Surfactants effluents

Surfactant effluents Anionic surfactants, nonionic surfactant, EDTA Improvement of biodegradablity... 

Waste aqueous metalworking fluids may be successfully treated by conventional means for removal of tramp oil, surfactants, and other chemical agents to provide suitable effluent water quaUty (78). 

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). 

Further examinations have been done in the biodegradation ecotoxicity sequence rest (BEST). In this test a realistic diluted effluent of the modified OECD confirmatory test (DIN 38412, part 26) is tested continually on daphnia reproduction over three generations. It can be said that the effluents of an OECD confirmatory plant (feed 10 mg/L LAS), containing nondegraded surfactants and catabolites, have no negative effect on the juvenile and adult daphnia even in the third generation and do not influence their reproduction [296]. 

In five pilot plants that can be used to simulate the route of anionic surfactants from the consumer via the effluent purification plant to the receiving water, possible toxic effects of residual surfactant content and breakdown products of the secondary alkanesulfonates were investigated [102]. As indicators of the effects on living organisms of the effluent in the receiving water, flora and fauna that are frequently encountered in the p-mesosaprobic zone were used as models. The embryo-larval test was also employed as an additional method for the detection of toxic compounds in the water. 

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. 

B. I. Tulbovich, L. V. Kazakova, and V. I. Kozhevskikh. Foam-forming composition—contains surfactant, in form of alkali effluent from... 

The core - flood apparatus is illustrated in Figure 1. The system consists of two positive displacement pumps with their respective metering controls which are connected through 1/8 inch stainless steel tubing to a cross joint and subsequently to the inlet end of a coreholder 35 cm. long and 4 cm. in diameter. Online filters of 7 im size were used to filter the polymer and brine solutions. A bypass line was used to inject a slug of surfactant solution. Two Validyne pressure transducers with appropriate capacity diaphragms are connected to the system. One of these measured differential pressure between the two pressure taps located about one centimeter from either end of the coreholder, and the other recorded the total pressure drop across the core and was directly connected to the inlet line. A two - channel linear strip chart recorder provided a continuous trace of the pressures. An automatic fraction collector was used to collect the effluent fluids. 

In-situ emulsion formation, as proposed by Kamath et al(19), with DAS surfactants may cause higher pressure drops across the core. This is because of the blocking tendency of the emulsion which has lower mobility. This could explain the earlier plugging of the core compared to other runs. Effluent pH and viscosity showed behavior similar to the previous runs. It is worthwhile noting here that such pressure drops were not manifested by face plugging of the core near the entrance. This was confirmed by simultaneously monitoring the pressure at the inlet end of the core as well as the differential pressure across the two pressure taps located about 1 cm. from each end of the core. The inlet end pressure transducer showed reasonably low pressures throughout the run for each experiment. 

Figure 5. Effluent profiles for oil-water-surfactant saturated Wilmington sand...

The sulfonate content was determined either by the well-known technique of two-phase titration with hyamine or by liquid chromatography (HPCL). Nonionic surfactants were analyzed by HPLC (16) in the reverse or normal phase mode depending on whether the aim was to determine their content in effluents or to compare their ethylene oxide distribution. 

Run n° Desorbent concentration used g/1 mM/1 PH effluents Surfactant retention (mg/g) Associated concentration in effluents (g/l) ... 

To mark the displacement front, 150 ppm of sodium iodide was incorporated in the surfactant micellar slug. This tracer can easily be detected in effluents with a UV detector at 229 nm. 

Figures 5 and 6 show that the concentration of the two surfactants in the effluents increases simultaneously with the production of the desorbent, which confirms the mixed micellization mechanism described above. Figure 5, where the three additives are produced lately, illustrates the phenomenon particularly well. At the lower pH corresponding to strong adsorption conditions for sulfonate (test 4), the one pore-volume micellar slug would have been entirely consumed by the medium in the absence of any desorbent.

A micellar flood was then started with the injection of the micellar slug, polymer buffer, and the drive water in succession, at a rate of 1.3 m/day. Two types of polymers - polyacrylamide polymer (Dow Pusher 700) and Xanthan Gum polymer (Kelzan XC) - were used as the polymer buffers. Sodium chloride brine (1%) was used as the drive water. Effluent was collected and analyzed for surfactant content using the IR and UV techniques. 

Figure 3. Typical plot of data output from the rig, showing values of the weight of effluent from the capillary test unit as a function of time, during an experiment. The portion of the curve from B - C shows the efflux of surfactant solution from the foam generator which precedes gas break-through. Portion C -D< shows the efflux of foam of increasing quality. At times larger than D only "dry gas, without liquid phase, emerges.

Since cyclodextrins form complexes with various other substances, including many dyes and surfactants, it is clear that they could be useful in effluent treatment. They are potentially suitable for the reduction or removal of polluting substances either by immobilisation or by solubilisation and extraction and thus can accelerate detoxification [30]. 

Aqueous scouring is expensive in terms of water use and effluent treatment and it can cause entanglement of delicate wool fibres. Solvent scouring offers an effective alternative but it is essential that the solvent does not enter the environment. Earlier solvent-based processes included the use of perchloroethylene in which 8-18% water had been emulsified with a surfactant. Current processes are based on hexane (de Smet process), 1,1,1-... 

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