Treatment of Leachate by Electrocoagulation Technique Using Iron And Hybrid Electrodes

8/10/2019 Treatment of Leachate by Electrocoagulation Technique Using Iron And Hybrid Electrodes

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International Journal of Scientific Research in Knowledge, 2(11), pp. 497-508, 2014Available online at http://www.ijsrpub.com/ijsrk

ISSN: 2322-4541; 2014; Author(s) retain the copyright of this articlehttp://dx.doi.org/10.12983/ijsrk-2014-p0497-0508

497

Review Paper

Treatment of Leachate by Electrocoagulation Technique Using Iron And HybridElectrodes

Mostafa Mohammadizaroun, Mohd Suffian Yusoff*

School of Civil Engineering, Engineering Campus, University Sains Malaysia, 14300 Nibong Tebal, Penang, Malaysia*Corresponding Author: [email protected]

Received 28 September 2014; Accepted 11 November 2014

Abstract. The most techniques for treating leachate and wastewater are physical, chemical, biological, advanced oxidation andelectrochemical techniques. Developed oxidation techniques lead to high treatment cost and mostly are used in purifying gradewaters. Among these techniques, the chemical coagulation technique not only is a slow process, but also produces a largeamount of sludge. Electrocoagulation has been used for treating industrial effluent and leachate as a potential technique

because of its compatibility and adaptability with environment. In this technique, a direct current source between metalelectrodes plunged in the effluent is used to dissolve the electrode plates into the effluent. The metal ions with appropriate pHcan create various types of coagulated species and metal hydroxides that in turn cause to rolling up and destabilizing theelements, or catalyzing and absorbing the dissolved pollutants. Therefore, the purpose of the current study is to examine the

potentials of electrocoagulation in treating the leachate and wastewater by treating the heavy metals and their colour andsalinity. Furthermore, the present study aims to investigate the electrocoagulation, electrochemical technologies and theirdesign and application in treating the leachate, water, and wastewater. This work mostly dealt with the electrocoagulation

(EC), electrodeposition, electroflotation (EF), and electrooxidation. It was shown that Electrodeposition is efficient in treatingthe wastewater stream and removing heavy metals. In addition, electrocoagulation was used for treating wastewater and producing clean water as well. It was also found that using aluminum, iron or the hybrid Al/Fe electrodes are more applicable.

Keyword: Electrocoagulation, Treatment, Leachate, Wastewater, Iron and Aluminum Electrode, Hydride electrode

1. INTRODUCTION

Electrocoagulation is an electrochemical method thatis employed for both wastewater and surface watertreatment. In this method, sacrificial anodes areoxidized and active coagulant precursors, such asaluminum or iron cations, are released into liquid.During this process, additional electrolytic reactions

produce gas at the cathode, which is usually in theform of hydrogen bubbles (Holt et al., 2005) .Drinking water that is polluted by heavy metals isdangerous for human health. One of the techniquesthat are used for purifying wastewater isElectrocoagulation. This technology employselectrolytic oxidation of anode materials and in-situgeneration of coagulation (Wan et al., 2011) . The

purpose of using electrocoagulation (EC) is removingvarious types of pollutants such as heavy metal ions

from water and wastewater effluents (Shafaei et al.,2010) . .electrocoagulation (EC) has attracted the attention

of the environmental sectors largely as an efficientway to treat different types of water and wastewater

during the last two decades, and especially during thelast few years. The purpose of the present work is tostudy some related researches that were conductedmainly on the widespread use of practicalelectrocoagulation in treating different types of waterand wastewater during 2008-2014.

Due to the large amount of wastewater comingfrom industry and its variety, its purification is still anoteworthy environmental problem in the world (Zodiet al., 2009) . Some of these wastewater types canshow evidence of high chemical oxygen demand(COD), dark color, and strong bad smell. Thus it isessential to treat the sewerage before dischargingthem into the environment and water sources. For this

purpose, electrocoagulation has been employed to purify different types of wastewater generated byindustry section in recent years (Khemis et al., 2006) .Accordingly, EC method has absorb the interest of

many researchers for being applied to treat the waterand wastewater. It is one of the recently developedwater technologies that has been used successfully in

purifying different types of wastewaters (Tchamangoet al., 2010) .
mailto:[email protected]:[email protected]:[email protected]:[email protected]


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Mohammadizaroun and YusoffTreatment of Leachate by Electrocoagulation Technique Using Iron And Hybrid Electrodes

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The applications of Electrocoagulation (EC)method in this study has been classified into ninecategories including: tannery, pulp and paper industrywastewater, textile and colored wastewater, foodindustry wastewater, oily wastewater, laundry anddairy wastewater, other types of industrial wastewater,surface and model water and wastewater that containheavy metals, cyanide, nutrients, and other elements,and ions. Moreover, the current study aims to outlinethe best conditions in the process of treatment such astreatment time, existing density and pH as well as thehigh level of efficiency in removing pollutants whileapplying the EC under discussion (Kuokkanen et al.,2013) .

One of the appropriate ways for purifying dairywaste is applying Electrocoagulation with aluminum

anode because there is acceptable reduction ofdifferent parameters such as turbidity, total phosphorous, and nitrogens (Tchamango et al., 2010) .In addition, this process requires fewer reagents, i.e.the quantity of aluminum that is liquefied in this

process is lower than the amount of aluminum saltdissolved in chemical coagulation (Tchamango et al.,2010) .

By using Electrocoagulation (EC), which is a typeof cheap and green method for removing heavy metalsfrom wastewater, some chromium can be removedfrom industrial effluents, namely metallurgy,

electroplating, leather tanning, chemicalcatalysts, pigments, corrosion inhibitors and printing inks(Mouedhen et al., 2009) .

2. LEACHATE

Leachate is a very complex liquid with highconcentration of pollution that makes its treatmentvery hard and providing the removal standards isdifficult. Among other types of wastewaters, leachateis the most difficult one to treat because it containscomplex structure that is produced within a landfill.Accordingly, the variety types of pre-treatment andmixed methods of treatment were used to treatleachate (Welander et al., 1998) .

2. ELECTROCOAGULATION REACTORS FORHEAVY METALS REMOVAL

According to the recent studies on the reactor designsand functions, it is found that the easiest way and low-cost facility for treating localized water could be a setof reactor systems that has vertical plate electrodes. Indesigning the reactor being made of electrolytic gasflotation, the separation of the aggregated pollutants inelectrodes is the primary goal (Holt et al., 2005) .

Electrocoagulation (EC) has been introduced formore than one century. Electrocoagulation with

aluminum and iron has already been awarded in theUS in 1909. Due to its applicability, EC has beeninvestigated broadly in the US and Soviet Union(former USSR) during the second half of 20 th century.However, despite the extensive studies in those times,its broad feasibility in treating water was not foundclearly. Perhaps the main reason was the high costs ofelectricity and investment in those days (Chen, 2004) .

Electrocoagulation (EC) has been investigated andapplied for purifying the wastewater by manyresearchers previously and the results show that thereare several differences in the processes of chemicalcoagulation. The review of literature demonstratesthat Electrocoagulation is a useful process in treatingdifferent wastes such as soluble oils, liquid generated

by food, industrial materials, and fibers and effluents

come from the paper industry (Carmona et al., 2006) .EC is an electrochemical method used in purifying the polluted water by which sacrificial anodes areoxidized so that active coagulant precursors such asaluminum or iron cations could be released intoliquid. Additional electrolytic reactions produce gas atthe cathode, which is usually in the form of hydrogen

bubbles (Holt et al., 2005) . An electrocoagulationreactor, essentially, is an electrochemical cell bywhich a sacrificial metal anode, which is occasionallymade of iron and usually of aluminum, is utilized tomeasure the amount of polluted water by suing a

coagulating agent (Holt, 2006) .Electrocoagulation (EC) application is considered

as a conventional development technology with possibility to improve the space-time efficiency. It hasalso been used to produce water or purify wastewater.Using aluminum, iron, or the hybrid Al/Fe electrodesare found to be more applicable as well (Chen, 2004) .Despite the fact that electrocoagulation technique has

been introduced for more than one century, itsapplication efficiency in purifying wastewater hasfound recently. The design of an industrial plant andan electrocoagulation cell are mostly based on

previous empirical studies that had little attention tothe electrocoagulation mechanism (Calvo et al.,2003) . Electrocoagulation (EC) is known as the easyand efficient electrochemical method for treatingdifferent types of water and wastewater (Tezcan et al.,2006) . The characteristics of this technique are: easyin operation, simple equipment, and decreased amountof mud. In this process, the generation of coagulant byelectrolytic oxidation of a proper anode material at a

proper pH leads to unsolved metal hydroxide that laterremoves the various types of contaminant (Adhoumand Monser, 2004) .


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2.1. Types of reactors used

As it was referred earlier, according to the previousstudies about reactor designs and functions, it is foundthat the simplest method and low-cost facility for

purifying wastewaters is a set of reactor system whoseintegral characteristic and function is separating theaggregate contaminant by using electrolytic gasflotation (Holt et al., 2005) .

As it was mentioned earlier, all electrocoagulationreactors have electrochemical units. All of thesereactors have an electrode set that is in contact withthe polluted water. One of their specific characteristicsis a coagulant production in situ. A practical probabledifference between the electrodes is required forreleasing the coagulant. The electrochemical half-cell

reactions that occur at each electrode can reduce the potential requirements for electrodes. Each electrodewill differ according to the efficient pH and the grouptype that exists in the system.

2.2. Electrode materials

Different materials could be used as electrodes forelectrocoagulation and electrode material has beenknown to be an important factor influencing the

performance of the electrocoagulation process. AlsoIron and Aluminum or hybrid (Al/Fe) usually used as

electrode in electrocoagulation process (Ratna et al.,2004) . Electrode material is known to be an importantfactor influencing the performance of theelectrocoagulation process. Different materials can beused as electrodes for electrocoagulation. Iron,Aluminum, and hybrid (Al/Fe) are usually used aselectrode in electrocoagulation process as well.

3. EFFECTING OF FACTORS ONELECTROCOAGULATION PROCESSES

3.1. Effect of temperature

According to the findings of studies done on removingwaterborne bacteria from geothermal water, it wasdemonstrated that one of the vital affecting factorsthat has a significant positive effect on the process ofelectroquagulation is temperature (Yilmaz et al.,2008) . Yilmaz et al. (2008) found that, like manyother chemical reactions, temperature helpselectrochemical reaction rate enhances. Theydemonstrated that if the temperature reaches to 40 oC,efficiency of Borne removal increases 12% formingcoagulate of flocked ions on anode surface. Thus theincrease in temperature could not contributed as lineeffect effect factor on the process ofelectroquagulation (Yilmaz et al., 2008) .

In studied range, temperature, in comparison withthe effect of electrode charge per liter and origin pH,was slightly effective in removing natural organicmatter (NOM). In fact, temperature had major effectthrough the various dissolving rate of the electrodes(Vepslinen et al., 2009) 4) In a study done by Kataland Pahlavanzadeh (2011) , Electrocoagulation wasexamined as a possible way to reduce the color,

phenol, and COD pollutants from wastewater of papermill. It was found that efficiencies tend to to constantvalues after 30 minutes of electrocoagulation (Kataland Pahlavanzadeh, 2011) .

3.2. PH effecting

The electrolyte pH plays an important role in the

operation of the electrocoagulation process (Chen etal., 2000) . In order to verify the efficiency oflectrolyte pH on the electro-coagulation effectiveness,many empirical studies have been carried out atdifferent pH and various observations were obtained.The utmost percentage of removal COD was observedat the pH of 7 for mild steel. The increase in theelectrolyte pH more than 7 did not get any upgradingon percentage of removal COD (Kalyani et al., 2009) .This can be justified by the fact that the solvability ofFe(OH) 3 could cause the increase pH value beyonf 7that results in forming the solvable Fe(OH)4, this is

not associated to the reduction of COD (Kobya et al.,2003) . The primary pH at the beginning has asignificant influence on the application ofelectrocoagulation process (Song et al., 2007; Wang etal., 2009) . The findings showed that the increase in

pH could increase the removal efficiency (Akbal andCamc, 2011 ).

5) According to Can et al. (2003) and Daneshvar etal. (2003), one of the significant factors that influencethe performance of electrochemical process is theinitial pH. The efficiency of treatment process wasvery low at both high and low pH (Aoudj et al., 2010) .

3.3. Distance between electrodes

The other important factor that is known to beinfluencing the efficiency of the electrocoagulation

performance is distance between electrodes.

3.4. Effect of current density

According to the findings, it is expected that theincrease amount of existing density will result inincrease of removal efficiency (Akbal and Camc ,2011) . On the other words, the increase in the appliedcurrent density results in an increase in effectivenessof removing heavy metals such as Cr, Cu, Ni, and Crfor the Fe-Fe pairs of electrocoagulation (Akbal and


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Camc , 2011) . Many researchers have reported thatthe current density has significant influence on theeffectiveness of process of electrocoagulation. It can

be explained by the fact that the ammount of anodicdissolution increases at the high current densities,which in turn, the increased amount ofhydroxocationic complex leads to increased CODremoval. In addition, the rates of coagulant (flocksstructure) and bubble production can be determined

by the current density applied in the process. This, inturn can impact on the efficiency of the process. Onthe other hand, the increased density of gas bubbleswith the reduced size results in increase in upwardsflux that leads to increased degradation of pollutantsand mud floating (Kobya et al., 2003) .

Holt et al. (2002) states that the coagulant dosage

rate and the bubble production rate, size, and flockgrowth can be determined by current density, which inturn can affect the efficiency of treatment byelectrocoagulation (Holt et al., 2002)

In addition, current density is recognized as asignificant operational factor that affects mechanismdominating the pollutant removal (Holt et al., 2005) .

3.5. Effect of operation time

According to the Faradays law, the factor that canalso affect the efficiency of removing Cr (VI) in the

process of electrocoagulation is the reaction time. Itcan also determine the rate of producing Fe 2+ or Fe 3+ ions from electrodes (Mollah et al., 2004) .

3.6. Effect of conductivity

The results of related studies showed that increasedremoval efficiency is dependent on the increase inconductivity. In addition, the decrease of spendingenergy and electrode results from increasingconductivity (Akbal and Camc, 2011 ).

3.7. Supporting electrolyte concentration

The findings show that the increase in the supportingelectrolyte density results in the increase in the CODremoval efficiency. This is explanable that with the

presence of cholorides in the solution, C12 and OC1are produced. The OC1 is a strong oxidant thatoxidize the organic cells existing in the water.Consequently, not only does the supporting electrolyte

increase the efficiency and productivity of the process, but also it functions as a strong oxidizing factor. Thesimilar result was reported for the percentage ofefficiancy in removing the color (Kalyani et al.,2009) .

4. ADVANTAGES AND DISADVANTAGES OFEC

(1) EC is a simple equipment and easy to work withadequate operational scope that can overcome most ofthe problems that may be encountered during theoperation.

(2) The water after purification are palatable, clear,colorless, and without odor.

(3) The sludge produced during the process is

ready to be set again and easy to be dried out, becausethey mostly contain metallic oxides and hydroxides.(4) The flocs that are produced by EC are similar

to the chemical flocs; however, it is expected to belarger and contain less bound water, be more stableand acide-resistant that can, consequently, beseparated faster by filters.

(5) In comparison with the chemical treatment, EC produces sewage that contains less total dissolvedsolids (TDS) contents. Consequently, if this water isgoing to be reused, the low TDS level requires lowerrecovery cost.

(6) The EC process removes the lower amount ofcolloidal elements, because the used electric field setsthem in faster movement by which the coagulation isfacilitated.

(7) In EC, there is not any problem of neutralizingexcess chemicals as well as the possibility ofsecondary pollution resulted from chemicalsubstances that are added at high density, becauseunlike chemical coagulation of wastewater, EC doesnot use chemicals.

(8) In EC, the bubbles of gas that are producedduring the electrolysis process carry the contaminantto the top of the liquid and from there it can be easilycollected and removed out.

(9) The EC process requires less maintenance because the electrolytic processes in the EC cell arecontrolled electrically with no moving parts.

(10) This technique can be easily applied in ruralareas where even the electricity is not available

because a solar board is attached to it that might besufficient for operating the process.


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Fig. 1: bench-scale Electrocoagulation reactor with monopolar electrode in parallel concetion (Pretorius, Johannes et al. 1991)

5. DISADVANTAGES OF EC

(1) The 'sacrificial electrodes' need to be replacedregularly due to oxidation and being dissolved into thewastewater streams.

(2) Using electricity could be expensive in many places.

(3) Sometimes a waterproof oxide film is locatedin the cathode to lessen the possibility of loss ofefficiency of the process.

(4) In this system, a high conductive wastewatersuspension is required.

(5) Sticky hydroxide sometimes tends to bedissolved in some cases (Mollah et al., 2001) .

Mechanism of electrocoagulation techniqueAn electrocoagulation reactor, in the simplest

form, has a monopolar electrode with one anode andone cathode. When the external power source isconnected to it, the anode will be oxidized and flakedelectrochemically, but the cathode remains passive.However, this process is not suitable for wastewater

purification because for this purpose a large surface ofelectrodes is required in order to be able to dissolvethe pollutants. This has been achievable by using cellswith monopolar electrodes that are connected either in

parallel or in series. A simple system ofelectrocoagulation (EC) cell with two anodes and twocathodes connected in parallel is illustrated in Fig. 1.

Fig. 1 shows that it, in essence, is made up of pairsof conductive metal plates that are located betweentwo parallel electrodes and a dc power source. Thisinvestigational system also needs a resistance box tocontrol the present density as well as a multi-meter forreading the existing values. The conductive metal

plates are generally known as 'sacrificial electrodes'.The sacrificial anode reduces the possibility ofdissolution of the anode and lessens the passivation ofthe cathode. The conductive metal plates (thesacrificial electrodes) could be the same or differentmaterials as of anodes (Pretorius et al., 1991) .

The mechanism of EC is greatly reliant on thechemical type of watery medium, particularly itsconductivity. The procedure of generating ions by ECis like iron and aluminum that are used as cathode andanode in this study. That is, in an electrolytic system,iron generates iron hydroxide. If the anode is made upof iron or steel or aluminum, for the production of themetal hydroxide, two mechanisms have been

proposed (Chen, 2004) .


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6. APPLICATION OF

ELECTROCOAGULATION IN THETREATMENT OF PAPER MILLWASTEWATER

Katal and Pahlavanzadeh (2011) have done a study onthe effectiveness of electrocoagulation on thetreatment of wastewater of paper mill by using varioustypes of electrodes with different combination ofaluminum (AL) and iron (Fe). They also investigatedthe effect of pH, current density, and temperature onthe removing process (Katal and Pahlavanzadeh,2011) .

7. APPLICATION OF

ELECTROCOAGULATION IN THE REMOVALOF CYANIDE

Because of strong affinity of cyanide with othermetals, it is used widely in different industries. So freecyanide and its related compounds can be found indifferent forms and density in the industrialwastewater that enter into the environment (Dash etal., 2009) .The aim of present study was to evaluate theefficiency of EC reactor with iron plate to remove free

cyanide from wastewater. The finding showed thatregarding the operational conditions, the mosteffective process was occurred at the voltage of 40 V,detention time of 90 min, and influent concentration


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of 50 mg/l. Using EC technology for removingcyanide, in comparison with other removal methods,has many advantages economically. Despite usingelectrical power makes it costly, having no need to

prepare chemical material, which makes storing itsafer, enhances its efficiency and reliability. Due to itsefficiency in removing free cyanide and its relatedcomponents, EC can be used as a substitute methodfor removing cyanide from wastewater effluentscontaining cyanide (Hassani et al., 2011) .

8. REMOVAL OF TEXTILE DYEWASTEWATER BY ELECTROCOAGULATIONTECHNIQUE

Wastewaters that are produced by textile industries

contain a great deal of toxic aromatic combinations, particularly azodyesn. Due to increased amount ofeffluent wastewater in the environment, theinvestigations done in recent years were mostlyfocused on purifying wastewaters by application ofelectrocoagulation (EC) because it is a simple andspecific technique for producing drinking water andtreating wastewaters (Daneshvar et al., 2005) .

9. APPLICATION OFELECTROCOAGULATION IN THETREATMENT OF TANNERY WASTEWATER

Some characteristics of tannery wastewater are asfollows: it contains high chemical oxygen demand,

high total of floating solids, high biochemical oxygendemand, elevated oil and grease substances along withthe high chromium concentration and unpleasantcolor. Based on the mentioned characteristics, tannerywastewater can be severely problematic forenvironment. Thus one of the functions ofelectrocoagulation process was removing differentcontaminants and chromium from tannery wastewaterat the ambient temperature of the laboratory,simultaneously with other EC performances (Kongjaoet al., 2008)

10. CONCLUSION

Based on the conducted investigation, the best methodfor leachate treating is electrocoagulation technique

because leachate consists of high toxin mater such asheavy metal, cyanide, Colloid particle some of whichcannot be removed by other techniques. Accordingly,due to the mentioned advantages ofElectrocoagulation technique as well as itsadaptability with the environment, it has beenemployed as a practical method for industrial effluentand leachate treatment. The results of data in Table 1show that some of optimum conditions inelectrocoagulation process are: one centimeterdistance between electrodes, PH of 7-8.5, and theapproximate temperature of 28

Table 1: Effect of operational parameters on pollutant removal efficiency in electrocoagulation processRemo.

efficiency%

Effect oftemperatu

re(C)

Reactiontime

(minute)

Currentdensity

A/cm2

PH Distance betweenelectrode

(cm)

Type ofelectrodes

Surface ofelectrode

Cm 2

Removalfactor

PollutantSource

Studyscale

Lab/Pilot/Site

Location Reference

93.598.9

NG 4 NG 7 NG Al NG arsenic(As)

potablewater

Lab Turkey Mehmet

Kobya

a, 2011,

94.1,99.3

NG 2.5 2.5 6.5 NG Fe NG arsenic(As)

potablewater

Lab Turkey Mehmet

Kobyaa, 201

1, NG 30-90 60-140 3-

112 Al COD,

Turbidity,TS

Industrywastewater

Lab France (Zodi,Potieret al.2010)

96.2 NG 30 8 8 1 Fe 40cm Cr PlatingIndustrial

Wastewater

Lab India (Bhagawan,Poodari etal.

2014)

100 NG 20 0.01A/cm 2

3 0.1 Al- Fe NG Cr,Cu, Ni

Platingwastewater

Lab Turkey (Akbal and

Camc2011)


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56 NG 30 348-631

NG

6.5 Al 45 COD, NH 4-H

leachate Lab Germany (Ilhan,Kurtet al.2008)

35 NG 30 348-631

NG

65 Fe 45 COD, NH 4-H

leachate Lab Germany (Ilhan,Kurtet al.2008)

92,84

NG NG NG NG

1.5 Steel,Al

16 Color Pulp and paper

Industrialeffluent

Lab Malaysia (Kalyani,

Balasu bramanian et

al.2009)

95,89

NG NG NG NG

1.5 NG COD Lab Malaysia (Kalyani,

Balasu bramanian et

al.2009)

94,87,90

28 90 0.015A/cm 2

7 3 NG NG Colour,BOD,COD

Pulp, paperindustry

Lab India (Sridhar,

Sivak umaret al.2011)

99 NG 20-110 56-222 5 NG Al/Fe NG Cr Wastewater

Lab Iran (Keshmirizadeh,

Yousefi etal.

2011) 98 NG 30 0.00187

A/cm 2 6 1.5 Al- Fe 40 Colour Textile

industryLab Algeria (Aoud

j,Khelif a et al.2010)

88.4 20 30 0.070A/cm 2

5-7 NG Al- Fe 80 COD paper millwastewater

Lab Iran (Kataland

Pahlavanzad

eh2011)

63.8 20 NG Fe-Fe80

Colour techniquein the

treatmentof paper

millwastewater

Lab Iran Kataland

Pahlavanzad

eh2011)

99.9 20 Al-Al 80 Colour techniquein the

treatmentof paper

millwastewater

Lab Iran Kataland

Pahlavanzad

eh2011)

97 NG 90 40 1 Fe 60 CyanideSynthetic

WW

Lab Iran (Hassani,

Nasser i et al.2011)

97.5 NG 140 0.2 7 0.5 Al NG Cd water Lab India (Vasudevan,Lakshmi et

al.2011)

96.2 NG 140 7 0.5 Al NG (Vasudevan,Lakshmi et

al.2011)

85

80

14 0.03125A/cm 2

6-9 1 NG NG Red dye

COD

textile dyewastewater

Lab Tunisia (Merzouk,

Gourich et

al.2009)


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505

Most of EC studies carried out in tempered climateand some of them had been assessed in tropical area.

Based on the information which filled in Table 1we can say that :

(1) Al and Fe are the most common electrode thatscientist use in researches

(2) Fe and Al can be used in both anode or cathode(3) Each of Fe and Al could be apply in both of

anode and cathode

(4) Depending on the type of wastewater andremoval factor ,retention time will be different

between 2.5 -140 minute(5) Distance of electrodes as a critical factor could

be controlled from 0.1- 6.5 Cm to achieve differentefficiency

(6) Since EC is a co treatment method for potablewater ,so efficiency of this method should be high

Fig. 2: experimental set up (Apparatus of the electrode process)

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