desinfection of biofilms - how to (Mar/03/2009 )

hallo all,

I was wondering if anyone here has any experience in the field of desinfection of wastewater/biofilms.
I am mainly looking for some environment friendly methods. I know of the standard methods like UV, Ozon, chlorine etc.. and combinations, but I am wondering if anyone here has other experiences (experiences with the regular used ones is good too.) at their company, research units?


I was thinking on trying out a combination of fysical and chemical desinfection.

Another idea I had was the use of salt. I do not know if anyone here has ever had the idea to use an excessive amount of salt to kill of bacteria, fungi.
It seems easy to recuperate the salt and thus not harm the environment.
However I have not looked into the details.

I am mainly doing some general research at the moment and looking for some good articles , if you have any reference, that would be appreciated.

I have both lab and industrial experience. None of the treatments mentioned (nor salt) is reliable to disinfect biofilms. The critical target is what is usually a polysaccharide matrix and biocides don't penetrate.

Biofilm of what microbes are you thinking?

GeorgeWolff on Mar 3 2009, 11:22 PM said:

It is wastewater that needs to be desinfected.
However I do not have enough details yet about what kind of water, but in general we will be testing the "common" bacteria.

I'll have get some more details, we are still a bit working in "the dark".

So you do not have any good experiences with it.
Thats not good news for me.

Industrial applications that demand high purity (purified water) usually rely on dramatic interventions when biofilms are present such as caustic (NaOH) rinses.

GeorgeWolff on Mar 5 2009, 01:32 PM said:

Well I have gotten some more information.

It seems they want to make some pilotproject.
They are going to create biofilms "poluted" with Pseudomonas a

GeorgeWolff on Mar 5 2009, 01:32 PM said:

Well I have gotten some more information.

It seems they want to make some pilotproject.
They are going to create biofilms "poluted" with Pseudomonas, E.coli and 2 others that they are still discussion.
(they are trying to get the most common polution , however (strangely enough) they do not seem to have a "real" case scenario , meaning : what kind of water they are going to desinfect eg. from where does the water come...)
Thy are really going to create an artificial polution.


It will be a small project on water treatment.
The techniques they want us to look at are Uv, ultrasound, chlorine, elektrolyses , peroxide and javel water.

How would you figure out what treatment works best? Just plating out the samples before and after and count cfu's ?

Pito - I am amazed. Who are these ignorant "they" folks. It's clear they know little to nothing of microbiology but why can't they read? The literature is full of relevant reports on biofilms. some of these treatments are simply ludicrous efforts re. biofilms (UV and ultrasound) and others are well known to be useless (hypochlorite, peroxide).

To confirm (here. lack of) efficacy, test the surface material(s). Looking for free-floating (planktonic) cells is not helpful.

As I said pito, this is really stupid for an adult effort. Looks like a glorified 9th grade science fair effort.

GeorgeWolff on Mar 5 2009, 02:03 PM said:

Yeah, well I was thinking less or more the same.

You have any good literature references ?

look up Costerton and center for Biofilm Engineeering at Bozeman.

GeorgeWolff on Mar 7 2009, 01:25 AM said:

Ok thanks.

I'll check it out.
Anyway, I am gonna look into the use of chloride desinfection and the use of UV.
But indeed as you said, against biofilms they seem to be useless. However the combination of UV and substances that give free radicals might work.
And chloride is well known as a desinfectant.