I'm attempting to grow chlorella algae in a polyethylene film bag (which contains the growth medium) submerged in a temperature-moderating, above-ground swimming pool. This presents a challenge in that I would like to kill algae in the pool with $\ce{ClO2}$ while cultivating it in the bag despite diffusion of $\ce{ClO2}$ across the polyethylene film.
How often must I replace the growth medium?
The constraining quantities:
- 7.62e-16kg/m/m^2 Pa $\ce{ClO2}$ diffusion across polyethylene
- Polyethylene film thickness 0.5mm
- Bag volume to surface area ratio 5cm
- 5mg/L average $\ce{ClO2}$ concentration in the pool
- 0.1mg/L maximum $\ce{ClO2}$ concentration in chlorella growth medium
Justifications for my choice of constraints:
- Chlorella 30 minute kill rates:
- 0% @ 3ppm (and below)
- 80.7% @ 4mg/L
- 87.2% @ 5mg/L
- 99.0% @ 6mg/L
High concentrations of $\ce{ClO2}$ are desirable for disinfectant power. I'd like to keep the pool at an average of 5mg/L (swinging between 6mg/L and 4mg/L) to suppress infection and keep the chlorella growth medium at 0.1mg/L since according to the below table, the "Experimental phenomenon", shows "ball in shape" morphology at 0mg/L which is lost at some concentration below the sublethal 2mg/L. Such loss of morphology implies a potential impact on growth rate.
Table 5 of "Disinfection effect of chlorine dioxide on viruses, algae and animal planktons in water":
