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CAFEO 28 HANOI VIETNAM, 30 NOV - 2 DEC., 2010

TITLE:

COD AND COLOUR REMOVAL OF SECURE LANDFILL LEACHATE BY FERRIC CHLORIDE,

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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**

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 Fe2+/H2O2 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 Fe2+/H2O2 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

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 Fe2+/H2O2

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 m3, and it is treated by combustion in cement kiln It is cost of combustion 100-133 dollar/ m3

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 FeCl3 (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

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+ /H2O2

Pre-experiment analysis concentrate of hydrogen peroxide was determined using permanganate titration Then determination of hydrogen peroxide initial concentration Added different amounts of the H2O2 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 H2SO4 and NaOH Then determination of the concentration of hydrogen peroxide appropriate The optimum of the H2O2 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 H2O2 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)

1 pH

2 COD

3 COLOR

4 BOD

5 TSS

6 TDS

7 HEAVY METAL (Pb, Hg, As, Cr,

Cd)

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 FeCl3 gave better results At addition of 100 mgL−1 to

1000 mgL−1 Result that at added FeCl3 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

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+ /H2O2

A complete removal of target compounds requires an optimum dose of H2O2 in the oxidation process Therefore, it is necessary to determine its optimum dose to maximize catalytic oxidation In this study, the dose of H2O2 was varied from 10 to 200 g/L and the pH was varies from 3-12 The effects of the H2O2 doses on COD and color removal are depicted

in Fig 8 After added H2O2 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 H2O2 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%,

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 H2O2 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 Fe2+/H2O2 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

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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

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