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

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HAWAf COUNTY MECHANICAL - BIOLOGICAL TREATMENT FACILITY CONCEPTUAL DESIGN equipment, is typically used as a design basis. Different processing areas within the facility should be segregated with walls to discourage transfer of large volumes of airflow and migration of odors and dust between individual areas. Treatment of odorous air through biofiltration is generally sufficient to render odors to an acceptable level. An additional level of treatment can be achieved by using enclosed "engineered" biofilters with a secondary activated carbon "polishing" cell. In outdoor operating areas, the degree of control that the design has over odors is limited relative to enclosed operating areas. Odor control in outdoor areas is achieved primarily through the implementation and maintenance of good operating practices. The following features should be incorporated into the design of outdoor areas of each facility: • Working surfaces should be sloped at a minimum of 0.5 percent grade to promote drainage and prevent standing water which can become an odor source and attract vectors. • Working surfaces should be designed to provide all- weather access for site equipment, and to resist rutting and settlement which can lead to standing water. • Windrows and stockpiles should be oriented parallel to the slope of working surfaces to promote drainage and prevent the base of windrows from becoming saturated. Residuals Storage Experience in other jurisdictions indicates that as much as 50 percent of the material processed through MBT facilities is non - recoverable and becomes a residual. These residuals are normally removed from the facility at various points during the pre - processing, processing and post - processing stages. Depending upon the point at which they are removed from the process and their characteristics, it may be possible to re- introduce and re- process a portion of these residuals, or use them in secondary application (e.g., landfill daily cover). Generally, the residuals are not suitable for use as soil amendments. Once residuals are removed, they must be stored and handled in a manner that does not result in objectionable odors or litter being generated. Typically, residuals are stored in roll -off waste containers, long -haul transfer trailers, or in an enclosed building until sufficient volumes accumulate to warrant transporting them offsite. Similar to feedstocks, residuals should be managed on a "first in -first out" basis. It is also recommended that residuals be stored for a maximum of three days. Product Storage and Distribution The inventory of finished compost must be stored in a manner that preserves the product's quality (e.g., prevents weed propagation and pathogen reintroduction). This generally means that product stockpiles are stored on prepared surfaces which are kept free of vegetation. There must also be sufficient area at the site to store product produced during months when product sales or shipments are low. Typically, a storage capacity large enough to accommodate 3 to 6 months of product is necessary once markets are fully developed. During the initial 2 to 4 years of a facility's operation (before markets are fully developed) a larger storage capacity may be necessary. 16