Biodegradation Of Surfactants Research Articles

Ester Quats: The Novel Class of Cationic Fabric Softeners

Esterquats, which are quaternary ammonium compounds having two long (C(16)-C(18)) fatty acid chains with 2 weak ester linkages, represent a new generation of fabric softening agents, having replaced the dialkyldimethylammonium salts (e.g. DTDMAC and DSDMAC). The inclusion of ester linkages into the aliphatic chains has significantly improved the kinetics of biodegradation of the cationic surfactants, lowering the environmental exposure levels. This new generation of fabric softening agents combines a good environmental profile with the structural features required for an effective fabric conditioner. The present paper reviews the synthesis, types, actives combines a good environmental profile with the structural features required for a properties and applications of esterquats.

Effect of photochemical treatment on the biocompatibility of a commercial nonionic surfactant used in the textile industry

The degradability of surfactants is a frequent and complex issue arising both at domestic as well as industrial treatment facilities. The present paper describes a laboratory study conducted to elucidate the photochemical and biochemical treatability of a nonionic, alkyl polyethylene ether-based surfactant formulation commonly used in the textile preparation stage. The application of H 2O 2/UV-C advanced photochemical oxidation appeared to be a suitable treatment alternative and 90% COD removal (COD 0≈500 mg/L) could be achieved under optimized process conditions. A significant COD removal efficiency (74%) could also be reached after biodegradation (final COD=135 mg/L) of the surfactant; however, necessitated an acclimation period of at least 6 weeks for the achievement of steady-state conditions. H 2O 2/UV-C treatment efficiency was seriously retarded upon elevation of the initial COD to around 1000 mg/L, resulting in 46% COD and 38% TOC removal after 120 min photochemical oxidation (H 2O 2,0=1020 mg/L; pH 0=9.1). The BOD 5/COD ratio increased from 0.23 to 0.31 after the application of H 2O 2/UV-C revealing that photochemical pretreatment may have a positive effect on the ultimate biodegradation of the nonionic surfactant. Although the time required for activated sludge treatment to reach steady-state conditions could be reduced to 3 weeks for the photochemically pretreated surfactant formulation biochemical COD removal efficiency dramatically decreased from 74% to 39% for the nonionic surfactant being subjected to H 2O 2/UV-C pretreatment (ultimate COD after activated sludge treatment=265 mg/L).

Biodegradability of Surfactants under Aerobic, Anoxic, and Anaerobic Conditions

The biodegradability of two surfactants, Triton X-100 and Rhamnolipid, was tested under aerobic, nitrate reducing, sulfate reducing, and anaerobic conditions in a respirometer. The results indicated that from a biodegradation standpoint, Rhamnolipid is superior to Triton X-100 since it is biodegradable under all conditions, whereas the Triton X-100 is partially biodegradable under aerobic conditions and nonbiodegradable under anaerobic, nitrate reducing, and sulfate reducing conditions.

Effect of river sediment on the biodegradation kinetics of surfactant and non-surfactant compounds

The half-time of biodegradation of the surfactant sodium dodecylsulfate (SDS) by Pseudomonas species C12B, was reduced two fold by the presence of a riverine sediment. The sediment alone gave comparatively negligible biodegradation of SDS under otherwise equivalent conditions. The sediment had no effect on the kinetics of biodegradation of the non-surfactant pyruvate by Pseudomonas strain C12B. In the light of (i) the known strong adsorption of the surfactant SDS, but not pyruvate, to river sediment and (ii) the SDS-stimulated attachment of Pseudomonas C12B and other SDS-degraders to the sediment, the above observations indicate that acceleration of biodegradation was the result of simultaneous attachment of both SDS and biodegradation competent bacteria to the sediment. This interpretation was strengthened by analysis of the biodegradation kinetics. The data obtained for biodegradation in the absence of sediment, were fitted best by a model involving logistic growth on the added surfactant. The biodegradation data in the presence of sediment were fitted to variants of this model, including one allowing growth on material endogenous to the sediment. Of the several models tested, the data were fitted best by one which is consistent with accumulation of both bacterial cells and substrate at the sediment surface. The enhancement of surfactant biodegradation by sediment is discussed in the context of the design of biodegradability tests and environmental acceptability.

Biokinetics of biodegradation of surfactants under aerobic, anoxic and anaerobic conditions

The present investigation aims at estimating the biodegradation coefficients of surfactants. The biodegradabilities of Triton X-100 and Rhamnolipid were tested under aerobic, nitrate reducing, sulphate reducing and anaerobic conditions using a respirometer. The results indicated that in terms of biodegradability, Rhamnolipid is superior to Triton X-100, since it is biodegradable under all conditions, whereas Triton X-100 is partially biodegradable under aerobic conditions and non-biodegradable under anaerobic, nitrate reducing and sulphate reducing conditions.

Benzotriazoles, Alkylphenols and Bisphenol A in Municipal Wastewaters and in the Glatt River, Switzerland

Many organic micropollutants occur at trace concentrations in municipal wastewater effluents and in the aquatic environment. Some of these xenobiotic chemicals can be considered as 'emerging' contaminants and some are suspect to have endocrine disrupting effects. Among the latter are nonylphenol (NP), octylphenol (OP) and bisphenol A (BPA), which deserve special attention due to their ubiquitous occurrence in the aquatic environment. The complexing agents benzotriazole (BT) and tolyltriazole (TT) are applied as anticorrosive agents (e.g. in cooling and hydraulic fluids, in antifreezing fluids, in aircraft deicing fluids, in dish washing liquids for silver protection), as antifogging agents and as intermediates for the synthesis of various chemicals. The environmental occurrence of NP and OP is caused by the fact that they are intermediate products (metabolites) in the biodegradation of alkylphenol polyethoxylate surfactants. BPA is globally used for the production of polycarbonate and epoxy resins. BT, TT, NP, OP and BPA were quantitatively determined in municipal wastewater effluents in Switzerland and in the Glatt River. The analytes were enriched by solid-phase enrichment. BT and TT were determined underivatized by electrospray LC/tandem MS. Reversed-phase LC was performed on octylsilica columns with isocratic water/methanol elution. Multiple reaction monitoring of the positive ions provided selective and sensitive detection for reliable quantifications. NP, OP and BPA were determined by GC/MS after derivatization with N-methyl-N-(trimethylsilyl)-trifluoroacetamide. BT and TT concentrations in primary and secondary effluents of municipal wastewater treatment plants varied from below 10 to 100 microg/L. The ranges of the concentrations in the Glatt River in ng/L were 636-3,690 for BT, 122-628 for TT, 68-326 for NP, 6-22 for OP and 9-76 for BPA. The corresponding mass flows in g/d were 93-1,870 for BT, 18-360 for TT, 24-183 for NP, 1-16 for OP and 2-72 for BPA. The concentrations and mass flows of NP in the River Glatt were drastically lower than the analogous values found 15 years ago. Thus, a substantially decreased environmental exposure can be observed due to the reduction of the use of alkyphenol polyethoxylate surfactants in Switzerland. The current concentrations of NP, OP and BPA are within the ranges reported for weakly impacted surface waters. The investigated contaminants occur at quantitatively measurable but varying concentrations in municipal wastewaters and in the Glatt River reflecting their ubiquitous input into wastewaters and their different behaviour during biological wastewater treatment.

Cationic Gemini Surfactants: A Review

Recently new classes of gemini surfactants have emerged which are composed of two hydrobhobic tails and two cationic head groups linked by spacer group i.e cationic gemini surfactants. Now a days, different types of cationic geminis have been synthesized .In comparison with corresponding single chain surfactants, these surfactants are more efficient in lowering surface tension and have much lower cmc. Due to their higher surface activity they have excellent properties of dispersion stabilization and soil cleanup. These compounds are widely used as an effective emulsifiers, dispersing and anti-foaming agents etc. Cationic gemini surfactants show good antimicrobial activities. Some of these geminis show good biodegradability too. This review paper deals with synthesis, properties, applications, and biodegradability of new cationic gemini surfactants.

Ozonation Impact on Degradation and Toxicity of Non-Ionic Surfactants

Aqueous solutions of five selected non-ionic surfactants: Triton (i-octylphenolethoxylates), Tergitol (2,6,8-trimethyl-4-nonanoloxethylates), Symperonic (n-nonylphenol-oxethylates) and Brij (fatty alcohol ethoxylates) were investigated in this study. Using the bioluminescent bacteria Vibrio fischeri the toxicity of the surfactants solutions were determined. An attempt was made to relate rather low biodegradability of nonionic surfactant solutions measured by the BOD5/COD ratio (ranging from 1 to 17%) to their toxicity. The ozonation process was carried out in a 1.5 dm3 stirred cell reactor equipped with two ozone detectors. The following parameters were analyzed: pH, COD, BOD5, DOC, TOC, polarography as well as UV spectrum. The positive effect of ozonation, represented by decay of UV absorption, was visible in almost complete destruction of the surfactants, with exception of Triton X-705 (only 65% degradation after absorption of 2000 mgO3/dm3). The most striking results were obtained in toxicity tests for ozonated solutions of the non-ionic surfactants – an increase of the bacterial growth inhibition (1.5 to 4 times increase in toxicity due to ozonation). The obtained results were discussed taking into account the literature and our own experimental data on mechanisms of ozonation and biodegradation of non-ionic surfactants of the Triton-type and similar chemical structures.

Bleaching Product Development in View of Ecological Aspects

Abstract The new European Detergents Regulation will enter into force 8 October 2005, dealing with the aerobic biodegradation of surfactants so far. An expansion of the regulation regarding all main organic detergent ingredients and anaerobic biodegradation aspects shall be reviewed until April 2009. Within the scope of this expansion also bleach activators will be affected, whereat in our opinion thought should been given to a specific characteristic of this ingredients category: whereas other detergent ingredients as surfactants, builders or solvents act in the washing process due to physical effects and therefore arrive at the environment in a chemical unchanged way, bleach activators react with per-oxo compounds during the washing process and hence change their chemical structure. So, regarding bleach activators, the environmental relevant compound differs from the compound being existent in the washing agent. This issue shall be pointed out considering various bleach activators as example.

Anaerobic biodegradability of Tween surfactants used as a carbon source for the microbial reductive dechlorination of hexachlorobenzene

Three structurally-related, nonionic, polysorbate surfactants (Tween 60, 61, and 65) were used as the sole carbon source to sustain the microbial, sequential reductive dechlorination of hexachlorobenzene (HCB) in a mixed, methanogenic culture derived from a contaminated estuarine sediment. The surfactants were partially degraded and fermented to methane with no measurable accumulation of volatile fatty acids, indicating that methanogenesis was rapid relative to the rates of hydrolysis and acidogenesis. Addition of the methanogenesis inhibitor 2-bromoethanesulfonic acid resulted in acetate accumulation without impact on the sequential dechlorination of HCB. An anaerobic biodegradability assay was performed and the following data were obtained for the Tween 60, 61, and 65, respectively: 53, 62, and 62% COD destruction; 35, 57, and 48% COD to methane conversion; and 38, 38, and 45% COD to acetate conversion. These data suggest that the hydrophobic moiety (stearate) of the surfactants was preferentially degraded, most likely through beta-oxidation, to acetate and ultimately to methane and carbon dioxide. Between 38 and 47% of the initial surfactant COD remained after 46 d incubation, which most likely corresponds to the hydrophilic polyoxyethylene moiety. An anaerobic biodegradation pathway of the Tween surfactants is proposed.

Primary aerobic biodegradation of cationic and amphoteric surfactants

AbstractThe primary aerobic biodegradation of several cationic and amphoteric surfactants has been studied by using the shaking‐flask degradation test and orange II spectrophotometric analysis. The results show that cationic and amphoteric surfactants can be readily biodegraded, with their degradation exceeding 94%. The degradation kinetics can be accurately described by the Boltzmann model. The relationship between structure and biodegradability is discussed. The presence of hydrophobic groups has a strong effect on the biodegradability of these surfactants. Biodegradability decreases with increasing chain length. The presence of hydrophilic groups mainly affects the degradation rate of these surfactants, but not their ultimate biodegradeability. Bio‐degradability is deterred and degradation is slowed as steric hindrance increases. Degradation rates increase markedly when hydrophilic groups containing an amide bond are pres‐ent.

Quantitative assessment of alkyl chain branching in alcohol‐based surfactants by nuclear magnetic resonance

AbstractSurfactants with branched hydrophobes have gained considerable interest, since these can be used in formulations for laundry cleaning at a wide range of conditions. The claims range from improved dissolution rate to hardness tolerance and stain removing efficacy. In contrast to the historically known heavily branched surfactants, novel branched surfactants are less compromised by increased biodegradability. These properties find their basis in the structural characteristics of the hydrophobe, such as number, position, and type of alkyl chain branches. Our current understanding of structure‐property relations, however, is hampered by the lack of generic methodology needed to obtain structural data on hydrophobe branching. A nuclear magnetic resonance (NMR) approach was developed by which we could obtain a comprehensive set of quantitative hydrophobe branching parameters in alcoholbased surfactants. The13C and1H NMR spin systems of hydrophobe branched species were assigned by means of twodimensional NMR techniques. These assignments allowed the quantitative assessment of these branched species by straight‐forward signal integration in the1H and13C NMR spectra. The quantified NMR data can be used to understand product performance and the biodegradation of surfactants with branched hydrophobes.

Cleavable Ortho Ester Type Surfactants

Abstract With the focus on quaternary ammonium compounds, this paper describes how the ortho ester chemistry can be used as a versatile tool for synthesis of cleavable surfactants of various types. This class of chemodegradable surfactants hydrolyzes rapidly under mild acidic conditions at the same time as they are long-term stable in alkaline aqueous solutions. Further, the rate of cleavage can be modified by varying the structure of the surfactant. An additional feature is the possibility to design surface active compounds that release a daughter surfactant with different properties upon cleavage. Ortho ester-based surfactants could be of use in a large number of applications as exemplified in the paper. Good biodegradation data are of importance for virtually all types of surfactants nowadays. However, there actually seem to exist very few, if any, investigations regarding the biodegradation of cleavable surfactants under both hydrolytical and non-hydrolytical conditions. Data from the initial part of such a study on cationic ortho ester surfactants are presented and discussed in this paper. The results strongly indicate rapid biodegradation for this class of compounds under varying conditions.

Disinfection and the prevention of infectious disease: No adverse effects?

We write in response to the publication by Cozad and Rhona in the American Journal of Infection Control, which we have read with great interest. The review was undertaken to assess what evidence there is to support disinfection as an infection control measure. The authors reach the conclusion that the use of disinfection is beneficial in preventing infectious disease and thus results in a public health benefit. However, we believe the scientific approach used in the work and, correspondingly, the authors’ findings deserve comment. The work was financed by the Consumer Specialty Product Association, a ‘‘premier trade association representing the interests of the consumer specialty products industry—a dynamic industry that provides households institutions and industrial customers with products that help provide a cleaner and healthier environment.’’ The association’s product range includes among other things items designed to control or eliminate microbes in any environment. Moreover, both the authors are members of Scientific and Regulatory Consultants, Inc, whose staff offers ‘‘expertise gained from over 50 years of combined service to the antimicrobial industry.’’ Thus, the work is not without bias, takes a one-sided approach, and disregards the known adverse effects of using surface disinfection in infection control. What do we know about the role of the hospital environment as a reservoir for infectious diseases? According to current scientific knowledge, microbial contamination of the patient’s inanimate environment seems to be only a minor causative factor within the complex nature of nosocomial infection. Maki and

Potentiometric Flow Injection Analysis of Anionic Surfactants in Industrial Products and Wastes

A new sensor for anionic surfactants with a membrane consisting of 33 wt% poly(vinyl chloride) (PVC), 66 wt% dioctylphthalate (DOP) plasticizer, and 1 wt% tridodecylmethylammonium chloride (TDMAC) is developed and used for flow injection analysis. The sensor displays a working response range of 5×10−7–5×10−3 M dodecylbenzene sulfonate (DBS−) with a Nernstian slope of 58.5±0.2 mV decade−1, a response time of 30 s and a detection limit of 1.5×10−7 M DBS−. Selectivity measurements with different anionic species indicate good membrane selectivity towards DBS−. The sensor is used to measure anionic surfactants (DBS−) in different wastewater samples, commercial detergent products, and for monitoring the rate of surfactant biodegradation in sewage treatment plants. The results obtained agree fairly well with data obtained by the standard extraction-spectrophotometric method. The proposed potentiometric method offers the advantages of simplicity, accuracy, automation feasibility, and applicability to turbid and colored sample solutions.

Primary biodegradation and mineralization of hair shampoos in fresh, brackish and marine waters of the Niger Delta

Two methods, the methylene blue active stain (MBAS) river die away method for monitoring primary biodegradation of surfactants and the ultimate biodegradability method for monitoring mineralization of the total biodegradable organic component in a compound were employed to determine the biodegradability of three hair shampoos, (Hair fruit shampoo, New Goldmax super antidandruff shampoo and Goldmax antidandruff shampoo) for a 28-day period. Sodium dodecyl sulphate (SDS) served as the reference chemical. After 28 days, the percentages of MBAS remaining in fresh, brackish and marine waters respectively were: for hair fruits shampoo, 83.8, 95 and 2; for New Goldmax super antidandruff shampoo, 83.8, 80 and 12.5; for Goldmax antidandruff shampoo, 66.7, 59.5 and 17.3. However, the percentages of mineralization were: for carbon of hair fruit shampoo, 13.5, 8.6 and 95.2; for carbon of New Goldmax super antidandruff shampoo, 53.9,72.9 and 99.7, and for carbon of Goldmax antidandruff shampoo, 90.2, 83.2 and 99.8. Primary biodegradation and mineralization of SDS was independent of water type. The extent of both primary biodegradation and mineralization followed the trend: marine water > brackish water = fresh water. These results indicated that the extent of Primary biodegradation and mineralization was greatest with marine water of Bonny estuary and the two test methods produced the same results. Key words; Primary biodegradation, Mineralization, Shampoos, Freshwater, Brackish water, Marine water. [Global Jnl Environ Sci Vol.2(2) 2003: 88-95]

Biodegradable ionic liquids: Part I. Concept, preliminary targets and evaluation

The design, preparation and evaluation of biodegradable ionic liquids containing ester or amide groups in the alkyl side chain are presented. Factors improving the biodegradation of surfactants were successfully applied to ionic liquids. These novel ionic liquids can be prepared from readily available starting materials in high yield. The introduction of a group susceptible to enzymatic hydrolysis greatly improves the biodegradation (OECD 301D ‘Closed Bottle Test’) compared with the commonly used dialkylimidazolium ionic liquids, bmimBF4 and bmimPF6. For the 3-methyl-1-(alkyloxycarbonylmethyl)imidazolium bromide series, the greatest biodegradation was observed when alkyl = butyl, pentyl, hexyl and octyl. The corresponding amide analogs proved to be poorly biodegradable.

Effects of surfactants on the dechlorination of chlorinated ethenes.

The influence of surfactants on a perchloroethene (PCE) dechlorinating mixed culture was investigated in laboratory experiments. Surfactants (Steol CS-330, Aerosol MA 80-I, alpha olefin sulfonate 14 to 16, Neodol 25-7, Tween 80, alkyl polyglycoside, C16TAB [trimethylammonium bromide], and sodium dodecyl sulfate) were evaluated for their effects on the rate and extent of PCE reductive dechlorination and their potential biodegradation by the mixed culture. Limited, if any, surfactant biodegradation was observed for the surfactants tested, and all surfactants impaired dechlorination in either the rate of PCE dechlorination or the terminal dechlorination products observed. Based on initial testing, a nonionic surfactant, Tween 80, and an anionic surfactant, Steol CS-330, were selected for additional investigation. Dechlorination of PCE to dichloroethene (DCE), vinyl chloride (VC), and ethene (ETH) occurred in all Tween 80-amended microcosms, with a depressed rate of ETH production as the only adverse effect. Steol CS-330, however, inhibited dechlorination beyond DCE at all surfactant concentrations exceeding 25 mg/L. Attempts to acclimate a culture to Steol CS-330 were unsuccessful. Inhibition of VC and ETH production was reversible on dilution of the surfactant to a concentration of 10 mg/L or less, indicating that surfactant interactions with the enzyme system responsible for reductive dechlorination of DCE may be the cause of inhibition.

Model development and application for surfactant biodegradation in an acclimatising activated sludge system

A model for the biodegradation of non-ionic surfactants in an activated sludge system during acclimatisation was developed, based on respirometric and titrimetric experimental data. The data were obtained in a sequencing batch reactor (SBR) using a non-ionic surfactant as sole carbon source and sludge previously acclimatised to a different surfactant. The model was successfully applied to successive SBR-cycles of sludge acclimatisation processes subjected to two ethoxylated surfactants. The model was validated using the corresponding total organic carbon data. The evolution of the model parameters along the acclimatisation process was examined. An acclimatisation model was developed using the evolution of two of these parameters (affinity constant and inhibition constant), supported by two independently calculated acclimatisation indicators. This acclimatisation model was then applied to determine an optimal surfactant concentration sequence to feed non-acclimatised sludge during a period of 41 days, in order to induce pre-acclimatisation to this surfactant before it replaces another one in the wastewater. The model was also useful in the economical assessment of this and alternative procedures to cope with frequent changes in activated sludge feed composition.

Biodegradation of Nonylphenol Ethoxylate Surfactants in Biofilm Reactors

AbstractThe primary degradation of a technical nonylphenol ethoxylate surfactant with an average chain length of 10 ethoxylate units (NPEO‐10) was studied in a flow‐through system by means of miniaturized biofilm reactors (mBFR) with bacteria from an activated sludge plant. 5 mg/L of the test compound (total EO concentration) were spiked in synthetic wastewater (SWW) and fed to the reactors continuously for 64 days. Compound removal and the formation of degradation products (DP) were monitored under both oxic and anoxic conditions. Solid‐phase extraction and RP‐HPLC with fluorescence detection were employed for sample preparation and analysis. Better removal of the parent compound was seen with the oxic reactors (50 to 70%) than with the anoxic reactors (30 to 50%). Compared to SWW organic matter, the test compound proved to be of refractory nature. The appearance of degradation products in the effluent was earlier with anoxic reactors despite their lower elimination efficiency. After extraction of biomass only minor amounts of NPEO‐10 and metabolites were found, indicating that small amounts were present in adsorbed or intracellular form. Ultimate biodegradation of NPEO‐10 and of octylphenol ethoxylates (OPEO‐9.5; average chain length of 9.5 EO units) was tested by means of manometric respirometry at a theoretical oxygen demand (ThOD) of 100 mg/L. Whereas NPEO‐10 was biodegraded by only 26%, at best, in 28 days, OPEO‐9.5 degradation amounted to (40 ± 5)%.