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196   Industrial Wastewater Treatment, Recycling, and Reuse


          its character, as well as temperature, have a substantial influence on final effi-
          ciency. The Fenton reagent destroys a wide variety of organic compounds
          without the formation of toxic by-products. Among the different technol-
          ogies reported in the literature for the treatment of highly contaminated
          effluents, Fenton’s reagent is characterized by its cost effectiveness, simplic-
          ity, and suitability for treating aqueous wastes showing variable composi-
          tions. This method offers a cost-effective source of highly oxidizing
          species, using easy-to-handle reagents. The important advantage of the
          Fenton process is that oxidation and coagulation take place simultaneously
          (Barbusi nski, 2009).
             The electrochemical oxidation process has been known for many years as
          a potential technology for water treatment using in situ generated oxidants
          such as chlorine and sodium hypochlorite. Commercialization of boron-
          doped diamond (BDD) technology has brought a revolutionary change in
          the electrochemical oxidation process. It has been proved that BDD, when
          used as an anode, is able to generate hydroxyl radicals (as generated in the
          Fenton process) without the use of any chemicals. BDD anodes are able
          to generate other more stable oxidants such as hydrogen peroxide, perox-
          ides, and hypochlorite along with hydroxyl radicals for effective wastewater
          treatment.


          4.3 FENTON PROCESS: ADVANCED OXIDATION
          TECHNOLOGIES
          The Fenton process as an advanced oxidation technology has several
          advantages:
          1. Simple to implement
          2. Low capital cost
          3. Effective across a broad range of organic compounds
          4. Nonselective in oxidation of organics
          5. Effective as pretreatment to a biological process.
          The Fenton process is the simplest of all the advanced oxidation processes.
          It can be executed by mixing readily available oxidants and catalysts (see
          Figure 4.1; www.xh2osolutions.com). The reaction can be carried out using
          either a batch mode or a continuous mode with simple reactor design. The
          capital cost of the Fenton process is relatively low due to the simple nature
          of the reactor design involved. Hydroxyl radicals generated from the Fenton
          process are the most powerful radicals that unselectively destroy organic
          compounds. One of the biggest benefits of Fenton oxidation is that it has
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