TABLE 1.
Characteristics of different membrane types used for the manufacturing of the in situ mesocosm systema
| Membrane type | Mesh width (μm) | % Open surface | Diffusion rate (t95%) of 3CBA (h)b | Mass transport coefficient (K) (liters h−1) of 3CBA | Diffusion rate (t95%) of Zn (h)b | Mass transport coefficient (K) (liters h−1) of Zn | Time (h) for equilibrium migration of one bacterial strain | Time (h) for equilibrium migration of a bacterial population |
|---|---|---|---|---|---|---|---|---|
| 72 RVS 25/25 | 25 | 25 | 12 | 0.07 | 7.1 | 0.13 | ND | ND |
| 72 RVS 140/32 | 140 | 32 | 4 | 0.22 | ND | ND | ND | ND |
| 49 PA 1/1 | 1 | 0.8 | 140 | 0.01 | ND | ND | ND | ND |
| 49 PA 6/5 | 6 | 5 | 55 | 0.08 | 35.5 | 0.03 | 25 | 25 |
| 49 PA 15/10 | 15 | 10 | 40 | 0.02 | 25.8 | 0.05 | 5 | ND |
| 49 PA 25/14 | 25 | 14 | 22 | 0.04 | ND | ND | ND | ND |
a
None of the membranes showed sorption of BTEX. Other membranes tested for sorption included polypropylene, ethylene-tetrafluorethylene, and polyester membranes with different mesh widths and amounts of open surface. None of those materials showed significant sorption. ND, not determined.
b
Number of hours after which 95% of the equilibrium (when the contaminant concentrations in both chambers were the same) was reached.