Fate of linear alkylbenzene sulfonate (LAS) in activated sludge plants.
Monitoring data were collected in a pilot-scale municipal activated sludge plant to assess the fate of the C12-homologue of linear alkyl benzene sulfonate (LAS-C12). The pilot-plant was operated at influent LAS-C12 concentrations between 2 and 12 mg l(-1) and at sludge retention times of 10 and 27 days. Effluent and waste sludge concentrations varied between 5 and 10 microg l(-1) and between 37 and 69 microg g(-1) VSS, respectively. In the sludge samples only 2-8% was present as dissolved LAS-C12, whereas the remaining 92-98% was found to be adsorbed to the sludge. In spite of this high degree of sorption, more than 99% of the LAS-C12 load was removed by biodegradation, showing that not only the soluble fraction but also the adsorbed fraction of LAS-C12 is readily available for biodegradation. Sorption and biodegradation of LAS-C12 were also investigated separately. Sorption was an extremely fast and reversible process and could be described by a linear isotherm with a partition coefficient of 3.2 l g(-1) volatile suspended solids. From the results of biodegradation kinetic tests it was concluded that primary biodegradation of LAS-C12 cannot be described by a (growth) Monod model, but a secondary utilisation model should be used instead. The apparent affinity of the sludge to biodegrade LAS-C12 increased when the sludge was loaded with higher influent concentrations of LAS-C12.
Temmink
H
H
Sub-department of Environmental Technology, Wageningen University, Bomenweg 2, PO Box 8129, Wageningen 6700 EV, The Netherlands. hardy.temmink@wur.nl
Klapwijk
Bram
B
D000327:Adsorption; D017738:Alkanesulfonic Acids / Q000032:analysis* / Q000378:metabolism*; D001673:Biodegradation, Environmental; D019149:Bioreactors; D007700:Kinetics; D012722:Sewage / Q000737:chemistry; D013501:Surface-Active Agents / Q000032:analysis* / Q000378:metabolism*; D014835:Volatilization; D014865:Waste Disposal, Fluid / Q000379:methods*; D014874:Water Pollutants, Chemical / Q000032:analysis*
D017738:Alkanesulfonic Acids; D012722:Sewage; D013501:Surface-Active Agents; D014874:Water Pollutants, Chemical; C030641:alkylbenzyl sulfonic acid