Coagulant/flocculant adsorption

This book covers the latest advances in oxidation technologies, ozonation, membrane technology, micropollutant removal, and filtration processes including biological filtration, membrane filtration, and ultrafiltration. Also covered are fundamental processes such as coagulation, flocculation, adsorption, ozonation, preozonation, and granular activated carbon. 

Conventional methods of As removal from drinking water include oxidation/precipitation, coagulation/flocculation, adsorption, ion-exchange and membrane technologies. Similar approaches can be used also for defluoridation (Meenakshi and Maheshwari, 2006) and removal of U from driiiking water (Katsoyiannis and Zouboulis, 2013) although some of these methods have been tested at laboratory or pilot scale only. 

For color removal, ozonization has achieved the greatest practical importance as seen by the plethora of articles and patents on this method (147—163). Ozonization in combination with treatments such as coagulation, flocculation, carbon adsorption, uv irradiation, gamma radiation, and biodegradation significantly and successfully remove dye wastes and reduce costs (156,164—170). 

The coagulation, flocculation, and adsorption processes were modeled mathematically using classical coagulation theory as a starting point. The Smoluchowski equation for orthokinetic coagulation in laminar flow is written (18)... 

Table II. Halftimes for Coagulation, tg, Adsorption, t, and Flocculation, tp. G = 1800 s"l, nQ = 2x10 m, Molecular Weight = 1x10, Initial Polymer Concentration = OFC...

Treatment of dye wastewater involves physical, physico-chemical, chemical, and biological methods. Physical processes are dilution, filtration, and gamma radiation. Physico-chemical includes adsorption, coagulation, flocculation, precipitation, reverse osmosis, ion exchange, etc. 

Chemical and physical methods including adsorption, coagulation-flocculation, advanced oxidation and electrochemical methods are very efficient in color removal. These methods are quite expensive and have operational problems. High sludge formation, regeneration requirement and cost of adsorbent make adsorption an unattractive method for decolorization purposes. So biodegradation begins to play an important role in decolorization of azo dyes. 

Chemical coagulation — flocculation sedimentation Coalescers Membrane processes Biological processes Carbon adsorption Inorganics Organics... 

Physicochemical treatment of pharmaceutical wastewater includes screening, equalization, neutralization/pH adjustment, coagulation/flocculation, sedimentation, adsorption, and ozone and hydrogen peroxide treatment. Detailed descriptions of the various physicochemical treatment processes are described in the following sections. 

Conventional methods for treating wastewater containing dyes, aromatic compounds, or heavy metals are coagulation, flocculation, reverse osmosis, nanofiltration and pervaporation (Paul and Ohlrogge, 1998), and activated carbon adsorption, the latter of which is combined with membrane processes like nanofiltration (Eilers and Melin, 1999) or ultrafiltra-tion (Lenggenhager and Lyndon, 1997). 

MF can remove particles above a certain size (often referred to as turbidity) from surface waters. The removal of organics is possible if they are associated with particulates. This can be achieved by a coagulation/flocculation processes or by the adsorption of organics onto particles. 

Julien F., Gueroux B., Mazet M (1994), Comparison of organic compounds removal by coagulation-flocculation and by adsorption onto preformed hydroxyde floes. Water Research, 28,12,2567-2574. 

The zeta potential is involved in the interaction and adsorption mechanisms between particles and ions, as well as their coagulation, flocculation and sedimentation behavior. This potential may be calculated from measurements of the streaming... 

Intensive physical and chemical treatment, extended treatment and disinfection e.g. chlorination to break-point, coagulation, flocculation, decantation, filtration, adsorption (activated carbon), disinfection (ozone, final chlorination). 

Harrelkas, R, Azizi, A., Yaacoubi, A., Benhammou, A., Pons, M. N. (2009). Treatment of textile dye effluents using coagulation-flocculation coupled with membrane processes or adsorption on powdered activated carbon. Desalination, 235, 330-339. 

Chemical Processes. Tertiary treatment uses many methods to remove pollutants that do not settle out in primary or secondary treatment. These include coagulation, flocculation, nitrification, denitrification, adsorption, ion exchange, and electrodialysis. These have high capital investment and operation costs and require highly skilled personnel for... 

Water treatment technologies consist of many steps, such as sedimentation, oxidation, coagulation, flocculation, filtration, flotation, ion exchange, adsorption, and reverse osmosis. They are intended for the destruction of water contaminants and their removal from treated water bulk. At that, water is disinfected by different methods, namely, chlorination, ozonation, ultraviolet light treatment, and ultrasound treatment. 

Several water treatment technologies have been used for removal of U below the MCL including activated carbon (Coleman et al., 2003), coagulation-flocculation (Gafvert et al., 2002), ion exchange (Barton et al., 2004), adsorption (Shuibo et al., 2009) and ultrafiltration with precom-plexation (Kr3woruchko et al., 2004). However, very few studies focused on removal ofU from... 

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