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

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HAWAII COUNTY MECHANICAL - BIOLOGICAL TREATMENT FACILITY CONCEPTUAL DESIGN surfaces should also be suitably reinforced, coated, or otherwise constructed to withstand the normal wear and tear from vehicle traffic and scraping from wear edges of wheel - loader buckets. Building components (including but not limited to HVAC units and associated ducting, light fixtures, cable trays, electrical cables and conduits, water lines, natural gas lines, and sprinkler systems) should be situated in a manner and location that does not interfere with the unloading of delivery vehicles and the use of mobile equipment in the building. Processing Areas The composting process is generally broken down into three stages: primary, secondary, and curing. The primary composting stage typically takes several weeks and is typified by high temperatures, rapid decomposition of feedstocks, and objectionable odors. It is recommended that the processing areas at the two facilities be enclosed to prevent attraction of birds and wildlife, and to control odors and leachate generated by the composting process. The secondary composting stage typically involves a slower degradation rate and slightly lower process temperatures. Because much of the initial breakdown of feedstocks has occurred during primary composting process, feedstocks are for the most part no longer recognizable and do not attract birds and animals. However, there is still a high potential for odor generation. In light of these considerations, as well as the island climate, it is recommended that the secondary composting stage be enclosed and that active aeration be employed as a process and odor management tool. The curing stage typically involves low temperatures and does not generate objectionable odors provided proper operating practices are followed. After the secondary composting stage, the product resembles soil and it is less likely to attract wildlife and birds. It is accepted practice in the industry to cure materials outdoors. However, given the amount of rainfall on in the eastern portion of the County (i.e., in excess of 100 inches per year), there is a real potential that outdoor curing piles could become saturated, which could lead to anaerobic conditions and odors. As a result, it is recommended that curing at the East Hawaii facility be done using some form of covered composting system (e.g., Poly -flex's Ag -bag system, or windrows covered with Compostex or similar tarp -like fabric). Odor Control Systems Odorous emissions are a byproduct of the MSW handling and biological degradation process that occurs at MBT facilities. However, if the facility is properly designed and operated, these emissions should not be excessive or become a nuisance either onsite or at neighbouring properties. Emissions control and treatment systems must be included for all material receiving and processing buildings to prevent release of fugitive odors and dusts. This is typically achieved through building ventilation systems and process aeration systems that maintain negative atmospheric pressure in the buildings. For material receiving and processing buildings, a ventilation air flow rate of six air changes per hour or greater, combined with source capture of emissions from specific processing 15