Table 1. Mean +/− standard deviation of nutrient concentrations before and after EC treatment of raw wastewater and tertiary-treated wastewater with the benchtop unit. A negative t-statistic signifies an increase in nutrient concentrations after EC treatment. 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.
| Mean concentration +/− standard deviation (μM) | |||||
|---|---|---|---|---|---|
| Wastewater Sample | Nutrient | Pre-EC treatment | Post-EC treatment | Two-tailed student's t-test results | % Mean reduction |
| Raw | Nitrate + Nitrite | 11.20 +/− 0.79 | 10.63 +/− 0.31 | t = 1.36, p = 0.2218 | N/A |
| Nitrite | 0.52 +/− 0.07 | 0.33 +/− 0.06 | t = 3.83, p = 0.0087 | 64.48 | |
| Ammonium | 1349.34 +/− 10.88 | 1155.76 +/− 63.67 | t = 5.99, p = 0.0079 | 14.35 | |
| Phosphate | 62.76 +/− 20.17 | 2.65 +/− 0.42 | t = 19.93, p = 0.0003 | 95.79 | |
| Tertiary-treated | Nitrate + Nitrite | 2.88 +/− 0.22 | 1.49 +/− 0.38 | t = 6.34, p = 0.0007 | 48.35 |
| Nitrite | 0.11 +/− 0.03 | 0.41 +/− 0.02 | t = −15.87, p < 0.0001 | N/A | |
| Ammonium | 3.08 +/− 0.19 | 4.78 +/− 0.29 | t = −9.74, p < 0.0001 | N/A | |
| Phosphate | 3.95 +/− 0.20 | 0.15 +/− 0.02 | t = 37.87, p < 0.0001 | 96.33 | |