Occurrence of Linear Alkylbenzene Sulfonates, Nonylphenol Ethoxylates and Di(2-ethylhexyl)phthalate in Composting Processes: Environmental Risks

Composting is an important waste management strategy, providing an economical and environment-friendly approach to sanitizing and stabilizing biosolids for land soil amendment. However, the resulting product can contain a large number of organic pollutants that may have adverse effects on the ecosystem. This paper presents the occurrence of eight widely used organic pollutants (four linear alkylbenzene sulfonates (LAS C10-C13), nonylphenol and its mono- and di-ethoxylates (NPE) and a di(2-ethylhexyl)phthalate (DEHP)) in full-scale composting processes. LAS homologues were detected at the highest concentrations (range of ∑LAS: 2068–9375 mg kg−1 dm), exceeding the limit fixed in the EU Directive draft. The concentration levels of the NPE and DEHP were significantly lower (up to 27.5 and 156.8 mg kg−1 dm, respectively) and did not exceed their fixed limits in the EU Directive draft. Ecotoxicological risk assessment for when compost is amended onto soils has also been evaluated. The concentrations measured represented a medium-low risk for most compounds, although it was not enough in the case of LAS C11 and C13 and NP.

Biodegradation of Linear Alkylbenzene sulfonate-Anthracene Mixture by a Microbial Consortium isolated from Sediment

Linear alkylbenzene sulfonate and anthracene are chemical compounds which form pollutant mixtures with high toxic potential, causing damage to ecosystems. The process known as biodegradation is an effective, low-cost process carried out by microbial populations that reduces the toxic effect of linear alkylbenzene sulfonate and anthracene. In the present study, biodegradation was determined at different concentrations of linear alkylbenzene sulfonate, anthracene and the mixture of both compounds. The resulting reduction in toxicity produced by the mixture, the compounds separately and their biodegradation intermediaries was assessed using a microbial model. The ISO 9439 system was used to assess the biodegradation effect of a microbial consortium isolated from polluted sediment on 5, 10 and 20 mg/l of linear alkylbenzene sulfonate and the same concentrations of anthracene. Toxicity was determined by measuring inhibition of Bacillus cereus dehydrogenase activity produced by 0.25 ml aliquots of the linear alkylbenzene sulfonate, anthracene and the mixture of both compounds before and after they had been subjected to the biodegradation test. After 11 days, the linear alkylbenzene sulfonate -anthracene mixture was biodegraded to a greater degree than the compounds individually (3057.36 μmol CO2), but at a concentration of 20 mg/l of both compounds, a marked inhibition of biodegradation was observed. A reduction in toxicity produced by the biodegradation of linear alkylbenzene sulfonate and its mixture with anthracene at 5 and 10 mg/l respectively was observed.

Microscopic Diffusion Characteristics of Linear Alkylbenzene Sulfonates on the Surface of Anthracite: The Influence of Different Attachment Sites of Benzene Ring in the Backbone

In order to explore the effect of the attachment site of the benzene ring in the backbone of the surfactant on its diffusion characteristics on the surface of anthracite, the molecular dynamics simulation method was used, and the four isomers (m-C16, m = 2,4,6,8; m represents the attachment site of the benzene ring in the backbone) of sodium hexadecyl benzene sulfonate (SHS) were selected. Binary models of surfactant/anthracite, surfactant/graphene modified by oxygen-containing functional groups, and a ternary model of water/surfactant/anthracite were constructed. By analyzing a series of properties such as interaction energy, contact surface area, relative concentration distribution, radial distribution function, hydrophobic tail chain order parameter, etc., it is concluded that the adsorption strength of 4-C16 on the surface of anthracite is the highest; the reason is that 4-C16 has the highest degree of aggregation near the oxygen-containing functional groups on the surface of anthracite. Further investigations find that 4-C16 can be densely covered on the ketone group, and the longer branch chain of 4-C16 has the highest degree of order in the Z-axis direction.

Bacillus licheniformis SMIA-2 protease used as an additive in detergent formulations

Microbial proteases, especially from Bacillus spp., have been widely exploited for a broad variety of applications, such as the improvement of the cleaning efficiency of conventional detergents. In this work, the statistical design of the experiment was used to optimize the concentrations of a three-component mixture: Bacillus licheniformis SMIA-2 protease, Linear Alkylbenzene Sulphate and hydrogen peroxide, in an attempt to prepare an environmentally correct cleaning formulation. The results demonstrated that the combination of 1% (w/v) protease with 1.5% (w/v) LAS and 1% (w/v) H2O2 was effective in removing blood from cloth pieces and that a protease concentration decrease from 1.0% to 0.5% (w/v) would not have a significant impact on percent blood removal if LAS concentrations between 1.5-2.0% (w/v) in combination with lower (<0.5%, w/v) concentrations of H2O2 were used. Thus, the protease from Bacillus licheniformis SMIA-2 can be effectively incorporated into cleaning formulations together with LAS and hydrogen peroxide to formulate more sustainable detergents.

Effect of Co-Surfactants and Pasteurization for Preservation of Natural Rubber

This research was a study of the effect of addition linear alkylbenzene sulfonates (LAS), NaHCO3, and NaCl and pasteurization on the preservation of natural rubber (NR). The samples were collected from rubber plantations of Chiang Rai province which were added with three surfactants in samples already. Physical and chemical properties were evaluated using pH, deterioration, viscosity, color, and odor. Then, the samples were stored at 28-30&deg;C periods times of 0, 15, 30, 45, and 60 days. The experiment found that the color, viscosity, odor, and texture of NR samples were not spoiled after being preserved for 30 days but after 45 and 60 days found some coagulation of NR. In the case of non-preserved NR was found that spoiled NR in every period time range of 15-60 days. The pH testing found that increasing period times affect decreased pH value and increased viscosity due to salt of sulfate, carbonate, chloride, and thermal treatment of pasteurization which kill microorganisms and evaporated water. It concluded that the reagents were the process of cosurfactants with heat and frozen for increased effectiveness of anti-acid-producing bacteria and can use as short and long-term preservation of NR under the planting area condition of Thailand.

Greywater Treatment of Emerging Pollutant Linear Alkylbenzene Sulfonate By Adsorption With Leather Shave Waste Activated Carbon

This study aims to evaluate the use of leather shave waste activated carbon (ACLW) as an alternative for the treatment of wastewaters containing Linear Alkylbenzene Sulphonate (LAS). Batch adsorption tests were carried out (pH effect, isotherms, kinetics). The activated carbon was tested for its life cycle by desorption with solvents and it was also evaluated as a real wastewater treatment for bath greywater. Under the optimum pH of 2.5, the equilibrium isotherms correlated better with the Freundlich and Redlich-Peterson models, indicating a possible multilayer formation, and classifying the isotherm as having a high affinity. Adsorption was shown to be endothermic (∆H0 = +73.89 kJ mol-1), entropy driven (∆S0 = +0.46 kJ mol-1 K-1) and occurs spontaneously. The kinetic studies showed a best correlation with the pseudo-second order model, with activation energy of 27.5 kJ mol-1. The use of ethanol solution was effective for the regeneration of the adsorbent. The adsorption was applied in real wastewater, removing contaminants from bath greywater, especially anionic surfactants with up to 95% removal efficiency.