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DocuSign Envelope ID: D07924E6-3D94-4398-AO66-B683COBAB33E <br /> February 24,2021 <br /> Angela Aalbers,Chantell Johnson <br /> Page 11 of 12 <br /> Reference: Biological Sulfate Reduction Bench-Scale Test Results-Revision 1 <br /> Table 10 -WET Test Water Quality <br /> Hardness pH Alkalinity Dissolved Conductivity Calculated Ammonia as <br /> (mg/L) (mg/L) Oxygen (mg/L) (µs) TDS (mg/L) N (mg/L) <br /> 780 8.4 1,356 7.6 3,800 1,864 0.08 <br /> 610 8.6 1,200 8.1 3,840 1,880 0.09 <br /> 690 8.5 1,220 8.8 3,950 1,933 0.04 <br /> 450 7.5 842 7.1 3,880 1,900 0.02 <br /> 650 7.6 1,380 7.1 3,850 1,885 0.02 <br /> Table 11 -WET Test Results (as provided by GEI) <br /> Treatment 'l Survival Reproduction/Growth <br /> (g OC/g SO4) Species <br /> IC25 NOEC %Survival IC25 NOEC %Effects <br /> 0.5 65.7 80 0 36.4 20 99.3 <br /> 1.0 65 100 60 42.3 40 99.5 <br /> 0.25 C Dubia 43.3 40 0 48.6 40 100 <br /> 0.5 N/A <100 0 N/A <100 100 <br /> (Softened, pH) <br /> 0.5 (pH) N/A <100 0 N/A <100 100 <br /> 0.5 N/A 100 72.5 N/A <100 49.3 <br /> 1.0 N/A 100* 75 N/A 100* 34.7 <br /> 0.25 P. N/A 100 95 N/A <100 24.7 <br /> 0.5 Promelas N/A <br /> <100 45 N/A <100 75.4 <br /> (Softened, pH) <br /> 0.5 (pH) N/A <100 0 N/A <100 100 <br /> "Control Criteria not met. <br /> SUMMARY OF TESTING AND ANALYTICAL RESULTS <br /> Four test conditions have been conducted for sulfate reduction using the BSR process. The main test variant <br /> was the organic carbon (ethanol)to raw water sulfate concentration in the test feed system influent. <br /> Based on available laboratory data, rates of sulfate reduction in the tests range from approximately 800 to <br /> 1,050 mg/L in the final test effluent. These sulfate reduction rates meet the primary test objectives to reduce <br /> potential toxicity due to elevated sulfate concentrations in the raw seep water. <br /> Despite the reduced sulfate concentrations in the treated test effluent, the WET test results have not achieved <br /> the objective of passing with sufficient survival and reproductive rates. Two potential reasons for not meeting <br /> WET objectives have been identified: (1) excess TDS or(2) calcite oversaturation. The excess TDS is <br /> considered a potential reason because the reduction in sulfate concentration does not necessarily translate to <br /> Desi� h community in mii <br /> dpg llus0321-ppfss01lshared_projects\233001407\reports\6_bench_scale_report\rpLbench_scale_report_24feb2O20_final_rl.docx <br />