Effective Treatment of Humic Acid Foulants in SAGD Produced Water

Humic acids, one major type of organic foulants in steam assisted gravity drainage (SAGD) produced water, can precipitate on surface and downhole equipment in SAGD facilities, resulting in high cleaning costs, potential equipment damage and decrease of injectivity of disposal wells. In this paper, a cost-effective chemical solution is presented where an alcohol ethoxylate surfactant/chelating agent package can efficiently disperse the organic fouling molecules in SAGD produced water; therefore, the approach is expected to significantly mitigate the humic acid related fouling issues in the SAGD system. In this study, a variety of commercially available surfactant products were evaluated for their aids in well injectivity on humic acid molecules in the freshly obtained SAGD produced water. The lab testing filtration apparatus was specially designed to simulate the sandstone formation geology of SAGD disposal wells. An "efficiency factor" was defined to grade the dispersing performance of the surfactant and/or surfactant/chelating agent package in the lab filtration tests. The efficiency factor provides a reasonable estimation regarding how well the chemical can reduce the plugging risk in a disposal well as compared to the untreated produced water. Among all the surfactant products tested, an alcohol ethoxylate surfactant with the appropriate molecular structure shows distinguished dispersing performance on humic acids in SAGD produced water. However, the surfactant alone was found inconsistent in the dispersing performance when different batches of the produced water were involved. Inclusion of the specific metal chelating agents to the above surfactant formulation improved the dispersing performance consistency. The chelator molecules presumably help destroy the intermolecular bridges among humic acid molecules in the SAGD produced water; thereby, increasing the dispersing effectiveness of the alcohol ethyoxylate surfactants. Tests show that the efficiency factor of the surfactant/chelating agent package is higher than 8, which implies that the formulation could lead to eight times extension of the interval between workovers on SAGD disposal wells, a significant reduction for the operational downtime and costs. This study presented a cost-effective chemical solution to help disperse the humic acid molecules in SAGD produced water, which can help significantly reduce the fouling risk caused by organic foulants, improve injectivity and extend the intervals between workovers of SAGD disposal wells.

Interaction of surfactants with barley leaf surfaces: time-dependent recovery of contact angles is due to foliar uptake of surfactants

Main conclusion Time-dependent contact angle measurements of pure water on barley leaf surfaces allow quantifying the kinetics of surfactant diffusion into the leaf. Abstract Barley leaf surfaces were sprayed with three different aqueous concentrations (0.1, 1.0 and 10%) of a monodisperse (tetraethylene glycol monododecyl ether) and a polydisperse alcohol ethoxylate (BrijL4). After 10 min, the surfactant solutions on the leaf surfaces were dry leading to surfactant coverages of 1, 10 and 63 µg cm−2, respectively. The highest surfactant coverage (63 µg cm−2) affected leaf physiology (photosynthesis and water loss) rapidly and irreversibly and leaves were dying within 2–6 h. These effects on leaf physiology did not occur with the lower surfactant coverages (1 and 10 µg cm−2). Directly after spraying of 0.1 and 1.0% surfactant solution and complete drying (10 min), leaf surfaces were fully wettable for pure water and contact angles were 0°. Within 60 min (0.1% surfactant) and 6 h (1.0% surfactant), leaf surfaces were non-wettable again and contact angles of pure water were identical to control leaves. Scanning electron microscopy investigations directly performed after surfactant spraying and drying indicated that leaf surface wax crystallites were partially or fully covered by surfactants. Wax platelets with unaltered microstructure were fully visible again within 2 to 6 h after treatment with 0.1% surfactant solutions. Gas chromatographic analysis showed that surfactant amounts on leaf surfaces continuously disappeared over time. Our results indicate that surfactants, applied at realistic coverages between 1 and 10 µg cm−2 to barley leaf surfaces, leading to total wetting (contact angles of 0°) of leaf surfaces, are rapidly taken up by the leaves. As a consequence, leaf surface non-wettability is fully reappearing. An irreversible damage of the leaf surface fine structure leading to enhanced wetting and increased foliar transpiration seems highly unlikely at low surfactant coverages of 1 µg cm−2.

Effect of Floor Cleaner Combination of Alcohol Ethoxylate-Sodium Lauryl Ether Sulfate and Combination of Carbol-Pine Oil on Ascaris lumbricoides Eggs

Disinfectants are chemical agents used in disinfection in liquid form or solution form and are well-known as microbicidal, fungicidal, and virucidal but still unknown as parasiticidal, especially the effect to A. lumbricoides. In Indonesia, the prevalence of ascariasis is about 30,4% and still high. Ascariasis is caused by A. lumbricoides helminth that human swallows in egg form. Ascaris lumbricoides egg's characteristics are hydrophobic and sticky, making it easy to stick on the floor, household, and skin. This research aims to find the difference between the combination of the effects of Alcohol Ethoxylate-Sodium Lauryl Ether Sulfate and the combination of Carbol-Pine Oil to A. lumbricoides eggshell and larva development as prevention and to break the life cycle chain of A. lumbricoides. The research results showed no effects from Alcohol Ethoxylate- Sodium Lauryl Ether Sulfate combination and Carbol-Pine Oil combination to A. lumbricoides eggshell and embryo development. Keywords: Disinfectants, ascariasis, concentration, eggshell, larva development.

Potential effect of wetting agents added to agricultural sprays on the stability of soil aggregates

The presented research deals with the issue of the potential effect of adjuvants/wetting agents (WA) added to the spray mixture for stability of soil aggregates (SAS) in agricultural soil. Nine localities were chosen in the Czech Republic. Each locality was mapped using soil pits (depth min. 1.4 m). A total of 54 mixed samples were collected from the topsoil horizon in the selected localities. The samples were exposed to the action of four different types of wetting agents (organosilicone wetting agent; methyl ester of rapeseed oil; mixture of methyl ester palmitic and oleic acids; Isodecyl alcohol ethoxylate). SAS was determined before and after the addition of WA. Average values of SAS across the sampling point exhibited a demonstrable trend: the SAS value of control sample (without WA application) was at all times higher than in samples with the addition of WA (organosilicone wetting agent; mixture of methyl ester palmitic and oleic acids; Isodecyl alcohol ethoxylate), on average by more than 15 %. If the measured SAS values are compared in terms of overall means, it is obvious that the control variant always exhibited the highest SAS value (44.04 %) and the variants with the application of WA showed always SAS values lower by min. 16 %. All soil samples were also analysed for basic soil parameters (glomalin, Cox, pH, Na, P, Ca, K, Mg) in order to determine their potential influence on SAS and a possible elimination of the negative impact of WA. In this respect, only a significant influence of Cox content on SAS was recorded, which positively correlated with SAS.

Ecotoxicological Impact Assessment of the Production of Cotton Fabric

Textiles and garments are increasingly being included in life cycle assessment (LCA) studies because the use of chemicals in industrial production of these items has potential environmental impacts. The USEtox model, characterized by ecotoxicity characterization factors based on abundant data, is a useful tool for assessing the toxicity of chemical pollutants. The objectives of this study were to estimate characterization factors of cotton fabric-related chemicals based on data from a quantitative structure–activity relationship (QSAR) model and assess the ecotoxicological impact of cotton woven fabric. The research boundary ranged from fabric production to wet treatment. Wet treatment was found to contribute more to ecotoxicity than fabric production did, with primary alcohol ethoxylate and sodium hydroxide being the main pollutants.