Sediment membrane filtration

Most of the pollutants may be effectively removed by precipitation of metal hydroxides or carbonates using a reaction with lime, sodium hydroxide, or sodium carbonate. For some, improved removals are provided by the use of sodium sulfide or ferrous sulfide to precipitate the pollutants as sulfide compounds with very low solubilities. After soluble metals are precipitated as insoluble floes, one of the water-solid separators (such as dissolved air flotation, sedimentation, centrifugation, membrane filtration, and so on) can be used for floes removal.911 The effectiveness of pollutant removal by several different precipitation methods is summarized in Tables 5.15-5.17. 

Recently, Wang100 introduced a membrane sequencing batch reactor (membrane-SBR) process for groundwater decontamination, water purification, and industrial effluent treatment. A membrane-SBR is similar to conventional SBR except that membrane filtration is used (instead of sedimentation) for the separation of mixed liquor suspended solids (MLSS) from the mixed liquor. 

Tests should also be carried out for sediment if the naphtha has been subjected to events (such as oxidation) that could lead to sediment formation and instability of the naphtha and resulting products. Test methods are available for the determination of sediment by extraction (ASTM D473, IP 285) or by membrane filtration (ASTM D4807 IP 286) and the determination of simultaneously sediment with water by centrifugation (ASTM D96, D1796, D2709, D4007 IP 373, 374). 

Coagulation, Sedimentation, Granular Media Filttation Ion Exchange Membrane Filtration Adsorption ... 

Sedimentation and/or filtration (26,28) will be feasible for separating the insoluble chromium hydroxide precipitates (or chemical floes) from a wastewater. Other feasible solid-water separation processes for removing the insoluble chromium hydroxide include membrane filtration (such as ultrafiltration and microfiltration), continuous DAF, PC-SBR-sedimentation, PC-SBR-DAF. The following is a summary of the solid-water separation processes feasible for the combined application of chemical reduction and precipitation. 

Both insoluble Mn02 and Fe(OH)3 are then removed by one or more solid-water separation processes, such as sedimentation (1,14,28), dissolved air flotation (16,22), filtration (23,26), membrane filtration (20,21,25,26), electroflotation (17), physicochemical sequencing batch reactor (18,19), or precoat filtration (29,46). 

Sediment is also determined by an extraction method (ASTM D-473, IP 53) or by membrane filtration (ASTM D-4807). In the former method (ASTM D-473, IP 53), an oil sample contained in a refractory thimble is extracted with hot toluene until the residue reaches a constant mass. In the latter test, the sample is dissolved in hot toluene and filtered under vacuum through a 0.45-pm-porosity membrane filter. The filter with residue is washed, dried, and weighed. 

Membrane filtration is used for treating high-turbidity waters, surface waters high in TOC and for tertiary water treatment, and provides a more stable and superior water quality than coagulation-sedimentation and media filtration. It is a simple and cost-effective alternative to conventional water treatment operations. 

It is obvious that the use of one membrane filtration method as a single separation technique cannot give comprehensive information on metal speciation in aqueous media. Combinations of UF with FFF, sedimentation, ion exchange, and liquid-liquid extraction are useful for the identification of the species of an element. However, membrane filtration itself is a rather powerful means if a number of membranes having different pore size are used for studying one sample. 

I. Collect by membrane filtration a portion of the wine containing the sediment onto two separate membranes. 

Rinse the sediment or crystals with a small volume of distilled water, transfer to a membrane filtration apparatus, and apply vacuum. 

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