Scouring effluents

Non-biodegradable branched chain anionic surfactants are now replaced by readily biodegradable straight chain compounds and thus pollution load in waste 

Scouring of wool is mainly done by detergent and solvent. The main components of wool scouring waste water are wool grease, suint and dirt and excrement. Table 13.13 shows the pollutant load of the wool scouring effluent. The detergent 

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Suspensions of oil in water (32), such as lanolin in wool (qv) scouring effluents, are stabilized with emulsifiers to prevent the oil phase from adsorbing onto the membrane. Polymer latices and electrophoretic paint dispersions are stabilized using surface-active agents to reduce particle agglomeration in the gel-polarization layer. 

Jones, RW. and Westmoreland, D.J. (1998). Degradation of nonylphenol ethoxylates during the composting of sludges from wool scour effluents. Environmental Science and Technology 32, 2623-2627. 

Sun, C. and Baird, M. (1998). The determination of alkyl phenol ethoxylates in wool-scouring effluent. Journal of the Textile Institute 89, 677-685. 

Another approach consists of an in-situ acetylation and extraction of NPEOs and further analysis of the acetyl derivatives. The method has been applied to analyse effluent water and sewage sludges [102,103], sediments [104] and river waters [105]. Silylated derivatives [106] using BSA or BSTFA have also been used to determine NPEO (n < 6) in seawater [107] and wastewater [107,108], sediments [109] and sludges from wool scour effluents [110]. Halogenated derivatives of alkylphenols (AP) can also be formed as a result of chlorination practices in water treatment or wastewater if bromide is present. Brominated OPs and NPs (BrAPEOs) have been identified by GC-MS in sewage [111] and tap water [89], respectively. 

It was generally assumed that the endocrine disruptor nonylphenol (NP) is the most persistent metabolite of NPEO. However, experimental data on the formation of the metabolite NP from NPEO are surprisingly scarce, and mostly under anaerobic conditions NP has been reported to be formed [126,127]. Only one article reports a slight increase in NP concentration from the aerobic degradation of NPEO during the composting of wool scour effluent sludge [128]. 

While the formed-in-place or dynamic hydrous zirconium oxide membranes on porous stainless steel supports have been studied mostly for biotechnology applications, they have also demonstrated promises for processing the effluents of the textile industry [Neytzell-de-Wilde et al, 1989]. One such application is the treatment of wool scouring effluent. With a TMP of 47 bars and a crossflow velocity of 2 m/s at 60-70°C, the permeate quality was considered acceptable for re-use in the scouring operation. The resulting permeate flux was 30-40 L/hr-m. Another potential application is the removal of dyes. At 45 C, the dynamic membranes achieved a color removal rate of 95% or better and an average permeate flux of 33 L/hr-m under a TMP of 50 bars and a crossflow velocity of 1.5 m/s. 

Typical Data from Treatment of Wool Scour Effluent... 

Tertiary treatment processes are used only to eliminate materials which are not amenable to secondary treatment. A treatment method for wool scouring effluent has been developed, consisting of evaporation and incineration plant in combination with a biological plant [56]. The resulting condensates from the evaporation plant and the incineration residues are recycled so that the water, ammonia and scouring aids are returned to the production plant [57]. 

A. Elice-Invaso, J. Maheswaran, K. I. Peveril, J. R. Christoe, and C. Skourtis, Wool Scour Effluent as a Potassic Fertiliser. ASSI NZSS National Soils Conference, Aural Papers, Melbourne, Australia, July 1996, p. 75. 

Jones, F. W., D. J. Westmoreland, Degradation of NPE during composting of sludges from wool scour effluents. Environ. Sci. Technol., 1998,32, 2623—2627. 

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