Additional Comments Summary Response to Additional Comments

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RESPONSE SUMMARY REVISED DRAFT ORDER OF APPROVAL NO. 10052 Comment Period – September 13 – October 28, 2010 Commenter Comment Synopsis department's concern about the potential for vector access to the food waste component of the residential collections. Cedar Grove also believed that use of the tarps would incidentally reduce the potential for odors from the piles. Cedar Grove did not believe these zones to be significant odor sources. However, Cedar Grove learned that at least one PSCAA inspector was telling residents that "garbage" odors they were experiencing were attributable to Cedar Grove accepting food waste for composting. In fact, that inspector acknowledged earlier this week that he had never smelled a "garbage" odor offsite from Cedar Grove that he attributed to the compo sting facility. Nevertheless, there has continued to be public speculation that acceptance of food waste had increased odors from the Maple Valley facility. Cedar Grove told PSCAA management about the idea of using the tarps on Zones 1-6 earlier this year, and launched a pilot in June to see if the tarps would alter the composting process. The pilot showed that the covered piles remained aerobic and composted normally. Unfortunately, PSCAA's inspector took the position that this pilot violated Cedar Grove's permits for zones 1-6. Accordingly, Cedar Grove suspended the experiment in early July. In considering ways to respond to odor complaints during July and August of this year, Cedar Grove suggested that approval for use of the tarps on Zones 1-6 be included in this revised Draft Order. PSCAA informed Cedar Grove that this request had been made too late in the process, and would have to be addressed in a separate NOC. PSCAA's air engineer also requested more information about the effect of the tarps on performance of the existing negative aeration system serving Zones 1-6, and on the compo sting process. In order to demonstrate that the tarps would not adversely affect either the composting process or the negative aeration system, Cedar Grove initiated another pilot with use of the tarps in Zones 1-6. As part of the pilot, Cedar Grove had a third party contractor take air samples on top of piles that were covered and uncovered and ship those sampled to a lab for odor analysis. Also, responding to the concern about the impact of residential food waste on odors, Cedar Grove prepared a pile consisting only of yard waste and collected an air sample above that pile as well. This sampling showed that the pile containing a mix of yard and food waste actually produced about half as much odor as the yard waste pile. Part of the explanation appears to be a higher carbon content in the mixed waste pile, due for example to the paper based feedstocks (pizza boxes, etc.) that routinely accompany residential food waste. Incidentally, this sampling disproves the concern that the addition of a small food waste component in Zones 1-6 has increased odors from the site. The sampling also showed, not surprisingly, that odors above the tarped pile were much lower; about half of the result above the mixed waste pile, and about a quarter of that of the yard waste pile. Pile temperatures and oxygen levels demonstrated that the covered pile remained aerobic and composted properly. Cedar Grove's contractor also compared static pressure and fan operations between a
RESPONSE SUMMARY REVISED DRAFT ORDER OF APPROVAL NO. 10052 Comment Period – September 13 – October 28, 2010 Commenter Comment Synopsis covered and uncovered pile, and found them comparable and within normal operating ranges. Accordingly, use of the tarps on Zones 1-6 appears to be a success. Unfortunately, PSCAA's inspector once again objected to their use, issuing an order to Cedar Grove on October 12 to remove them from the piles immediately. Cedar Grove complied. Next week, Cedar Grove plans to submit a request to PSCAA for a determination that no NOC is required for use of the tarps, since they do not alter existing odor control equipment and do not increase emissions. The information described in these comments will accompany that application. Cedar Grove also is evaluating whether the tarps could be used on the secondary zones at Maple Valley. Differences in the aeration system serving that portion of the facility could make that difficult. Also, there has been no indication that the secondary zones are a significant source of off site odors. Still Cedar Grove intends to continue to evaluate this option, and will consider other opportunities to reduce the potential for odors from the Maple Valley site as they arise. Specific Comments On Proposed Permit Conditions No Legal Basis for New Conditions. PSCAA has acknowledged that the NOC does not request any production increases, nor any modifications to Cedar Grove's operations beyond those previously reviewed and approved by PSCAA. The sole purpose of the NOC, which Cedar Grove agreed to submit as part of the 2008 settlement agreement between the parties, is to consolidate the conditions of previously issued PSCAA Orders of Approval and to incorporate requirements established in the 2008 settlement agreement into a single Order of Approval. As Cedar Grove has neither established a new source nor modified a source in a manner that would increase air emissions, there is no legal basis under RCW 70.94.152 or PSCAA Regulation I, Article 6 to impose either new plant-wide emission limits or new requirements on specific control devices. Continuous Monitoring of Biofilter Airflow. PSCAA has proposed requirements for the continuous monitoring of velocity pressure, static pressure, and temperature of the inlet gas stream to each biofilter. These parameters are not meaningful indicators of biofilter performance, nor is continuous monitoring warranted. Air pressure measurements will vary for the aerated static piles ("ASP") depending on how many piles are in use and activities on the ASP pads. While biofilters serving the grinding and tipping building will not see the same level of variation, their air pressure readings also are likely to vary over time. These variations, particularly on a short term basis, have no implications for biofilter performance. Similarly, PSCAA has not identified any correlation between instantaneous biofilter inlet gas temperatures and biofilter performance. At a minimum, PSCAA should not require continuous electronic monitoring, which may be difficult and expensive to install while producing data with little or no
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Additional Comments Summary Response to Additional Comments

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