Simultaneous Biodegradation of Linear Alkylbenzensulfonate in Anaerobic Reactors, in Two Stages

Abstract

Surfactants are organic compounds capable of altering the surface or interfacial tension of a system; they alter the hormonal system of aquatic organisms and can penetrate porous materials, disperse solid particles, emulsify oils and fats or produce foam when agitated. They are used in the manufacture of cleaning and personal hygiene products, manufacturing of products with agricultural, industrial and commercial applications. But they are highly polluting due to their special chemical composition, they cause eutrophication problems in natural bodies of water due to the amount discharged and the frequency with which they are discharged, in addition to affecting ecosystems. One of the most used anionic surfactants in the manufacture of commercial detergents due to its excellent detersive properties and low cost, is LAS. The objective of this research was to evaluate the effect of the concentration and organic loading rate of the anionic surfactant “LAS” on the performance of a two-stage anaerobic reactors system for its simultaneous biodegradation. The results showed that both at concentrations of 200 mg/L (experiment V) and 300 mg/L of “LAS” (experiment VI), the acidogenic reactor showed greater robustness in the biodegradation (86.7 and 55%) at an organic loading rate of 5.92 ± 0.04 and 6.8 ± 0.09 kgCOD/m^3.d; the methanogenic reactor was more sensitive to the presence of the surfactant (experiments V and VI), biodegrading it by 13.8 and 14.3% with respect to the LAS remaining in the effluent of the acidogenic reactor with which it was fed, to 3.56 ± 0.02 and 4.48 ± 0.15 kgCOD/m^3.d respectively.

Graphical Abstract