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THE 28 TH CONFERENCE OF THE FEDERATION OF ENGINEERING ORGANIZATIONS CAFEO 28 HANOI VIETNAM, 30 TH NOV. - 2 ND DEC., 2010 TITLE: COD AND COLOUR REMOVAL OF SECURE LANDFILL LEACHATE BY FERRIC CHLORIDE, ZEOLITE AND HYDROGEN PEROXIDE. YOUR PHOTO (or you can attach a separate file for photo) AUTHOR(S)’ NAME(S): Warunthorn Kumpila* Associate Professor, Doctor Thares Srisatit** ORGANIZATION & DESIGNATION: Department of Environmental Engineering, Chulalongkorn University, Bangkok Thailand ADDRESS: 487 Moo 13 Sub District Kudkao District Munjakiri* Province Khonkean 40160* Department of Environmental Engineering** Chulalongkorn University, Bangkok Thailand** TEL: 087-3833946* 02-2186679** FAX: 02-2186666 EMAIL: pe_sci@hotmail.com*, thares.S@chula.ac.th** Warunthorn Kumpila COD AND COLOUR REMOVAL OF SECURE LANDFILL LEACHATE BY FERRIC CHLORIDE, ZEOLITE AND HYDROGEN PEROXIDE. Warunthorn Kumpila* and Thares Srisatit** Department of Environmental Engineering, Chulalongkorn University, Bangkok Thailand Email: pe_sci@hotmail.com *, thares.S@chula.ac.th** ABSTRACT Secure landfill leachate is always a high-strength wastewater characterized by extremes of pH, chemical oxygen demand (COD), biochemical oxygen demand (BOD), inorganic salts and toxicity. At the same time, its composition is variable over the time and space at a particular landfill. It contains a mixture of many chemical compounds originated from the various disposed materials or they may also result from biotic and abiotic processes in the system. The composition of the leached wastewater is based on the composition and the degree of contouring and compacting of solid wastes, physicochemical conditions at the landfill, geology and landfill age. This research was studies the ability of using ferric chloride, zeolite and hydrogen peroxide for COD and color removal from leachate of the secure landfill in Thailand. In this research, divides to are four experiment, the first study the character at the beginning of the leachate, for example pH, COD, BOD, TDS, TSS, Heavy Metal, colour. The second study the ability of using ferric chloride for COD removal by jar test. The third batch test by zeolite. The forth oxidation process with Fe 2+ /H 2 O 2 . The results found that the concentration of ferric chloride 300 mg/l at pH 3 can reduce 50% of COD then continuous process that filtrated by 10 g/l of leachate of zeolite at pH 5, contact time 180 min, can reduce 30% of COD when the process oxidized by Fe 2+ /H 2 O 2 can reduce 20% and 30% of COD and color respectively. Totally this process cans removal 70-80% of COD. The aim of research is the practical method, easy operate more over low cost as the results can be accepted when compare with the standard value. Introduction Secure landfill leachate is always a high-strength wastewater characterized by extremes of pH, chemical oxygen demand (COD), biochemical oxygen demand (BOD), inorganic salts and toxicity. At the same time, its composition is variable over the time and space at a particular landfill. It contains a mixture of many chemical compounds originated from the various disposed materials and/or they may also result from biotic and a biotic process in the system. The composition of the leached wastewater is based on the composition and the degree of contouring and compacting of solid wastes, physicochemical conditions at the landfill, local rainfall regime that regulates moisture level, geology and landfill age (Zgajnar, Tisler and Zagorc-Kon, 2009). Present compounds could constitute a potential risk to the quality of receiving water bodies, when leachates are released into the environment, because they are usually toxic, resistant to environmental degradation and have other characteristics which makes them hazardous to the environment. The understanding, monitoring and management of quantity and quality of landfill leachate during operation and after secure landfill closure are of a great importance. Careful site management can reduce the quality and pollution potential of the formed leachate, but it cannot completely eliminate it. These substances should be caught and treated properly, to avoid contamination of receiving environment. Treatment methods must be matched to the actual characteristics of the particular leachate. For many years, conventional biological treatments and classical physicochemical methods were considered the most appropriate technologies for manipulation and management of high-strength effluents like landfill leachate. Various techniques, such as sequencing batch reactor (SBR) and its modification, upflow anaerobic sludge blanket (UASB), coagulation–flocculation, adsorption, air stripping, and so on, have been used to treat secure landfill leachate. Physicochemical treatments can then act as a refining step for the stabilized effluent of biologically treated leachate. The purpose of this research was studies the ability of using ferric chloride, zeolite and hydrogen peroxide for COD and color removal from secure landfill leachate. In this research, divides to are four experiment, the first study the character at the beginning of the leachate, for example pH, COD, BOD, TDS, TSS, Heavy Metal, color. The second study the ability of using ferric chloride for COD removal by jar test. The third batch test by zeolite. The forth oxidation process with Fe 2+ /H 2 O 2 . Material and methods 1. Characterization of secure landfill leachate Secure landfill leachate originated from a landfill, where various wastes from several production phases of the industrial factory and is located in Mabtaphud Industry is show in Fig. 1. Secure Landfill used for hazardous waste that has been stabilized process and has been made into solid. The secure site has been prepared with the technology used for hazardous waste, which effectively prevents the water or pollutant from escape into the environment. Compacted until the water seepage rate in 1x10 -7 cm/s and then lined with 8 layers of materials with leachate collection properly. After the wastes have filled up, it is covered by soil and it has a system for separate collection of rain water. It has been in operation for the past 10 years. Leachate is collected by drainage pipes into the basin. The average daily leachate collected is between 20 and 30 m 3 , and it is treated by combustion in cement kiln. It is cost of combustion 100-133 dollar/ m 3 . The raw leachate was collected several times all year around from the reservoir, where all entrapped leachate is collected (Zgajnar, Tisler and Zagorc-Kon, 2009). It has been stored in a room temperature prior to experiments. The Fig. 2 show secure landfill leachate compare with water supply. Analyses of raw leachate and monitoring of the treatment procedures included pH, BOD, COD, TDS (Total Suspended Solid), TDS (Total dissolves Solid) Heavy metal (Pb, Hg, As, Cr, Cd) are show in Table 1. 2. Coagulation and flocculation Coagulation–flocculation experiments were performed with jar test equipment (FC 6S, VELP scientific) comprising six paddle rotors equipped with six beakers of 1 L each 500 mL of the leachate sample were put in each of the beakers, pH has been measured (SevenEasy, Mettler Toledo) and mixing speed was set up at 120 rpm. Some experiments were also conducted at lower pH which were attained by addition of 1M HCl p.a. prior to additions of coagulant and flocculants (Hamidi et al., 2007; Huo et al., 2009; Zong et al., 2002; Zhen et al., 2009). The different amounts of the coagulants FeCl 3 (from 100mg L −1 to 1000mg L −1 ). The final gravity settling stage lasted for another 2 h before sampling for COD analysis. Fig. 1 Study Area. Fig. 2 Characteristic of leachate Mabtaphud Industry Clean water Landfill leachate Table 1 Analysis parameter 3. Batch test by zeolite Batch experiments were conducted at ambient temperature using the optimum conditions of all pertinent factors, such as dose, pH, agitation speed, and contact time. Subsequent adsorption experiments were carried out with only optimized parameters. The optimum conditions for the adsorption batch study taken from the previous study are dose 0.01-10 mg, pH 4-7, 200 rpm of shaking speed and 5-1440 min of contact time in 250 ml flasks containing 100 ml of the leachate sampler (Foo and Hameed, 2009). Adsorption isotherm tests were also carried out in the reaction mixture consisting of 100 ml of leachate solution with varying adsorbent weight. COD and color was determined using closed reflux colorimetric method and spectrophotometric method respectively. 4. Oxidation process with Fe 2+ /H 2 O 2 Pre-experiment analysis concentrate of hydrogen peroxide was determined using permanganate titration. Then determination of hydrogen peroxide initial concentration. Added different amounts of the H 2 O 2 from 10 g L −1 to 200 g L −1 in 150 ml flasks containing 50 ml of the leachate sample and stirrer 1 h. The final gravity settling stage lasted for another 24 h before sampling for COD, color and iodometric titration analysis. Subsequent find the appropriate pH conditions. Added different pH 3-12 in 150 ml flasks containing 50 ml of the leachate sample and stirrer 1 h. The final gravity settling stage lasted for another 24 h before sampling for COD, color and iodometric titration analysis. This experiment were also conducted pH which were attained by addition of H 2 SO 4 and NaOH. Then determination of the concentration of hydrogen peroxide appropriate. The optimum of the H 2 O 2 from previous experiment in 150 ml flasks containing 50 ml of the leachate sampler and stirrer 1 h. The final gravity settling stage lasted for another 24 h before sampling for COD, color and iodometric titration analysis. The last experiment were study ferrous catalyst of coagulation with oxidation by hydrogen peroxide (Mohan and Gandhimathi, 2009; Yanyu et al., 2010). The optimum amounts of the H 2 O 2 and pH from previous experiment and add different ferrous sulfate in 150 ml flasks containing 50 ml of the leachate sample and stirrer 1 h. The final gravity settling stage lasted for another 24 h before sampling for COD, color and iodometric titration analysis (Eyup, 2009; Hui, Heung and Chin-Pao, 2009). Parameter unit Analytical Method 1. pH 2. COD 3. COLOR 4. BOD 5. TSS 6. TDS 7. HEAVY METAL (Pb, Hg, As, Cr, Cd) 8. CONCENTRATION OF H 2 O 2 mg/l pt.co mg/l mg/l mg/l mg/l mg/l pH meter Closed reflux colorimetric method Spectrophotometric method Dilution method Gravimetric, 103-105° C Gravimetric, 103-105° C Atomic Absorption Spectrophotometry Permanganate titration and Iodometric titration Results and discussion 1. Characterization of secure landfill leachate The physico-chemical characteristics of the leachate sample analyzed are shown in Table 2. From the values reported in Table 2, it can be concluded that the leachate contains heavy metals such as Pb, Cd, Cr and Hg. The results indicate that many parameter were exceeded effluent standards in Thailand, such as COD, BOD, TSS and TDS. Table 2 Characteristics of leachate for the experiment from secure landfill [14 June 2010]. 2. Coagulation and flocculation Coagulation experiments with FeCl 3 gave better results. At addition of 100 mgL −1 to 1000 mgL −1 . Result that at added FeCl 3 300 mgL −1 can remove 21.72% of COD [Fig. 3]. Which is the highest of reduced COD, when it is compare between other concentrate. Initial pH were to 1.0-9.0, but the highest treatment efficiency was obtained at pH 3.0 [Fig. 4]. Which can remove 24.40% of COD. At the both results find that % removal rather less. Which cause of added HCl or NaOH attained pH. Parameter unit Concentration 1. pH 2. COD 3. COLOR 4. BOD 5. TSS 6. TDS 7. HEAVY METAL Pb Cr Cd Hg As mg/l pt.co mg/l mg/l mg/l mg/l mg/l mg/l mg/l mg/l 8.3 30,240 2,444 18,144 101 45,452 0.045 0.005 0.4658 0.002 0.001 Fig. 3 Percentage of COD removal at different concentration of coagulants. Fig. 4 Percentage of COD removal at different pH. 3. Batch test by zeolite This experiment study about %COD removal and color by adsorption process. Which have zeolite is adsorbent. At the time added dosage zeolite 0.01-10 g in the leachate sample. The result indicates that dosage of zeolite at 10 g can remove 29.71%, 24.75% of COD and color respectively. Which the highest %COD removal and color. The results show that in Fig. 5. After that study about %COD removal and color by adsorption process, which have zeolite is adsorbent. At the time added optimum of dosage zeolite and different pH 4-7 in the leachate sample. Result that at pH 5 have the highest %COD removal and color were 26.20%, 20.38% respectively [Fig. 6]. The last experiment for study adsorption process. The determine optimum contact time. Added the optimum dosage of zeolite and pH in the leachate sample and vary contact time 5-1440 min. The result indicates that at 180 min can remove COD and color at 24.39%, 19.07% respectively. The results show that in Fig. 7. Fig. 5 Percentage of COD and color removal using zeolite as adsorbent. Fig. 6 Percentage of COD and color removal using zeolite at different pH. Fig. 7 Percentage of COD and color removal using zeolite at different contact time. 4. Oxidation process with Fe 2+ /H 2 O 2 A complete removal of target compounds requires an optimum dose of H 2 O 2 in the oxidation process. Therefore, it is necessary to determine its optimum dose to maximize catalytic oxidation. In this study, the dose of H 2 O 2 was varied from 10 to 200 g/L and the pH was varies from 3-12. The effects of the H 2 O 2 doses on COD and color removal are depicted in Fig. 8. After added H 2 O 2 into the flask, the maximum removal of organic compounds by the combined treatment improved to 17.00% with the higher concentration of COD and can remove 28.31% of color. This result is significantly higher than those of the H 2 O 2 oxidation at the same initial COD concentration. Fig. 9 were show about effect of pH on COD and color removal. The result that both of COD and color the highest at pH 4 were 19.95%, 29.58% respectively. The last experiment study effect of oxidation of H 2 O 2 with Fe (II) catalytic. The results indicate that at increase Fe (II) %removal of COD and color as a result increasing. Which this results show at Fig. 10 Fig. 8 Effect of hydrogen peroxide dosage on COD and color removal. Fig. 9 Effect of pH on COD and color removal. Fig. 10 Effect of H 2 O 2 with different Fe (II) on COD and color removal. Conclusions The results found that the concentration of ferric chloride 300 mg/l at pH 3 can reduce COD at for 50% then continuous process that filtrated by 10 g/l of leachate of zeolite at pH 5, contact time 180 min, can reduce COD and color approximate at 30%, 20% respectively. When the process oxidized by Fe 2+ /H 2 O 2 can reduce COD and color approximate at 20%, 30% respectively. Totally this process can remove 70-80% of COD. However, In this study can be applied the best method for wastewater treatment. In order improve efficiency of COD and color removal and to reduce treatment cost. Reference Eyup, A., 2009. Treatment of landfill leachate by using electro-Fenton method. Journal of Hazardous Materials. 163, 109–114. Foo, K.Y. and Hameed, B.H., 2009. An overview of landfill leachate treatment via activated carbon adsorption process. Journal of Hazardous Materials. 171, 54–60. Hui, Z., Heung, J.C. and Chin-Pao, H., 2009. 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