Earth Tech Memo Re Information Related To
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Memo Date: February 3, 2000 EPA Region 5 Records Ctr. 224388 From: Barry Christian, Earth Tech Subject: Illinois Central Spring Earth Tech Project Number 28522 On January 26, 2000, Britt Luther asked us to compute some parameters related to storm events at the Illinois Central Spring site in Bloomington. Indiana. These parameters included the following: 1. the peak flow rates produced by each of the three storm events; 2. the percent of PCB (i.e., TSS) removal with 2-acre and 4-acre feet of storage capacity under 2-year, 10-year and 25-year storm event conditions; 3. the total volume under the hydrograph for these three storm events; and 4. the total flow volume that bypasses the treatment system under each of the three storm events. This memo and its attachments provide the information requested. The information requested is summarized in Table 1 of Attachment 1. An explanation of the work we performed to generate the infonnation for each of these four items is presented below. Items 1 and 2 The first step in preparing this information for you was to define the 2-year and 10-year storm parameters based on the January 22, 1997 storm event. The 25-year storm event was previously defined. This first step resulted in the generation of two factors to scale up the flow rate, TSS concentration and PCB concentration from the January 22, 1997 storm event to the 2-year and 10-year storm events. Attachment 2 of this memo describes the scale-up factors and the methods and assumptions employed to calculate them. Attachment 2 consists of a memo from Aaron Volkening. The methods and assumptions employed to compute these parameters were the same as previously employed to define the 25-year storm event upon which the treatment system design is based. The methods and assumptions previously employed are largely described in the following three documents: a memo from Barry Christian to Britt Luther dated December 10, 1998; a memo from Garth Greenan to Barry Christian dated December 18, 1998; and a report titled, Assumptions Employed in the Design of the ICS Facility..." published by Earth Tech in April 1999. The second step in preparing this infonnation was to use the scale up factors (described in Attachment 2) to generate flow rates, TSS concentrations and PCB concentrations for the 2-year and 10-year storm events. Peak flow rates for the 2-year and 10-year storm events (item 1. above) came from completing this step. Infonnation generated during this step was then used to compute the TSS and PCB recovery by EARTH INTERNATIONAL LTD COMPANY the treatment system during the 2-year and 10-year storm events assuming both 2-acre feet and 4-acre feet of storage capacity (item 2, above). The computations are included in the spreadsheets presented as Taibles 3 and 4 for the 2-year and 10-year storm events, respectively (see Attachment 1). For completeness, the computations for the 25-year event, which Earth Tech published in 1999 are included as Table 2 (see Attachment 1). Items 3 and 4 Table 5 consists of a spreadsheet that defines the entire hydrograph for the January 22, 1997 storm event. Note that this was not previously done by Earth Tech. The methods and assumptions used to define the entire hydrograph are described in Aaron Volkening's memo included in Attachment 2. The entire hydrograph was then scaled up using the same scale-up factors previously described for the 2-year, 10- ye.ir and 25-year storms. The scaled-up hydrographs for these storm events are also presented in Table 5. The spreadsheet itself is cumbersome. It will help a reader to understand that the spreadsheet is 12 pages in length, 3 pages deep and 4 pages wide. The total discharge volume from the spring and the total discharge volume that bypasses the treatment system for the three storm events are computed and displayed on pages 6, 9 and 12 of Table 5. They are also summarized in Table 1 of Attachment i. EARTH A tlfCO INTERNATIONAL LTD. COMPANY ATTACHMENT 1 iLA Table 1 Comparison of Storm Events Parameters and TSS Recovery for Three Storm Events and Various Storage Volumes 25-Year Storm 10- Year Storm 2 -Year Storm Storage Capacity Storage Capacity Storage Capacity Storm Parameters 2 Acre-Feet 4 Acre-Feet 2 Acre-Feet 4 Acre-Feet 2 Acre-Feet 4 Acre-Feet Multiplier Applied to January 1997 Hydrograph Data 2.958 2.958 2.342 2.342 1.806 1.806 Pounds TSS Generated 8008 8008 5020 5020 2985 2985 Pounds TSS Recovered Process+Storage) 3804 5603 3124 4249 2261 2838 'ercent TSS Recovery Process+Storage) 48 70 62 85 76 95 'eak Discharge During Event (GPM) 5403 5403 4278 4278 3299 3299 V Total Volume Under lydrograph (gallons) 17,300,000 13,700,000 10,600,000 Volume Bypassed (Untreated) 8,200,000 5,100,000 2,600,000 Table 2 Illinois Central Spring Storm Event Analysis and Process Design Parameters 25 Year Storm Event Tim* January 22. 1997 Storm Event Parameters Rain Flow 1 PCB's TSS Basis of Potal Flow] PCB TSS3 TSS Mass Cumulative Design Time Serial Date/Time Rain Rate Rate Concentration <Concentration Flow Rate TSS Mass Period Number (in.) (gpm1) (ppb2) (mg/L) (Ib/hr) Flow (Ib) <£m>amm B0t/22fl997!;0;00* •0- 159.2 5.1 0 0 0 01/22/19971:00 •o- 182.5 0 0 0 0 01/22/1997 2:00 rj.os 206.7 5.5 0 0 0 01/22/1997 3:00 0.02 246.8 0 0 0 0 01/22/1997 4:00 0.12 347.9 5.7 0 0 0 ,__ 01/22/19975:00 0.02 510.4 0 0 0 0 ffBWC&wMSfftfcZMWnfcWS 0.06 715.5 18 12 A 4 01/22/1997 7:00 0.06 992.4 13 78 39 43 01/22/1997 8:00 0.22 1157.5 18 110 64 107 01/22)1997 9:00 0.23 1358.2 120 140 95 202 01/22/1997 10:00 0.04 1797.8 120 140 126 328 01/22/1997 11:00 "0- 1826.6 170 110 101 429 01/22/1997 12:00 "0- 1784.8 51 51 46 474 01/22/1997 13:00 "0- 1766.0 74 86 76 550 01/22/1997 14:00 "0" 1790.4 63 57 51 601 01/22/1997 15.00 "o- 1785.9 38 44 39 641 01/22/1997 16:00 ro- 1792.3 44 35 31 672 501/22/1997^7:00; "0- 1776.8 35 30 27 699 01/22/199718:00 •o- 1751.9 38 8 7 706 01/22/1997 19:00 "0" 1714.7 26 3 3 708 01/22/199720:00 •0- 1651.9 30 6 5 713 01/22/199721:00 •0" 1626.2 17 7 6 719 1 01/22/199722:00 •0" 1579.2 16 6 5 724 01/22/1997 23:00 •0" 1523.8 11 7 5 729 01/23/1997 0:00 •o- 1507.5 16 6 5 734 01/23/1997 1:00 "0" 1465.6 9.9 2 1 735 01/23/19972:00 •0" 1428.3 8.6 15 11 746 01/23/1997 3:00 "0" 1392.1 8.9 0 0 746 01/23/1997 4:00 "0" 1361.4 13 2 1 747 01/23/1997 5:00 •0" 1320.7 6.5 0 0 747 01/23/19976:00 "0" 1285.0 6.8 7 5 752 01/23/19977:00 •0" 1242.4 6.4 4 2 754 SMr01/23/.199mOOJ "o- 1209.7 4.1 6 4 758 I 01/23/19979:00 "0" 1181.4 0 0 0 758 01/23/1997 10:00 TT 1161.3 0 0 0 758 01/23/1997 11:OC •0" 1141.7 0 0 0 758 01/23/1997 12:00 "0" 1122.3 3.2 0 0 758 PoameM* 1 . gpm - gallons per minute. 2. ppb - parts per billion. 3. TSS - Total Suspended Solids. 4. Values based on process TSS capture for entire storm event (1739 Ib.) plus cumulative TSS captured in storage. L:Vwofk\28522\pro)admin\25yrstormevent PageloTS 02/02/2000 Table 2 Illinois Central Spring Storm Event Analysis and Process Design Parameters 25 Year Storm Event Time Model 25-Ytar Storm Parameters Flow PCB's TSS PCB TSS TSS Basis of nstantaneous Concentration CB Mass umulative Concentration Concentration SS Mass umulative Design Time Serial Date/Time Flow Rate Cumulative w/safety low Rate CB Mass Based on with 20% Safety low Rate SS Mass Period Number (gpm) Flow (gal) factor(ppb) (Ib/hr) Flow (Ib) Model (mg/L) Factor (mg/L) (Ibs/hr) low (Ibs.) SjorageiT lilig 01/22/1997,'0:OOS 471 28255 18 0.004 0.004 0 0 0 0 ilwilaStS »m 01/22/1997 1:00 540 60645 0 0.000 0.004 0 0 0 0 01/22/19972:00 611 97330 ' 20 0.006 0.010 0 0 0 0 01/22/19973:00 730 141132 0 0.000 0.010 0 0 0 0 01/22/1997 4:00 1029 202877 20 0.010 0.021 0 0 0 0 01/22/1997 5:00 1510 293463 0 0.000 0.021 0 0 0 0 jgSBrOCfSBMft 01/22M997-.6:001 2116 420450 64 0.068 0.089 35 43 45 45 %'QMm$mM 01/22/1997 7:00 2936 596581 46 0.068 0.157 231 279 410 455 01/22/19978:00 3424 802014 64 0.110 0.267 325 393 674 1129 01/22/19979:00 4018 1043068 429 0.862 1.130 414 500 1006 2135 01/22/1997 10:00 5318 1362141 429 1.141 2.271 414 500 1332 3466 01/22/1997 11:00 5403 1686326 607 1.643 3.914 325 393 1063 4529 01/22/1997 12:00 5279 2003093 182 0.482 4.396 .