[Transformation of linear alkylbenzene sulphonate in the anaerobic-anoxic-oxic wastewater treatment process].

The removal characteristics of linear alkylbenzene sulphonate (LAS) was studied in anaerobic/anoxic/oxic (AAO) municipal wastewater treatment processes. A removal (biological degradation and sorption) model was formulated, and kinetic parameters were evaluated with batch experiments under anaerobic, anoxic, oxic conditions. The resulting model calculations were then compared with sampling campaigns performed on AAO process. The results show that the removal efficiency of LAS in the AAO activated sludge processes is more than 99%. Effluent concentrations vary between 0 and 20 microg L(-1). The concentration of LAS adsorbed by sludge in anaerobic tank, anoxic tank, aerobic tank is 490 - 710 microg g(-1), 280 - 390 microg g(-1) and 69 - 109 microg g(-1) respectively. From the result of biodegradation kinetic tests, it can be concluded that LAS is well biodegraded under anaerobic/anoxic/oxic conditions, and the removal rate of LAS in anaerobic and anoxic conditions accounts for respectively 67% and 71% of that in oxic condition. The model can well forecast the effluent quality of anaerobic/ anoxic/oxic tank of the AAO process, and the relative error is less than 8%.