Accurate assessment of the biodegradation of cationic surfactants in activated sludge reactors (OECD TG 303A).
The continuous-fed activated sludge test (OECD TG 303A) was used to predict the removal of cationic surfactants from wastewater in activated sludge plants. However, a method to differentiate between adsorption and biodegradation is not provided in these guidelines. Assessment of removal by biodegradation was possible with analysis of the surfactant present in mixed liquid suspended solids in combination with a simple equation. This equation was derived from the mass balance of the activated sludge unit in steady state. The removal by biodegradation of decylamine, tetradecylamine, octadecylamine, dioctadecylmethylamine and dioctadecyldimethylammonium chloride that have different capacities to adsorb was >99.9%, >99.9%, 98.2%, 94.2%, and 69.0%, respectively. The total removal of all five cationic surfactants from the influent was ≥98.8%. The removal of octadecylamine spiked at different influent concentrations indicated first order kinetics.
AkzoNobel N.V., P.O. Box 9300, 6800 SB Arnhem, The Netherlands. Electronic address: roy.geerts@akzonobel.com.
Roy
R
Geerts
AkzoNobel N.V., P.O. Box 9300, 6800 SB Arnhem, The Netherlands.
Cornelis G
CG
van Ginkel
Laboratory of Microbiology, Wageningen University, Dreijenplein 10, 6703 HB Wageningen, The Netherlands.
Caroline M
CM
Plugge
D000327:Adsorption; D001673:Biodegradation, Environmental; D019149:Bioreactors; D004784:Environmental Monitoring / Q000379:methods*; D007700:Kinetics; D008962:Models, Theoretical; D012722:Sewage / Q000737:chemistry*; D013501:Surface-Active Agents / Q000378:metabolism*
D012722:Sewage; D013501:Surface-Active Agents
Activated sludge reactors; Adsorption; Biodegradation; Cationic surfactants; OECD TG 303A