Degradation Of Linear Alkylbenzene Sulfonate Research Articles

A novel membrane-aerated biofilm reactor using flexible and adjustable plate membrane modules: Treatment of wastewater containing anionic surfactants

Membrane-aerated biofilm reactors (MABRs) are a promising biofilm technology for wastewater treatment; however, achieving high pollutant removal in MABR systems with a low specific membrane surface area, low air-based aeration pressure and flexible aeration control remains a substantial challenge. In this study, a flexible and adjustable plate membrane module was developed and applied in an air-based plate MABR (PMABR) for treating anionic surfactant wastewater. The plate membrane module achieved high oxygen mass transfer under a low air-based membrane aeration pressure. When the influent linear alkylbenzene sulfonate (LAS) load was 0.559±0.010 kg/m3·d and a gradient-pressure membrane aeration scheme of (8,7,6) kPa was adopted, the LAS removal rate reached 99.2±0.1%, and the LAS removal load per unit membrane area reached 14.08±0.25 g/m2·d. The bacteria participating in the degradation of LAS were mainly Parvibaculum, Pseudomonas, Desulfovibrio, Flavobacterium and Holophagaceae. The dominant microbial communities of different biofilms in the PMABR played an important role in ω-oxidation, β-oxidation, benzene ring breaking and sulfonic acid group shedding in the degradation of LAS. The developed plate membrane module and PMABR provide a clean, energy-saving and flexible technical solution for MABR applications in wastewater treatment.

Use of nitrate, sulphate, and iron (III) as electron acceptors to improve the anaerobic degradation of linear alkylbenzene sulfonate: effects on removal potential and microbiota diversification.

Linear alkylbenzene sulfonate (LAS) is a synthetic anionic surfactant that is found in certain amounts in wastewaters and even in water bodies, despite its known biodegradability. This study aimed to assess the influence of nitrate, sulphate, and iron (III) on LAS anaerobic degradation and biomass microbial diversity. Batch reactors were inoculated with anaerobic biomass, nutrients, LAS (20mg L-1), one of the three electron acceptors, and ethanol (40mg L-1) as a co-substrate. The control treatments, with and without co-substrate, showed limited LAS biodegradation efficiencies of 10 ± 2% and 0%, respectively. However, when nitrate and iron (III) were present without co-substrate, biodegradation efficiencies of 53 ± 4% and 75 ± 3% were achieved, respectively, which were the highest levels observed. Clostridium spp. was prominent in all treatments, while Alkaliphilus spp. and Bacillus spp. thrived in the presence of iron, which had the most significant effect on LAS biodegradation. Those microorganisms were identified as crucial in affecting the LAS anaerobic degradation. The experiments revealed that the presence of electron acceptors fostered the development of a more specialised microbiota, especially those involved in the LAS biodegradation. A mutual interaction between the processes of degradation and adsorption was also shown.

Sunlight Assisted Degradation of Linear Alkylbenzene Sulfonate by Floating Catalyst TiO2-Coconut Fiber

The increasing number of laundry businesses in Pontianak causes increased laundry waste, which is dangerous for health and the environment because anionic surfactants such as Linear Alkylbenzene Sulfonate (LAS) are hard degradable. Photocatalyst is a method that can be used to degrade the LAS structure. TiO2 carried in coconut fiber can optimize sunlight irradiation in degrading LAS content when light reaches the water's surface. This study aims to determine the characteristics and optimum activity time of photocatalyst TiO2-coconut fiber in degrading LAS. Photocatalyst characterization was carried out using XRD, XRF, and DR-UV, while the optimum activity test of photocatalysts in degrading LAS was carried out using a UV-Vis spectrophotometer. XRD diffractogram analysis showed the peaks of coconut fiber at 2θ = 22.2º, 34.8º and TiO2 at 2θ = 25.3º, 37.8º, 48.1º, 55.1º, and 62.1º. The TiO2 attached to the fiber after being synthesized was 21.12%. The band gap of TiO2 and TiO2-coconut fiber is 3.21 and 3.18 eV, with light absorption at 386.5 and 390.3 nm. Photocatalyst was carried out in LAS with a mass ratio of TiO2 and coconut fiber of 20:80; 30:70; 40:60, and 50:50 w/w with a time range of 0, 30, 60, 90, and 120 minutes. The results of photocatalysis of TiO2-coconut fiber in a ratio of 20:80 w/w showed the optimum photocatalytic activity at 120 minutes with the highest degradation rate of 80.43%. This research is expected to be applied as an alternative to handling LAS in laundry industry waste.

Highly Efficient Degradation of Linear Alkylbenzene Sulfonate Surfactant by MIL‐53 (Fe) Metal Organic Framework Derived Electro‐Fenton Applicable in Water Treatments

AbstractMIL‐53 (Fe) Metal‐organic framework (MOF) was synthesized by a hydrothermal method and characterized by SEM, XRD, FT‐IR, and Brunauer‐Emmett‐Teller techniques. The synthesized MOF was successfully applied as an efficient catalyst in Electro‐Fenton degradation of linear alkylbenzene sulfonate (LAS) surfactant, so that degradation rate constant, Kapp, for LAS degradation showed significantly higher amounts in presence of Fe MOF. Effect of experimental parameters on Electro‐Fenton degradation including pH, MOF amount, applied current, Fe (II) concentration, and electrodes distance were investigated and optimized amounts were found. Applying of MOF caused efficient removal of LAS in compared to when MOF was not applied. Catalytic electrochemical degradation in this work showed removal of more than 98 % of initial surfactant in 150 min which was completely satisfying for LAS removal.

Microbiome degrading linear alkylbenzene sulfonate in activated sludge

As the most widely used anionic surfactant, linear alkylbenzene sulfonate (LAS) requires biological alkane degradation when it is treated using an activated sludge (AS) process in a wastewater treatment plant because of its structural carboxylic unavailability. As consumption of LAS is gradually increasing, LAS loading into the WWTP is accordingly increasing. However, fewer studies have examined the involvement of the AS microbial community in the LAS degradation. In this study, metagenomic approaches were used to define microbiomes involved in LAS degradation in AS, with a particular focus on ω-hydroxylation. The abundance and diversity of alkane-degrading genes were investigated, and these genes were integrated with reconstructed metagenome-assembled genomes (MAGs). Additionally, the association of functional genes and MAGs with respect to LAS degradation was investigated. The results showed that alkB and cytochrome P450 genes were only shared within specific MAGs. Unique sets of genes with diverse abundances were detected in each sample. The MAGs with the alkB and cytochrome P450 genes were strongly associated with the other MAGs and involved in positive commensal interactions. The findings provided significant insights into how the AS microbiomes, which have continuously treated anionic surfactants for decades, potentially metabolize LAS and interact with commensal bacteria.

Thickening and Storage of Sewage Sludge Contribute to the Degradation of LAS and EOX and the Humification of Organic Matter

Land application of sewage sludge on agricultural soils can be sustainable only if pollutant contents and organic matter quality meet the requirements imposed by minimization of environmental risks. This study investigated the degradation of linear alkylbenzene sulfonates (LAS) and extractable organic halogens (EOX) and the formation of humic substances (HS) during the thickening and storage phases of sewage sludge treatment. Changes in spectroscopic properties (UV-Vis, FT-IR, and excitation-emission matrix (EEM) fluorescence) of HS were also evaluated to assess the occurrence of biological activities during these curing phases of sewage sludge (SS). Humic acids (HA), fulvic acids (FA), EOX, and LAS were extracted from sewage sludge sampled from four municipal wastewater treatment plants of different size and treatment sequence, before and after 90 days of aerobic or anaerobic storage. During storage, the loss of organic C in the SS ranged from almost null to 31%. No significant changes of FA were registered, whereas HA increased in almost all samples, up to 30%. The amount of humic substances synthesized during storage correlated with the percentage of C lost. Spectroscopic changes of FA and HA showed an increase in their aromaticity, with a corresponding decrease in the aliphatic contribution. These changes show the improved agronomical quality of SS. LAS decreased during storage up to 30%, surprisingly more under anaerobic than aerobic conditions, whereas EOX decreased significantly in all samples, even up to 81%. In conclusion, although storage may be normally considered not influencing the quality of SS, their organic matter quality improved and contamination decreased during 90 days of storage, whatever the conditions of oxygen availability applied.

Degradation of linear alkylbenzene sulfonate (LAS) using TiO2-chitosan composite as a photocatalyst

Linear Alkylbenzene Sulfonate (LAS) is an anionic surfactant that is widely used as an active ingredient in synthetic detergent formulation. Being a component in domestic waste, LAS can potentially be harmful to the environment. In this research, the degradation of LAS using TiO2-chitosan composite as a photocatalyst was investigated. The optimum dose of TiO2-chitosan to be used was determined, and the effect of pH towards the degradation effectiveness was also studied. The results showed that a dose of 1 g/100 mL composite at pH 6 gave an optimum result for the LAS degradation. In this optimum condition, the decrease in LAS concentration was up to 95.20% from its initial concentration.

Degradation of Linear Alkylbenzene Sulfonate by UV/H2O2 Process

ABSTRACT In this study, we investigated the degradation of linear alkylbenzene sulfonate (LAS) by an ultraviolet/hydrogen peroxide (UV/H2O2) process. In a collimated beam experiment with UV light of wavelength 222 or 254 nm, faster LAS degradation rates occurred at elevated H2O2 concentrations. The degradation behavior varied with the wavelength of the light source. Furthermore, according to the results of a degradation experiment in a tubular reactor, the reaction rate was faster in the UV/H2O2 process than in the UV-only process.

Use of Visible Light for Photo Degradation of Linear Alkyl-benzene Sulfonate in Laundry Wastewater over Ag-doped TiO2

Use of Visible Light for Photo Degradation of Linear Alkyl-benzene Sulfonate in Laundry Wastewater over Ag-doped TiO2

Anaerobic reactor applied to laundry wastewater treatment: Unveiling the microbial community by gene and genome-centric approaches

Gene and genome-centric approaches were applied to investigate the microbial taxonomic and metabolic diversity profiles from a lab-scale anaerobic reactor applied to laundry wastewater treatment with increasing concentrations of linear alkylbenzene sulfonate (LAS). Therefore, metagenomic analysis was carried out with reactor samples collected under three conditions, (i) Stage I, the reactor was fed with synthetic medium, (ii) Stage II, synthetic medium was replaced by diluted laundry wastewater with specific LAS loading rates (SLLRs) of 1.0 ± 0.3 mgLASgTVS−1d−1 and (iii) Stage III, SLLRs increased to 2.7 ± 0.7 mgLASgTVS−1d−1. Shotgun metagenomic sequencing was performed on an Illumina HiSeq 2 × 150 bp platform. Gene-centric analysis of each step of the metabolic pathway (fumarate addition, β-oxidation, ring cleavage and desulfonation) for anaerobic aromatic degradation showed eight over-representative genera (Achromobacter, Pelodictyon, Pseudomonas, Psychrobacter, Rhodococcus, Stenotrophomonas, Sulfurovum and Syntrophobacter), suggesting a microbial core with an important role in LAS biodegradation. Some of these genera were also recovered through a differential binning method, representing fifteen bacterial and one archaeal metagenome-assembled genomes (MAGs). Biodegradation pathway reconstruction of LAS using six MAGs unveiled the syntrophism for complete degradation of the LAS molecule. Only the MAGs with taxonomic annotation for Syntrophobacter showed genetic potential for fumarate addition, whereas in the ring cleavage, there was a predominance of genes in MAGs with taxonomic annotation for Pseudomonas fragi and Rhodococcus. This work represents the first report of genome-centric approach to study biological reactors applied in anionic surfactant degradation, contributing with detailed metabolic information of the key microbial actors in LAS degradation and opening perspectives for future biotechnological strategies aiming at bioaugmentation and/or biostimulation of indigenous microbial populations.

Scale-up evaluation of anaerobic degradation of linear alkylbenzene sulfonate from sanitary sewage in expanded granular sludge bed reactor

Sanitary sewage composed of 6.2 ± 3.2 mgLAS L−1, low diversity of organic acids (21.4 ± 18.9 and 2.1 ± 3.9 mg L−1, for acetic and propionic, respectively), metals (Fe, Zn, Pb, Mn, Ni, Cr, Cu) and xenobiotic compounds (limonene, terpinene, phenol, indolizine) were used in the pilot-scale EGSB reactor feed (69 L). For influent load of 1.4 ± 0.7 mgLAS gVS−1d−1 and 50 ± 15 mgCOD gVS−1 d−1, removal efficiencies were 60 ± 30% and 77 ± 28% for LAS and COD, respectively. According to the alpha diversity indices (Shannon, Chao-1and Simpson), the sanitary sewage composition did not negatively affect the microbial richness throughout the 314 days of EGSB reactor operation. Bacteria related to LAS degradation such as Synergistes, Syntrophus, Clostridium and Geobacter were identified. For the Archaea Domain, Methanosaeta was the dominant genus. Therefore, in the present study the application of a pilot-scale EGSB reactor was considered viable for the LAS bioremediation in sanitary sewage.

PH-Based Strategies for an Efficient Addition of H2O2 During Ozonation to Improve the Mineralisation of Two Contaminants with Different Degradation Resistances

Ozonation is an efficient process for the primary degradation of most substrates but not for their mineralisation. In this work, the ozonation enhanced with the addition of H2O2 was studied for two substrates with very different oxidation resistances: the dye rhodamine 6G (R6G) and the surfactant linear alkylbenzene sulfonate (LAS). With O3 only, the primary degradation of R6G was completed in less than 10 min but its TOC removal only reached 45% in 1 h. By adding H2O2, TOC removal was increased to 70% with a molar ratio (mol H2O2/mol substrate) of 10. The analysis of pH decrease served to define the specific basicity loss (SBL). The optimum conditions for the R6G mineralisation were found to be associated with a SBL value between 1 and 10 ((min/g)/L)−1, through an adequate addition of H2O2. Moreover, in the case of LAS, the addition of H2O2 for a greater efficiency should occur after the foaming period, above all formed at acid pH. LAS degradation was also considerably improved, and the optimum for primary degradation achieved in 10 min with a TOC removal of over 65% with a molar ratio (mol H2O2/mol substrate) of 20.

Study on the membrane bioreactor for treating surfactant wastewater

Abstract The main component of surfactant is linear alkylbenzene sulfonate (LAS), which is toxic to the ecological environment and can cause serious harm. In this study, some activated sludge was taken from the aerobic and anaerobic tank of a sewage treatment plant in Shenzhen, then cultivated and domesticated in a membrane bioreactor with artificial surfactant wastewater. The start-up phase of the reactor adapted the constant-flux filtration, and the HRT was 12 h. The pH was below 5.5, which needed the addition of NaHCO3 after 6 days to adjust to the more optimal level (pH 6.5–7.5). After operation for 20 days, the start-up of the system was considered successful. At the early stage, the removal rates of chemical oxygen demand (COD) and LAS were relatively stable, reaching as high as 85.49%–93.31% and 80%, respectively. When the LAS concentration reached over 175 mg/L and the COD declined to about 83%, the removal rate of LAS also significantly decreased. LAS removal rate further decreased to about 60% when the dosage reached 200 mg/L, indicating that the resistance of microorganisms against LAS toxicity was also limited. LAS degradation could have been mainly driven by Dechloromonas, Gemmata, Pseudomonas and Zoogloea in the system.

Robustness and Microbial Diversity of a Fluidized Bed Reactor Employed for the Removal and Degradation of an Anionic Surfactant from Laundry Wastewater

AbstractA fluidized bed reactor (FBR) was employed to evaluate the removal and degradation of linear alkylbenzene sulfonate (LAS) from laundry wastewater without supplementary feeding. After immobi...

Degradation of Linear Alkylbenzene Sulfonate (LAS) by using multi-Contact Glow Discharge Electrolysis (m-CGDE) and Fe2+ ion as catalyst

Multi-Contact Glow Discharge Electrolysis (m-CGDE) technique have successfully degraded linear alkylbenzene sulfonate (LAS) surfactant with high efficiency. The degradation process was conducted in 0.02M electrolyte solution NaOH with electrical voltage at 800V and anode at 10mm depth. The anode number and addition of Fe2+ ion greatly influenced the efficiency of the degradation. In the experiment using number of anode of 4, the percentage of LAS degradation achieved approximately 99.46% in 90min, with energy consumption of 721.06kJ/mmol. The addition of Fe2+ ions will increase the LAS degradation, by using 40mg/L of Fe2+ ions in the reactor, LAS was degraded approximately 97.95% and 807.82kJ/mol energy consumed during the operation.

Hydroxyl radical production on contact glow discharge electrolysis for degradation of linear alkylbenzene sulfonate

Contact Glow Discharge Electrolysis (CGDE) is one of the plasma electrolysis technologies for producing hydroxyl radicals that can be used for the process of waste degradation. This study has been conducted to establish the influence of voltage, electrolyte concentration, and anode depth in the Linear Alkylbenzene Sulfonate (LAS) degradation process using CGDE and its energy consumption. The results indicated that the greatest LAS degradation at a rate of 96.19% was achieved with an energy consumption of 2692 kJ/mmol, that was obtained using 600 V, at a Na2SO4 concentration of 0.03 M, and anode depth of 20 mm during 30 minutes of the process. Meanwhile, the lowest energy consumption was 1802 kJ/mmol with the LAS degradation at the rate of 82.11% that was obtained when using 600 V, at a Na2SO4 concentration of 0.03 M and anode depth of 0.5 mm during 30 minutes of the process. These results showed that CGDE is an effective method to degrade LAS. © 2016 American Institute of Chemical Engineers Environ Prog, 35: 962–968, 2016

Experimental studies and modelling of a simplified CIP system using ozone and linear alkylbenzenesulfonate

The degradation of linear alkylbenzenesulfonate by ozone in a simplified CIP system has been explained considering jointly a first-order kinetic model for the ozone decomposition reaction in aqueous solutions and a first-order kinetic model for the reaction of ozone and homologues of linear alkylbenzenesulfonate (LAS). The kinetic constants found for the homologues of LAS at the same temperature are similar and show good dependence on temperature (0.960<r2<0.995) following the Arrhenius equation, indicating that ozone has similar affinity for the different alkyl chain homologues.The cleaning of soiled substrate using LAS solutions and ozonated LAS solutions has also been analysed. Under these experimental conditions, the detergency was almost the same without affecting the washing effectiveness. However, a degradation of the surfactant is obtained when ozone is used, reducing the toxicity of the washing solutions. This indicates that LAS could have potential as a surfactant in CIP system with ozone.

Evaluation of the microbial diversity in sequencing batch reactor treating linear alkylbenzene sulfonate under denitrifying and mesophilic conditions using swine sludge as inoculum

The objective of this study was to evaluate the degradation of Linear Alkylbenzene Sulfonate (LAS) in anaerobic sequencing batch reactor (ASBR) under denitrifying conditions using swine sludge as inoculum. The reactor was operated for 104 days with synthetic substrate containing nitrate, and LAS was added later (22 mg/L). Considering the added mass of the LAS, the adsorbed mass in the sludge and discarded along with the effluent, degradation of the surfactant at the end of operation was 87%, removal of chemical oxygen demand was 86% and nitrate was 98%. The bacterial community was evaluated by cutting the bands and sequencing of polymerase chain reaction (PCR) fragments and denaturing gradient gel electrophoresis (DGGE). The sequences obtained were related to the phylum Proteobacteria and the alpha-and beta-proteobacteria classes, these bacteria were probably involved in the degradation of LAS. The efficiently degraded LAS in the reactor was operated in batch sequences in denitrifying conditions.

Anaerobic degradation of anionic surfactants by indigenous microorganisms from sediments of a tropical polluted river in Brazil.

Linear alkylbenzene sulfonate (LAS) is widely used in the formulation of domestic and industrial cleaning products, the most synthetic surfactants used worldwide. These products can reach water bodies through the discharge of untreated sewage or non-effective treatments. This study evaluates the ability of the microorganisms found in the Tiete river sediment to degrade this synthetic surfactant. The experiment was conducted in a bioreactor, operated in batch sequences under denitrifying conditions, with cycles of 24 hours and stirring at 150rpm, using 430 mL of sediments and 1 070mL of a synthetic substrate consisting of yeast extract, soluble starch, sodium bicarbonate and sucrose. LAS was added at different concentrations of l5mg/L and 30mg/L. The reactor operation was divided into the biomass adaptation to the synthetic substrate without LAS and three experimental conditions: a) addition of l5mg/L of LAS; b) 50% reduction the co-substrate concentration and 15 mg/L of LAS, and c) addition of 30mg/L of LAS and 100% co-substrate concentration. The results showed that the degradation efficiency of LAS was directly related to the addition of co-substrates and the population of denitrifying bacteria. The removal of LAS and nitrate can be achieved simultaneously in wastewater with low organic loads. The reduction in the co-substrates concentration was directly influenced by the number of denitrifying bacteria (2.2x10(13) to 1.0 x 10(8) MPN/gTVS), and consequently, LAS degradation (60.1 to 55.4%). The sediment microorganisms in the Tiete river can be used as an alternative inoculum in the treatment of wastewater with nitrate and LAS contamination.

Evaluation of the microbial community of upflow anaerobic sludge blanket reactors used for the removal and degradation of linear alkylbenzene sulfonate by pyrosequencing

The microbial communities from two upflow anaerobic sludge blanket (UASB) reactors treating synthetic wastewater supplemented with linear alkylbenzene sulfonate (LAS) (RS) and laundry wastewater (RL) were analyzed by pyrosequencing of 16S rRNA genes. A higher LAS degradation rate was observed in RL (82 ± 9%) than RS (45 ± 16%). A high proportion of the LAS removal rate (55–90%) was observed in the PS region for both reactors, most likely due to the low concentration of co–substrates and oxygen diffusion in this region. A microbiological analysis of samples taken at 112 days of operation from the sludge blanket (SB) and the phase–separator (PS) region of both reactors confirmed these findings. The distinct microbial communities found in each reactor resulting from the different wastewaters used were related to the LAS degradation rates obtained. The microbial community from reactor RL was more capable of degrading LAS, most likely because of the presence of xenobiotics.