Four identical pilot-scale landfill reactors with different alternative composite liners were sim... more Four identical pilot-scale landfill reactors with different alternative composite liners were simultaneously operated for a period of about 540 days to investigate and to simulate the migration behaviors of phenolic compounds (phenol, 2-CP, 2-MP, 3-MP, 4-MP, 2-NP, 4-NP, 2,4-DNP, 2,4-DCP, 2,6-DCP, 2,4,5-TCP, 2,4,6-TCP, 2,3,4,6-TeCP, PCP) and heavy metals (Pb, Cu, Zn, Cr, Cd, Ni) from landfill leachate to the groundwater. Alternative landfill liners of four reactors consist of R1: Compacted clay liner (10 cm+ 10 cm, k = 10 −8 m/sn), R2: Geomembrane (2 mm HDPE) + compacted clay liner (10 cm + 10 cm, k = 10 −8 m/sn), R3: Geomembrane (2 mm HDPE) + compacted clay liner (10 cm, k = 10 −8 m/sn)+ bentonite liner (2 cm) + compacted clay liner (10 cm, k = 10 −8 m/sn), and R4: Geomembrane (2 mm HDPE) + compacted clay liner (10 cm, k = 10 −8 m/sn) + zeolite liner (2 cm) + compacted clay liner (10 cm, k = 10 −8 m/sn). Wastes representing Istanbul municipal solid wastes were disposed in the reactors. To represent bioreactor landfills, reactors were operated by leachate recirculation. To monitor and control anaerobic degradation in the reactors, variations of conventional parameters (pH, alkalinity, chloride, conductivity, COD, TOC, TKN, ammonia and alcaly metals) were also investigated in landfill leachate samples. The results of this study showed that about 35–50% of migration of organic contaminants (phenolic compounds) and 55–100% of migration of inorganic contaminants (heavy metals) to the model groundwater could be effectively reduced with the use of bentonite and zeolite materials in landfill liner systems. Although leachate contaminants can reach to the groundwater in trace concentrations, findings of this study concluded that the release of these compounds from landfill leachate to the groundwater may potentially be of an important environmental concern based on the experimental findings.
One-dimensional (1D) advection–dispersion transport modeling was conducted as a conceptual approa... more One-dimensional (1D) advection–dispersion transport modeling was conducted as a conceptual approach for the estimation of the transport parameters of fourteen different phenolic compounds (phenol, 2-CP, 2-MP, 3-MP, 4-MP, 2-NP, 4-NP, 2,4-DNP, 2,4-DCP, 2,6-DCP, 2,4,5-TCP, 2,4,6-TCP, 2,3,4,6-TeCP, PCP) and three different inorganic contaminants (Cu, Zn, Fe) migrating downward through the several liner systems. Four identical pilot-scale landfill reactors (0.25 m 3) with different composite liners (R1: 0.10 + 0.10 m of compacted clay liner (CCL), L e = 0.20 m, k e = 1 Â 10 À8 m/s, R2: 0.002-m-thick damaged high-density polyethylene (HDPE) geomembrane overlying 0.10 + 0.10 m of CCL, L e = 0.20 m, k e = 1 Â 10 À8 m/s, R3: 0.002-m-thick damaged HDPE geomembrane overlying a 0.02-m-thick bentonite layer encapsulated between 0.10 + 0.10 m CCL, L e = 0.22 m, k e = 1 Â 10 À8 m/s, R4: 0.002-m-thick damaged HDPE geomembrane overlying a 0.02-m-thick zeolite layer encapsulated between 0.10 + 0.10 m CCL, L e = 0.22 m, k e = 4.24 Â 10 À7 m/s) were simultaneously run for a period of about 540 days to investigate the nature of diffusive and advective transport of the selected organic and inorganic contaminants. The results of 1D transport model showed that the highest molecular diffusion coefficients, ranging from 4.77 Â 10 À10 to 10.67 Â 10 À10 m 2 /s, were estimated for phenol (R4), 2-MP (R1), 2,4-DNP (R2), 2,4-DCP (R1), 2,6-DCP (R2), 2,4,5-TCP (R2) and 2,3,4,6-TeCP (R1). For all reactors, dispersion coefficients of Cu, ranging from 3.47 Â 10 À6 m 2 /s to 5.37 Â 10 À2 m 2 /s, was determined to be higher than others obtained for Zn and Fe. Average molecular diffusion coefficients of phenolic compounds were estimated to be about 5.64 Â 10 À10 m 2 /s, 5.37 Â 10 À10 m 2 /s, 2.69 Â 10 À10 m 2 /s and 3.29 Â 10 À10 m 2 /s for R1, R2, R3 and R4 systems, respectively. The findings of this study clearly indicated that about 35–50% of transport of phenolic compounds to the groundwater is believed to be prevented with the use of zeolite and bentonite materials in landfill liner systems.
In this study, characterization and electrocoagulative treatability of nanofiltration concentrate... more In this study, characterization and electrocoagulative treatability of nanofiltration concentrate from a full-scale landfill leachate treatment plant (Istanbul, Turkey) were investigated. The average concentrations of COD, TKN and ammonia were determined as 6200, 587.5, and 110 mg/L, respectively. Membrane concentrate also have almost neutral pH, high conductivity and color. Besides, nanofiltration concentrate contains low metal concentrations. After the characterization of the concentrate, treatment of the concentrate by electrocoagulation method with aluminum plate electrodes was investigated. The effects of electrode type, current intensity and treatment time on the treatment of nanofiltration concentrate by EC process were investigated. According to the results, the most acceptable current intensity for COD, color, and phosphorus removal was determined to be 15.9 mA/cm 2 and the most acceptable treatment time was determined to be 30 min. The treatment efficiencies for COD, color, and phosphorus at 15.9 mA/cm 2 and 30 min were determined as 45%, 60%, and 91.8%, respectively. According to the results of this study, EC process may be an acceptable solution for the treatment of leachate nanofiltration concentrate. More detailed studies however need to be done for the determination of the optimum operational parameters of the electrocoagulative treatment of membrane concentrate.
In this study, a survey containing 28 questions concerning general information about the healthca... more In this study, a survey containing 28 questions concerning general information about the healthcare services, waste collection, training, waste quantities, storage and general evaluation was applied to 311 healthcare services. The response rate was 82%, which was considered acceptable for the evaluation of the results. The separate collection of medical waste and sharps was completely achieved in all of the healthcare services participating in the survey and 82.6% of the healthcare services used containers for separate collection of medical waste. Only 5% of the containers used for waste collection and temporary storage were inappropriate for collecting medical waste. Almost 33% of healthcare services organized courses monthly, 40% quarterly and 20% at least twice a year. A total of 88% of the hospitals have temporary storage depots for medical waste and all of these depots complied with the Medical Waste Control Regulation. The results of this study showed that the medical waste generation rate was 2.35 kg bed À1 day À1. The amount of liquid waste and sharps was determined for the first time in Turkey. The rate of separate collection for recyclables increased to 94%, having been 83% in 2006. The results indicate that in the period 2006–2009, the healthcare services conformed completely to the Medical Waste Control Regulation as it applied. Any deficiencies observed will be satisfied by precautionary actions that will be taken by hospital managers and local administrations.
Four identical pilot-scale landfill reactors with different alternative composite liners were sim... more Four identical pilot-scale landfill reactors with different alternative composite liners were simultaneously operated for a period of about 540 days to investigate and to simulate the migration behaviors of phenolic compounds (phenol, 2-CP, 2-MP, 3-MP, 4-MP, 2-NP, 4-NP, 2,4-DNP, 2,4-DCP, 2,6-DCP, 2,4,5-TCP, 2,4,6-TCP, 2,3,4,6-TeCP, PCP) and heavy metals (Pb, Cu, Zn, Cr, Cd, Ni) from landfill leachate to the groundwater. Alternative landfill liners of four reactors consist of R1: Compacted clay liner (10 cm+ 10 cm, k = 10 −8 m/sn), R2: Geomembrane (2 mm HDPE) + compacted clay liner (10 cm + 10 cm, k = 10 −8 m/sn), R3: Geomembrane (2 mm HDPE) + compacted clay liner (10 cm, k = 10 −8 m/sn)+ bentonite liner (2 cm) + compacted clay liner (10 cm, k = 10 −8 m/sn), and R4: Geomembrane (2 mm HDPE) + compacted clay liner (10 cm, k = 10 −8 m/sn) + zeolite liner (2 cm) + compacted clay liner (10 cm, k = 10 −8 m/sn). Wastes representing Istanbul municipal solid wastes were disposed in the reactors. To represent bioreactor landfills, reactors were operated by leachate recirculation. To monitor and control anaerobic degradation in the reactors, variations of conventional parameters (pH, alkalinity, chloride, conductivity, COD, TOC, TKN, ammonia and alcaly metals) were also investigated in landfill leachate samples. The results of this study showed that about 35–50% of migration of organic contaminants (phenolic compounds) and 55–100% of migration of inorganic contaminants (heavy metals) to the model groundwater could be effectively reduced with the use of bentonite and zeolite materials in landfill liner systems. Although leachate contaminants can reach to the groundwater in trace concentrations, findings of this study concluded that the release of these compounds from landfill leachate to the groundwater may potentially be of an important environmental concern based on the experimental findings.
One-dimensional (1D) advection–dispersion transport modeling was conducted as a conceptual approa... more One-dimensional (1D) advection–dispersion transport modeling was conducted as a conceptual approach for the estimation of the transport parameters of fourteen different phenolic compounds (phenol, 2-CP, 2-MP, 3-MP, 4-MP, 2-NP, 4-NP, 2,4-DNP, 2,4-DCP, 2,6-DCP, 2,4,5-TCP, 2,4,6-TCP, 2,3,4,6-TeCP, PCP) and three different inorganic contaminants (Cu, Zn, Fe) migrating downward through the several liner systems. Four identical pilot-scale landfill reactors (0.25 m 3) with different composite liners (R1: 0.10 + 0.10 m of compacted clay liner (CCL), L e = 0.20 m, k e = 1 Â 10 À8 m/s, R2: 0.002-m-thick damaged high-density polyethylene (HDPE) geomembrane overlying 0.10 + 0.10 m of CCL, L e = 0.20 m, k e = 1 Â 10 À8 m/s, R3: 0.002-m-thick damaged HDPE geomembrane overlying a 0.02-m-thick bentonite layer encapsulated between 0.10 + 0.10 m CCL, L e = 0.22 m, k e = 1 Â 10 À8 m/s, R4: 0.002-m-thick damaged HDPE geomembrane overlying a 0.02-m-thick zeolite layer encapsulated between 0.10 + 0.10 m CCL, L e = 0.22 m, k e = 4.24 Â 10 À7 m/s) were simultaneously run for a period of about 540 days to investigate the nature of diffusive and advective transport of the selected organic and inorganic contaminants. The results of 1D transport model showed that the highest molecular diffusion coefficients, ranging from 4.77 Â 10 À10 to 10.67 Â 10 À10 m 2 /s, were estimated for phenol (R4), 2-MP (R1), 2,4-DNP (R2), 2,4-DCP (R1), 2,6-DCP (R2), 2,4,5-TCP (R2) and 2,3,4,6-TeCP (R1). For all reactors, dispersion coefficients of Cu, ranging from 3.47 Â 10 À6 m 2 /s to 5.37 Â 10 À2 m 2 /s, was determined to be higher than others obtained for Zn and Fe. Average molecular diffusion coefficients of phenolic compounds were estimated to be about 5.64 Â 10 À10 m 2 /s, 5.37 Â 10 À10 m 2 /s, 2.69 Â 10 À10 m 2 /s and 3.29 Â 10 À10 m 2 /s for R1, R2, R3 and R4 systems, respectively. The findings of this study clearly indicated that about 35–50% of transport of phenolic compounds to the groundwater is believed to be prevented with the use of zeolite and bentonite materials in landfill liner systems.
In this study, characterization and electrocoagulative treatability of nanofiltration concentrate... more In this study, characterization and electrocoagulative treatability of nanofiltration concentrate from a full-scale landfill leachate treatment plant (Istanbul, Turkey) were investigated. The average concentrations of COD, TKN and ammonia were determined as 6200, 587.5, and 110 mg/L, respectively. Membrane concentrate also have almost neutral pH, high conductivity and color. Besides, nanofiltration concentrate contains low metal concentrations. After the characterization of the concentrate, treatment of the concentrate by electrocoagulation method with aluminum plate electrodes was investigated. The effects of electrode type, current intensity and treatment time on the treatment of nanofiltration concentrate by EC process were investigated. According to the results, the most acceptable current intensity for COD, color, and phosphorus removal was determined to be 15.9 mA/cm 2 and the most acceptable treatment time was determined to be 30 min. The treatment efficiencies for COD, color, and phosphorus at 15.9 mA/cm 2 and 30 min were determined as 45%, 60%, and 91.8%, respectively. According to the results of this study, EC process may be an acceptable solution for the treatment of leachate nanofiltration concentrate. More detailed studies however need to be done for the determination of the optimum operational parameters of the electrocoagulative treatment of membrane concentrate.
In this study, a survey containing 28 questions concerning general information about the healthca... more In this study, a survey containing 28 questions concerning general information about the healthcare services, waste collection, training, waste quantities, storage and general evaluation was applied to 311 healthcare services. The response rate was 82%, which was considered acceptable for the evaluation of the results. The separate collection of medical waste and sharps was completely achieved in all of the healthcare services participating in the survey and 82.6% of the healthcare services used containers for separate collection of medical waste. Only 5% of the containers used for waste collection and temporary storage were inappropriate for collecting medical waste. Almost 33% of healthcare services organized courses monthly, 40% quarterly and 20% at least twice a year. A total of 88% of the hospitals have temporary storage depots for medical waste and all of these depots complied with the Medical Waste Control Regulation. The results of this study showed that the medical waste generation rate was 2.35 kg bed À1 day À1. The amount of liquid waste and sharps was determined for the first time in Turkey. The rate of separate collection for recyclables increased to 94%, having been 83% in 2006. The results indicate that in the period 2006–2009, the healthcare services conformed completely to the Medical Waste Control Regulation as it applied. Any deficiencies observed will be satisfied by precautionary actions that will be taken by hospital managers and local administrations.
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