Waste water size mixtures

Ultrafiltration — This process has been successful with mixtures difficult to separate, such as oily machining wastes and oily wastewater. A pressure-driven filtration membrane separates multicomponent solutes from solvents, according to molecular size, shape and chemical bonding. Substances below a preselected molecular size are driven through the membrane by hydraulic pressure, while larger molecules, such as oil droplets, are held back. Effluent oil concentration depends on influent concentration, but properly operated ultrafiltration units can produce oilfree water (less than 0.1 ppm for all practical purposes). 

The increasing demand for solvent-free paints led to the introduction of water-based paints. Both in the production and in the application of this type of paint quite often a water-paint waste mixture results. Two examples are leftovers, diluted with (cleaning) water and water used in water curtains in spray booths, which becomes increasingly contaminated with paint. Using ceramic membranes with pore sizes of 0.1 micron [35], it is possible to concentrate the paint particles to a very high degree (35-65% dry matter) and at the same time produce an effluent containing less than 0.1% paint. This can be... 

Concrete is a cheap fire and corrosion resistant material. However, active species, especially easily soluble ions such as cesium, can be leached from it by water. Addition of plastic binders to the concrete in order to improve its properties have been suggested. In the continuous bitumen extruder process for semi-liquid wastes all water is directly eliminated, considerably reducing the waste volume. The bitumen mixture is placed in steel drums of standard size (150-2001). When additional shielding is desired, the filled drums are placed into disposable or reusable sleeves of concrete, iron, or lead. Such a sleeve of 12 cm lead weighs 7 t, and reduces the surface dose rate by a factor of —10. A typical unshielded bitum i drum may have a surface dose rate of 1 Sv h necessitating remote handling. 

Section 20.6 describes two processes for the production of high surface area hydrated lime, with BET areas of 30 to 50m /g, and median particle sizes of about 2 Lun. One uses a methanol-water mixture for the hydration process, while the other uses water containing an additive. The higher surface areas enable the required acid gas emission concentrations to be achieved at lower levels of excess hydrate and with reduced amounts of waste material. 

Clay was supplied by a clay quarry located in Bailen, Jaen (Spain) and was obtained by mixing three types of raw clay in equal parts red, yellow and black clay. Clay was crushed and ground to yield a powder with a particle size suitable to pass through a 150 pm sieve. The waste, olive wastewater and olive oil wastewater were supplied by a local olive oil extraction plant and used directly without any prior pretreatment. The ceramic paste for the extrusion was prepared by adding fresh water (FW) or residue resulting from olive oil extraction (OW or OOW) to the clay in a mixer. The amoimt of added water in the mixer depends on clay plasticity and on its consistency while performing the extrusion. In the present work 22 wt % of FW, OW or OOW was added to the clay. The same value as used at industrial scale for this kind of clay mixture. Extrusion was carried out in a laboratory Venco extruder. Extruded test pieces were dried at room temperature for about 24 h, and then heated in an oven at 110 °C until constant weight for at least 24 h. 

The ore is initially crushed from rock matrix to mineral grain size or smaller. Often this rock powder is mixed with water and/or chemical reagents to form slurry. This mixture is injected with air and agitated by stirring. The mineral particles then attach themselves to air bubbles and float off as a concentrate, while the wet grains of rock (waste) sink to the bottom. 

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