TABLE 3.
Particle concentrations in wastewater biofilms and corresponding water phase before and after applying a turbulent regime for 1 min (from 30 to 380 rpm)
| Microorganism | Size | Concn in wastewater biofilm (log units·cm−2)a:
|
% Detachmentb | Concn in water phase (log units·liter−1)c:
|
||||||
|---|---|---|---|---|---|---|---|---|---|---|
| Before turbulent regimen
|
After turbulent regimen
|
Before turbulent regimen
|
After turbulent regimen
|
|||||||
| Avg | SD | Avg | SD | Avg | SD | Avg | SD | |||
| Giardia | 10 μm | 2.02 | 0.49 | 1.10 | 0.66 | 88 | 4.40 | 3.32 | 5.48 | 0.25 |
| Cryptosporidium | 5 μm | 2.67 | 0.51 | 1.78 | 0.67 | 87 | 4.40 | 0 | 5.59 | 0.16 |
| Total bacteria | 1 μm | 7.54 | 0.09 | 6.88 | 0.08 | 78 | ND | NA | ND | NA |
| Thermotolerant coliforms | 1 μm | 3.26 | 0.09 | 2.62 | 0.03 | 77 | 4.10 | NA | 5.93 | NA |
| Heterotrophic plate count bacteria | 1 μm | 5.80 | 0.04 | 5.22 | 0.03 | 74 | 7.85 | NA | 9.02 | NA |
| Infectious poliovirus | 30 nm | 3.05 | 0.10 | 2.44 | 0.01 | 75 | 5.58 | 0.37 | 5.91 | 0.09 |
| Poliovirus genome | 3.21 | 0.16 | 2.77 | 0.19 | 64 | 5.57 | 0.10 | 6.26 | 0.27 | |
a
For average concentrations, n = 3.
b
Percentages of detachment were calculated according to the following formula: % detachment = (1 − [10C after/10C before]) × 100, where “C after” and “C before” are the concentrations in wastewater biofilms before and after the turbulent regimen.
c
n = 2 for all parameters except for the heterotrophic plate count bacteria and thermotolerant coliforms, where n = 1. ND, not determined; NA, not applicable.