Performance Evaluation of Electrocoagulation Technique for Removing Groundwater Hardness of Tikrit University

Abstract

The performance of Electrocoagulation (EC) process for removal of hardness in groundwater(GW) of Tikrit University in Salahaddin province, north of Baghdad in Iraq has been studied using aluminum (Al)electrodes with both bipolar and monopolar configurations. The effect of initial pH, applied voltage(U), electrolysis time(t), and electrodes configurations on the performance of EC has been investigated. It was found that the best initial pHvalue to remove hardness(HD)was 9.5. The results indicated that increasing U and t had a positive effect on the hardness removal efficiency(hardness %E) to reach 90.4%andit was influenced by the electrodes configuration in which hardness %E was 83.5% in bipolar connection compared with 66.2%in monopolar connection.Also The electrical energy consumption hardness %E and the experimentally and theoreticallyelectrodes consumption (exp W) and (theo W)were calculated.It was absorbed,as determined, that there is no significant difference between pseudo-first and second-order kinetic model except at 40 volt that the pseudo second-order kinetic model fits better than the first-order kinetic model with the data of the electrocoagulation process. Finally the cost at themost favorable conditions for EC process was calculatedresulting that the electrocoagulation process is successfully applied to remove the hardness rate from groundwater with high performance. ‫ﻛﻔﺎءة‬ ‫وﺗﻘﯾم‬ ‫دراﺳﺔ‬ ‫اﻟﺟوﻓﯾﺔ‬ ‫اﻟﻣﯾﺎه‬ ‫ﻣن‬ ‫اﻟﻌﺳرة‬ ‫ازاﻟﺔ‬ ‫ﻓﻲ‬ ‫اﻟﻛﮭرﺑﺎﺋﻲ‬ ‫اﻟﺗﺧﺛﯾر‬ ‫ﻋﻣﻠﯾﺔ‬ ‫ﺗﻛرﯾت‬ ‫ﺟﺎﻣﻌﺔ‬ ‫ﻣﻧطﻘﺔ‬ ‫ﻓﻲ‬ ‫اﻟﻣوﺟودة‬ ‫اﻟﺧﻼﺻﺔ‬ ‫اﻟﻛﮭرﺑﺎﺋﻲ‬ ‫اﻟﺗﺧﺛﯾر‬ ‫ﻋﻠﯾﺔ‬ ‫ﻛﻔﺎءة‬ ‫دراﺳﺔ‬ ‫ﺗم‬ ‫اﻟﺑﺣث‬ ‫ھذه‬ ‫ﻓﻲ‬ ‫ﻹزاﻟﺔ‬ ‫اﻟﻣوﺟودة‬ ‫اﻟﺟوﻓﯾﺔ‬ ‫اﻟﻣﯾﺎه‬ ‫ﻣن‬ ‫اﻟﻌﺳرة‬ ‫دﯾن‬ ‫اﻟ‬ ‫ﻼح‬ ‫ﺻ‬ ‫ﺔ‬ ‫ﻣﺣﺎﻓظ‬ ‫ﻲ‬ ‫ﻓ‬ ‫ت‬ ‫ﺗﻛرﯾ‬ ‫ﺔ‬ ‫ﺟﺎﻣﻌ‬ ‫ﺔ‬ ‫ﻣﻧطﻘ‬ ‫ﻲ‬ ‫ﻓ‬ ‫وم‬ ‫اﻷﻟﻣﻧﯾ‬ ‫ﺎب‬ ‫أﻗط‬ ‫ﺗﺧدام‬ ‫ﺑﺎﺳ‬ ‫ﺔ‬ ‫ﻣﺧﺗﻠﻔ‬ ‫ط‬ ‫رﺑ‬ ‫رق‬ ‫ﺑط‬ ‫اﻟﻘطب‬ ‫أﺣﺎدﯾﺔوﺛﻧﺎﺋﯾﺔ‬. ‫ﺗم‬ ‫وﻗد‬ ‫دراﺳﺔ‬ ‫ﺑﻌض‬ ‫ﺗﺄﺛﯾر‬ ‫ﻣﺛﻼ‬ ‫اﻟﻣﻌﺎﯾﯾر‬ ‫اﻟﮭﯾدروﺟﯾﻧﻲ‬ ‫ﻟرﻗم‬ ‫اﻷوﻟﻲ‬ pH ‫واﻟﺟﮭد‬ ، ‫اﻟﻣزود‬) U (‫ت‬ ‫واﻟوﻗ‬ ،) t (‫و‬ ، ‫ط‬ ‫رﺑ‬ ‫ﺔ‬ ‫طرﯾﻘ‬ ‫ﺎب‬ ‫اﻷﻗط‬ ‫أداء‬ ‫ﻰ‬ ‫ﻋﻠ‬ ‫ﺎﺋﻲ‬ ‫اﻟﻛﮭرﺑ‬ ‫ر‬ ‫اﻟﺗﺧﺛﯾ‬ ‫ﺔ‬ ‫ﻋﻣﻠﯾ‬. ‫أن‬ ‫د‬ ‫وﻗدوﺟ‬ ‫ﺔ‬ ‫درﺟ‬ ‫اﻟﺣﻣوﺿﺔ‬ ‫اﻷوﻟﯾﺔ‬ ‫اﻟﻣﺛﻠﻰ‬ ‫ﻹزاﻟﺔاﻟﻌﺳر‬ ‫ة‬) HD (‫ﻧ‬ ‫ﺎ‬ ‫ﻛ‬ ‫ت‬ 9.5. ‫و‬ ‫أﺷﺎرت‬ ‫ﺎدة‬ ‫أﻧزﯾ‬ ‫ﻰ‬ ‫إﻟ‬ ‫اﻟﻧﺗﺎﺋﺞ‬ U ‫و‬ t ‫ﺎﺑﻲ‬ ‫أﺛرإﯾﺟ‬ ‫ﮫ‬ ‫ﻟ‬ ‫ﺎن‬ ‫ﻛ‬ ‫ﻰ‬ ‫ﻠ‬ ‫ﻋ‬ ‫ﻛﻔﺎءة‬ ‫إزاﻟﺔ‬ ‫اﻟﻌﺳرة‬ ‫إﻟﻰ‬ ‫ﻟﺗﺻل‬ 90.4% ‫و‬ ، ‫ھﻲ‬ ‫ﻛذﻟك‬ ‫ﺗ‬ ‫ﺗ‬ ‫ﺄﺛر‬ ‫رﺑط‬ ‫ﺑطرق‬ ‫اﻟﻛﮭرﺑﺎﺋﯾﺔ‬ ‫اﻷﻗطﺎب‬ ‫ﻲ‬ ‫ﻓ‬ ‫اﻟ‬ ‫ﺧﻠﯾﺔﺣﯾث‬ ‫ﻧ‬ ‫ﺎ‬ ‫ﻛ‬ ‫اﻟﻌﺳرة‬ ‫إزاﻟﺔ‬ ‫ﻧﺳﺑﺔ‬ ‫ت‬ 83.5% ‫ﺛﻧﺎﺋﻲ‬ ‫ﻧوع‬ ‫اﻟرﺑط‬ ‫ﻓﻲ‬ ‫اﻟﻘطﺑﯾن‬ ‫ﺣﯾن‬ ‫ﻓﻲ‬ ‫وﺻﻠت‬ ‫اﻟرﺑط‬ ‫ﻓﻲ‬ ‫اﻟﻘطب‬ ‫أﺣﺎدي‬ ‫ﻰ‬ ‫إﻟ‬ 66.2 ٪. ‫ﺣﺳﺎب‬ ‫ﻛﻣﺎﺗم‬ ‫اﺳﺗﮭﻼك‬ ‫اﻟطﺎﻗﺔاﻟﻛﮭرﺑﺎﺋﯾﺔواﺳﺗﮭﻼك‬ ‫اﻷﻗطﺎب‬ ‫ﺗﺟرﯾﺑﯾﺎ‬) exp W (‫وﻧظرﯾﺎ‬) theo W (. ‫ﺎ‬ ‫ﻣ‬ ‫ﻛ‬ ‫ﺎﺋﻲ‬ ‫اﻟﻛﮭرﺑ‬ ‫اﻟﺗﺧﺛﯾر‬ ‫ﻋﻣﻠﯾﺔ‬ ‫وﺣرﻛﯾﺔ‬ ‫ﻧﻣذﺟﺔ‬ ‫ﺣﺳﺎب‬ ‫ﺗم‬ ، ‫ﯾن‬ ‫وﺗﺑ‬ ‫إن‬ ‫ﺔ‬ ‫ﺣرﻛﯾ‬ ‫ﺔ‬ ‫درﺟ‬ ‫ﺎﺋﻲ‬ ‫اﻟﻛﮭرﺑ‬ ‫ر‬ ‫اﻟﺗﺧﺛﯾ‬ ‫ﺔ‬ ‫ﻋﻣﻠﯾ‬ ‫ن‬ ‫ﻣ‬ ‫ﻛﺎن‬ ‫اﻟﺛﺎﻧﯾﺔ‬ ‫اﻟدرﺟﺔ‬ ‫أﻓﺿل‬ ‫وأدق‬ ‫اﻟدرﺟﺔ‬ ‫ﻓﻲ‬ ‫ﻣﻣﺎ‬ ‫اﻷوﻟﻰ‬ ‫اﻟﻌﻣﻠﯾﺔ‬ ‫اﻟﺗﺟﺎرب‬ ‫ﻣن‬ ‫اﻟﻣﺳﺗﺣﺻﻠﺔ‬ ‫ﻟﻠﺑﯾﺎﻧﺎت‬ ‫ﺗﺑﻌﺎ‬. ‫وأﺧﯾرا‬ PDF created with pdfFactory Pro trial version www.pdffactory.com Hardness of Tikrit University 3269 ‫اﻟﻌﻣﻠﯾﺔ‬ ‫ﻟﮭذه‬ ‫اﻻﻗﺗﺻﺎدﯾﺔ‬ ‫اﻟﻛﻠﻔﺔ‬ ‫ﺣﺳﺎب‬ ‫ﺗم‬ ‫واﻟﺗﻲ‬ ‫أﺷﺎرت‬ ‫إﻟﻰ‬ ‫ﻧﺟﺎح‬ ‫اﻟﻛﮭرﺑﺎﺋﻲ‬ ‫اﻟﺗﺧﺛﯾر‬ ‫ﻋﻣﻠﯾﺔ‬ ‫رة‬ ‫اﻟﻌﺳ‬ ‫إزاﻟﺔ‬ ‫ﻓﻲ‬ ‫اﻟﺟوﻓﯾﺔ‬ ‫اﻟﻣﯾﺎه‬ ‫ﻣن‬. INTRODUCTION uitable and available water for human consumption is highly limited and likewise, available drinking water has been reduced because of the pollution created naturally and artificially. Among water quality parameters, hardness has always been investigated as an important factor.Hardness which is one of the chemical characteristics of water is caused mainly by the presence of calcium and magnesium [1] .Hardness of waters varies considerably from place to place. In general, groundwater is harder than surface waters andwater gets harder if the amount of calcium and magnesium is increased. Hardness can be expected in regions where large amounts of limestone are found [2]. Hardness ions create a lot of problems for life and industry [3] ,therefore knowing the hardness of water is important in evaluating its use as a domestic or industrial water supply [2]. There are various techniques for the removal of water hardness, such as using electromembrane processes, nano-filtration [4] chemical or natural substances [5] , ion exchange resins [6] , and electrodialysis [7]. Recently, growing demand for high quality water has justified the development of modern and low cost technologies for hard and very hard water softening [4] .One of these techniques is electrochemical technology such as electrocoagulation process, which is being used for the removal of colloidal and suspended particles, ions [7] heavy metals [8] , dyes, [9] , organic matters [10] and oily matters [11] from water and aqueous environments. Electrocoagulation is a complex process occurring via serial steps such as; electrolytic reactions at electrode surfaces, formation of coagulants in aqueous phase, adsorption of soluble or colloidal pollutants on coagulants which are removed by sedimentation or flotation [3]. A simple electro-coagulating batch reactor is made up of anode and cathode with monopolar or bipolar configuration [12]. When a potential is applied from an external power source, the anode material undergoes oxidation, while the cathode will be subjected to reductive deposition of elemental metals [13]. Following equations, describe EC process in relation to Al electrode: Atanode: