Waste oxidative treatment

Corrective Action Application At a hazardous waste treatment storage and disposal facility in Washington State, a cyanide-bearing waste required treatment. The influent waste stream contained 15 percent cyanide. Electrolytic oxidation was used to reduce the cyanide concentration to less than 5 percent. Alkaline chlorination was used to further reduce the cyanide concentration to 50 mg/1 (the cleanup objective). The electrolytic process was used as a first stage treatment because the heat of reaction, using alkaline chlorination to treat the concentrated cyanide waste, would be so great that it would melt the reactor tank. 

It was quite recently reported that La can be electrodeposited from chloroaluminate ionic liquids [25]. Whereas only AlLa alloys can be obtained from the pure liquid, the addition of excess LiCl and small quantities of thionyl chloride (SOCI2) to a LaCl3-sat-urated melt allows the deposition of elemental La, but the electrodissolution seems to be somewhat Idnetically hindered. This result could perhaps be interesting for coating purposes, as elemental La can normally only be deposited in high-temperature molten salts, which require much more difficult experimental or technical conditions. Furthermore, La and Ce electrodeposition would be important, as their oxides have interesting catalytic activity as, for instance, oxidation catalysts. A controlled deposition of thin metal layers followed by selective oxidation could perhaps produce cat-alytically active thin layers interesting for fuel cells or waste gas treatment. 

Waste Water Treatment Using Cuprous Oxide Nanomaterials... 

Adverse oxidation of membrane occurs at higher concentrations of oxidizers such as chlorine, ozone and hydrogen peroxide. The chemicals are important for slime control, and rather high concentrations of the chemicals are dosed for sterilization of RO feed system, especially in cases of ultrapure water system, and of waste water treatment system. The evaluation of membrane durability against oxidizing chemicals informs us the proper procedures for RO maintenance. 

The stability of iron oxide suspensions is relevant to fields as varied as the paint industry, extraction of iron from its ores, the structure of soils, hydrometallurgy and waste water treatment. The ease of homogensisation of paint, for example, is controlled by proper adjustment of the stability of the pigment suspensions. In ground waters, the settling behaviour of small iron oxide particles influences transportation of trace elements and radio-nuclides. The stability of a dispersion of magnetic particles can determine the quality of ferrofluids and magnetic tapes. 

Barratt P A, Baumgartl A, Hannay N, Vetter M, Xiong F (1996) CHEMOX Advanced waste water treatment with the impinging zone reactor in Clausthaler Umwelt-Akademie Oxidation of Water and Wastewater, A Vogelpohl (Hrsg.), Goslar 20.-22. Mai. 

Coarse (dP = 50-100 pm) porous disks are the most frequently applied diffusers in large-scale drinking water treatment systems (Masschelein, 1994). They are seldom used in industrial waste water treatment applications. The reason is that blocking or clogging can easily occur, e. g. by means of precipitation of chemicals, like carbonates, aluminum or ferrous oxides, manganese oxides, calcium oxalate or organic polymers. This is also valid for ceramic filter tubes, which are sometimes used as mass transfer systems in drinking water applications. 

Mass transfer in most drinking water treatment processes generally occurs in regime 1, with (very) slow reaction rates. The concentration of pollutants and consequently the oxidation rates are very low. The process is completely controlled by chemical kinetics. In waste water treatment, the concentration of pollutants is often higher by a factor of 10 or more. In this case, ozonation takes place in regime 4 or 5, with considerable mass transfer limitation. This has to be considered in the kinetics of waste water ozonation. 

Ozone is one of the strongest oxidants in drinking and waste water treatment. Due to the slow reaction rate constants and mostly incomplete mineralization with the direct reaction of ozone, treatment methods with an even stronger oxidant, the OH-radical, were developed such as ... 

Ozone is applied in three-phase systems where a selective ozone reaction, oxidation of residual compounds and/or enhancement of biodegradability is required. It can be used to treat drinking water and waste water, as well as gaseous or solid wastes. Especially in drinking water treatment full-scale applications are common, e. g. for particle removal and disinfection, while in waste water treatment sludge ozonation and the use of catalyst in AOP have been applied occasionally. Current research areas for three-phase ozonation include soil treatment and oxidative regeneration of adsorbers. Ozonation in water-solvent systems is seldom studied on the lab-scale and seems favorable only in special cases. In general, potential still exists for new developments and improvements in ozone applications for gas/watcr/solvent and gas/waler/solid systems. 

Hauptmann, E.G. et al., Strategies for treatment mixtures of bleach plant effluents and waste water treatment sludges by supercritical water oxidation, preprints of papers to be presented at the annual meeting, 80(B), B71-B77, 1994. 

Mixed element oxides such as Fe Si O, Fe Mg O, and Fe Mg Si-O complex oxides have also been used as catalysts for Fenton-like oxidations [58], Some of these catalysts exhibited selectivity for phenol hydroxylation. Whereas these catalysts are unlikely to be useful for in situ applications, they may be valuable for waste stream treatment, especially when a well-defined waste stream with specific pollutants exists. 

Because of the slower kinetics for hydroxyl radical formation with mineral catalysts, most applications of Fenton oxidation for in situ remediation or waste stream treatment involve the addition of dissolved iron(II). 

Smith de Sucre V, Watkinson AP. Anodic oxidation of phenol for waste water treatment. Can J Chem Eng 1981 59 52-59. 

Comninellis C, Pulgarin C. Electrochemical oxidation of phenol for waste-water treatment using Sn02 anodes. J Appl Electrochem 1993 23 108-112. 

Kirk DW, Sharifian H, Foulkes FR. Anodic oxidation of aniline for waste water treatment. J Appl Electrochem 1985 15 285-292. 

Farmer JC, Wang FT, Hawley-Fedder RA, Lewis PR, Summers LJ, Foiles L. Electrochemical treatment of mixed and hazardous wastes oxidation of ethylene glycol and benzene by silver. J Electrochem Soc 1992 139 654-662. 

Fig. 7.3. Analogies between adsorptive, membrane and reverse-flow reactors for flue gas denitrification and oxidative catalytic waste gas treatment.

Since the extreme oxidizing power of the oxyl spin centers is successfully employed in waste water treatment, an application of these intermediates seems to be self-contradictory in terms of synthetic use. However, alkoxylation of hydrocarbons is a very important technical field since it allows the installation of functionalities without using the detour via halogenations. The selective introduction of functional groups on a completely nonactivated hydrocarbon has not yet been realized by BDD technology. In contrast, the direct anodic methoxylations of activated carbons exhibiting benzylic or allylic moieties can be performed at BDD anodes. The results obtained with BDD electrodes are quite similar to those when graphite serves as anode [57]. The anodic synthesis of benzaldehyde dimethyl ketals is industrially relevant and performed on the scale of several thousand tons. A detailed study of the anodic methoxylation of 4-tert-butyltoluene (10) at BDD was performed [58]. Usually, the first methoxylation product 11 and the twofold functionalized derivative 12 are found upon electrochemical treatment (Scheme 5). 

Gas/liquid contacting is frequently encountered in chemical reaction and bioprocess engineering. For reactions in gas/liquid systems (oxidation, hydrogenation, chlorination, and so on) and aerobic fermentation processes (including biological waste water treatment), the gaseous reaction partner must first be dissolved in the liquid. In order to increase its absorption rate, the gas must be dispersed into fine bubbles in the liquid. A fast rotating stirrer (e.g. a turbine stirrer), to which the gas is supplied from below, is normally used for this purpose (see the sketch in Fig. 34). 

Iniesta, J., Michaud, P.A., Panizza, M. and Commninellis, Ch. (2001a) Electrochemical oxidation of 3-methylpyridine at a boron-doped diamond electrode applications to electroorganic synthesis and waste water treatment. Electrochem. Commun. 3, 346-351. 

Further investigation is needed in order to clarify better the role of the long-life oxidants produced in the bulk solution and to establish their fate during oxidative treatment. Moreover, the specific composition of the waste has to be considered in order to evaluate if, rather than as main process, the electrochemical treatment with diamond anodes can be more efficiently used in combined processes in which this technology may be used as a pre-treatment or a finishing stage. 

The application of Fenton s reagent as an oxidant for waste water treatment is attractive due to the fact that iron is a highly abundant and non-toxic element,... 

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