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John - Can you share the report? I'd love to see it. Yes, composting organic materials releases VOCs. However, one of the key questions to me is: If a tree (or a leaf) falls in the forest and no one is there to compost it, does it release any more or less VOCs? This is important because, from what I understand, regulatory agencies looking at this (at least in CA) believe that regulating VOCs from composting will help them achieve overall emission reduction targets. Supposedly the agencies account for naturally-occurring VOCs, but if the amount of VOCs released from composting is substantially the same as would be released naturally, we're not getting true emission reductions, we're just double counting. Another important question is what emissions would that same volume of organic material release in the anaerobic environment of a landfill? Since that is the likely destination for collected organic materials if they can't be composted (or if the required emissions controls are not cost-effective). I would assume that a compost site would only generate significant NOx from burning diesel fuel to run grinders, turners, screens and trucks. I haven't seen a good analysis of whether it is "better" to put food in the under-sink disposal and thus to the Wastewater Treatment Plant or in a separate container with the yard trimmings to be brought to the compost site. It would seem as if we have a very mixed system. Many (though I haven't seen reliable numbers) houses have under-sink disposers, but many don't. Even in those homes that do have them, I've seen some research (and it seems reasonable) that even in homes with under-sink disposers, people don't use them 100 percent of the time. This explains why most solid waste characterization studies continue to show plenty of food scraps in the solid waste stream. And as Rick pointed out, the Treatment Plant may or may not have the capacity to handle the increased load of food. In Oakland, CA, a hauler and a wastewater treatment plant are experimenting with trucking source-separated commercial food scraps to the treatment plant for co-digestion with the other wastewater solids. It is believed that this practice may increase gas production. The remaining digested solids would then be composted (or land applied). Matthew Cotton Integrated Waste Management Consulting, LLC 19375 Lake City Road Nevada City, CA 95959 (530) 265-4560 Fax (530) 265-4547 mattcotton@no.address On Aug 11, 2006, at 12:09 PM, Reindl, John wrote: <x-tad-bigger>Does anyone have a life cycle assessment of the environmental impacts of alternative methods of handling food scraps? Recently, we received a report based on the EPA Decision Support Tool that indicated that composting has a lot of negative impacts due to VOCs from the compost sites and, if I remember right, NOx.</x-tad-bigger> --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "GreenYes" group. To post to this group, send email to GreenYes@no.address To unsubscribe from this group, send email to GreenYes-unsubscribe@no.address For more options, visit this group at http://groups.google.com/group/GreenYes -~----------~----~----~----~------~----~------~--~--- |
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