Appendices to Integrated Resources & Solid Waste Management Plan - Dec 2009

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ATTACHMENT D Sampling Methodology and Calculations Sampling Methodology Objective This study was intended to produce statistically valid data on the types and quantities of waste disposed at the West Hawaii Landfill during FY 2008. The results of this study were combined with the results of the 2001 study conducted at the South Hilo Landfill resulting in a waste composition profile for the entire County. Substream Definition The waste hauled to the West Hawai'i Landfill can be divided into the following three categories (called substreams): 1. Transfer Station - is composed of waste hauled from nine transfer stations on the west side of the island. It is transported to the West Hawaii Landfill in transfer station compactor boxes. Transfer station loads are made up primarily of residential waste. 2. Commercial - is composed of waste hauled by commercial hauling companies. Commercial haulers use a variety of vehicles to transport this waste to the West Hawai'i Landfill, including: packer trucks (garbage trucks), roll -offs (primarily open boxes), and other vehicles (e.g. flatbeds, pickups, etc.). This waste is collected from both residences and businesses. Commercial samples were allocated to each of these three vehicle types. 3. Self -Haul - is composed of waste that residents, contractors, businesses, and public entities haul directly to the West Hawaii Landfill. These loads are transported either in small vehicles (e.g. autos, pick -ups, etc.) or large vehicles (e.g. dump trucks, flatbeds, etc). As with waste in the commercial substream, self -haul waste comes from both residences and businesses. Sample Allocation The total number of samples allocated to each substream and sampled on each day of the study is provided in Exhibit D -1. Note that no samples were allocated to the self -haul substream. There is relatively little mixed self -haul material delivered to the West Hawai'i Landfill (1,200 of 128,000 tons in FY 2008, or less than 1 percent). Therefore, it was decided that overall sampling accuracy would be improved by using self -haul sampling results from the 2001 study to represent the composition of mixed self -haul loads in West Hawai'i, and assigning samples that would have been obtained from the self -haul stream to the other two substreams. The composition profile of mixed self -haul loads from the 2001 study was used to estimate the mixed self -haul composition for the West Hawai'i Landfill. The project budget allowed for a total of 100 total loads to be sampled. The allocation of samples between the substreams was determined according to each substrearri s APPX B WASTE COMPOSITION REPORT 121709DOC D -1