Equipment
  1. Technical Brief
  2. Technology Focus
  3. Application

Fenton Family
Advanced Oxidation Technologies for Wastewater Treatment

Part A. Technical Brief

Stastic Chart picture There is a lot of industrial wastewater treatment plant, that requires additional high-level wastewater processing units to achieve the effluent standards of the local government. The development of advanced wastewater treatment technologies includes ozone oxidation method, activated carbon adsorption method, membrane separation method, wet oxidation method, Fenton oxidation method, etc. Among them, Fenton oxidation (H2O2/Fe2+) method is considered to be one of the most effective, simple and economical method as compared to other methods which is either too high in the initial setup costs or operational costs thus, beyond industrial acceptance. Although Fenton oxidation method has its advantages of high efficiency and low operation cost, it has a major drawback where it produces large amounts of iron due to sludge application. Since 1994, the Fenton Family advanced oxidation process technology is being used the key principle of Fenton oxidation method to produce ·OH (hydroxyl radical) - the basis for the development of improved low-sludge wastewater advanced oxidation treatment technology.

The reactive equation of Fenton oxidation is expressed in equation (1), the resulting ·OH (hydroxyl radical) oxidation capacity in all oxidants ranked second, only inferior to fluorine.

H2O2  +  Fe2+   →  ·OH  +  OH-  +  Fe3+   →   Fe(OH)3 ↓           (1)

Factors that affects the Fenton Oxidation reaction and the reaction rate are the following:

  1. Reactant own characteristics
  2. H2O2 dose
  3. Fe2 + concentration
  4. PH value [ the pH value of reaction of Fenton method generally about 3 ~ 4 ]
  5. Response time
  6. Temperature

Fenton Family method improves the shortcomings of Fenton method that induces too much sludge by using electric field or crystal technology to enhance treatment efficiency and reduce chemical sludge production greatly increases the scope of application. Fenton Family of advanced process technology evolved from the traditional Fenton method, Electrolytic Oxidation-Fenton method (referred to as Fenton II ), electrolytic reduction-Fenton method (referred to as Fenton III ), to the fluidized bed-Fenton method (referred to as Fenton IV ).

Next figure illustrated Fenton family of advanced process technology development process, Fenton III and Fenton IV respectively. It represents the high concentration and low concentration of low-sludge wastewater treatment technology.

Fenton family of advanced process technology development process Fenton system developing chart

Comparison of Fenton family of processing technology and other advanced processing technology
Item Baseline: COD = 200 mg/L till COD = 100 mg/L
Thin film Separation Method Active carbon absorption method Chemical Adsorption Method Ozone oxidation method Traditional Fenton Method Electrolytic reduction -Fenton method Fluidized bed -Fenton Method
Character Concentrate Pollutant Absorb Organic matters Mix and coagulate Organic matters Oxidizes Organics Oxidizes Organics Oxidizes Organics Oxidizes Organic Matters
COD remove rate
( ¢H )		 90 ~ 95 20 ~ 75 20 ~ 50 30 ~ 60 65 ~ 85 70 ~ 90 70 ~ 90
Equipment cost
( 10,000 dollars / m3 )		 0.5 ~ 1 0.225 ~ 0.375 0.05 ~ 0.125 0.5 ~ 1 0.05 ~ 0.125 0.125 ~ 0.375 0.0625 ~ 0.175
Operation cost
( Dollars / m3 )		 3.75 ~ 8.75 3 ~ 10 0.75 ~ 3.75 6.25 ~ 8.75 2.5 ~ 6.25 1 ~ 3.75 2 ~ 3.75
Operation cost
( Dollars / kg COD )		 37.5 ~ 87.5 25 ~ 100 7.5 ~ 37.5 62.5 ~ 87.5 25 ~ 62.5 20 ~ 37.5 25 ~ 37.5
Difference of technologies Need Concentrator Need regenerate Active carbon Need sludge treatment Need O3 waste air Treatment Need sludge treatment Amounts of sludge less than 80% of traditional Fenton method Amounts of sludge less than 70% of traditional Fenton method


In the next figure, it shows the Application of Fenton Family Method which applies the electrolytic reduction-Fenton method (Fenton III ) for high concentrations of bio-refractory wastewater (COD> 1000mg / L) treatment. It can be used as biological pre-treatment to improve water quality, and enhance the follow-up bio - processing capacity; . Fluidized bed-Fenton method (Fenton IV ) is also applicable for low concentrations of biological decomposition of waste water (COD <1000mg / L, are generally used for COD <500mg / L) treatment, . It can be used for biological post-treatment to enhance and release stream, which ensures the quality of the discharge water quality.

The application of Fenton Family processing technology

Fenton system flow

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Part B. Technology Focus

1. Electro-reduction-Fenton method


Electro-reduction-Fenton method is the use of electrolytic reduction method. Fe3+ in the cathode is reduced to Fe2+ catalyst, pH reaction is operating at about 1.5 or so. This is particularly suitable for treatment of high COD and hard biodegradable organic waste, catholic reactions (as in equation.2) ,. Therefore, the original (as in equation.1) reacts and can be amended to equation (3), which will have little reaction process iron sludge.
Fe<sup>3+</sup> reduce to Fe<sup>2+</sup> catalyst

During the reaction process, H2O2 is added directly and continuously to electrolytic reduction cells which produced the electrolysis reaction of Fe2+ for the oxidation of organic matter in waste water, while the Fe3+ produced by the reaction can also directly reduced to Fe2+ in the cathode and the steady flow of participation in response to so that the oxidation of H2O2 efficiency elevates, reducing the dose of H2O2 and reducing the operational costs. In addition, the anode electrodes may also remove part of the organic matter. Reaction after the completion of Fe2+ and Fe3+ mixed solution can be used as an iron-based coagulant.

The electro-reduction-Fenton method of waste water treatment effect is usually better than Fenton method for High concentration of COD of waste water (COD> 1000mg / L), this may be due to post-Fenton Oxidation of organic intermediates segment which is more than a simple organic acids (such as the acetic acid, oxalic acid, formic acid), ·OH (hydroxyl radical) that has lower reaction rate to molecular state of these organic acids, especially when there is water, inorganic ions (such as PO43-, Cl-, HCO3-), the inorganic ions will be in competition with ·OH (hydroxyl radical), which lowers the COD removal rate. However, in electro-reduction-Fenton system, the organic acid will be ionized into a plasma state, which greatly improves organic acids ·OH rate.

The treatment result of a variety of high concentration COD wastewater treatment by using Electro-reduction-Fenton Process
Waste water source COD (mg/L) pre-treatment COD (mg/L) after Treatment COD removal rate(¢H)
Waste ink in Chemical plant 74601 2387 96.8
HEXA waste water in Chemical plant 29640 38 99.9
Nickel effluent in electroplating factory 27870 1942 93.0
Black liquor in Handmade paper mill 30880 347 98.9
AN waste effluent in Latex plant 5800 564 90.3
Resin wastewater in chemical plant 2480 358 85.8
RG waste water in man-made fiber plant 24900 619 97.5
Waste in Junior College laboratory 23900 4780 80.0


Appearance of Fenton III treatment vats
Appearance of Fenton III Vats

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2. Fluidized Bed-Fenton method

Fluidized-bed-Fenton method is a new technology which generated majority of ferric iron to crystallization or precipitation in fluidized-bed coated surface of Tam body of the plane is a combination of in-phase chemical oxidation (Fenton method), heterogeneous chemical oxidation (H2O2/FeOOH), fluidized-bed crystallization and dissolution of FeOOH reduction, the schematic figure of this method is as shown below. This technology outshines the traditional Fenton oxidation method significantly. It can reduce a large number of chemical sludge productions of Fenton method as Tam body formed on the surface of iron oxide has the effect of heterogeneous catalysis, and while the fluidized bed method also facilitated the chemical oxidation reaction, mass transfer efficiency, and enhance the COD removal rate.

Diagram of the Fluidized Bed-Fenton method: Diagram of the Fluidized Bed-Fenton method

Appearance of Fluidized Bed-Fenton Vats - Chongqing Lee & Man Paper Manufacturing Ltd.
Appearance of Fenton ¢¼Vats

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Designing focus of Fenton family
Item Description
Design criteria of electrolytic-reduction-Fenton treatment chamber
  1. Material choice”GMaterial of cathode and anode
  2. Shape of cathode/anode as well as layout design
  3. Spec of power supply
  4. dosage method, percentage of dosing
  5. Volume, shape, height, reflux ratio of the treatment chamber
Design criteria of fluidized-bed-Fenton treatment chamber
  1. choice of Tam material”Gmaterial, weight, density and particle size
  2. The distribution plate design
  3. Upstream speed, reflux ratio
  4. Dosing method, location and rate of drug use
  5. volume, shape, height of the processing chamber

Technical principles and characteristics of Fenton family
Name of technology Applicable COD ( mg / L ) Main principle Technology character
Traditional Fenton method 50 ~ 1000 H2O2 + Fe2+ → ·OH + OH- + Fe3+ Homogeneous reaction, much iron sludge, easily to be disturbed by the pollutant
Electrolytic-Fenton method”]Fenton¢», Fered-Fenton”^ 1000 ~ 50000 Fe3+ + e- → Fe2+ ,
H2O2 + Fe2+ → ·OH + OH- + Fe3+		 Electro-reduction Fe(¢») to reuse iron, reducing 80% of iron sludge
Fluidized bed -Fenton method(Fenton¢¼, FBR-Fenton) 50 ~ 1000 H2O2 + Fe2+ → ·OH + Fe(OH)2 + → .... → FeOOH , H2O2 + FeOOH → ... Homogeneous and heterogeneous catalytic reaction formed FeOOH and reducing 70% of iron slunge.

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Part C. Application

Fenton Family technology can be applied to numerous industries such as:

  1. Waste water in petrochemical industry: mainly used in biological pre-treatment.
  2. Waste water in chemical industry: it can be used for all kinds of stream high COD wastewater such as the distillation of waste processing, and color and COD removal after biological treatment, so that standards for effluents is up to 98 years.
  3. Waste water in man-made fibers, textile wastes: can be used in biological pre-treatment and biological treatment of water quality checks, effluents is up to standard.
  4. Waste water in dyeing and finishing industry: mainly used for biological treatment of the color, foam and COD removal, so that standards for effluents are up to 98 years.
  5. Waste water in the metal plating industry wastewater: Mainly used for all kinds of stream of high COD wastewater , such as degreasing waste water treatment in order to avoid coagulation effect of chemical coagulation units.
  6. Waste water in the printed circuit board (PCB) industry: it can be used for all kinds of stream of high COD wastewater such as cleaning agents, waste stripping film imaging processing and biological treatment of water quality checks.
  7. Waste water in IC, the semiconductor industry: it can be used for all kinds of stream of high COD wastewater such as developing wastewater, photo resist wastewater treatment.
  8. Waste water in papermaking: mainly used for biological treatment of color and COD removal, so that standards for effluents are up to 98 years.
  9. Waste water in synthetic resin industry: mainly used for biological treatment of water quality checks.
  10. Waste water in pharmaceuticals, leather industry: it used in biological pre-treatment and biological treatment of water quality checks.

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