EFFECT OF LAS (LINEAR ALKYLBENZENE SULFONATES) ON ORGANIC-MATTER BIODEGRADATION

LAS (linear alkylbenzene sulphonates) are still the main surfactants u sed in formulated detergent products and are an important component of urban sewage. Surfactants could be toxic for microorganisms responsib le for the degradation treatment and to organisms present in natural e cosystems. However, sewage treatment plants are not designed to elimin ate surfactants. It is interesting therefore to study the effect of LA S on microorganisms in microbiological treatment units to determine th e residual LAS concentration reaching the collector channels. This art icle discusses the effect of LAS on the purification efficiency of aer obic sewage treatment plants, and LAS biodegradation itself in such pl ants. The results of this study suggest that LAS influence pH self-reg ulation capacity in aerobic degradation of organic matter when its con centration is greater than 20 ppm. For this, external neutralisation i s required in such cases. Likewise, LAS influence the degradation capa city of both organic matter and itself in aerobic processes, reducing the biodegradation rate and increasing the residual COD and LAS concen trations obtained.