Interaction between phosphorus and biodegradable organic carbon on drinking water biofilm subject to chlorination.
OBJECTIVE
To examine whether phosphorus and biodegradable organic carbon interact to impact biofilm density and physiological function of biofilm-forming bacteria under conditions relevant to chlorinated drinking water distribution systems.


RESULTS
The 2 x 2 factorial experiments with low and high levels of phosphorus and biodegradable organic carbon were performed on 4 -week-old drinking water biofilms in four separate pipe systems in the presence of chlorine. Experimental results revealed that biofilm heterotrophic plate count levels increased with the increase in biodegradable organic carbon concentration, showed no response to increases in levels of phosphorus and was not affected by interaction between phosphorus and biodegradable organic carbon. However, a significant positive interaction between phosphorus and biodegradable organic carbon was found to exist on biofilm mass and physiological function and/or metabolic potentials of biofilm communities; the effects of biodegradable organic carbon on biofilm mass and physiological function of biofilm-forming bacteria were accelerated in going from low to high level of phosphorus.


CONCLUSIONS
Biodegradable organic carbon was found to be the primary nutrient in regulating biofilm formation in drinking water regardless of the presence of chlorine. It can be therefore concluded that the removal of an easily biodegradable organic carbon is necessary to minimize the biofilm growth potential induced by the intrusion of phosphorus.


CONCLUSIONS
Phosphorus introduced to drinking water may interact with biodegradable organic carbon, thus leading to measurable impact on the biofilm formation.
Park
S-K
SK
Division of Environmental Science and Engineering, National University of Singapore, Singapore, Singapore. parkphd@empal.com
Hu
J Y
JY
D001419:Bacteria / Q000187:drug effects / Q000254:growth & development / Q000378:metabolism; D018441:Biofilms / Q000187:drug effects / Q000254:growth & development*; D002244:Carbon / Q000378:metabolism*; D002713:Chlorine / Q000494:pharmacology; D005618:Fresh Water / Q000382:microbiology; D054879:Halogenation; D010758:Phosphorus / Q000378:metabolism*; D014871:Water Microbiology; D018508:Water Purification / Q000379:methods*
D010758:Phosphorus; D002713:Chlorine; D002244:Carbon