2009-01-26_HYDROLOGY - C1980007 - Laserfiche WebLink

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Ms. Kelly Morgan January 15, 2009 Page 2 of 3 permit be modified to reflect the correct wastewater treatment classification in a letter dated October 30, 2008. d. The Colorado Rural Water Association has been requested to visit the site and examine our system in an effort to identify potential improvements to MCC's wastewater treatment facility to maintain compliance with current limits. 2. Two Exceedances of Percent Removal of Total Suspended Solids MO AVG MIN at Outfall 007. a. Outfall 007A is an internal domestic wastewater discharge point that flows into a large lined pond that discharges through Outfall 004. b. These exceedances occurred on November 4, 2008 at 9:30 a.m. and December 4, 2008 at 9:00 a.m. The TSS measured in the influent at Outfall 007 was 80 and 43 mg/1 and the effluent, 33 and 7 mg/1, respectively. The percent removal was calculated as 58.8 and 83.7%, respectively. These calculated percent removals were less than the minimum percent removal permit limit for TSS of 85%. These percent removal exceedances are attributable to the amount of grey water in the influent to Outfall 007A from showers, sinks and floor drains. The low concentration of solids in the grey water makes consistently meeting the 85% removal for TSS extremely difficult. To address the percent removal issue, MCC met with you and Mr. Andrew Neuhart on September 11, 2008. At that meeting, we discussed modifying the permit to change the requirement from percent removal to establishing a mass loading limit for TSS. Mr. Neuhart indicated that the WQCD understands this issue and has made this change in permits for facilities in a similar situation. MCC submitted a permit modification request to the WQCD on October 30, 2008. c. The Colorado Rural Water Association has been requested to visit the site and examine our system to identify potential improvements to MCC's wastewater treatment facility to address the percent removal issue in an effort to comply with current limits. 3. Exceedance of Percent Removal of BOD5 DAY MO AVG MIN at Outfall 007. a. Outfall 007A is an internal domestic wastewater discharge point that flows into a large lined pond that discharges through Outfall 004. b. The exceedance occurred on December 4, 2008 at 9:00 a.m. BOD5 measured in the influent was 24.1 mg/1 and the effluent was 6.0 mg/l. The percent removal was calculated to be 75.0%, which is less than the minimum percent removal stated in the permit for BOD5 of 85%. Similar to the TSS percent removal exceedances described above, MCC believes the reason for the percent removal exceedance is attributable to the amount of grey water in the influent to Outfall 007A from showers, sinks and floor drains. The low concentration of solids in the grey water makes consistently meeting the 85% removal for BOD5 extremely difficult. To address the percent removal issue, MCC met with you and Andrew