Item A - PH on MWMC/Metro Plan - Laserfiche WebLink

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File Numben 55999 Page 5 of 26 Pages d. Groundwater ' ' · (1) All wastewffter and process related residuals shall be managed and disposed of in a manner that will prevent: A violation of the Department's Groundwater QUality .'.,.. Protection Rtiles (OAR 340-040); and A violation of any permit-specific groundwater concentration limits, established pursuant to OAK 340-040-0030, which have been'; 'subsequently incorporated into this .permit. (2) The Department may reopen this permit, if ne. ce. ssary; t.o inc. lud,e,group, dw.a, ter p .ar. am, et, e~, concentration limits, and'compliance points that are aeterm~nea oasea on uae rewsea aa~a analysis report required by Schedule C. NOTES: 1. 'The CBOiJs concentration limits are considered equivalent to the minimum design criteri~for BeDs specified in Oregon Administrative Rules (OAK) 340-41. These limits and CBOD5 mass limits may be adjusted (up or down) by permit action if more acc.u, rate information reg~rdi/ag. CBOD~BOD5 becomes available. - 2. If a single sample 'exceeds 406 organisms per 1.00 rnl, then five consecutive re-sampIes may.b~ taken at four- hour intervals beginning within 28 hours after the original sample was taken. If the log mean of the five re- samples is less than or equal to 126 organisms per 100 ml, a violation shall not be triggered. '~. If continuous monitoring for pH is conduCted, pH values shall .not be outside the range 6.0 to 9.0 for more than a total of 7 hours and 26 minutes in any calendar m. onth; and no individual excursion fxom thisrange shall exceed 60 minutes. ' ~ 4. ' Upon review and approval of the engineering studies specified in Schedule D, Conditioh 8., and at the request of the permittee, the Department intends t.o modify this permit and include revised permit limits.. ,~nozn~ ~,.~ l'4~;ranu;re~th uermitteetoorovia~wnu=n.¢locumcnmuonwtmu~=mv. Y . ~ ~.. .......... '~-----:++-- ~^-,,,~-ntation will nrovlde a detailed explanation for tbe excursion. . permittee ~z~ show that the excursion did not result m a stream condition which exc~ds the water quality standard for chlorine, then the excursion shall not be considered a violation of this penuit. Continuous monitoring of the effluent Total Residual Chlorine using.~, alytica, l methods ,not appr.o.,ve.d, ~n 40 C~i~FR. Part 136 may be used for process control, but will not be usea mr verifying compliance wua mis perm 6. The excess thermal lo~d limit was calculated using the average dry weather design flow and tiae 7-day moving average maximum effluent temperature. The excess thermal load limit applies only during the summer discharge season between May 1 and October 31, when the Willamette River is water quality limited for temperature. The excess thermal load limit was calculated using the average dry weather design flow and the degrees Fahrenheit that the maximum 7-day-moving average effluent temperature exceeds the applicable stream temperature standard, as follows: 49 DADWF (MGD). x 1,000,000 x g.34 lbs/gallon x (71.6 maximum effluent temperature in °F - 64 applicable standard in °F) =3.1 Billion BTUs/day (rounded to two significant figures). The weekly average excess thermal load (BTUs/day)'will be calculated as follows: ' Weekly average flow (MGD) x 1,000,000 x 8.34 (lbs/gallon) x (weekly average of daily maximum effluent temperature in OF - 64 OF). "' 7. The permit limitations for ammonia are based upon the current Ore~on Water Quality Standards, OAR 340- 041 Table 20. This permit may be re-opened and the limits modified upon adoption a new Oregon standard fo, mon,,o n 40 CFR Part 136 may be used for process control, but wm not Ge usea mr venq, m~ uoml~ permit. 4-29