Odor management at compost sites may be accomplished using any one or a combination of air contact, surface contact, and incorporation products. The determination of which odor control method to use is normally based on the types of materials being composted, the composting method or technology being used, the site layout and topography, and the process activity generating the majority of odors. When air contact is the chosen method, a perimeter nozzle system or nozzles attached directly to row turning equipment or front end loaders is implemented as with landfills. This may be especially effective if the majority of problems and complaints occur when the composting material is turned. If problems occur during screening or mixing or any other specific activity, nozzles may be attached directly to the equipment involved or to infeed and discharge conveyors supporting the equipment.
Many site operators prefer a more direct approach on an "as-needed" basis. Surface contact products are an ideal choice in these situations. With proper nozzles, surface treatment may be applied directly from the row turner to the composting material as it is being turned. Treatment of leachate and standing water may be accomplished with surface contact as well. Any kind of spraying equipment is suitable for deodorizing trucks and unloading areas with surface contact. Surface contact may also be utilized in situations where difficult topography makes perimeter treatment impractical or ineffective. Pressure sprayers, water cannons, and even hand-held sprayers are often implemented.
Incorporation treatment is utilized in limited row turn static pile or aerated static pile operations. While management has the option to treat the piles topically after formation, it is usually more beneficial to incorporate a single treatment product into the mix as the pile is being formed. This may be accomplished easily if the various component feedstocks are blended in a batch mixer. The treatment product is simply added into each batch in the correct dosage. At sites where loaders or turners accomplish mixing, nozzles may be attached directly to the equipment in the proper size and capacity to administer the product. In these situations and any time the spray apparatus is attached to moving equipment, a separate tank, pump, and power source are also attached.
Indoor composting operations are often plagued by odor problems just as outdoor sites are. Any of the three methods may be adapted to indoor use. In buildings which have fixed exhaust points or where air is collected and run through biofilters, specific methodologies should be employed. Air contact products may be atomized into the exhaust stacks or ports to treat odorous air as it leaves the location. Biofilters may be sprayed topically for surface control, or incorporation products may be added to improve efficiency and longevity of the filter media.
In-vessel composting systems may employ incorporation treatment during the curing phase of the process. The treatment is applied by means of nozzles at the discharge conveyor from the vessel. Surface treatment is also an option for these sites during the curing period.
