Surfactants In Wastewater Research Articles

Perfluorooctane surfactants in waste waters, the major source of river pollution

Perfluorooctanoate (PFOA) and perfluorooctane sulfonate (PFOS) are persistent and widely distributed in the environment. Recently, the discharge of municipal waste water has been shown to be an important route of such perfluoroalkyl surfactants into the aquatic environment. The aim of this study was to assess the mass flow of PFOA and PFOS from typical waste water treatment plants (WWTPs) into surface waters. Samples were collected at different stages of treatment of four WWTPs in Northern Bavaria, Germany, and from the rivers receiving the treated waste waters (WW). The outflow of PFOA from the WWTPs to the rivers was 20-fold higher than the inflow to the plants; about a tenth was removed with the sludge. For PFOS, the increase from inlet to outlet was about 3-fold; almost half of it was retained in the sludge. Both surfactants were released into river water from the WWTP of a medium-sized city with domestic, industrial and commercial waste waters; in domestic waste waters the surfactants were found at much lower levels.

Treatability of Surfactants in Wastewater from a Pharmaceutical Facility Using Chemical Oxidation and Advanced Oxidation Processes

Treatability of Surfactants in Wastewater from a Pharmaceutical Facility Using Chemical Oxidation and Advanced Oxidation Processes

Effect of anionic and nonionic surfactants on the kinetics of the aerobic heterotrophic biodegradation of organic matter in industrial wastewater

While using the contemporary mathematical models for activated sludge systems, it is necessary to describe quantitatively the kinetics of microbiological processes and to characterise substrate (wastewater components in the influent) as well as biomass (activated sludge). In this paper, the kinetic parameters of the aerobic biodegradation of organic matter in wastewater containing synthetic surfactants in an activated sludge system were determined and discussed. Also, the composition of the tested wastewater was estimated and expressed as COD fractions. Five synthetic surfactants, three anionic and two nonionic, of different chemical structure were investigated. Each of them was tested separately and dissolved in wastewater to obtain a concentration of 50 mg l −1, which can be found in some industrial wastewater. The presence of the elevated amount of synthetic surfactants in wastewater decreased the affinity of biomass to substrate. Nevertheless, maximum specific growth rates ( μ max) of heterotrophic biomass exposed to wastewater containing surfactants were high but usually lower than μ max estimated for wastewater without surfactant. Surfactants, which contain a benzene ring, were the most likely to deteriorate wastewater treatment processes in the activated sludge systems.

The influence of the selected nonionic surfactants on the activated sludge morphology and kinetics of the organic matter removal in the flow system

Synthetic surfactants are believed to act on the structure of activated sludge flocs and some of them are toxic towards aquatic organisms. Nevertheless, the number of studies concerning their effect on the activity of sludge biomass and flocs morphology is limited. In this work, the removal of two different nonionic surfactants: alcohol ethoxylate and alkyl phenol ethoxylate in the activated sludge wastewater treatment processes was investigated. In contrast to our previous study, in which the influence of anionic surfactants on flocs morphology was the main aim, in this paper also the chosen aspects of the kinetics of the tested processes were included. Moreover, the influence of two most common groups of synthetic surfactants: anionics and nonionics, on the activated sludge flocs and biomass is compared and discussed. The presence of nonionic surfactants in wastewater at the concentration of 50 mg L −1 in the influent causes a decrease of flocs size when the dilution rate is equal to or higher than 0.102 h −1. The removal rate of organic pollutants for both nonionics tested is lower than in the control run for this range of dilution rates and so is the degree of COD removal, which then does not exceed 80%. The affinity of substrate to the biomass, expressed as a COD half-saturation constant, decreases in the presence of synthetic surfactants, as this constant is elevated in all surfactant runs. The strongest effect was exerted by the anionic surfactants: sodium alkyl benzene sulphonate, while nonionics acted moderately on the affinity of the substrate.

The removal of sodium dodecylbenzene sulfonate surfactant from water using silica/titania nanorods/nanotubes composite membrane with photocatalytic capability

This paper reports experimental results on removal of sodium dodecylbenzene sulfonate (SDBS), using silica/titania nanorods/nanotubes composite membrane with photocatalytic capability. This multifunctional composite membrane has been successfully prepared from colloidal X-silica/titania sols ( X denotes molar percent of silica) by the sol–gel technique. The prepared nanorods/nanotubes composite membranes were characterized by X-ray diffraction (XRD), scanning electron microscope (SEM), scanning probe microscope (SPM) and UV–vis diffuse reflectance spectra (DRS). XRD patterns confirmed that the embedding of amorphous silica into nanophase titania matrix helped to increase the thermal stability of titania and control the size of titania particles. The small size titania particles with anatase phase played an important role in formation of silica/titania nanorods/nanotubes composite membranes with photocatalytic capability. The percentage of anatase phase titania reached 93% when 20%-silica/titania nanorods/nanotubes composite membrane calcined at 400 °C for 2 h. Most (95%) of the pore volume was located in mesopores of diameters ranging from 1.4 to 10 nm. The experimental results showed that the removal of SDBS achieved 89% after 100 min by combining the photocatalysis with membrane filtration techniques. Although the SDBS was not completely decomposed by photocatalysis, the degradation of the SDBS helped to enhance composite membrane flux and prevent membrane fouling. It was possible to treat successfully surfactant wastewater using multifunctional silica/titania nanorods/nanotubes composite membrane by means of a continuous process; this could be interesting for industrial applications.

Large scale application of membrane bioreactor technology for the treatment and reuse of an anionic surfactant wastewater

The treatment of an anionic surfactant rich wastewater by a powerful Citrobacter braakii strain was investigated at large scale. This bacterium was inoculated into a 4.5 m 3 continuous stirred tank reactor (CSTR) without a membrane. At volumetric loading rates ranged between 0.44 and 0.96 g COD l −1 d −1, a weak C. braakii population density was observed in the reactor which results in slow anionic surfactants degradation kinetics. The augmented bacterium was diluted and replaced by protozoa and other forms of bacteria after a prolonged experience run. The CSTR was then coupled to a cross-flow ultrafiltration membrane. This allowed complete biomass recycling and partially retention of the surfactants in the reactor. C. braakii became again dominant in the medium. At volumetric loading rates of 0.6–1.5 g l −1 d −1, the anionic surfactant concentration in the permeate varied from 0 to 40 mg l −1 with a mean value of 18 mg l −1. After 2 months of running, mixed liquor volatile suspended solids (MLVSS) in the reactor increased from 0.71 to 5.92 g l −1 and the permeate-flux slightly decreased from 28.75 to 23.75 l h −1 m −2. The reclaimed water could be reused either for the washing of the material and soil, and to irrigate the parkland of the factory.

Determination of non-ionic polyethoxylated surfactants in wastewater and river water by mixed hemimicelle extraction and liquid chromatography–ion trap mass spectrometry

The capability of hemimicelles-based solid phase extraction (SPE)/liquid chromatography/atmospheric pressure chemical ionisation in positive mode, ion trap mass spectrometry (LC/(APCI +-IT)–MS) for the concentration, separation and quantitation of non-ionic surfactants has been investigated. Concentration was based on the formation of mixed aggregates of analytes [alkylphenol ethoxylates (APE, octyl and nonyl) and alkyl ethoxylates (AE, C 12–C 16)] with the anionic surfactant sodium dodecyl sulphate (SDS) that is adsorbed on alumina. Parameters affecting SPE were investigated on the basis that hemimicelles are dynamic entities in equilibrium with the aqueous phase. The performance of ion trap mass spectrometry for MS and MS/MS quantitation of non-ionic homologues was assessed. Recoveries of analytes from wastewater influent and effluent and river water samples ranged between 91 and 98% and were found independent on the length of the alkyl chain under the optimised conditions. Anionic surfactants did not interfere to the levels found in environmental samples. The detection limits ranged between 14 and 111 ng/l for wastewater influent, 10 and 40 for wastewater effluent and 4 and 35 for river water, after concentration of 250, 500 and 750 ml of sample, respectively. The approach was applied to the determination of AE and APE in influent and effluent samples from four wastewater treatment plants and four river samples. The concentrations of individual non-ionic surfactants found ranged between 0.3 and 373 μg/l.

Degradation of Recalcitrant Surfactants in Wastewater by Ozonation and Advanced Oxidation Processes: A Review

ABSTRACT Surfactants are used in varieties of industrial cleansing processes as well as in consumer products. Spent surfactants normally enter domestic or industrial wastewater and are treated biologically. However, some of them are resistant to biodegradation and are released into the environment. Thus, the toxicity and environmental persistence of these surfactants are emerging concerns. Based on extensive review of the literature, ozonation and advanced oxidation using various combinations of ozone, hydrogen peroxide, ultraviolet light irradiation, and iron salts were found effective in degrading recalcitrant surfactants, including linear alkylbenzene sulfonates, alkylphenol ethoxylates, and quaternary ammonium surfactants. Biodegradability of these surfactants was improved after the treatment to some extent in the aqueous solution as well as in real wastewaters.

Interaction of Indigo Carmine with Cetyltrimethylammonium Bromide and Application to Determination of Cationic Surfactant in Wastewater

The microsurface adsorption - spectral correction (MSASC) technique has been applied to the interaction of indigo carmine (IC) with cetyltrimethylammonium bromide (CTAB). The aggregation of IC on CTAB obeys Langmuir isothermal adsorption. The results show that both the monomer complex <TEX>$IC{\cdot}CTAB$</TEX> and the micellar complex <TEX>$(IC{\cdot}CTAB)_{78}$</TEX> were formed. The binding constant of the monomer complex was calculated to be <TEX>$K_{IC{\cdot}CTAB}$</TEX> = 2.20 <TEX>${\times}10^5L{\cdot}mol^{-1}$</TEX>, and the molar absorptivity of the micellar complex was calculated to be <TEX>${\varepsilon}_{(IC{\cdot}CTAB)78}\;^{560nm}$</TEX> = 8.58 <TEX>${\times}10^5L{\cdot}mol^{-1}{\cdot}cm^{-1}$</TEX>. The aggregation was applied to the determination of cationic surfactant in wastewater.

Direct spectrophotometric determination of alkylphenol polyethoxylate nonionic surfactants in wastewater

A new spectrophotometric method is proposed for direct determination of alkylphenol polyethoxylate, RO(CH 2CH 2O) n H (where R is alkylphenyl and n is the degree of polymerization), in wastewater. The method is based on the formation of ternary complex, Pb(II)–meso-tetra-(3,5-dibromo-4-hydrooxyphenyl)-Porphyrin (T(DBHP)P)–alkylphenol polyethoxylate (APE). Under optimum reaction conditions, T(DBHP)P reacts with lead(II) and APE to form a yellow ternary complex with the maximum absorption peak at 479 nm. The color reaction is rapidly completed and the absorbance remains stable for at least 24 h under room temperature. The apparent molar absorption coefficients were 0.4–4.3×10 4 L mol −1 cm −1 for n=5–50. As little as 0.02 μg mL −1 of APE can be detected. The effects of various substances on the determination of APE were also investigated in detail. It was found that all the studied co-existing substances, especially cationic and anionic surfactants, which always seriously interfere in some reported methods, could be tolerated in considerable amounts. The method offered the advantages of simplicity, rapidity, sensitivity and selectivity without any prior separation or extraction.

Biogeochemistry of Aromatic Surfactants in Microtidal Estuaries

This paper summarizes several studies on input, distribution, and fate of two different types of aromatic surfactants, the anionic linear alkylbenzene sulphonates (LAS) and nonionic alkylphenol polyethoxylates (APnEO), in a karstic estuary characterized by sharp salinity gradients. A combination of reversed-phase and normal-phase HPLC analysis followed by spectrofluorimetric detection allowed detailed characterization of homologue and oligomer compositions of aromatic surfactants in wastewater and estuarine waters. The distribution patterns of homologues and/or oligomers in the wastewater plume reveal a significant alteration of the original composition of both surfactants by biotransformation and physico-chemical partitioning. The vertical distribution of surfactant residues in the estuarine water column is characterized by pronounced maxima at the air–brackish water and brackish water–sea water interface. The brackish water–sea water interface is a very efficient barrier, which prevents spreading of surfactants into the deeper layers. In addition, the interface seems to be a site of high biological activity, including biotransformation of surfactant residues. As a consequence, this layer can contain enhanced levels of lipophilic metabolites of APnEO. Biotransformation is the main mechanism for the removal of both surfactant classes from the water column. However, our studies suggest that a significant percentage of surfactant residues discharged into the stratified estuaries reaches the coastal sea due to the incomplete removal in the estuary. This situation is a consequence of a rather fast flushing of the brackish layer and a very slow biotransformation kinetics in the saline layer, especially in the winter period.

Chemical treatment of an anionic surfactant wastewater: electrospray-ms studies of intermediates and effect on aerobic biodegradability

The effect of wet air oxidation on the aerobic biodegradability of a model wastewater containing 1000 mg L −1 of linear alkylbenzene sulfonate (LAS) has been investigated. Semibatch oxidation experiments were performed at a temperature of 473 K, an oxygen partial pressure of 1.3 MPa and residence times varying from 40 to 390 min, while continuous oxidation experiments were performed at a residence time of 120 min. Oxygen uptake tests were performed to assess the aerobic biodegradability of both the oxidised and the original LAS solutions using cultures that had been adapted to both LAS and oxidation intermediates. The concentration of total organic carbon, chemical oxygen demand and active detergent were followed throughout the wet oxidation and biodegradation experiments, while the main intermediates formed during wet oxidation were identified by means of Electrospray-MS and high performance liquid chromatography. It was found that LAS could be easily oxidised at 473 K to yield a group of molecules with short alkyl chains which do not behave as active detergents. Sulfonated aromatics are produced as intermediates which have had the alkyl chain shortened. The segments of alkyl chains broken off the intermediate compounds appear primarily as short chain organic acids. The original, unoxidised 1000 mg L −1 LAS solution was found to be readily biodegradable in the laboratory aerobic reactors operating at low organic loadings and substrate to microorganism concentration ratios. However, wet oxidation resulted in effluents that were less readily biodegradable than the original LAS with biodegradability decreasing with increasing degree of oxidation. These results suggest that, at the conditions under consideration, a combined chemical pre-oxidation and biological post-treatment process may be less effective in removing LAS than a single-stage biological or chemical process.

Identification of photocatalytic degradation products of non-ionic polyethoxylated surfactants in wastewaters by solid-phase extraction followed by liquid chromatography-mass spectrometric detection.

The photodegradation of non-ionic surfactants (nonylphenol- and alcohol-polyethoxylates, NPEOx and CnEOx) was investigated in different waters with and without a photoinducter (Fe(III)). Deionized water and industrial effluent spiked at 0.5 mg/L with C10EO6 and NPEO9 were irradiated using a xenon arc lamp. Aliquots of the test solutions were taken at different time intervals and were preconcentrated using solid phase extraction (SPE) with C18 cartridges. Liquid chromatography-atmospheric pressure chemical ionization-mass spectrometry (LC-APCI-MS) was used to identify the chemical species generated from phototransformation of non-ionic surfactants. The intermediates detected included nonylphenol diethoxylate (NPEO2) and nonylphenol ethoxy acetic acid (NPE2C). Much smaller amounts of degradation products of NPEO9 having only the alkyl chain carboxylated were also formed in the photocatalysis experiment. The identified C10EO6 photoproducts included fatty alcohols and acids. Polyethylene glycols (PEGs) were also formed as the consequence of the central scission of C10EO6 and the deethoxylation of NPEO9. The photodegradation in wastewater samples was more efficient than in deionized water being the half-life (t(1/2)) of C10EO6, 48 h and 29 h in deionized water and wastewater, respectively, and for NPEO9, 17 h and 14 h in deionized water and wastewater, respectively. When induced photodegradation was undertaken, the t(1/2) for NPEO9 was 21 min and 29 min in deionized water and wastewater, respectively. Disappearance of parent compounds was observed after 120 h from the beginning of the photodegradation experiment, or after 210 min of irradiation for the photocatalysis.

Solid-contact potentiometric sensors based on ion pairs of cetylpyridinium with dodecylsulfate and tetraphenylboratc for various surfactants

Compositions of active membrane components for solid-contact potentiometric sensors selective to various surfactants were proposed. The stoichiometric ratios of components and the solubility and thermal stability of organic ion-exchangers were estimated. The main electroanalytical parameters of sensors were determined. Procedures for the potentiometric determination of nonionic surfactants in wastewater, cationic surfactants in hair rinses, and separate determination of nonionic and anionic surfactants in shampoos and synthetic detergents were developed.

Determination of incorporated amounts of poly(ethylene glycol)-derivatized lipids in liposomes for the physicochemical characterization of stealth liposomes

We describe a method for determining incorporated amounts of poly(ethylene glycol) (PEG)-derivatized lipids in liposomes for the physicochemical characterization of PEG-coated liposomes. This method is based on the spectrophotometric determination of complexes of polyethers with sodium ions after their extraction as picrates into 1,2-dichloroethane, developed by Favretto for measuring levels of polyoxyethylene alkylphenyl-ether non-ionic surfactants in waste water. The same assay was applied to the estimation of PEG-derivatized lipids in liposomes and percent incorporation of PEG-derivatized lipids into liposomes was successfully determined. To prevent the interference from liposomal lipids other than PEG-derivatized lipids in this assay, liposomal samples were diluted at least to a concentration of less than 0.2 mM. The percent incorporation of PEG-lipids varied, depending on the molecular weight of PEG and anchor acyl chain length in PEG-lipids and it was suggested that the percent incorporation of PEG-lipids into liposomes would be a good parameter of quality control of PEG-liposomes in manufacturing facility and the picrate method used in the present study allows for the determination of this parameter without the need for hazardous radioisotopes.

Inter-laboratory comparison of liquid chromatographic techniques and enzyme-linked immunosorbent assay for the determination of surfactants in wastewaters

Seven laboratories participated in an inter-laboratory comparison exercise within the framework of the PRISTINE, SANDRINE and INEXsPORT European Union Projects. Solid-phase extraction (SPE) methodologies were used for the extraction of target analytes from wastewaters. The analytical strategies were based on liquid chromatography (LC) coupled to mass spectrometric (MS) or to fluorescent (FL) detection in all cases with the exception of one laboratory using a test-tube enzyme-linked immunosorbent assay kit. Samples were spiked with the surfactants nonylphenolpolyglycol ether, coconut diethanolamide, linear alkylbenzene sulfonate, nonylphenolpolyglycol ether sulfate, alkylpolyglycol ether and secondary alkane sulfonate. After enrichment on previously conditioned SPE cartridges, the SPE cartridges were distributed among the participating laboratories without the information about the amount of spiked surfactants. In addition, SPE cartridges loaded with a real-world environmental sample containing a tannery wastewater were also analyzed. The results of the programme showed that SPE followed by LC–MS techniques are reliable for the surfactants determination at submicrogram to microgram per liter levels in wastewaters. Inter-laboratory precision values were calculated as the reproducibility relative standard deviation (RSD R) which was determined from the reproducibility standard deviation ( s R) and the average concentration at a particular concentration level. When data from all laboratories were pooled, the RSD R values ranged from 5.1 to 28.3% for the determination of target analytes. The most accurate result corresponded to that given for linear alkylbenzene sulfonates. Taking into account that different methodologies were used (including non-chromatographic techniques) and the complexity of the samples analyzed, it can be considered that acceptable reproducibility values were obtained in this inter-laboratory study.

Selection and study of surfactant and mineral oil-degrading microbial consortia

The formation of microbial biocatalysts in laboratory sectional aerobic biotreatment plants for purification of non-ionic surfactant and oil-containing waste-waters was studied. Analysis of the microbial composition of biocatalysts from both plants showed that different microbial consortia, containing 13 (in oil waste-water purification plant) or 18 (in surfactant waste-water purification plant) species of microorganisms, formed in the plant columns. The degradative and emulsifying activities and the distribution of strains in the plant columns were analysed. It was established that the degradative activity of strains, with respect to different chemical structures of pollutants, changed from column to column.

Operating characteristics and kinetic studies of surfactant wastewater treatment by Fenton oxidation

The present study is to investigate the treatment of surfactant wastewater by the Fenton process. The surfactants considered here were anionic alkylbenzene sulfonate (ABS) and linear alkylbenzene sulfonate (LAS), both being widely used in the household and industrial detergents. Experiments were conducted to examine the effects of pH, amounts of ferrous sulfate (FeSO 4) and hydrogen peroxide (H 2O 2) and temperature on the surfactant removal. Chemical coagulation was also considered as an addition in improving the turbidity and dissolved Fe removal after the Fenton process. A first-order kinetic model was adopted to represent the Fenton oxidation of surfactant wastewater. The relation between the reaction rate coefficient and the ferrous sulfate and hydrogen peroxide concentrations and operating temperature was experimentally established using the test data.

Enhanced electrochemical oxidation of anionic surfactants

The surfactant wastewater treatment by electro‐chemical oxidation with or without peroxide hydrogen was investigated. The two anionic surfactants studied here were alkylbenzene sulfonate (ABS) and linear alkylbenzene sulfonate (LAS), both of them being widely used in the household and industrial detergents. Experiments were conducted to examine the effects of pH, electrolyte concentration, time of electrochemical oxidation, power input and amount of hydrogen peroxide (H2O2) on the surfactant removal and other water quality parameters. Optimum operating conditions were experimentally determined. The enhanced version of electrochemical oxidation (i.e. with addition of hydrogen peroxide) was found to be significantly more efficient than that without.

Integration of crop production with CELSS waste management

Lettuce plants were grown utilizing water, inorganic elements, and CO 2 inputs recovered from waste streams. The impact of these waste-derived inputs on the growth of lettuce was quantified and compared with results obtained when reagent grade inputs were used. Phytotoxicity was evident in both the untreated wastewater stream and the recovered CO 2 stream. The toxicity of surfactants in wastewater was removed using several treatment systems. Harmful effects of gaseous products resulting from incineration of inedible biomass on crop growth were observed. No phytotoxicity was observed when inorganic elements recovered from incinerated biomass ash were used to prepare the hydroponic solution, but the balance of nutrients had to be modified to achieve near optimal growth. The results were used to evaluate closure potential of water and inorganic elemental loops for integrated plant growth and human requirements.