There are a lot of sources explaining microbial growth dynamics.
The set of data I am working on lacks initial values during lag phase. This creates difficulties in estimating the growth rate. I am looking for lag phase values that could inform a possible estimate.
Thank you.
- I don't think this is a correct question there there is no such thing as waste water bacteria as an individual species and for it to define growth rate.
- There are thousands of bacterial species which might have different growth rate in in-vivo and in-vitro conditions.
- The growth rate would also be influenced by the presence of archaea or fungi etc in in-vivo conditions.
Agree with Abhijeet Singh. You also need to provide more information about your experiment or the WWTP that you try to model. Metcalf and Eddy (https://www.booktopia.com.au/wastewater-engineering-inc-metcalf-and-eddy/prod9780073401188.html) may have some empirical values.
Lag-phase is conventionally observed in batch cultures and influenced by preculture conditions (growth stage of preculture; any differences in temperature, pH, growth medium composition to name but a few) and amount of bacteria added [g] per volume of solution (L). If we add a preculture that entered plateau phase the lag phase can expected to be longer than precultures harvested during log phase. If temperature of preculture is greater than main culture it takes bacteria longer to adapt.
Good responses by Robert and Abhijeet. I don't have my Metcalf and Eddy with me right now, but I would guess that they would use steady state levels of microbes in MLSS and not include a growth lag.
agree with the said above. check with a usual wastewater engineering handbook. do the usual pretests for sludge yield and sludge growth if You want to establish sludge plant.
Thank you all for your answers. For better clarity I attach a simple diagram.
Note:
Line 1 would be the linear fitting of the experimental data (black dots)
Line 2 would estimate a steady growth using origin (0,0) and first data point
Line 3 would estimate considering a lag phase.
Without data, what could be a reasonable guess for x?
Thank you
If you know the initial concentration of microorganism (as suggested by the grey sigmoidal curve) and know/assume a specific growth rate typical for your inoculum and the growth conditions, you should be able to determine the time exponential growth started and hence the lag phase.
i agree with the response by Abhijeet Singh. hence also note the recommendations by Robert Thomas Bachmann.
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