Surfactants wastewater

Besselievre, E.B. The Treatment of Industrial Wastes-, McGraw-Hill New York, NY, 1969. Brownell, R.P. Chemical-biological treatment of surfactant wastewater. Proceedings of the 30th Industrial Waste Conference, Purdue University, Lafayette, IN, 1975, Vol. 30, 1085. 

The effluent from the isolation wash belt is the principal wastewater stream from the polymerization process. It contains highly diluted acetic acid and a surfactant that is not biodegradable. The wastewater streams are sent to sewage treatment plants where BOD is reduced to acceptable levels. Alternative biodegradable surfactants have been reported in the Hterature (173). 

When the primary target is oil removal, we should distinguish between the forms of oil. There are two forms of oil that we find in wastewater. Free oil is oil that will separate naturally and float to the surface. Emulsified oil is oil that is held in suspension by a chemical substance (Detergents - Surfactants) or electrical energy. When making an evaluation, free oil will normally separate by gravity and float to the surface in approximately 30 minutes. Emulsified oil is held in a molecular... 

The ionic associates of malachite green cation with dodecyl sulfate anion has been suggested for monitoring nonionic surfactant levels in industrial wastewaters by spectrophotometric determination at 650 nm [196]. 

Alcohol sulfates and alcohol ether sulfates separated by HPLC on a styrene-divinylbenzene copolymer column with 4 1 (v/v) methanol and 0.05 M ammonium acetate aqueous solution as the mobile phase were analyzed by simultaneous inductively coupled argon plasma vacuum emission spectroscopy (IPC), monitoring the 180.7-nm sulfur line as a sulfur-specific detector [294]. This method was applied to the analysis of these surfactants in untreated wastewaters. 

Therefore in many countries the use of surfactants derived from phosphonic acid are limited by law, especially for surfactants of mass products like household detergents that will flow into wastewater effluents. The difficulty in formulating detergents without inorganic polyphosphates is discussed in Ref. 206. 

As mentioned previously, deca-BDE was considered for a long time as a practically non-toxic compound, due to its low availability. However, the results of both experiments have clearly demonstrated that this pollutant is bioavailable in aqueous phase in the presence of Tween 80. Considering that wastewater discharged into the environment often contains different types of surfactants,... 

LLE has been used in the past for the extraction of pesticides from environmental water samples [17]. However, its application in the extraction of waste-water samples is scarce due to the low efficiency of extraction, especially for polar analytes. Because of the vast amount of surfactants and natural products present in wastewater samples, emulsions are formed which complicate the process of extraction and lead to low extraction recoveries. However, there have been some useful applications of LLE to wastewater analyses. For example, LLE was found to be effective for the isolation of herbicide and pesticide organic compounds from industrial wastewater samples and also from complex matrices [18]. 

Other membrane processes such as microfiltration, ultrafiltration, reverse osmosis, and colloid-enhanced ultrafiltration have been applied to the separation of beta-cypermethrin from wastewater samples [27]. In this study, a separation of above 92% was performed by reverse osmosis by the use of composite membranes and above 80% by colloid-enhanced ultrafiltration by the use of nonionic surfactants. 

Even if quantitative results are more often expected for wastewater quality measurement, qualitative information is of great interest, as is the case for other applications of the analytical sciences (in the health sector, the use of test kits and biodiagnostic systems leads to quick and useful information, often far from a classical analytical result). In fact, quantitative analysis gives the concentration not only of one substance, but also of a group of comparable substances (surfactants, PAH,...), and even the value of a specific (TOC, TKN,...) or aggregate (BOD, COD, toxicity,...) parameter. In this context, total indices are often proposed as parameters complementary to classical analytical results [1]. 

Both urban and industrial wastewater often contains high concentrations of surfactants. Cationic (like alkylbenzene sulphonates) and non-ionic surfactants (like alcohol ethoxylates) are among the most-used surfactants and are discharged into sewers in widely varying concentrations. Two on-line methods have been designed for the monitoring of cationic surfactants with UV spectrophotometry [46] and non-ionic surfactants by on-line titration [47]. The detection limits are around 10 mg L. ... 

Recent studies, including the use of Microtox and ToxAlert test kits [55,56], were carried out for the determination of the toxicity of some non-ionic surfactants and other compounds (aromatic hydrocarbons, endocrine disruptors) before implementation on raw and treated wastewater, followed by the identification and quantification of polar organic cytotoxic substances for samples with more than 20% inhibition. Furthermore, the study of their contribution to the total toxicity was obtained using sequential solid-phase extraction (SSPE) before liquid chromatography-mass spectrometry (LC-MS) detection. This combined procedure allows one to focus only on samples containing toxic substances. 

A derived combined approach uses an amperometric biosensor [57] with a whole-cell (E. coli) sensing part, for industrial application (textile and tannery wastewaters) and detection of phenolic compounds, non-ionic surfactants and benzenesulphonate compounds. As in the previous studies, chemical analysis (SSPE followed by LC-MS) revealed the pollutants responsible for the observed toxicity. 

In order to study simultaneously the behaviour of parent priority surfactants and their degradation products, it is essential to have accurate and sensitive analytical methods that enable the determination of the low concentrations generally occurring in the aquatic environment. As a result of an exhaustive review of the analytical methods used for the quantification within the framework of the three-year research project Priority surfactants and their toxic metabolites in wastewater effluents An integrated study (PRISTINE), it is concluded that the most appropriate procedure for this purpose is high-performance (HP) LC in reversed phase (RP), associated with preliminary techniques of concentration and purification by solid phase extraction (SPE). However, the complex mixtures of metabolites and a lack of reference standards currently limit the applicability of HPLC with UV- or fluorescence (FL-) detection methods. 

The presence of both surfactants and their degradation products in different aquatic matrices, such as wastewater, surface water and marine water besides biota is discussed and its importance for the environment evaluated. 

Despite the large amounts of surfactants discharged into wastewater, the qualitative and quantitative determination in water or sludge samples according to the compound groups causes problems to the analysts even today. The property of surface activity, which imparts to surfactant molecules non-volatility, high polarity and therefore an excellent water-solubility, poses the analyst considerable problems. 

Thus, more sophisticated methods including preconcentration, chromatographic separation and sensitive and accurate detection are required for the compound-specific analysis of the broad range of surfactants. The request for more specific methods is further increased when the investigations not only centre on the parent compound, but also aim at the qualitative and quantitative determination of degradation intermediates, often formed at low concentrations, during the wastewater treatment process. 

---