The current study investigated the effects of S2O82 and S2O82/H2O2 oxidation processes on the b... more The current study investigated the effects of S2O82 and S2O82/H2O2 oxidation processes on the biodegradable characteristics of an anaerobic stabilized leachate. Total COD removal efficiency was found to be 46% after S2O82 oxidation (using 4.2 g S2O82/1 g COD0, at pH 7, for 60 min reaction time and at 350 rpm shaking speed), and improved to 81% following S2O82/H2O2 oxidation process (using 5.88 g S2O82 dosage, 8.63 g H2O2 dosage, at pH 11 and for 120 min reaction time at 350 rpm). Biodegradability in terms of BOD5/COD ratio of the leachate enhanced from 0.09 to 0.1 and to 0.17 following S2O8 2 and S2O8 2/H2O2 oxidation processes, respectively. The fractions of COD were determined before and after each oxidation processes (S2O8 2 and S2O82/H2O2). The fraction of biodegradable COD(bi) increased from 36% in raw leachate to 57% and 68% after applying S2O82 and S2O82/H2O2 oxidation, respectively. As for soluble COD(s), its removal efficiency was 39% and 78% following S2O82 and S2O82/H2O2 oxidation, respectively. The maximum removal for particulate COD was 94% and was obtained after 120 min of S2O82/H2O2 oxidation. As a conclusion, S2O82/H2O2 oxidation could be an efficient method for improving the biodegradability of anaerobic stabilized leachate
International Journal of Scientific Research in Knowledge (IJSRK), 1(3), pp. 34-43, 2013
Abstract. Sequencing batch reactor (SBR) process uses for treatment of different types of wastewa... more Abstract. Sequencing batch reactor (SBR) process uses for treatment of different types of wastewaters such as municipal wastewater, landfill leachate, dairy wastewater, slaughterhouse wastewater etc. Operation parameters of SBR technique are cycle time, aeration rate, volume of reactor, hydraulic retention time (HRT) and other parameters. In this work, operational parameters and removal efficiencies of pollutants for SBR method were studied. In addition, boundaries for operational parameters in SBR process were explained as well.
Key words: Landfill leachate, Treatment, Sequencing batch reactor, Operational parameters, Biological process, Aeration
Abstract
A combination of ozonation and persulfate (O3/S2O82−) was used to treat stabilized land... more Abstract
A combination of ozonation and persulfate (O3/S2O82−) was used to treat stabilized landfill leachate. COD, color, and NH3-N, ozone and persulfate doses, pH and reaction time were evaluated to define the optimum operational conditions. The results indicated that under optimum operation conditions (i.e. 210 min of ozonation, a COD/S2O82− ratio (1g/7 g), and pH 10), the best removal values of COD, color, and NH3-N were 72%, 93%, and 55%, respectively. The biodegradability (BOD5/COD ratio) has improved from 0.05 to 0.29. The ozone consumption for COD removal was 0.76 kg O3/kg COD. The results obtained by employing the combined use of persulfate and ozone were compared with those by employing ozone only and persulfate only. The results achieved with the combined use of persulfate and ozone were compared with those obtained with ozone only and persulfate only. The combined method (i.e., O3/S2O82−) achieved higher removal efficiencies for COD, color, and NH3–N compared with other studied applications. Additionally, the combined of ozone/persulfate method proved to be more efficient than the combined use of ozone/Fenton in advanced oxidation processes in the treatment of the same studied leachate.
The objective of this study was to investigate the performance of employing persulfate reagent in... more The objective of this study was to investigate the performance of employing persulfate reagent in the advanced oxidation of ozone to treat stabilized landfill leachate in an ozone reactor. A central composite design (CCD) with response surface methodology (RSM) was applied to evaluate the relationships between operating variables, such as ozone and persulfate dosages, pH, and reaction time, to identify the optimum operating conditions. Quadratic models for the following four responses proved to be significant with very low probabilities (<0.0001): COD, color, NH3–N, and ozone consumption (OC). The obtained optimum conditions included a reaction time of 210 min, 30 g/m3 ozone, 1g/1g COD0/S2O82−ratio, and pH 10. The experimental results were corresponded well with predicted models (COD, color, and NH3–N removal rates of 72%, 96%, and 76%, respectively, and 0.60(kg O3/kg COD OC). The results obtained in the stabilized leachate treatment were compared with those from other treatment processes, such as ozone only and persulfate S2O82− only, to evaluate its effectiveness. The combined method (i.e., O3/S2O82−) achieved higher removal efficiencies for COD, color, and NH3–N compared with other studied applications. Furthermore, the new method is more efficient than ozone/Fenton in advanced oxidation process in the treatment of the same studied leachate.
ABSTRACT
The objective of this study was to investigate the performance of employing Fenton’s r... more ABSTRACT
The objective of this study was to investigate the performance of employing Fenton’s reagent in the advanced oxidation of ozone to treat stabilized landfill leachate in an ozone reactor. A central composite design (CCD) with response surface methodology (RSM) was applied to evaluate the relationships between operating variables, such as ozone and Fenton dosage, pH, and reaction time, to identify the optimum operating conditions. Quadratic models for the following four responses proved to be significant with very low probabilities (<0.0001): chemical oxygen demand (COD), color, NH3–N, and ozone consumption (OC). The obtained optimum conditions included a reaction time of 90 min, 30 g/m3 ozone, 0.01 mol/L H2O2, 0.02 mol/L Fe2+, and pH 5. COD, color, and NH3–N removal rates of 79%, 100%, and 20%, respectively, and 0.18 kg O3/kg COD OC were obtained. The predictions correspond well with experimental results (COD, color, and NH3–N removal rates of 78%, 98.5%, and 19%, respectively, and 0.29 kg O3/kg COD OC). This method reduces the treatment time and improves the treatment efficiency relative to a previously published method that used Fenton’s reagent prior to ozonation.
Abstract
This study investigated the effects of O3 and O3/H2O2/Fe+2 in the advanced oxidation p... more Abstract
This study investigated the effects of O3 and O3/H2O2/Fe+2 in the advanced oxidation process (AOPs) on the biodegradable and soluble characteristics of semi-aerobic stabilized solid waste leachate. The biodegradability (BOD5/COD) ratio improved from 0.034 to 0.05 and 0.1 following O3 and O3/H2O2/Fe+2, respectively. Fractions of biodegradable COD(bi) (24%), non-biodegradable COD(ubi) (76%), soluble COD(s) (59%), biodegradable soluble COD(bsi) (38%), non-biodegradable soluble COD(ubsi) (62%), and particulate COD (PCOD) (41%) in stabilized leachate were also investigated. The fraction of COD(bi) increased to 28% and 36% after applying O3 and O3/AOPs, respectively. COD(S) increased to 59% after O3 and to 72% after O3/AOPs, whereas COD(bsi) increased to 38% and 51% after O3 and O3/AOPs, respectively. The removal efficiency of COD(S) was obtained at 5% after O3 alone and improved to 51% following ozone-based AOPs, whereas the removal efficiency of PCOD improved from 25% after O3 to 71% after ozone-based AOPs.
Abstract
Ozonation, combined with the Fenton process (O3/H2O2/Fe2+), was used to treat matured l... more Abstract
Ozonation, combined with the Fenton process (O3/H2O2/Fe2+), was used to treat matured landfill leachate. The effectiveness of the Fenton molar ratio, Fenton concentration, pH variance, and reaction time were evaluated under optimum operational conditions. The optimum removal values of chemical oxygen demand (COD), color, and NH3–N were found to be 65%, 98%, and 12%, respectively, for 90 min of ozonation using a Fenton molar ratio of 1 at a Fenton concentration of 0.05 mol L-1 (1700 mg/L) H2O2 and 0.05 mol L-1 (2800 mg/L) Fe2+ at pH 7. The maximum removal of NH3–N was 19% at 150 min. The ozone consumption for COD removal was 0.63 kg O3/kg COD. To evaluate the effectiveness, the results obtained in the treatment of stabilized leachate were compared with those obtained from other treatment processes, such as ozone alone, Fenton reaction alone, as well as combined Fenton and ozone. The combined method (i.e., O3/H2O2/Fe2+) achieved higher removal efficiencies for COD, color, and NH3–N compared with other studied applications.
Abstract
Leachate pollution is one of the main problems in landfilling. Researchers have yet to ... more Abstract
Leachate pollution is one of the main problems in landfilling. Researchers have yet to find an effective solution to this problem. The technology that can be used may differ based on the type of leachate produced. Coliform bacteria were recently reported as one of the most problematic pollutants in semi-aerobic (stabilized) leachate. In the present study, the performance of the Electro-Fenton process in removing coliform from leachate was investigated. The study focused on two types of leachate: Palau Borung Landfill leachate with low Coliform content (200 MPN/100 m/L) and Ampang Jajar landfill leachate with high coliform content (>24 x 104 MPN/100 m/L). Optimal conditions for the Electro-Fenton treatment process were applied on both types of leachate. Then, the coliform was examined before and after treatment using the Most Probable Number (MPN) technique. Accordingly, 100% removal of coliform was obtained at low initial coliform content, whereas 99.9% removal was obtained at high initial coliform content. The study revealed that Electro-Fenton is an efficient process in removing high concentrations of pathogenic microorganisms from stabilized leachate.
The current study investigated the effects of S2O82 and S2O82/H2O2 oxidation processes on the b... more The current study investigated the effects of S2O82 and S2O82/H2O2 oxidation processes on the biodegradable characteristics of an anaerobic stabilized leachate. Total COD removal efficiency was found to be 46% after S2O82 oxidation (using 4.2 g S2O82/1 g COD0, at pH 7, for 60 min reaction time and at 350 rpm shaking speed), and improved to 81% following S2O82/H2O2 oxidation process (using 5.88 g S2O82 dosage, 8.63 g H2O2 dosage, at pH 11 and for 120 min reaction time at 350 rpm). Biodegradability in terms of BOD5/COD ratio of the leachate enhanced from 0.09 to 0.1 and to 0.17 following S2O8 2 and S2O8 2/H2O2 oxidation processes, respectively. The fractions of COD were determined before and after each oxidation processes (S2O8 2 and S2O82/H2O2). The fraction of biodegradable COD(bi) increased from 36% in raw leachate to 57% and 68% after applying S2O82 and S2O82/H2O2 oxidation, respectively. As for soluble COD(s), its removal efficiency was 39% and 78% following S2O82 and S2O82/H2O2 oxidation, respectively. The maximum removal for particulate COD was 94% and was obtained after 120 min of S2O82/H2O2 oxidation. As a conclusion, S2O82/H2O2 oxidation could be an efficient method for improving the biodegradability of anaerobic stabilized leachate
International Journal of Scientific Research in Knowledge (IJSRK), 1(3), pp. 34-43, 2013
Abstract. Sequencing batch reactor (SBR) process uses for treatment of different types of wastewa... more Abstract. Sequencing batch reactor (SBR) process uses for treatment of different types of wastewaters such as municipal wastewater, landfill leachate, dairy wastewater, slaughterhouse wastewater etc. Operation parameters of SBR technique are cycle time, aeration rate, volume of reactor, hydraulic retention time (HRT) and other parameters. In this work, operational parameters and removal efficiencies of pollutants for SBR method were studied. In addition, boundaries for operational parameters in SBR process were explained as well.
Key words: Landfill leachate, Treatment, Sequencing batch reactor, Operational parameters, Biological process, Aeration
Abstract
A combination of ozonation and persulfate (O3/S2O82−) was used to treat stabilized land... more Abstract
A combination of ozonation and persulfate (O3/S2O82−) was used to treat stabilized landfill leachate. COD, color, and NH3-N, ozone and persulfate doses, pH and reaction time were evaluated to define the optimum operational conditions. The results indicated that under optimum operation conditions (i.e. 210 min of ozonation, a COD/S2O82− ratio (1g/7 g), and pH 10), the best removal values of COD, color, and NH3-N were 72%, 93%, and 55%, respectively. The biodegradability (BOD5/COD ratio) has improved from 0.05 to 0.29. The ozone consumption for COD removal was 0.76 kg O3/kg COD. The results obtained by employing the combined use of persulfate and ozone were compared with those by employing ozone only and persulfate only. The results achieved with the combined use of persulfate and ozone were compared with those obtained with ozone only and persulfate only. The combined method (i.e., O3/S2O82−) achieved higher removal efficiencies for COD, color, and NH3–N compared with other studied applications. Additionally, the combined of ozone/persulfate method proved to be more efficient than the combined use of ozone/Fenton in advanced oxidation processes in the treatment of the same studied leachate.
The objective of this study was to investigate the performance of employing persulfate reagent in... more The objective of this study was to investigate the performance of employing persulfate reagent in the advanced oxidation of ozone to treat stabilized landfill leachate in an ozone reactor. A central composite design (CCD) with response surface methodology (RSM) was applied to evaluate the relationships between operating variables, such as ozone and persulfate dosages, pH, and reaction time, to identify the optimum operating conditions. Quadratic models for the following four responses proved to be significant with very low probabilities (<0.0001): COD, color, NH3–N, and ozone consumption (OC). The obtained optimum conditions included a reaction time of 210 min, 30 g/m3 ozone, 1g/1g COD0/S2O82−ratio, and pH 10. The experimental results were corresponded well with predicted models (COD, color, and NH3–N removal rates of 72%, 96%, and 76%, respectively, and 0.60(kg O3/kg COD OC). The results obtained in the stabilized leachate treatment were compared with those from other treatment processes, such as ozone only and persulfate S2O82− only, to evaluate its effectiveness. The combined method (i.e., O3/S2O82−) achieved higher removal efficiencies for COD, color, and NH3–N compared with other studied applications. Furthermore, the new method is more efficient than ozone/Fenton in advanced oxidation process in the treatment of the same studied leachate.
ABSTRACT
The objective of this study was to investigate the performance of employing Fenton’s r... more ABSTRACT
The objective of this study was to investigate the performance of employing Fenton’s reagent in the advanced oxidation of ozone to treat stabilized landfill leachate in an ozone reactor. A central composite design (CCD) with response surface methodology (RSM) was applied to evaluate the relationships between operating variables, such as ozone and Fenton dosage, pH, and reaction time, to identify the optimum operating conditions. Quadratic models for the following four responses proved to be significant with very low probabilities (<0.0001): chemical oxygen demand (COD), color, NH3–N, and ozone consumption (OC). The obtained optimum conditions included a reaction time of 90 min, 30 g/m3 ozone, 0.01 mol/L H2O2, 0.02 mol/L Fe2+, and pH 5. COD, color, and NH3–N removal rates of 79%, 100%, and 20%, respectively, and 0.18 kg O3/kg COD OC were obtained. The predictions correspond well with experimental results (COD, color, and NH3–N removal rates of 78%, 98.5%, and 19%, respectively, and 0.29 kg O3/kg COD OC). This method reduces the treatment time and improves the treatment efficiency relative to a previously published method that used Fenton’s reagent prior to ozonation.
Abstract
This study investigated the effects of O3 and O3/H2O2/Fe+2 in the advanced oxidation p... more Abstract
This study investigated the effects of O3 and O3/H2O2/Fe+2 in the advanced oxidation process (AOPs) on the biodegradable and soluble characteristics of semi-aerobic stabilized solid waste leachate. The biodegradability (BOD5/COD) ratio improved from 0.034 to 0.05 and 0.1 following O3 and O3/H2O2/Fe+2, respectively. Fractions of biodegradable COD(bi) (24%), non-biodegradable COD(ubi) (76%), soluble COD(s) (59%), biodegradable soluble COD(bsi) (38%), non-biodegradable soluble COD(ubsi) (62%), and particulate COD (PCOD) (41%) in stabilized leachate were also investigated. The fraction of COD(bi) increased to 28% and 36% after applying O3 and O3/AOPs, respectively. COD(S) increased to 59% after O3 and to 72% after O3/AOPs, whereas COD(bsi) increased to 38% and 51% after O3 and O3/AOPs, respectively. The removal efficiency of COD(S) was obtained at 5% after O3 alone and improved to 51% following ozone-based AOPs, whereas the removal efficiency of PCOD improved from 25% after O3 to 71% after ozone-based AOPs.
Abstract
Ozonation, combined with the Fenton process (O3/H2O2/Fe2+), was used to treat matured l... more Abstract
Ozonation, combined with the Fenton process (O3/H2O2/Fe2+), was used to treat matured landfill leachate. The effectiveness of the Fenton molar ratio, Fenton concentration, pH variance, and reaction time were evaluated under optimum operational conditions. The optimum removal values of chemical oxygen demand (COD), color, and NH3–N were found to be 65%, 98%, and 12%, respectively, for 90 min of ozonation using a Fenton molar ratio of 1 at a Fenton concentration of 0.05 mol L-1 (1700 mg/L) H2O2 and 0.05 mol L-1 (2800 mg/L) Fe2+ at pH 7. The maximum removal of NH3–N was 19% at 150 min. The ozone consumption for COD removal was 0.63 kg O3/kg COD. To evaluate the effectiveness, the results obtained in the treatment of stabilized leachate were compared with those obtained from other treatment processes, such as ozone alone, Fenton reaction alone, as well as combined Fenton and ozone. The combined method (i.e., O3/H2O2/Fe2+) achieved higher removal efficiencies for COD, color, and NH3–N compared with other studied applications.
Abstract
Leachate pollution is one of the main problems in landfilling. Researchers have yet to ... more Abstract
Leachate pollution is one of the main problems in landfilling. Researchers have yet to find an effective solution to this problem. The technology that can be used may differ based on the type of leachate produced. Coliform bacteria were recently reported as one of the most problematic pollutants in semi-aerobic (stabilized) leachate. In the present study, the performance of the Electro-Fenton process in removing coliform from leachate was investigated. The study focused on two types of leachate: Palau Borung Landfill leachate with low Coliform content (200 MPN/100 m/L) and Ampang Jajar landfill leachate with high coliform content (>24 x 104 MPN/100 m/L). Optimal conditions for the Electro-Fenton treatment process were applied on both types of leachate. Then, the coliform was examined before and after treatment using the Most Probable Number (MPN) technique. Accordingly, 100% removal of coliform was obtained at low initial coliform content, whereas 99.9% removal was obtained at high initial coliform content. The study revealed that Electro-Fenton is an efficient process in removing high concentrations of pathogenic microorganisms from stabilized leachate.
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characteristics of an anaerobic stabilized leachate. Total COD removal efficiency was found to be 46%
after S2O82 oxidation (using 4.2 g S2O82/1 g COD0, at pH 7, for 60 min reaction time and at 350 rpm shaking
speed), and improved to 81% following S2O82/H2O2 oxidation process (using 5.88 g S2O82 dosage,
8.63 g H2O2 dosage, at pH 11 and for 120 min reaction time at 350 rpm). Biodegradability in terms of
BOD5/COD ratio of the leachate enhanced from 0.09 to 0.1 and to 0.17 following S2O8 2 and S2O8 2/H2O2
oxidation processes, respectively. The fractions of COD were determined before and after each oxidation
processes (S2O8 2 and S2O82/H2O2). The fraction of biodegradable COD(bi) increased from 36% in raw leachate
to 57% and 68% after applying S2O82 and S2O82/H2O2 oxidation, respectively. As for soluble COD(s),
its removal efficiency was 39% and 78% following S2O82 and S2O82/H2O2 oxidation, respectively. The maximum
removal for particulate COD was 94% and was obtained after 120 min of S2O82/H2O2 oxidation. As a
conclusion, S2O82/H2O2 oxidation could be an efficient method for improving the biodegradability of
anaerobic stabilized leachate
Key words: Landfill leachate, Treatment, Sequencing batch reactor, Operational parameters, Biological process, Aeration
A combination of ozonation and persulfate (O3/S2O82−) was used to treat stabilized landfill leachate. COD, color, and NH3-N, ozone and persulfate doses, pH and reaction time were evaluated to define the optimum operational conditions. The results indicated that under optimum operation conditions (i.e. 210 min of ozonation, a COD/S2O82− ratio (1g/7 g), and pH 10), the best removal values of COD, color, and NH3-N were 72%, 93%, and 55%, respectively. The biodegradability (BOD5/COD ratio) has improved from 0.05 to 0.29. The ozone consumption for COD removal was 0.76 kg O3/kg COD. The results obtained by employing the combined use of persulfate and ozone were compared with those by employing ozone only and persulfate only. The results achieved with the combined use of persulfate and ozone were compared with those obtained with ozone only and persulfate only. The combined method (i.e., O3/S2O82−) achieved higher removal efficiencies for COD, color, and NH3–N compared with other studied applications. Additionally, the combined of ozone/persulfate method proved to be more efficient than the combined use of ozone/Fenton in advanced oxidation processes in the treatment of the same studied leachate.
The objective of this study was to investigate the performance of employing Fenton’s reagent in the advanced oxidation of ozone to treat stabilized landfill leachate in an ozone reactor. A central composite design (CCD) with response surface methodology (RSM) was applied to evaluate the relationships between operating variables, such as ozone and Fenton dosage, pH, and reaction time, to identify the optimum operating conditions. Quadratic models for the following four responses proved to be significant with very low probabilities (<0.0001): chemical oxygen demand (COD), color, NH3–N, and ozone consumption (OC). The obtained optimum conditions included a reaction time of 90 min, 30 g/m3 ozone, 0.01 mol/L H2O2, 0.02 mol/L Fe2+, and pH 5. COD, color, and NH3–N removal rates of 79%, 100%, and 20%, respectively, and 0.18 kg O3/kg COD OC were obtained. The predictions correspond well with experimental results (COD, color, and NH3–N removal rates of 78%, 98.5%, and 19%, respectively, and 0.29 kg O3/kg COD OC). This method reduces the treatment time and improves the treatment efficiency relative to a previously published method that used Fenton’s reagent prior to ozonation.
This study investigated the effects of O3 and O3/H2O2/Fe+2 in the advanced oxidation process (AOPs) on the biodegradable and soluble characteristics of semi-aerobic stabilized solid waste leachate. The biodegradability (BOD5/COD) ratio improved from 0.034 to 0.05 and 0.1 following O3 and O3/H2O2/Fe+2, respectively. Fractions of biodegradable COD(bi) (24%), non-biodegradable COD(ubi) (76%), soluble COD(s) (59%), biodegradable soluble COD(bsi) (38%), non-biodegradable soluble COD(ubsi) (62%), and particulate COD (PCOD) (41%) in stabilized leachate were also investigated. The fraction of COD(bi) increased to 28% and 36% after applying O3 and O3/AOPs, respectively. COD(S) increased to 59% after O3 and to 72% after O3/AOPs, whereas COD(bsi) increased to 38% and 51% after O3 and O3/AOPs, respectively. The removal efficiency of COD(S) was obtained at 5% after O3 alone and improved to 51% following ozone-based AOPs, whereas the removal efficiency of PCOD improved from 25% after O3 to 71% after ozone-based AOPs.
Ozonation, combined with the Fenton process (O3/H2O2/Fe2+), was used to treat matured landfill leachate. The effectiveness of the Fenton molar ratio, Fenton concentration, pH variance, and reaction time were evaluated under optimum operational conditions. The optimum removal values of chemical oxygen demand (COD), color, and NH3–N were found to be 65%, 98%, and 12%, respectively, for 90 min of ozonation using a Fenton molar ratio of 1 at a Fenton concentration of 0.05 mol L-1 (1700 mg/L) H2O2 and 0.05 mol L-1 (2800 mg/L) Fe2+ at pH 7. The maximum removal of NH3–N was 19% at 150 min. The ozone consumption for COD removal was 0.63 kg O3/kg COD. To evaluate the effectiveness, the results obtained in the treatment of stabilized leachate were compared with those obtained from other treatment processes, such as ozone alone, Fenton reaction alone, as well as combined Fenton and ozone. The combined method (i.e., O3/H2O2/Fe2+) achieved higher removal efficiencies for COD, color, and NH3–N compared with other studied applications.
Leachate pollution is one of the main problems in landfilling. Researchers have yet to find an effective solution to this problem. The technology that can be used may differ based on the type of leachate produced. Coliform bacteria were recently reported as one of the most problematic pollutants in semi-aerobic (stabilized) leachate. In the present study, the performance of the Electro-Fenton process in removing coliform from leachate was investigated. The study focused on two types of leachate: Palau Borung Landfill leachate with low Coliform content (200 MPN/100 m/L) and Ampang Jajar landfill leachate with high coliform content (>24 x 104 MPN/100 m/L). Optimal conditions for the Electro-Fenton treatment process were applied on both types of leachate. Then, the coliform was examined before and after treatment using the Most Probable Number (MPN) technique. Accordingly, 100% removal of coliform was obtained at low initial coliform content, whereas 99.9% removal was obtained at high initial coliform content. The study revealed that Electro-Fenton is an efficient process in removing high concentrations of pathogenic microorganisms from stabilized leachate.
characteristics of an anaerobic stabilized leachate. Total COD removal efficiency was found to be 46%
after S2O82 oxidation (using 4.2 g S2O82/1 g COD0, at pH 7, for 60 min reaction time and at 350 rpm shaking
speed), and improved to 81% following S2O82/H2O2 oxidation process (using 5.88 g S2O82 dosage,
8.63 g H2O2 dosage, at pH 11 and for 120 min reaction time at 350 rpm). Biodegradability in terms of
BOD5/COD ratio of the leachate enhanced from 0.09 to 0.1 and to 0.17 following S2O8 2 and S2O8 2/H2O2
oxidation processes, respectively. The fractions of COD were determined before and after each oxidation
processes (S2O8 2 and S2O82/H2O2). The fraction of biodegradable COD(bi) increased from 36% in raw leachate
to 57% and 68% after applying S2O82 and S2O82/H2O2 oxidation, respectively. As for soluble COD(s),
its removal efficiency was 39% and 78% following S2O82 and S2O82/H2O2 oxidation, respectively. The maximum
removal for particulate COD was 94% and was obtained after 120 min of S2O82/H2O2 oxidation. As a
conclusion, S2O82/H2O2 oxidation could be an efficient method for improving the biodegradability of
anaerobic stabilized leachate
Key words: Landfill leachate, Treatment, Sequencing batch reactor, Operational parameters, Biological process, Aeration
A combination of ozonation and persulfate (O3/S2O82−) was used to treat stabilized landfill leachate. COD, color, and NH3-N, ozone and persulfate doses, pH and reaction time were evaluated to define the optimum operational conditions. The results indicated that under optimum operation conditions (i.e. 210 min of ozonation, a COD/S2O82− ratio (1g/7 g), and pH 10), the best removal values of COD, color, and NH3-N were 72%, 93%, and 55%, respectively. The biodegradability (BOD5/COD ratio) has improved from 0.05 to 0.29. The ozone consumption for COD removal was 0.76 kg O3/kg COD. The results obtained by employing the combined use of persulfate and ozone were compared with those by employing ozone only and persulfate only. The results achieved with the combined use of persulfate and ozone were compared with those obtained with ozone only and persulfate only. The combined method (i.e., O3/S2O82−) achieved higher removal efficiencies for COD, color, and NH3–N compared with other studied applications. Additionally, the combined of ozone/persulfate method proved to be more efficient than the combined use of ozone/Fenton in advanced oxidation processes in the treatment of the same studied leachate.
The objective of this study was to investigate the performance of employing Fenton’s reagent in the advanced oxidation of ozone to treat stabilized landfill leachate in an ozone reactor. A central composite design (CCD) with response surface methodology (RSM) was applied to evaluate the relationships between operating variables, such as ozone and Fenton dosage, pH, and reaction time, to identify the optimum operating conditions. Quadratic models for the following four responses proved to be significant with very low probabilities (<0.0001): chemical oxygen demand (COD), color, NH3–N, and ozone consumption (OC). The obtained optimum conditions included a reaction time of 90 min, 30 g/m3 ozone, 0.01 mol/L H2O2, 0.02 mol/L Fe2+, and pH 5. COD, color, and NH3–N removal rates of 79%, 100%, and 20%, respectively, and 0.18 kg O3/kg COD OC were obtained. The predictions correspond well with experimental results (COD, color, and NH3–N removal rates of 78%, 98.5%, and 19%, respectively, and 0.29 kg O3/kg COD OC). This method reduces the treatment time and improves the treatment efficiency relative to a previously published method that used Fenton’s reagent prior to ozonation.
This study investigated the effects of O3 and O3/H2O2/Fe+2 in the advanced oxidation process (AOPs) on the biodegradable and soluble characteristics of semi-aerobic stabilized solid waste leachate. The biodegradability (BOD5/COD) ratio improved from 0.034 to 0.05 and 0.1 following O3 and O3/H2O2/Fe+2, respectively. Fractions of biodegradable COD(bi) (24%), non-biodegradable COD(ubi) (76%), soluble COD(s) (59%), biodegradable soluble COD(bsi) (38%), non-biodegradable soluble COD(ubsi) (62%), and particulate COD (PCOD) (41%) in stabilized leachate were also investigated. The fraction of COD(bi) increased to 28% and 36% after applying O3 and O3/AOPs, respectively. COD(S) increased to 59% after O3 and to 72% after O3/AOPs, whereas COD(bsi) increased to 38% and 51% after O3 and O3/AOPs, respectively. The removal efficiency of COD(S) was obtained at 5% after O3 alone and improved to 51% following ozone-based AOPs, whereas the removal efficiency of PCOD improved from 25% after O3 to 71% after ozone-based AOPs.
Ozonation, combined with the Fenton process (O3/H2O2/Fe2+), was used to treat matured landfill leachate. The effectiveness of the Fenton molar ratio, Fenton concentration, pH variance, and reaction time were evaluated under optimum operational conditions. The optimum removal values of chemical oxygen demand (COD), color, and NH3–N were found to be 65%, 98%, and 12%, respectively, for 90 min of ozonation using a Fenton molar ratio of 1 at a Fenton concentration of 0.05 mol L-1 (1700 mg/L) H2O2 and 0.05 mol L-1 (2800 mg/L) Fe2+ at pH 7. The maximum removal of NH3–N was 19% at 150 min. The ozone consumption for COD removal was 0.63 kg O3/kg COD. To evaluate the effectiveness, the results obtained in the treatment of stabilized leachate were compared with those obtained from other treatment processes, such as ozone alone, Fenton reaction alone, as well as combined Fenton and ozone. The combined method (i.e., O3/H2O2/Fe2+) achieved higher removal efficiencies for COD, color, and NH3–N compared with other studied applications.
Leachate pollution is one of the main problems in landfilling. Researchers have yet to find an effective solution to this problem. The technology that can be used may differ based on the type of leachate produced. Coliform bacteria were recently reported as one of the most problematic pollutants in semi-aerobic (stabilized) leachate. In the present study, the performance of the Electro-Fenton process in removing coliform from leachate was investigated. The study focused on two types of leachate: Palau Borung Landfill leachate with low Coliform content (200 MPN/100 m/L) and Ampang Jajar landfill leachate with high coliform content (>24 x 104 MPN/100 m/L). Optimal conditions for the Electro-Fenton treatment process were applied on both types of leachate. Then, the coliform was examined before and after treatment using the Most Probable Number (MPN) technique. Accordingly, 100% removal of coliform was obtained at low initial coliform content, whereas 99.9% removal was obtained at high initial coliform content. The study revealed that Electro-Fenton is an efficient process in removing high concentrations of pathogenic microorganisms from stabilized leachate.