06-13-11 Council Agenda & Packet

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Responses to IN TEK Comments on the Public Notice for Modification of Publicly Owned Treatment Works (POTW) Pretreatment Program — City of South Bend, IN I. Sec 17 -5 ( c ) (14) - Page 21, Any waters of wastes having a pH lower than 6.0 will be prohibited. This will require our permit to be modified, since our current Permit # 161591 -88966 has a minimum pH limit of 5.0. A minimum pH limit of 6.0 is typically applied as a water quality standard for the discharge into a water of the state in order to protect wildlife. However, it is not necessary to sped such a limit on a pretreatment facility since the final treatment facility (i. e., the POTW) has the capability adjust the pHprior to discharge to surface waters. The waiver of a pH limit at internal treatment facilities is recognized by the EPA as acceptable as long as the final treatment system discharge has a water quality based pH limit (see for example, 40 CFR 420.07). The determination to revise the minimum pH limitation was made due to problems associated with the conveyance of wastewater rather than the ability to ultimately treat and discharge water meeting pH water quality standards. The City of South Bend (City) hay` encountered several cases in which low pH discharges have been associated with damage to the POTW, specifically to pipes and structures in the collection system. Additionally, due to the nature of the material (sewage) being conveyed in the POTW, the addition of low pH discharges contributes to hydrogen sulfide generation which leads to corrosion, POTW worker safety concerns, and nuisance odors. . The lower pH limitation is being revised to address these concerns, and will remain at 6.0. 2. Sec. 17 -8 (d) (6) — Page 23, An Industrial User operating under a ermit 1 production-based Standard shall notify concentration D� ectoritwithm � `� from a q o 2 business days after the User has ,a reasonable basis to know that the production level will significantly change within the next calendar month Any user not notifying the Director of such anticipated-change will be required to.,meet the mass or concentration limit in its permit that .were based on the original estimate of the longterm average production rate. We currently provide our production data to the City of South Bend on a monthly basis in the Monthly Industrial Wastewater Discharge Report. The concern is having only 2 days to report a change before it happens in the next calendar month. Something as routine as a week long maintenance outage can have a big impact on monthly production. What is considered to be a significant change? - The purpose of this provision is to require Industrial Users to notify the Director (POTW Control Authority) when production levels change significantly enough to require a modification to limitations contained in the Industrial Users permit. In this case, any increase in production levels sufficient to cause the industrial user to be unable to comply