Abstract: Losses of surfactant due to sorption need to be
considered when selecting surfactant doses for soil bioremediation.
The degree of surfactant sorption onto soil depends primarily on the
organic carbon fraction of soil and the chemical nature of the
surfactant. The use of biosurfactants in the control of the
bioavailability of toxicants in soils is an attractive option because of
their biodegradability. In this work biosurfactants were produced
from a cheap raw material, trimming vine shoots, employing
Lactobacillus pentosus. When biosurfactants from L. pentosus was
added to sediments the surface tensión of the water containing the
sediments rapidly increase, the same behaviour was observed with
the chemical surfactant Tween 20; whereas sodyum dodecyl sulphate
(SDS) kept the surface tension of the water around 36 mN/m. It
means, that the behaviour of biosurfactants from L. pentosus is more
similar to non-ionic surfactatns than to anionic surfactants.
Abstract: A local wastewater treatment plant (WWTP)
experiencing poor nitrification tracked down high level of
surfactants in the plant-s influent and effluent. The aims of this project were to assess the potential inhibitory effect of surfactants on activated sludge processes. The effect of the
presence of TergitolNP-9, TrigetolNP-7, Trigetol15-S-9,
dodecylbenzene sulphonate (SDBS) and sodium dodecyl
sulfate (SDS) on activated sludge oxygen uptake rate (OUR) and nitrification were assessed. The average concentration of non-ionic and anionic
surfactants in the influent to the local WWTP were 7 and 8.7 mg/L, respectively. Removal of 67% to 90% of the non-ionic and 93-99% of the anionic surfactants tested were measured. All surfactants tested showed inhibitory effects both on OUR
and nitrification. SDS incurred the lowest inhibition whereas
SDBS and NP-9 caused severe inhibition to OUR and
Nitrification. Activated sludge flocs sizes slightly decreased
after 3 hours contact with the surfactant present in the test.
The results obtained indicated that high concentrations of
surfactants are likely to have an adverse effect on the
performance of WWTPs utilizing activated sludge processes.