Acclimation of activated sludge to degrade toxic levels of 2,4-dinitrophenol.
Biodegradation of 75 and 100 mg/l of 2,4-dinitrophenol (DNP) by activated sludge acclimated in a Sequencing Batch Reactor (SBR) consistently required less than 6 hours although a lag at the beginning of every 48-hour SBR cycle was observed. Other investigators have reported that DNP levels of 100 mg/l and higher are significantly toxic even to acclimated bacteria. The activated sludge acclimated to 75 mg/l initial DNP had over 100 times the DNP-degrading bacteria than an SBR acclimated to 10 mg/l DNP, although the MLSS concentration in both reactors was similar. Results suggest that two mechanisms are responsible for activated sludge acclimation to toxic levels of DNP: maintenance of DNP-degrading biomass sufficiently large to reduce initial DNP to non-toxic levels, allowing for subsequent rapid degradation; and extension of the aeration period well beyond the time required for degradation to prevent gradual accumulation of any by-product which might also be toxic.
Jo
Kwan-Hyung
KH
Department of Civil and Environmental Engineering, Chungwoon University, Hongseong, Chungnam, Korea. jokwan@chungwoon.ac.kr
Silverstein
JoAnn
J
D019297:2,4-Dinitrophenol / Q000378:metabolism* / Q000633:toxicity; D000332:Aerobiosis; D001419:Bacteria / Q000378:metabolism*; D001673:Biodegradation, Environmental; D018533:Biomass; D004783:Environmental Microbiology; D007700:Kinetics; D012722:Sewage / Q000382:microbiology*; D018505:Waste Management / Q000379:methods*
D012722:Sewage; D019297:2,4-Dinitrophenol