Due to the lower energy consumption and waste production compared to traditional methods, the environmental bioremediation methods based on natural processes have been gradually becoming more prevalent in environmental engineering. Biological methods are used in waste management, wastewater treatment, gas treatment or soil remediation. For the low solubility of some pollutants and lower bioavailability, the use of biological methods may be hampered. This problem might be mitigated with the use of surfactants. This paper presents the results of studies regarding the eff ect of dosing a selected surfactant from the Tween group (Tween 20) on the efficiency of toluene elimination from the air by biofi ltration. The obtained maximum biofi ltration rate was 21.2 g/m3/h and 19.8 g/m3/h for the control bed and for the bed to which the Tween 20 solution was dosed, respectively. The eff ect of Tween was neutral (the effectiveness of toluene removal was insignificantly comparable to the effectiveness of the control series), it did not affect the effectiveness or limited the development of the biofilter microflora.

Many techniques of soil bioremediation enhancement have been developed recently. Two of them are application of weak electric field which induces favorable electrokinetic phenomena in the soil environment and surface active agents application which increase the biodegradation degree of poorly soluble contamination. During experiments the influence of the electric field and surfactants (biosurfactants, non-ionic and anionic surfactants) on the Pseudomonas putida and Bacillus subtilis bacteria migration in soil was determined. The intensity of the biodegradation of contamination was also estimated. The results show substantial impact of the electric field and surfactants on the intensity and direction of bacteria migration in soil as well as on the intensity of the contamination biodegradation.

Surface water retention of leaves and fruits of apple ( Malus domestica Borkh.) and sweet cherry ( Prunus avium L.), was evaluated under controlled environmental conditions in order to determine the retention potential at different growth stages. Dipping and spraying, with and without non-ionic surfactant, were used as application systems. Water retention was expressed as the ratio between the weight difference of the organ before and post application and organ weight before application. Leaf water retention by dipping was 62 and 64% for ‘Royal Gala’ and ‘Fuji’ apples, respectively, and 37 and 50% by spraying. The surfactant tended to reduce foliar water retention by spraying on both species. An exponential reduction of fruit water retention was observed during their growth. Fruit dipping generated the highest water retention, with values of 50% at the earliest stage. Then, water retention stabilized at 1–2%, when the apples and sweet cherries diameter reached 25 and 15 mm, respectively, despite dipping or spraying. The surfactant tended to increase water retention at early fruit stages and to reduce it with fruit growth. These results can be useful for estimating the potential residue on leaves and fruits in apple and sweet cherry trees, in both the orchard (spraying) and the packing house (dipping).

In this study the effect of anionic surfactants on the morphology of activated sludge floes and biomass activity is quantitatively described. Three anionic surfactants: sodium dodecyl sulphate, sodium alkylbenzene sulphonate and sodium alkyltrioxyethylene sulphate were tested. The batch experiments were performed for a wide range of initial concentrations of anionics in wastewater from 2.5 to 2500 mgdm3. In spite of different chemical structure the action of all tested anionic surfactants resulted in the decrease of activated sludge floes dimensions at the similar level. It occurred that in the range of anionics concentrations, which are typical for domestic wastewater (2.5-25 mgdm3), they contributed to the decrease of mean projected area of floes by about 30%, whereas at the concentrations of 250 and 2500 mg-dm3 mean projected area decreased usually by 50-60%. Sodium alkylbenzene sulphonate exerted the strongest inhibition effect on dehydrogenase activity of activated sludge biomass. This effect coincided with the decreased degrees of removal for this surfactant and its biodegradation products, especially at its lower initial concentrations in wastewater.

The paper presents the effects of sodium chloride on the rheological properties of aqueous solutions of cocamidopropyl betaine (CAPB) and sodium dodecylbenzene sulfonate (SDBS) mixtures. Studies were carried out in the CAPB/SDBS molar ratio range of 0.95 to 3.5, at sodium chloride concentrations varying from 0.03 M to 0.75 M. Continuous and oscillatory flow measurements showed that the impact of sodium chloride concentration on shear viscosity and relaxation time was closely linked to the CAPB/SDBS molar ratio. The maximum shear viscosity and the longest Maxwell relaxation time were obtained at the CAPB/SDBS molar ratio of 2. Based on CryoTEM images, it was determined that the shear viscosity and relaxation time peaks identified at a certain concentration of sodium chloride could be attributed to the transition of the entangled wormlike micellar network into branched wormlike micelles. Changes in the micellar microstructure accompanying modifications of the CAPB/SDBS molar ratio and sodium chloride concentration were accounted for on the basis of the packing parameter.

The molecular dynamics of the well-known nematic liquid crystal 4-n-pentyl-4′-cyanobiphenyl geometrically restricted in Anopore and Synpor porous membranes with various pore structure and treated by different surfactants (namely decanoic acid and lecithin) is compared. In the Anopore membrane the chosen surfactants induce the homeotropic orientation of the molecules on the walls of the cylindrical pores and observed corresponding relaxation processes (librational modes) are practically the same. The dielectric measurements of lecithin treated Synpor membranes reveals the reorientation of the molecules from planar to homeotropic on the complex multilayer structure present in their volume. The dielectric strengths of the observed two molecular processes (δ-process and librational mode) are inversed in the ratio compared to the untreated membranes. The observed differences in molecular dynamics results from the orientation of the liquid crystal molecules in untreated and treated membranes and the structure of the membranes themselves.

Surfactants after their use are discharged into aquatic ecosystems. These compounds may be harmful to fauna and flora in surface waters or can be toxic for microorganisms of the activated sludge or biofilm in WWTP. In order to determine effectiveness of different advanced oxidation processes on the degradation of surfactants, in this study the degradation of anionic surfactants in aqueous solution using photolysis by 254 nm irradiation and by advanced oxidation process in a H2O2/UVC system was investigated. Two representatives of anionic surfactants, linear alkyl benzene sulphonate (LAS-R11–14) and ether carboxylic derivate (EC-R12–14E10) were tested. The influence of pH, initial surfactant concentration and dose of hydrogen peroxide on the degradation was also studied. Results show outstanding effectiveness of the H2O2/UVC system in the removal of surfactant from aqueous solutions.