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Wastewater toxic pollutants

Concentrations of Toxic Pollutants Found in Primary Aluminum Wastewater... [Pg.97]

Refining operations have two principal wastestreams, waste electrolyte and cathode and anode washwater. Spent electrolyte is normally recycled. A bleed stream is treated to reduce copper and impurity concentration. Varying degrees of treatment are necessary because of the differences in the anode copper. Anode impurities, including nickel, arsenic, and traces of antimony and bismuth, may be present in the effluent if the spent electrolyte bleed stream is discharged. Tables 3.14 and 3.15 present classical and toxic pollutant data for raw wastewater in this subcategory. [Pg.104]

Concentrations of Toxic Pollutants in the Raw Wastewater of the Secondary Copper Subcategory... [Pg.107]

Wastewater is generated in the primary zinc and primary cadmium recovery subcategories by acid plant blowdown, which results from sulfuric acid recovery, air pollution control, leaching, anode/ cathode washing, and contact cooling. The streams may contain significant concentrations of lead, arsenic, cadmium, and zinc. Tables 3.26 and 3.27 present classical and toxic pollutant data for the primary zinc and primary cadmium subcategories. [Pg.114]

Many toxic pollutants were detected in the process wastewaters from metal molding and casting processes. The toxic pollutants detected most frequently in concentrations at or above 0.1 mg/L were phenolic compounds and heavy metals. The pollutants include 2,4,6-trichlorophenol, 2,4-dimethyl-phenol, phenol, 2-ethylhexyl, cadmium, chromium, copper, lead, nickel, and zinc. Each type of operation in the foundry industry can produce different types of pollutants in the wastewater stream. Also, because each subcategory operation often involves different processes, pollutant concentrations per casting metals may vary. [Pg.163]

The pollutants characteristic of the industry wastewaters are summarized in Table 5.4 through Table 5.11, for both classical and toxic pollutants. The toxic pollutant data have been developed using a verification protocol established by U.S. EPA, with the exception of the following selenium, silver, thallium, and 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCCD). Table 5.12 presents the minimum detection limit for the toxic pollutants. Any value below the minimum limit is listed in the summary tables as below detection limit (BDL). [Pg.204]

The wastewater characterization data for the extrusion die cleaning rinse are summarized by classical and toxic pollutants in Table 5.6. [Pg.205]

Thirty plants in the aluminum forming industry use etch or cleaning lines. Rinsing is usually required following successive chemical treatments within these etch or cleaning lines. Wastewater discharge values tend to increase as the number of rinses increase. Table 5.11 summarizes the classical and toxic pollutant data for etch line rinses. [Pg.214]

Toxic pollutants found in the mercury cell wastewater stream include mercury and some heavy metals like chromium and others stated in Table 22.8, some of them are corrosion products of reactions between chlorine and the plant materials of construction. Virtually, most of these pollutants are generally removed by sulfide precipitation followed by settling or filtration. Prior to treatment, sodium hydrosulfide is used to precipitate mercury sulfide, which is removed through filtration process in the wastewater stream. The tail gas scrubber water is often recycled as brine make-up water. Reduction, adsorption on activated carbon, ion exchange, and some chemical treatments are some of the processes employed in the treatment of wastewater in this cell. Sodium salts such as sodium bisulfite, sodium hydrosulfite, sodium sulfide, and sodium borohydride are also employed in the treatment of the wastewater in this cell28 (Figure 22.5). [Pg.926]

Hazards prevention can also be a reason for wastewater quality monitoring, in order to protect biological treatment plants from toxic shock loads, for example, or to prevent potential toxic effects on the receiving medium. This application is mainly found in industrial contexts where the presence of toxic pollutants may occur. In this case, on-line systems are obviously preferable for real-time warning. [Pg.245]

A serious drawback is the large amount of CAN (up to 2.5 molar amounts) needed. Cerium salts are highly toxic pollutants and must be removed from industrial effluents and wastewaters. Cerium (III) solutions from penem pilot plant solutions containing up to 1.2 M Ce(III) were recycled in a two compartment Electro Syn Cell. Typical recycling conditions Nation diaphragm with coated Ti-anode, applied current densities = 50-150 A/em2 yield > 90% processed amount about 475 kg CAN [46,126,136,137], The simultaneous determination of Ce(III) and Ce(IV) in the pilot plant solution and in solid CAN can be performed polarographically. As little as 0.3% Ce(NH4)2(N03)5 can be determined in Ce(NH4)2(N03)6 [136]. [Pg.163]

AOPs are less appropriate for the complete treatment of wastewater streams containing high concentration of organic pollutants. The main reason is that the energy costs and costs of chemicals such as ozone and hydrogen peroxide are relatively high. In case of UV also the equipment costs may be substantially. To treat these concentrated waste streams the application of AOPs has to be focused on the selective oxidation of specific toxic pollutants or on the partial oxidation of pollutants. [Pg.240]

Some type of toxic pollutants which at present may be present in the wastewater will be banned out. This makes the composition of the wastewater less complex so that compounds can more easily be recovered for reuse. Taking these aspects into account, together with other specific aspects related to closed water loop systems, it can be expected that future developments in the treatment technology of wastewater will be focused on Anaerobic treatment... [Pg.251]

Keywords Ozone, selective oxidation, toxic pollutants, wastewater, mass transfer, limitations, reactor design... [Pg.255]

Many wastewater flows in industry can not be treated by standard aerobic or anaerobic treatment methods due to the presence of relatively low concentration of toxic pollutants. Ozone can be used as a pretreatment step for the selective oxidation of these toxic pollutants. Due to the high costs of ozone it is important to minimise the loss of ozone due to reaction of ozone with non-toxic easily biodegradable compounds, ozone decay and discharge of ozone with the effluent from the ozone reactor. By means of a mathematical model, set up for a plug flow reactor and a continuos flow stirred tank reactor, it is possible to calculate more quantitatively the efficiency of the ozone use, independent of reaction kinetics, mass transfer rates of ozone and reactor type. The model predicts that the oxidation process is most efficiently realised by application of a plug flow reactor instead of a continuous flow stirred tank reactor. [Pg.273]

Havash, J. and Oster, J., 1998, Is Your Wastewater Toxic to the Municipal Treatment Plant Pollution Engineering, March, pp. 52-54. [Pg.262]


See other pages where Wastewater toxic pollutants is mentioned: [Pg.885]    [Pg.885]    [Pg.382]    [Pg.484]    [Pg.7]    [Pg.96]    [Pg.101]    [Pg.104]    [Pg.108]    [Pg.110]    [Pg.114]    [Pg.204]    [Pg.267]    [Pg.310]    [Pg.358]    [Pg.885]    [Pg.945]    [Pg.255]    [Pg.256]   
See also in sourсe #XX -- [ Pg.163 ]




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