Flocculation and Clarification

Flocculation should be performed in a separate tank or compartment of a tank from neutralization. Organic electrolyte is added to aid in the agglomeration process. 

Flocculation systems should be capable of reducing the concentration of most common electroplated metals to less than 1 ppm, and suspended solids to below 20 ppm. If lower 

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Chemical treatment is a weU-proven technique and is less expensive. Generally, specific chemical precipitation is carried out in situ in big tanks holding the radioactive waste stream to remove radionuclides while permitting nonradioactive ions to be released in the effluent from the process. The radionuchdes present in the waste are precipitated, co-precipitated, carrier precipitated, or adsorbed by insoluble compounds. A clariflocculator is used for flocculation and clarification. This technique is used as a batch or a semibatch process for large volumes of effluents containing only low concentrations of activity. It provides lower DF values (10-100) than evaporation. 

Solids contact processes combine chemical mixing, flocculation and clarification in a single unit designed so that a large volume of previously formed floe is retained in the system. The floe volume may be as much as 100 times to in a "flow-through" system. This greatly increases the rate of agglomeration from particle contacts and may also speed up chemical destabilization reactions. 

The trend in the use of deep bed filters in water treatment is to eliminate conventional flocculators and sedimentation tanks, and to employ the filter as a flocculation reactor for direct filtration of low turbidity waters. The constraints of batch operation can be removed by using one of the available continuous filters which provide continuous backwashing of a portion of the medium. Such systems include moving bed filters, radial flow filters, or traveling backwash filters. Further development of continuous deep bed filters is likely. Besides clarification of Hquids, which is the most frequent use, deep bed filters can also be used to concentrate soflds into a much smaller volume of backwash, or even to wash the soflds by using a different Hquid for the backwash. Deep bed filtration has a much more limited use in the chemical industry than cake filtration (see Water, Industrial water treatment Water, Municipal WATERTREATiffiNT Water Water, pollution and Water, reuse). 

Suspended matter in raw water suppHes is removed by various methods to provide a water suitable for domestic purposes and most industrial requirements. The suspended matter can consist of large soflds, settleable by gravity alone without any external aids, and nonsettleable material, often colloidal in nature. Removal is generally accompHshed by coagulation, flocculation, and sedimentation. The combination of these three processes is referred to as conventional clarification. 

Most of water-soluble acrylamide polymers find practical applications as highly efficient flocculents for clarification and treatment of potable water and municipal and industrial effluents and in the mining, papermak-... 

Flocculation or clarification processes are solids-liquid separation techniques used to remove suspended solids and colloidal particles such as clays and organic debris from water, leaving it clear and bright. Certain chemicals used (such as alums) also exhibit partial dealkaliz-ing properties, which can be important given that the principal alkaline impurity removed is calcium bicarbonate—the major contributory cause of boiler and heat exchanger scales (present in scales as carbonate), although closely followed by phosphate. 

Clarification is the process of separating the clear liquid from the flocculated and settled sludge. 

Sedimentation and dissolved air flotation are the most common clarification processes for removal of precipitates. Either sedimentation or flotation is often preceded by chemical coagulation or precipitation, which converts dissolved pollutants to a suspended form, and by flocculation, which enhances clarification by flocculating suspended solids into larger, more easily separating particles. Simple sedimentation normally requires a long retention time to adequately reduce the solids content. The detention time of dissolved air flotation, however, is much shorter. When chemicals are used, retention times are reduced and clarification removal efficiency of either sedimentation or flotation is increased. A properly operated clarification system is capable of efficient removal of suspended solids, metal hydroxides, and other wastewater impurities.10-12... 

The mechanism for sedimentation (clarification) is based on the density difference between SS and liquid. In addition, SS with larger particle sizes can settle down more easily. Rectangular tanks, circular tanks, combination flocculator-clarifiers, and stacked multilevel clarifiers can be used.14 Oliveira et al.15 reported that flocculation and sedimentation were conducted in the cassava meal industry and reduced the effluent concentration of organics from 14,000 to 2000 mg/L in the bench-scale reactor, with a hydraulic retention time (HRT) of 37 min. 

Clarification is the process of separating the clear liquid from the flocculated and settled sludge. All of these individual processes may take place in a series of tanks or in a single multizoned tank. 

In most Interior Valley winery operations, the wines are racked once. After this racking, the wines are fined. This is a clarification process carried out by use of certain fining agents that cause flocculation and settling out of any cloudiness in wine. In addition, certain colloidal and proteinaceous soluble solids are absorbed by the fining agent. If not removed by fining, these soluble materials may later precipitate out in the bottle and cloud the wine. 

Actiflo 20-70 50-175 Micro-sand ballasted flocculation and lamella clarification Kruger... 

Clarification with Solids Recycle In many instances, the rate of clarification is enhanced by increasing the solids concentration in the flocculation zone of the clarifier. This is done in a full-scale operation by internally or externally recycling previously settled solids into the flocculation zone where they are mixed with fresh, coagulated feed. The higher population of solids improves the flocculation efficiency and clarification rate. 

Amerfloc . [Drew Ind. Div.] Polymers flocculant and coagulant aid for sludge conditioning, dewatering industrial slurries, water clarification. 

Until recently, the standard method for treatment of these wastes consisted of lime coagulation and flocculation with clarification by dissolved air flotation. Subsequently, the underflow is polished with sand or diatomaceous earth filtration. Finally, the sludge is dewatered by vacuum filtration. The effluent quality is variable and does not always meet discharge standards. 

Extracellular Organism type. Growth Clarification. Flocculation and... 

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