Table 5.
MS2 and HM‐175 reduction during alkaline stabilization at 4°C
| Time (h) | Average viral concentration (log10 total PFU ± SE)* | Significant§ | |||||
|---|---|---|---|---|---|---|---|
| MS2 PBS control | HM‐175 PBS control | HM‐175 sludge control | MS2 sludge control | HM‐175 sludge stabilization | MS2 sludge stabilization | ||
| 0 | 6·27 ± 0·15 | 6·82 ± 0·03 | 6·32 ± 0·06 | 5·19 ± 0·07 | 6·32 ± 0·06 | 5·19 ± 0·07 | |
| 0·1 | –† | – | 6·32 ± 0·02 | 5·13 ± 0·08 | 5·44 ± 0·31 | 2·48 ± 0·05 | Yes |
| 2 | – | – | 6·20 ± 0·06 | 3·81 ± 0·02 | 5·22 ± 0·39 | 2·21 ± 0·21 | Yes |
| 12 | – | – | 6·13 ± 0·08 | 3·67 ± 0·06 | 4·26 ± 0·18 | 1·85 ± 0·29 | No |
| 24 | 6·20 ± 0·17 | 6·66 ± 0·05 | 5·97 ± 0·10 | 3·50 ± 0·13 | 1·20 ± 1·20 | 0 | No |
| Reduction‡ | 0·07 ± 0·32 | 0·16 ± 0·08 | 0·35 ± 0·42 | 1·68 ± 0·37 | 5·12 ± 2·13 | 5·19 ± 0·63 | No |
*Average concentration of target virus ± SE from three trials under the following conditions: PBS control (virus spiked PBS, pH 7), sludge control (virus spiked in 4% TS sludge, pH 7), sludge stabilization (virus spiked into 4% TS sludge, treated with 8% (w/v) Ca(OH)2, pH 12 for 2 h then 11·5 an additional 22 h).
†Sample not tested (–).
‡Average total reduction of target virus, including loss because of experimental conditions, during three trials of stabilization ± SE.
§Significant difference between square root transformed viral concentrations of the test beakers at each time point determined by T‐HSD, P ≤ 0·05.