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ATTACHMENT 1 <br /> SCOPE OF WORK <br /> SOUTH RO PLANT CONCENTRATE DISPOSAL <br /> PERMIT RENEWAL <br /> Project Description and Understanding <br /> Indian River County ' s (IRC) South RO water treatment plant (Oslo Road) currently has <br /> a permit to dispose of concentrate to a surface water body under Florida Department of <br /> Environmental Protection (FDEP) Permit 31 -FL0037940 — Minor NPDES Non-POTW <br /> Discharge . The permit allows for 1 . 5 mgd maximum daily flow of concentrate disposal <br /> to the South relief canal and expires December 14 , 2005 . A permit renewal application, <br /> including supporting data, must be submitted at least 180 days (June 17 , 2005 ) before <br /> the expiration date of the permit in accordance with specific condition VII. C . 10 <br /> The concentrate, or byproduct of the water treatment process, is currently treated to <br /> remove hydrogen sulfide and increase dissolved oxygen. The treated byproduct is <br /> discharged through a 14" pipe, approximately 3 , 650 ft long into the Indian River <br /> County South Relief Canal, a Class III fresh water body. The outfall is downstream of a <br /> control structure and thence 10, 000 feet downstream into the Indian River, which is <br /> classified at that point a Class III marine body. Chlorination is performed to primarily <br /> eliminate the majority of hydrogen sulfide (H2S ), whereas air is injected into the stream <br /> to remove the remaining H2S and increase dissolved oxygen . A mixing zone is <br /> approved for three parameters : Gross Alpha, Combined Radium (Ra 226 and Ra228) and <br /> specific conductivity, all of which have different and distinct mixing zone limits . <br /> Turbidity and chromium were limits originally established under the original permit, <br /> however, based on historical levels measured well below standards , limits for these <br /> parameter were removed from the previous permit . <br /> Through discussions with staff, the South County RO plant has indicated historical <br /> failures of toxicity testing for mysidopsis bahia (mysid shrimp) and has reported these <br /> results to FDEP . Based on this, it is believed that ion imbalance toxicity exists and a <br /> variance for acute toxicity and/or a mixing zone for chronic toxicity will need to be <br /> addressed under this permit renewal process . IRC ' s current permit does not require <br /> testing for chronic toxicity. It is believed that FDEP will request that IRC conduct ion <br /> imbalance review and testing. <br /> SCOPE OF SERVICES <br /> In general , the following scope of services will include review of existing permit and <br /> pertinent data, meetings with FDEP and IRC staff, preparation and submittal of permit <br /> application including existing information (majority provided by IRC) , existing mixing <br /> models , and no changes in capacity or quality of concentrate, conducting ion imbalance <br /> water quality testing to address acute toxicity, toxicity investigation evaluation, and <br /> H:\044572009\South RO Plant Concentrate Disposal-revl .doc 1 <br />