Filtration and clarification

The use of MgO in the defecation process results in a higher density and faster settling mud, along with an increase in clarifier capacity. Filtration capacity is also increased since a thicker, denser mud is obtained. Filtering efficiency is also improved by virtue of the reduced volume of more easily filtered mud. 

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Corrective Action Application An acidic groundwater at a Florida site (pH 2.5-3) required treatment. The groundwater was collected by extraction wells, pumped to an above-ground reactor, and neutralized with lime. In the course of neutralizing the waste stream, precipitates were formed which were removed by clarification and filtration prior to discharge. Sludges produced from the clarification and filtration steps were dewatered by a filter press. 

Oliva, J., Paya, P., Camara, M. A. and Barba, A. 2007. Removal of famoxadone, fluquinconazole and trifloxystrobin residues in red wines Effects of clarification and filtration processes. Journal of Environmental Science and Elealth, Part B 42 775-781. 

Granular bed filters are used in ten coil coating plants to remove residual solids from the clarifier effluent, and are considered to be tertiary or advanced wastewater treatment. Chemicals may be added upstream to enhance the solids removal. Pressure filtration is also used in this industry to reduce the solids concentration in clarifier effluent and to remove excess water from the clarifier sludge. Figure 7.4 shows a granular bed filter and Table 7.13 presents the heavy metal removal data of a lime clarification and filtration system. 

Removal of Heavy Metals from Coil Coating Wastewater by Lime Precipitation, Clarification, and Filtration... 

In addition to the heavy metals stated in Table 22.10, ferro- and ferricyanide are also part of the pollutants in the wastewater generated in a chrome pigment plant. These wastes are generally combined and treated through reduction, precipitation, equalization, and neutralization to be followed by clarification and filtration processes. Most of the heavy metals are precipitated using lime or caustic soda at specific pH. Chromium is reduced by S02 to a trivalent form, wherein it is precipitated as chromium hydroxide at specific pH. Sodium bisulfide is also employed to precipitate some of the metals at a low pH. The treated water is recycled for plant use while the sludge is sent to landfills (Figure 22.7). 

Pectinases and (3-glucanases are the only enzymes allowed in wine-making by European legislation. They are used as clarification and filtration agents and also to release aroma compounds that are mostly present in grape as nonvolatile glycosidic precursors. Pectolytic enzymes are also reported to increase extraction of phenolic compounds and wine color... 

The black deposit produced by the action of sulphuric acid, after having been heated and subjected to pressure, yields about eighty per cent, of oil, which, after clarification and filtration, is little inferior to the oil first obtained. 

The process of pretreating hard water with lime and sometimes soda as well, based on standard precipitation methods, to reduce the hardness either to a minimum level or more usually to a preset level of, say, 85 ppm, thereby lowering the total treatment costs. Usually carried out in specially designed tanks and followed by clarification and filtration. Calcium bicarbonate is always removed, requiring one equivalent... 

At the completion of fermentation, mead undergoes a period of maturation that includes clarification and filtration. These are obligatory despite their increasing production costs. 

Lachman s recommendations for wines for the market still stand Wines should never be put on the market unless they are perfectly clear that is, they should hold clear and show brilliant before a candle. His recommendation that wines be aged at least eighteen months before bottling simply reflect the inadequacy of the clarification and filtration procedures of his time. 

Suspended solids can be removed or reduced in RO feed water using coagulation, clarification, and filtration (see chapter 8.1.1). 

Microfiltration as pretreatment to RO is used for bulk removal of suspended solids and bacteria. Microfiltration is a barrier technology that can in many cases replace conventional clarification and filtration. Advantages of MF over conventional clarification and filtration include the following ... 

Commercial pectinase preparations for clarification and filtration of juice and wine Ultrazym 100 G (Novo Nordisk)... 

In general work on a micro scale, hot-saturated solutions are used only when filtration and clarification are unnecessary or when the substance has little tendency to crystallize. However, to prevent crystallization during filtration, it is better to use solutions that are less than saturated even at room temperature after clarification and filtration, the dilute solution is concentrated until saturated hot or, alternatively, the dilute solution is evaporated to dryness and the residue is dissolved in a fresh small amount of the solvent. 

After clarification and filtration a dilute solution can be concentrated by heating it in a water-bath (see Figure 15 a) or on a controllable electric hotplate, a capillary being placed 1.0-1.5 cm above the surface of the solution and... 

Wines Improved yield of juice Clarification and filtration pectinase fungal 4,7,10... 

Aluminium Al"" Usually present as a result of floe carryover from clarifier can cause operation deposits and contribute to scaling Improved clarification and filtration... 

For the clarification and filtration of many dilute colloidal systems such as industrial wastes and municipal water supplies it is generally necessary to add a flocculating agent such as aluminum sulfate that markedly alters the potential of the colloids, causing flocculation and greater ease of separation. 

Control Method—Commercial Experience Clarification and filtration of the brine can eliminate suspended clay. Also, it can be removed by ion-exchange in the acidic medium, using the cation-exchange resins such as Duolite-467 or precipitated as magnesium-aluminum silicate dining the primary brine treatment. 

Dubourdieu et al. (1981) proposed two tests for glucans in wine at levels ranging from 3 to >15 mg/L. Concentrations >3 mg/L may create clarification and filtration problems. 

The flow scheme of these facilities is very similar to the one of a conventional water supply facility which treats surface water (in spite of the very different use). It usually consists of a physicochemical treatment (to reduce pollution associated with the colloids that escape from the secondary clarifiers of the WWTF) and a disinfection unit (to remove pathogens and prevent health issues related to the wastewater reuse). The first treatment follows a four-stage scheme coagulation, flocculation, clarification, and filtration. Membrane technology (i.e., reverse osmosis or electrodialysis) is sometimes proposed... 

Polysaccharides (glucans, pectins, or starch) may be present in juice and wines where they can contribute to difficulties in clarification, fining, and filtration. Concentrations of glucans greater than 3mg/L may create clarification and filtration problems. 

Fouling of internal surfaces of pipe systems by contained solids can cause heavy corrosion and erosion. De-sludging, sedimentation, clarification, and filtration arrangements should be made. 

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