Author Topic: Modelling the (inhibitory) effect of salt on activated sludge processes  (Read 856 times)

Enrico Remigi

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Does anyone have experience in (or can perhaps suggest a reference or two about ?) modelling the inhibition effect of salt (e.g. Cl-) on activated sludge processes? Form of the expression, parameter values, etc.?
Thanks
Enrico U. Remigi
Wastewater Process Modeller
DK Urban
Kortrijk (Belgium)

bendelBoy

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A simple method, reported in unpublished Israeli work, is to have an inhibition function I(C) = max(0, 1 - a C).

Some published work suggests that you can ignore inhibition, unless you propose to model adaptation to salinity:

C Dahl, C Sund, GH Kristensen and L Vredenbregt, 1997, "Combined biological nitrification and denitrification of high-salinity wastewater", Wat. Sci. Tech. 36(2/3) 345-352

Héctor Rey

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Hi Enrico,

I was checking the forum about any answer about how to consider salinity in WEST, and I have found this former topic. The only way to do it that I can imagine is, if there is information enough to do it (influent-effluent-operation data), to calibrate the model, but it implies time and information, and usually both are not available. Have you found any new solution to consider the inhibition of the salinity?

Thank you!

Héctor

 

Enrico Remigi

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No, not really Hector, sorry. Haven't work on this specific topic.
Enrico U. Remigi
Wastewater Process Modeller
DK Urban
Kortrijk (Belgium)

FaPo

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Hi Hector,

A number of studies have evaluated and modelled the effect of salinity (particularly Cl-) on microbial activity in actiavted sludge.
The main findings are that salinity tends to be inhibitory above 0.5-1% levels, and that phosphorus uptake are nitrite oxidation are by far the most sensitive processes.
The effect of salinity is most commonly described as a non-competitive inhibition mechanism, which is mathematically described through a switching function that decreases the maximum growth rate, i.e.

mu_max * (K_I / (S_salt + K_I) * …                     where S_salt is the salinity level and K_I the inhibition coefficient

Here are some useful references:
Kargi, F., Dincer, A.R. (1996). Effect of salt concentration on biological treatment of saline wastewater by fed-batch operation.
Intrasunghka, N., Keller, J., Blackall, L. (1999). Biological nutrient removal efficiency in treatment of saline wastewater.
Panswad, T., Anan, C. (1999). Impact of high chloride wastewater on an anaerobic/anoxic/aerobic process with and without inoculation of chloride acclimated seeds.
Bassin, J.P., Pronk, M., Muyzer, G., Kleerebezem, R., Dezotti, M., van Loosdrecht, M.C.M. (2011). Effect of elevated salt concentrations on the aerobic granular sludge process: Linking microbial activity with microbial community structure.