FIELD DOCUMENTS AND WORK PLANS 1990

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Marley Cooling Tower Company 2 19 June 1990 time is supposed to be 21 days (although the actual turn-around time is about 60 days) . MCTC is discussing this problem with Weston and are talking with other labs. The NPDES permit requires that monthly monitoring reports be submitted on the 15th day of the following month. So even with the standard 21 day turn-around with Weston, monitoring report submittals will still be late. Apparently, quicker (7 day) turn-around times are available at a 50% increased cost. MCTC is proposing to conduct a more extensive sampling and analytical program. Hexavalent chromium, total chromium, and copper levels will be measured (with an onsite Hach DR3000 unit) at various points in the treatment system, including the effluent. This type of monitoring could help reduce the duration of permit violations because of the instantaneous nature of the monitoring (i .e. , MCTC won't have to wait 60 days for results) , however, the test method's reliability and sensitivity are questionable, and the method is not certified by the state. I recommend that MCTC develop a three month Hach monitoring program. The objective of this program will be to identify the accuracy and precision of the Hach method in measuring levels of hexavalent chromium, total chromium, and copper. This program should include a detailed monitoring plan, a QA/QC program, and a contingency plan. The monitoring plan should include the location and frequencies of samples. QA measures should include a description of the procedures involved in the collection, preparation, and field testing of samples, field log sheets, data management, and training activities. QC measures should include at least 10% duplicate and 10% spike measurements utilizing the Hach method, and the validation of at least 10% of the Hach measurements with state certified laboratory analyses of split samples. The results of this program shall be reported, along with the regular monitoring results, in the monthly monitoring reports. At the conclusion of this three month period MCTC shall submit to us a technical report summarizing the data, statistically determining its accuracy and precision, evaluating its effectiveness, and recommending either continued implementation or modifications as appropriate. If the Hach procedure is determined to be inappropriate, MCTC should consider on-site chemical analyses utilizing wet chemical and/or atomic adsoption techniques. The second major problem discussed in MCTC's 4 June letter dealt with the cause of the permit effluent violations. According to MCTC the fouling of the ion exchange resins (either due to a buildup of iron on the resin from the ferric chloride pretreatment of storm water, or an organic buildup) is the cause of the permit violations. Apparently the resin was given a detergent wash between May 2nd and May 14th and samples of the resin, before and after the wash, were sent to the resin manufacturer for analysis. These results are not in yet. However, MCTC sampled the system following the detergent wash (May 14 and 15) , and the data from Weston labs indicates that the effluent is now within permit limitations for Total Chromium, Hexavalent Chromium, and Total Copper. MCTC has deduced that the system exceeded permit limitations because of a loss of ion exchange capacity in the resin due to the ferric chloride treatment of the storm water. They had this same problem last winter and they succeeded in resolving it in a similar manner (i .e, a detergent bath) .