Wastewater chemical oxidation

Framjoisse P, Gregor KH. Application of a new Fenton process (FSR process) without sludge production for the treatment of non biodegradable wastewater. Chemical Oxidation. Technologies for the Nineties. Vol. 6. Lancaster Technomic Publishing Co., 1997 208-220. 

Chemistry. Chemical processes are used to treat water and wastewater, to control air pollution, and for site remediation. These chemical treatments include chlorination for disinfection of both water and wastewater, chemical oxidation for iron and manganese removal in water-treatment plants, chemical oxidation for odor control, chemical precipitation for removal of metals or phosphorus from wastewater, water softening by the lime-soda process, and chemical neutralization for pH (acidity) control and for scaling control. 

Chemical Oxidation. Chemical oxidation can be appHed ia iadustrial wastewater pretreatment for reduction of toxicity, to oxidize metal complexes to enhance heavy metals removal from wastewaters, or as a posttreatment for toxicity reduction or priority pollutant removal. 

M. G. Noack and S. A. lacovieUo, "The Chemistry of Chlorine Dioxide in Industrial and Wastewater Treatment AppHcations," 2nd International Symposium on Chemical Oxidation Technologies Tor the 90 s, Vanderbilt University, NashviUe, Term., Feb. 19—21,1992. 

Oxidation. Oxidation is one of the main chemical methods to treat and decompose dyes in wastewater. The oxidation agents used ate chlorine, bleach, ozone, hydrogen peroxide, Fenton s reagent, and potassium permanganate. 

In addition to these three treatment options, several alternative technologies are applicable to the treatment of oily wastewater. These include coalescing, flotation, centrifugation, integrated adsorption, resin adsorption, ozonation, chemical oxidation, aerobic decomposition, and thermal emulsion breaking.18-20... 

Wang, L.K. New Water and Wastewater Treatment Technologies Chemical Oxidation and Emergency Response. Training Course. N S Dept, of Health No. ATC-232-2316-3645. N S Dept, of Environmental Conservation No. RTC-10234-07. Albany Water Treatment Plant, NY, May 18, 2007. 

Rautenbach and MeUis [75] describe a process in which a UF-membrane fermentor and a subsequent NF-treatment of the UF-permeate are integrated. The retentate of the NF-step is recycled to the feed of the UF-membrane reactor (Fig. 13.8). This process has been commercialised by Wehrle-Werk AG as the Biomembrat -plus system [76] and is well suited for the treatment of effluents with recalcitrant components. The process also allows for an additional treatment process, like adsorption or chemical oxidation of the NF-retentate, before returning the NF-retentate to the feed of the UF-membrane fermentor. Usually, the efficiency of these treatment processes is increased as the NF-retentate contains higher concentrations of these components. Pilot tests with landfiU leachates [75] and wastewater from cotton textile and tannery industry have been reported [77]. An overview of chemical oxygen demand (COD) reduction and COD concentrations in the permeate are shown in... 

At least nine United States pesticide manufacturers use chemical oxidation to treat wastewater [7]. In these systems, more than 98% of cyanide, phenol, and pesticides are removed COD and other organics are reduced considerably. Some plants use chemical oxidation to reduce toxic compounds from the wastewater to make the streams more suitable for subsequent biological treatment. 

The vendor states that its chemical oxidation (ChemOx) technology is very cost effective because no off-gas stream is formed, can be retrofitted in existing facilities, and can treat large volumes of wastewater (D17707V, p. 2). 

These factors have led researchers to examine novel methods for tire degradation of these contaminants, including liquid-phase photocatalytic oxidation. The treatment of wastewaters contaminated with agents like chlorinated aromatics has also prompted research into the optimum methods of integrating chemical oxidation techniques with existing water treatment methods, particularly biological treatment and ozonation techniques [37],... 

Kaiser R (1996) Wastewater treatment by Combination of Chemical Oxidation and Biological Processes in Clausthaler Umwelt-Akademie, Oxidation of Water and Wastewater, Vogelpohl (Ed.), Goslar 20-22 Mai 1996. 

Steensen M (1996) Chemical Oxidation for the Treatment of Leachate - Process Comparison and Results from Fullscale Plants in Clausthaler Umwelt-Akademie Oxidation of Water and Wastewater, A Vogelpohl (Hrsg.), Goslar 20.-22. Mai. 1996. 

Noack, M.G. and S.A. Iacoviello 1992. The chemistry of chlorine dioxide in industrial and wastewater treatment applications, 2nd International Symposium, Chemical Oxidation Technology for the Nineties, Nashville, TN, Technomic, Vol. 2, pp. 1-19. 

Chemical-oxidation treatments of wood preserving wastewaters containing phenols have been successfully conducted on both a laboratory and commercial scale using either chlorine or a chlorine compound, principally calcium hypochlorite. Its effectiveness varies with the type of phenolic compound in the effluent, either cresols from creosote treatments or pent achlorophenol from treatments enploying that chemical. Also influential in this regard are effluent pH, the effectiveness of pretreatment, particularly flocculation and filtration, and the amount and type of organic materials other than phenols present in the wastewater. 

A large proportion of the chlorine added to wastewater is consumed in oxidizing organic materials other than phenolic con-pounds. Thus, for example, in the work of Thompson and Dust cited above, the wastewater COD content averaged 20,400 mg/liter before and 10,400 mg/1 after treatment with chlorine at a rate of 2 g/liter. However, the OOD was further reduced to only 10,250 mg/liter upon the addition of 10 g/liter of additional chlorine. This result suggests that a portion of the organic content of the wastewater was resistant to chemical oxidation, as indicated above for phenolic compounds. 

In contrast to the chemical oxidation process in which strong oxidants (usually in the presence of catalysts) are used in order to achieve efficient treatment, the electrochemical process consumes mainly electrical energy. The specific energy consumption for the electrochemical treatment of a given wastewater can be estimated from the relation (Panizza et al. 2001a, b) ... 

When the waste contains more complex molecules such as compounds refractory to oxidation with OH radicals, as well as in the presence of inorganic ions which can be precursor of long-life oxidants, the Faradic yield cannot be calculated by (8.3) and different alternatives have been proposed. Faouzi and co-worker (Faouzi et al. 2006) proposed a comparison between electrochemical oxidation at BDD anodes and Fenton and Ozone treatments for the removal of dyes a specific parameter OCC (oxygen-equivalent chemical-oxidation capacity) was proposed which is defined as the kg of 02 equivalent to the quantity of oxidant used in each AOP to treat 1 m3 of wastewater. As highlighted by the authors, the parameter OCC may only give information on the chemical efficiency of the oxidants, but it does not give any information related to the real cost of the treatment, as the oxidants can... 

In the field of wastewater treatments, thermally activated persulfate has also been proposed and tested in a process called direct chemical oxidation (DCO) (Anipsitakis and Dionisiou 2002). In addition, the available literature contains promising experimental results at high-temperature range (110-390°C). These results demonstrate that use of this oxidant permits high oxidation rates to be achieved, i.e., the elimination of 4-chloro-3-methylphenol is completed with a very short reaction time (3 < i/2 < 59 s) (Kronholm et al. 2001). 

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