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Mr. William A. Bear -2- June 22, 1982 <br />• P. Brand name and manufacturer/supplier <br />C. Chemical or generic formula <br />D. Application rate/dosage <br />E. Use of any coagulant aids <br />. F. Lab results of jar tests <br />III. Monitoring of Effluent <br />A. Total volume of flocculant used per quarter <br />B. Discharges should be monitored for all surface water parameters in <br />Attachment A. (After a year's monitoring data, the Division may reduce <br />the number of parameters required, based on site-specific conditions.) <br />IV. Sediment Monitori <br />A. Sediment may need testing depending on type of coagulant and method of <br />disposal. These sediments may be toxic due to the concentration of <br />coagulant, or unsuitable due to colloids. <br />V. Operational Considerations <br />A. If discharge will continue after closing the mine, the company must <br />commit to treating as Iong as required. Under Section 4.05.2(2), <br />the facilities must be maintained until either the discharge continu- <br />• ously meets effluent limitations without treatment or until the discharge <br />has permanently ceased. <br />Second, it appears from the sediment control design presented that <br />water would discharge through the emergency spillway as the result <br />of a 10-year, 24-hour precipitation event. This is specifically <br />prohibited by Rule 4.05.6(3)(e) and the EPA regulations for waste <br />water treatment upon which the sediment control regulations are based. <br />In order to avoid discharging water through the emergency spillway during a <br />10-year, 24-hour storm, an open orifice dewatering device/principal spillway <br />would have to be incorporated into the pond design. Considerations for such <br />a device should include: <br />Z. flood routing to show detention time and to show that emergency <br />spillway discharges will not occur. <br />a. a detention time of 6 to 8 hours is sufficient for most <br />flocculated systems. <br />2.. sufficient storage below the elevation of the dewatering device <br />to allow for sediment storage. <br />3. a configuration designed to preclude discharge of material suspended <br />on the surface film (a common problem with coal fines, oil and grease). <br />• <br />n <br />