Rubber glove factory - Possible surfactant problem - Water and Wastewater.com Help Forum

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Question
At the moment I'm running a small biological simulation on treating water from a rubber glove factory.
The problem is the bacteria seem to die off after a few days. The residual COD first goes down, then goes up again. The biomass continuously decreases.

I've found out that the white foam might indicate that surfactants are involved. I've gone throughout the forum threads but didn't find any information on the surfactant they use. It's an ethoxylated acetylenic diol.
Could this surfactant cause the problem?

I'm currently using Poly Aluminum Chloride and anionic polymer in the pretreatment to remove suspended solids before the biological system.
Is there any way I can remove/neutralize the surfactant in the pretreatment?

They also use alkyl trimethyl ammonium bromide and ethylene oxide which might cause problems.
Is there any way I can remove/neutralize these chemicals in the pretreatment?

Answer
the 'ethoxylated acetylenic diols' are products of Airproducts limited - you might contact them for further information.
Though I would expect hard biodegradability of these surfactants due to their branched nature,however, they should not have a biocidic character.
Ethylene oxide is highly reactive and will therefore not be present in unreacted form.
The cationic surfactants should be removed by the anionic polymers, except all have been bound to the PAC. Eventually, anionic polymer should be added in a first step.

Please be aware that the rubber production uses further chemicals with low biocompatibility depending on the kind of rubber used.

Eventually adsorption of organic contaminants may reduce the problems.

Question
Tried to search on acetylenic diols and found some more information. According to the below you are right that they are not biocidic but very hard to biodegrade:
www.epa.gov/chemrtk/tetramet/c13452rt.pdf www.epa.gov/chemrtk/tetramet/c13452.pdf

I found some other articles mentioning that the surfactant is nonionic:

[0028] The water-based offset lithographic printing ink of the invention may include a nonionic surfactant. The nonionic surfactant selected may include any used routinely in the art for ink and ink-related applications. Examples of suitable nonionic surfactants include acetylenic glycols, ethoxylated glycols, sorbitan esters, and mixtures thereof. Particularly preferred are ethoxylated acetylenic diols. Such surfactants are available, for example, from Air Products and Chemicals, Inc., Allentown, Pa., U.S.A., under the mark SURFYNOL.RTM..

Does this mean I can't remove it? I understand the ethoxylation of the acetylenic diol makes it more soluble in water.

answer
# ethylene oxide issue
yes it is used for sterilization - the effect is due to its high reactivity with 'active hydrogen', i.e. -OH, -NH, -SH groups. However, this also means it has only a short term effect because surplus ethylene oxide is reacting with water forming polyglycols. Therefore no adverse effect has to be expected in wastewater treatment.

# removal of nonionic surfactants
the name 'surfactants' stand for 'surface active substances', i.e. it tends to accumulate at interfaces and can therefore be removed by adsorption.
Ethoxylation makes the practically insoluble 'acetylenic diols' compatible with water.
Eventually the surfactants are already removed by this mechanisms due to the PAC treatment.
Also in light of potential toxic effect of other organic contaminants you should try adsorption by clays or alternatively powdered activated carbon. This should also remove the cationic surfactant.

# biodegradation
by similarity it has to be expected that the polyethylene glycol chains are degraded leaving short chain oligomers with low aqueous solubility, i.e. these will accumulate in the sludge.