of the waste and visual surveying of select government buildings, schools, residential drop-offs and multifamily units. Since the City of Charlotte represents 80% of the County’s residential population, the County wanted a detailed understanding of the City’s household generation of garbage and recyclables, and to have a very accurate comparison between the on-week and off-week of its “every other week” recyclables collection. Therefore, a two-week sampling approach was used where a total of 82 loads were sampled from the City.
For the other waste streams of interest within the County, select loads or compactors were diverted to the waste sort area for sampling. This included loads from select County facilities such as the jail facilities, Central Piedmont Community College and from Charlotte-Mecklenburg Schools. Also included in the study were municipal solid waste loads from the county drop-off centers and from multifamily housing complexes. The study of the wastes from these locations also included site visits to ascertain how layout and participation may affect the recyclables in the waste stream. A total of 35 loads were sampled from these other locations.
The waste streams were sampled according to the Standard Test Method for Determination of the Composition of Unprocessed Municipal Solid Waste (ASTM D5231 – 92). This approach provides a cost-effective but still statistically significant picture of the waste and recyclables streams. The GBB team physically sorted the samples of MSW into forty-six (46) separate categories and weighed the materials in each category to determine the material percentage within the total waste sorted. Findings and results were presented in a final report to the County.