Table 1. Summary of Bulk Water Results for the Five Assays Used to Quantify Microbial Counts Throughout the Advanced Treatment Traina.
| result | assay | units | tertiary wastewater | ozone | BAC | MF/UF | MF/UF storage tank | RO | AOP |
|---|---|---|---|---|---|---|---|---|---|
| geometric mean | total ATP | nM | 6.86 × 10–1 | 1.05 × 10–1 | 9.50 × 10–2 | 4.42 × 10–3 | 1.11 × 10–2 | 1.54 × 10–4 | 1.00 × 10–4 |
| intracellular ATP | nM | 3.96 × 10–1 | 2.56 × 10–3 | 6.99 × 10–2 | 1.81×10–3 | 5.37 × 10-–3 | 7.52 × 10–5 | n.d. | |
| total cell count | cells/mL | 6.63 × 106 | 4.31 × 104 | 6.28 × 105 | 3.90 × 104 | 4.95 × 104 | 3.53 × 102 | 1.61 × 102 | |
| intact cell count | cells/mL | 4.77 × 106 | 2.89 × 104 | 5.57 × 105 | 2.65 × 104 | 4.30 × 104 | 2.04 × 102 | 2.95 × 101 | |
| 16S rRNA gene | gene counts/mL | 6.35 × 105 | n.d. | 1.30 × 105 | n.d. | 2.08 × 104 | 1.88 × 101 | n.d. | |
| geometric standard deviation (of the geometric mean) | total ATP | 1.34 | 3.52 | 1.39 | 2.11 | 2.38 | 1.42 | n.d. | |
| intracellular ATP | 1.53 | 3.43 | 1.51 | 2.98 | 2.06 | 2.25 | n.d. | ||
| total cell count | 1.40 | 2.93 | 1.23 | 3.08 | 1.45 | 3.32 | 2.40 | ||
| intact cell count | 1.42 | 3.06 | 1.20 | 2.26 | 1.37 | 3.28 | 1.32 | ||
| 16S rRNA gene | 2.10 | n.d. | 1.99 | n.d. | 2.71 | 3.98 | n.d. | ||
| log10 removal value | total ATP | n.d. | 0.73 | 0.04 | 1.33* | –0.34 | 1.82* | 0.44* | |
| intracellular ATP | n.d. | 2.20* | –1.44* | 1.59* | –0.36* | 1.82* | n.d. | ||
| total cell count | n.d. | 2.23* | –1.16* | 1.21* | –0.19 | 2.28* | 0.39* | ||
| intact cell count | n.d. | 2.24* | –1.28* | 1.32* | –0.12 | 2.21* | 0.86* | ||
| 16S rRNA gene | n.d. | n.d. | n.d. | n.d. | n.d. | n.d. | n.d. | ||
| cumulative log10 removal value | total ATP | n.d. | n.d. | 0.90 | n.d. | n.d. | 3.78 | n.d. | |
| intracellular ATP | n.d. | n.d. | 0.80 | n.d. | n.d. | 3.81 | n.d. | ||
| total cell count | n.d. | n.d. | 0.99 | n.d. | n.d. | 4.04 | n.d. | ||
| intact cell count | n.d. | n.d. | 0.90 | n.d. | n.d. | 4.16 | n.d. | ||
| 16S rRNA gene | n.d. | n.d. | 0.63 | n.d. | n.d. | 4.74 | n.d. |
a
The geometric mean and geometric standard deviation are shown for each assay. A negative log 10 reduction value indicates an increase in microbial biomass or activity. Log10 reductions that were different from zero with statistical significance based on Student’s t-test are indicated by an asterisk. Cumulative log 10 reduction values are shown for only BAC filtrate or RO permeate, which were calculated using only samples for which data from all five assays were available (n = 4). n.d. = not determined.