Table 3. Mean +/− standard deviation of personal care product concentrations before and after EC treatment of raw and tertiary-treated wastewater with the benchtop unit (n = 4, unless otherwise noted). Any undetected analytes are listed as less than the reported process limit of detection (<pLOD). When a two-tailed student's t-test (t) or Wilcoxon Rank Sum test (S) revealed a positive, significant difference (α = 0.05) between pre- and post- EC treatment concentrations, the mean percent reduction was calculated. Results that exceeded the calibration range but did not saturate the instrument detector are indicated with an E. Results that were likely underestimations (laboratory control sample spike below the control limit) are indicated with*.
| Raw wastewater | Tertiary-treated wastewater | |||||||
|---|---|---|---|---|---|---|---|---|
| Mean concentration +/− standard deviation (ng/L) | Mean concentration +/− standard deviation (ng/L) | |||||||
| Analyte | Pre-EC treatment | Post-EC treatmet | Test statistic and p-value | % Mean reduction | Pre-EC treatment | Post-EC treatment | Test statistic and p-value | % Mean reduction |
| Acetaminophen | 55750 +/− 28000E | 28000 +/− 4243E | S = 26.00, p = 0.0286 | 49.78 | <pLOD | <pLOD | N/A | N/A |
| Caffeine | 31250 +/− 3202E | 26250 +/− 4787E | S = 23.00, p = 0.1714 | N/A | <pLOD | 72 +/− 3 | N/A | N/A |
| Carbamazepine | 130 +/− 16 | 125 +/− 6 | S = 20.00, p = 0.6564 | N/A | 165 +/− 6 | 178 +/− 10 | N/A | N/A |
| DEET | 4075 +/− 263 | 3400 +/− 424E | t = 2.70, p = 0.0354 | 16.56 | 29 +/− 1 | 68 +/− 12 | N/A | N/A |
| Gemfibrozil | 2700 +/− 13 | 2350 +/− 82E | t = 4.58, p = 0.0038 | 12.96 | <pLOD | <pLOD | N/A | N/A |
| Ibuprofen | 12000 +/− 817E | 9950 +/− 900E | t = 3.37, p = 0.0150 | 17.08 | <pLOD | <pLOD | N/A | N/A |
| Iopromide | 4600 +/− 653* | 3325 +/− 619*, E | S = 26.00, p = 0.0286 | 24.77 | 505 +/− 31 | 350 +/− 26 | t = 7.67, p = 0.0003 | 31.00 |
| Meprobamate | 655 +/− 48 | 660 +/− 82E | t = 0.11, p = 0.9193 | N/A | 588 +/− 24E | 645 +/− 44E | N/A | N/A |
| Naproxen | 11250 +/− 500E | 11250 +/− 500E | S = 18.00, p = 1.0000 | N/A | <pLOD | <pLOD | N/A | N/A |
| Phenytoin | <pLOD | 130 +/− 0 (n = 2) | N/A | N/A | 183 +/− 15 | 208 +/−15 | N/A | N/A |
| Primidone | <pLOD | <pLOD | N/A | N/A | <pLOD* | <pLOD* | N/A | N/A |
| Salicylic Acid | 32500 +/− 5568 | 9425 +/− 961E | S = 26.00, p = 0.0286 | 71.00 | 61 (n = 1) | 78 +/−15 | N/A | N/A |
| Sulfamethoxazole | 1925 +/− 310 | 1700 +/− 548E | t = 0.72, p = 0.5013 | N/A | 24 +/− 5 | < RL | S = 26.00, p = 0.0286 | 58.76 |
| Thiabendazole | <pLOD | 15 +/− 1 | N/A | N/A | 20 +/− 1 | 18 +/− 1 | t = 3.00, p = 0.0240 | 10.00 |
| Triclocarban | 728 +/−200 | 113 +/− 75 | t = 5.77, p = 0.0012 | 84.54 | <pLOD | <pLOD | N/A | N/A |
| Triclosan | 1350 +/−238 | 248 +/− 89 | t = 8.68, p = 0.0001 | 81.67 | <pLOD | <pLOD | N/A | N/A |
| Trimethoprim | 488 +/− 54 | 508 +/− 48E | t = 0.56, p = 0.5986 | N/A | <pLOD | <pLOD | N/A | N/A |
| Warfarin | <pLOD | <pLOD | N/A | N/A | <pLOD | <pLOD | N/A | N/A |