Bio-fouling in ground-water / LNAPL remediation system piping
Bio-fouling in ground-water / LNAPL remediation system piping
(OP)
Anyone out there who knows of effective additives or methods for reducing bio-fouling in piping from GW remediation systems?
Our contaminants are BTEX/naphthalene from coking by-product LNAPL. pH is neutral, and we have carbon steel pipe from our sump to treatment plant. We probably have SOME iron-fouling bacteria, but we see a substantial slime layer at our GW/LNAPL interface, which is the fouling that's likely causing our problems (greatly reduced flow rate due to pipe fouling).
We have tried shock treatments with muriatic acid & dissolved chlorine pellets, and scheduled system shutdowns (1-2 weeks) to reduce fouling, each of which helps somewhat, but we're hoping to find something that is more effective, and hopefully is less corrosive to our piping than the acid and chlorine treatments.
Any suggestions for anti-bacterial products or other techniques or lessons learned? Could we expect better results from isolating & jetting out our pipes?
Our contaminants are BTEX/naphthalene from coking by-product LNAPL. pH is neutral, and we have carbon steel pipe from our sump to treatment plant. We probably have SOME iron-fouling bacteria, but we see a substantial slime layer at our GW/LNAPL interface, which is the fouling that's likely causing our problems (greatly reduced flow rate due to pipe fouling).
We have tried shock treatments with muriatic acid & dissolved chlorine pellets, and scheduled system shutdowns (1-2 weeks) to reduce fouling, each of which helps somewhat, but we're hoping to find something that is more effective, and hopefully is less corrosive to our piping than the acid and chlorine treatments.
Any suggestions for anti-bacterial products or other techniques or lessons learned? Could we expect better results from isolating & jetting out our pipes?





RE: Bio-fouling in ground-water / LNAPL remediation system piping
ChemE, M.E. EIT
"The only constant in life is change." -Bruce Lee
RE: Bio-fouling in ground-water / LNAPL remediation system piping
Basically, for now, we're just looking for ways to effectively reduce the biomass in our pipes so we can continue to pump at a rate sufficient to draw the LNAPL to our sump. We have dropped from >30 gpm to <9 gpm and are thus reducing our cone of depression and LNAPL recovery rates. So, I was just curious to see if anyone out there had similar experiences or knew of a bactericide or other alternative for our application. If we keep using HCl, we will have to dig up and replace our (carbon steel) pipes soon, and we would like to avoid this if possible.
RE: Bio-fouling in ground-water / LNAPL remediation system piping
Your problem is a common one, and there are no easy solutions. One method is to use low-dose acid more frequently, to prevent buildup. Another is the use of high-pressure jetting for well redevelopment. This technique doesn't use any acid, and prolongs the life of your pipe. However, this may not be economical if biofouling occurs rapidly - you will generally need a well-qualified drill contractor, and your pump will have to be pulled each time.
You might want to try one of the books below (I have not read them). Good luck.
Alford, G. and D.R. Cullimore. 1999. The Application of Heat and Chemicals in the Control of Biofouling Events in Wells. CRC Press Lewis Publishers, Boca Raton, FL, 181 pp.
Alford, G., S.A. Smith and R.L. Leach. 2000. Engineering and Design - Operation and Maintenance of Extraction and Injection Wells at HTRW Sites, EP 1110-1-27, U.S. Army Corps of Engineers.
RE: Bio-fouling in ground-water / LNAPL remediation system piping
We're planning to try your lower dose/higher frequency approach unless we find something more effective. We also found a biocide on-line called Oxygenics 2002 that we bought a sample of to try. If we have any luck with this product, I'll post our results in case it can help someone else out there.
RE: Bio-fouling in ground-water / LNAPL remediation system piping
RE: Bio-fouling in ground-water / LNAPL remediation system piping