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ATTACHMENT 4 To 05-06-04 Draft MWMC Minutes TSS capacity. As in the BOD calculation, We are now using a different per capita load of . · .21 rather than the. 19 used in the Master Plan. Why Such a large difference. I believe it is the combination in the draft facility plan of comparing dry weather average flow design capacity with maximum rather'than average flows and the change in the peaking factor (for calculation dry weather flow, which I did not discuss) and per capita loads for calculating the capacity of BOD and TSS. I don't know what peaking factors and pounds per capita that DEQ used. I do know that they did not compare maximum flows with average flow design capacity to calculate capacity. DEQ seems to have taken the most moderate approach compared to either the Master Plan or the Draft Facilities Plan and for that reason would appear to be more reliable in their capacity evaluations, (As an interesting Side note. In February of this year, CH2MHill and MWMC staff were actually using larger per capita loads for BOD and TSS - .20 and .22 respectively. If we were to use the February 0.22 pounds per capita and plug it into the TSS formula using the population estimates in the draft facility plan, we would be generating 72,800 lbs per day of TSS, which would actually exceed the design capacity of 71,600. The following month, the pounds per capita for both BOD and TSS were reduced by .01.) · Another indication of the difference in how CH2MHill and MWMC staff are calculating current biosolid loadings is in the tons currently being generated by the facility. In Table' C-3 of the Draft System Development Charge Methodology (page C-6), MWMC staff and CH2MHill indicate that we have a current loading of 5,927 tons per year.. DEQ, in · its 2002 evaluation of the facility, indicated that "The MWMC wastewater treatment facility generated 4,240 dry metric tons during the reporting period January 1, 2000 to December 31, 2000 (page 3)." I have not yet determined if the 5,927 tons ofbiosolids reported by CH2MHill is in metric tons or not, but even if you convert the DEQ number from metric tons to tons, the numbers aren't close. The mere passage of three years can not explain a 21% or 28% difference between DEQ's and MWMC's numbers. In short, my concern in the assumptions behind the facilities plan is the dramatic loss of capacity resulting from the new manner in which CH2MHill and MWiVIC is calculating capacity. To have a facility go from having a great deal of capacity to almost none in seven years is troubling. To indicate that this new method of calculating capacity is sanctioned by DEQ would seem to be unsupported by DEQ's own actions, given that DEQ used the more conventional method of calculating capacity in its 2002 evaluation of the MWMC facilities. How Much Capacity Do We Need? Maybe I should change this section to What Should We Build? I just got offthe phone with John Gasik, at the Medford DEQ. He told me that he was in the process of reviewing the MWMC facilities plan. Being ignorant of DEQ processes, I asked him why we didn't wait'and approve the facilities plan after he had had a chance to review it. He told me that he couldn't really review the plan until the jurisdiction had selected Attachment 4 Page 16 of 17 4-19