Effects of pilot-plant photochemical pre-treatment (UV/H2O2) on the biodegradability of aqueous linear alkylbenzene sulfonate (LAS)

The effects of the photochemical pre- treatment by using a pilot- plant UV/ H2O2 process on the biodegradability of aqueous linear alkylbenzene sulfonate ( LAS) were studied. It was observed that the photochemical pre- treatment of the LAS solutions by UV- 254/ H2O2 increased the biodegradability of LAS solutions. Aqueous solutions with higher concentrations of LAS (> 100mg/ L) were non- biodegradable. The ratio of BOD5/ COD of the pre- treated LAS solutions was increased, indicating that the pre- treated LAS solutions were more biodegradable. This ratio was improved as the LAS solutions were more pre- treated. Also, the biodegradability factor for the pre- treated LAS solutions was increased as the time of the photochemical pre- treatment was increased.