Landfill Lysimeter Research Articles

Mercury emission from sulfide/solidified mercury waste in a simulated landfill lysimeters

Mercury emission from sulfide/solidified mercury waste in a simulated landfill lysimeters

Dry tomb – bioreactor landfilling approach for enhanced biodegradation and biomethane generation from municipal solid waste Co-disposed with sugar mill pressmud

In this study, anaerobic co-landfilling of municipal solid waste (MSW) and sugar mill pressmud (PM) was performed in four different proportions [PM:MSW] viz. 0:1 (control: BR1), 1:3 (BR2), 1:1 (BR3) and 3:1 (BR4). Efficacy assessment of Dry tomb – Bioreactor landfill (DTLF – BRLF) operation was carried out through leachate characterization and biomethane production. Leachate recirculation as a part of bioreactor operation after 194th day onwards showed promising degradation of co-wastes. Moreover, leachate decontamination and methane production were reliant on co-disposal proportions of PM and MSW. Maximum biomethane generation of 46.355L was obtained in landfill lysimeter BR3 followed by BR4 (34.680L), BR2 (24.275L) and BR1 (12.850L). Both logistic function and Gompertz growth models showed efficient fitting (R2 > 0.99) for observed methane production. This research could be a baseline study for selective operation of combined dry tomb and bioreactor landfilling at full scale in co-disposal scenarios.

Antimony mobility from E-waste plastic in simulated municipal solid waste landfills

The fate of antimony (Sb) leached from electronic and electrical equipment plastic when disposed of in a municipal solid waste (MSW) landfill was assessed using simulated anaerobic landfill lysimeters and three different batch leaching tests: toxicity characteristic leaching procedure (TCLP), EPA method 1313, and MSW leachate extractions. Plastic from cathode ray tube televisions sets was noted to have the highest Sb concentrations, and was thus the focus of the study. Sb leachability from EPA 1313 stat and TCLP were similar at approximately 0.1% by weight at the same pH (4.93), while MSW landfill leachates extracted less Sb at approximately 0.02% by weight. Solution pH was not the controlling factor, and other conditions resulting from the landfill leachate resulted in lower concentrations of leached Sb. In simulated landfill experiments, Sb leached at approximately 0.01% by weight after a liquid-to-solid ratio of 3. Sb behaves differently in the landfill environment than arsenic leaching from a similar study, most likely from the reducing conditions brought on by the decomposing waste.

Metagenomic Analysis of Microbial Diversity in Landfill Lysimeter Soil of Ghazipur Landfill Site, New Delhi, India.

ABSTRACTWe report the soil microbial diversity and functional aspects related to degradation of recalcitrant compounds, determined using a metagenomic approach, in a landfill lysimeter prepared with soil from Ghazipur landfill site, New Delhi, India. Metagenomic analysis revealed the presence and functional diversity of complex microbial communities responsible for waste degradation.

Evaluating the ability of artificial neural network and PCA-M5P models in predicting leachate COD load in landfills

Waste burial in uncontrolled landfills can cause serious environmental damages and unpleasant consequences. Leachates produced in landfills have the potential to contaminate soil and groundwater resources. Leachate management is one of the major issues with respect to landfills environmental impacts. Improper design of landfills can lead to leachate spread in the environment, and hence, engineered landfills are required to have leachate monitoring programs. The high cost of such programs may be greatly reduced and cost efficiency of the program may be optimized if one can predict leachate contamination level and foresee management and treatment strategies. The aim of this study is to develop two expert systems consisting of Artificial Neural Network (ANN) and Principal Component Analysis-M5P (PCA-M5P) models to predict Chemical Oxygen Demand (COD) load in leachates produced in lab-scale landfills. Measured data from three landfill lysimeters, including rainfall depth, number of days after waste deposition, thickness of top and bottom Compacted Clay Liners (CCLs), and thickness of top cover over the lysimeter, were utilized to develop, train, validate, and test the expert systems and predict the leachate COD load. Statistical analysis of the prediction results showed that both models possess good prediction ability with a slight superiority for ANN over PCA-M5P. Based on test datasets, the mean absolute percentage error for ANN and PCA-M5P models were 4% and 12%, respectively, and the correlation coefficient for both models was greater than 0.98. Developed models may be used as a rough estimate for leachate COD load prediction in primary landfill designs, where the effect of a top and/or bottom liner is disputed.

Assessment of Treatment Efficiency of Lysimeter Leachate using Leachate Pollution Index

This study illustrates the leachate treatment efficiency based on leachate pollution index (LPI) of pre- treatment leachate as well as post-treatment leachate with chemical coagulants. Leachate samples were collected at regular intervals of time from the leachate collection chamber of the landfill lysimeter at KUET campus, Bangladesh to compute its pollution potential. The landfill lysimeter consists of one open dump lysimeter-A with leachate detection (A1) and collection system (A2) as well as two sanitary landfill lysimeters B and C having two different types of cap liner. The relevant parameters of leachate sample were measured in the laboratory to evaluate sub-pollution (sub-LPIs) in terms of LPI in organic pollutant (LPIor), inorganic pollutant (LPIin) and heavy metal (LPIhm) as well as the overall LPI. Moreover, the values of LPI in pre-treatment leachate were to be found 19.53, 25.33, 23.48 and 23.74 for the A1 and A2 systems of open lysimeter-A, as well as the collection systems of sanitary lysimeters- B and C, respectively. It reveals significantly the higher values than that of LPI of 5.77, 7.38 and 7.38 for the maximum leachate discharge standards of Bangladesh, India and Hong Kong, respectively. The leachate was then treated with ferric chloride (FeCl3), poly alluminum chloride (PAC), ferrus sulphate (FeSO4) and aluminum sulphate (Al2(SO4)3) in various dosages and pH values. The concentrations in post-treatment leachate by using FeCl3 at optimum dosage were to be found below the limit of maximum leachate discharge standards. Study also reveals the values of LPI of 5.32, 5.69, 5.32 and 5.24 in post-treatment leachate for the A1 and A2 systems of open lysimeter-A, as well as the collection systems of sanitary lysimeters-B and C, respectively belowthe values of LPI in leachate of maximum discharge standards. Finally, it can be concluded that differences in the level of contaminants of pre- treatment and post-treatment leachate indicated the role of leachate treatment system in minimizing the level of contaminants and lowering the risk of leachate contamination based on LPI.

Development of Modified Interface Apparatus and Prototype Cyclic Simple Shear Test Considering Chemical and Thermal Effects

Geosynthetics are widely used at waste landfill sites due to their mechanical and physical advantages. Geosynthetics inevitably involve interface problems corresponding to the parametric conditions, which affect the shear behavior of the geosynthetic-soil interface. In this research, chemical and thermal effects were considered in an investigation of the cyclic shear behavior of the geosynthetic-soil interface. The modified multipurpose interface apparatus (M-PIA), which was able to consider thermal condition, was introduced, and major modifications and improvements of the structure and units were described. Displacement capacity to reach peak strength subjected to the specimen size was verified by the static tests. Prototype cyclic simple shear tests were performed, and the disturbed state concept (DSC) was utilized to estimate quantitatively the cyclic shear stress degradation of the interface. The pH values of the solutions represented the chemical condition of the leachate because the pH value changed dramatically due to complicated biochemical reactions in the leachate (Bilgili et al. 2007, “Metal Concentrations of Simulated Aerobic and Anaerobic Pilot Scale Landfill Reactors,” J. Hazard. Mater., Vol. 145, Nos. 1–2, pp. 186–194), and pH was considered to be the most significant parameter affecting leachate concentration (Rafizul and Alamgir 2012, “Characterization and Tropical Seasonal Variation of Leachate: Results From Landfill Lysimeter Studied,” Waste Manage., Vol. 32, No. 11, pp. 2080–2095). Specimen temperatures of 20 and 60°C were applied and maintained during the tests to approximate the thermal conditions inside of the waste landfill. As a result, shear stress degradation with an increasing number of cycles was observed, and the greatest interface disturbance appeared under the acidic condition. The rapid increase in the disturbance was observed at a high temperature in acid and basic conditions; however, the disturbance function curves under the neutral condition were nearly identical despite the different temperatures. Therefore, it was deduced that an elevated temperature can degrade the shear resistance of the geosynthetic-soil interface under severe acid and basic conditions. An elevated temperature under a neutral condition did not affect the shape of the disturbance function curves.

Effect of moisture control and air venting on H2S production and leachate quality in mature C&D debris landfills.

The effect of air venting and moisture variation on H2S production and the leaching of metals/metalloids (arsenic, copper, chromium, and boron) from treated wood in aged mature construction and demolition (C&D) debris landfills were examined. Three simulated C&D debris landfill lysimeters were constructed and monitored, each containing as a major debris component either wooden pallets, chromated copper arsenate (CCA) treated wood, or alkaline copper quaternary (ACQ) treated wood. The lysimeters were operated with alternating periods of water addition (a total of 160 L in four equal amounts) and air venting (68.4 m(3)per day for 121 days in two phases). Moisture addition did not increase H2S levels in the long term, and a significant drop in H2S concentration was observed (up to 99%) when aerobic conditions were promoted through air venting. H2S concentrations increased after venting stopped up to values approximately two orders of magnitude lower than observed prior to venting. Venting had the immediate consequence of suppressing biological H2S production, and the longer-term effect of decreasing organic matter that could otherwise be utilized in this process. Under aerobic conditions, the levels of arsenic, chromium, and boron in leachate decreased up to 96%, 49%, and 68%, respectively, while copper was found to increase up to 200% in CCA and 445% in ACQ column leachates.

Leaching of brominated flame retardants from mixed wastes in lysimeters under conditions simulating landfills in developing countries

In developing countries, wastes are usually not separated before being disposed of in solid-waste landfills, most of which are open dumps without adequate measures to prevent environmental pollution. To understand the leaching behavior of brominated flame retardants (BFRs) from waste consumer products in landfills, we have been conducting a long-term landfill lysimeter experiment since 2006 under conditions designed to mimic three types of landfill conditions in developing countries: aerobic, semi-aerobic, and anaerobic. Pilot-scale lysimeters (60-cm i.d.) were filled with a 400-cm layer of mixed wastes consisting of 35wt% food, 20wt% paper, 20wt% paper pulp, 13wt% plastic, 10wt% wood chips, 1wt% glass, and 1wt% metals, proportions that are typical of unsorted municipal solid waste in Asian developing countries. In the present study, we determined the concentrations of polybrominated diphenyl ethers, tetrabromobisphenol A, tribromophenols, and hexabromocyclododecanes in leachate samples collected from the lysimeters during the first 3.5years of the experiment, to evaluate BFR elution behavior in early-stage landfills. Under all three conditions, BFR elution started at the beginning of the experiment. The BFR concentrations in the leachates from the aerobic lysimeter tended to be lower than those from the anaerobic lysimeter, suggesting that the presence of air inside landfills considerably reduces BFR elution to the surrounding environment. During the 3.5-year experiment, BFR outflow from the lysimeters was only 0.001–0.58% of the total BFRs in the loaded waste; that is, most of the BFRs in the waste remained in the lysimeters.

Formulation of Sub-Pollution Indices and Evaluation of Leachate Pollution Index of Pilot Scale Landfill Lysimeter

The principal concern of this study is to formulate the sub-pollution indices (sub-LPIs) and evaluate the individual and overall leachate pollutant index (LPI) of pilot scale landfill lysimeter at KUET campus, Bangladesh. To these endeavors, leachate samples from collection chamber of landfill lysimeter were sampling and the relevant parameters required for evaluating LPI were measured and monitored in the laboratory. Both the open dump and sanitary landfill conditions having a base liner and two different types of cap liner were simulated. Three sub-LPIs in terms of LPI in organic pollutant (LPI ), LPI in inorganic pollutant (LPI ) and LPI or in in heavy metals (LPI ) as well as overall LPI had been developed and reported. It can be noted that component hm of organic fraction in leachate for entire lysimeter operating system had highest against the other counter fraction i.e. inorganic and heavy metals fraction and consequently shows the highest LPI than that of LPI or in and LPI . it can be observed that sub-LPIs and overall LPI has decreased in relation to the increasing of hm elapsed period of MSW deposited in landfill lysimeter. Results showed that collection system of sanitary lysimeter-A had the highest sub-LPIs and overall LPI than that of other lysimeter operating systems. Finally, it can be monitored that overall LPI was significantly high for entire lysimeter operating systems and proper treatment will be necessary before discharging the leachate into the water bodies.

Assessment of Parameters Involved in Leachate Pollution Index and Evaluation of Contamination Potential of Pilot Scale Landfill Lysimeter using LPI

Assessment of Parameters Involved in Leachate Pollution Index and Evaluation of Contamination Potential of Pilot Scale Landfill Lysimeter using LPI

Construction and evaluation of simulated pilot scale landfill lysimeter in Bangladesh

This research concentrates the design, construction and evaluation of simulated pilot scale landfill lysimeter at KUET campus, Khulna, Bangladesh. Both the aerobic and anaerobic conditions having a base liner and two different types of cap liner were simulated. After the design of a reference cell, the construction of landfill lysimeter was started in January 2008 and completed in July 2008. In all construction process locally available civil construction materials were used. The municipal solid waste (MSW) of 2800–2985kg having the total volume of 2.80m3 (height 1.6m) and moisture content of 65% was deposited in each lysimeter by applying required compaction energy. In contrast, both the composition in terms of methane (CH4), carbon dioxide (CO2) and oxygen (O2) as well as the flow rate of landfill gas (LFG) generated from MSW in landfill lysimeter were measured and varied significantly in relation to the variation of lysimeter operational condition. Moreover, anaerobic lysimeter-C shows the highest composition of LFG in compare to the anaerobic lysimeter-B due to the providing of lower compaction of cap liner in anaerobic lysimeter-C. Here, it is interesting to note that in absence of compacted clay liner (CCL) and hence percolation of rainwater that facilitates rapid degradation of MSW in aerobic lysimeter-A has resulted in the highest settlement than that of anaerobic landfill lysimeter-B and C. Moreover, in case of anaerobic lysimeter-B and C, the leachate generation was lower than that of aerobic lysimeter-A due to the providing of cap liner in anaerobic lysimeter-B and C, played an important role to reduce the percolation of rainwater. The study also reveals that the leachate pollution index (LPI) has decreased in relation to the increasing of elapsed period as well as the LPI for collection system of aerobic lysimeter-A was higher than that of the collection system of anaerobic lysimeter-B and C. Finally, it can be depicted that LPI for lysimeter was significantly high and proper treatment will be necessary before discharging the lysimeter leachate into the water bodies.

Characterization and tropical seasonal variation of leachate: Results from landfill lysimeter studied

This study aims to characterize the leachate and to investigate the tropical climatic influence on leachate characteristics of lysimeter studies under different seasonal variations at KUET campus, Bangladesh. Three different situations of landfill were considered here as well as both the open dump lysimeter-A having a base liner and sanitary landfill lysimeter-B and C at two different types of cap liner were simulated. The leachate characteristics, leachate generation and climatic influence parameter had been continually monitored since June 2008 to May 2010, these periods cover both the dry and rainy season. The leachate generation had followed the rainfall pattern and the open dump lysimeter-A without top cover was recorded to have highest leachate generation. Moreover, the open dump lysimeter-A had lower total kjeldahl nitrogen (TKN), ammonia nitrogen (NH4-N) and TKN load, while both the COD concentration and load was higher compared with sanitary landfill lysimeter-B and C. In addition, sanitary landfill lysimeter-B, not only had lowest leachate generation, but also produces reasonable low COD concentration and load compared with open dump lysimeter-A. Result reveals that lysimeter operational mode had direct effect on leachate quality. Finally, it can be concluded that the knowledge of leachate quality will be useful in planning and providing remedial measures of proper liner system in sanitary landfill design and leachate treatment.

Toxicity of waste gasification bottom ash leachate

Toxicity of waste gasification bottom ash leachate from landfill lysimeters (112m3) was studied over three years. The leachate of grate incineration bottom ash from a parallel setup was used as reference material. Three aquatic organisms (bioluminescent bacteria, green algae and water flea) were used to study acute toxicity. In addition, an ethoxyresorufin-O-deethylase (EROD) assay was performed with mouse hepatoma cells to indicate the presence of organic contaminants. Concentrations of 14 elements and 15 PAH compounds were determined to characterise leachate. Gasification ash leachate had a high pH (9.2–12.4) and assays with and without pH adjustment to neutral were used. Gasification ash leachate was acutely toxic (EC50 0.09–62 vol-%) in all assays except in the algae assay with pH adjustment. The gasification ash toxicity lasted the entire study period and was at maximum after two years of disposal both in water flea (EC50 0.09 vol-%) and in algae assays (EC50 7.5 vol-%). The grate ash leachate showed decreasing toxicity during the first two years of disposal in water flea and algae assays, which then tapered off. Both in the grate ash and in the gasification ash leachates EROD-activity increased during the first two years of disposal and then tapered off, the highest inductions were observed with the gasification ash leachate. The higher toxicity of the gasification ash leachate was probably related to direct and indirect effects of high pH and to lower levels of TOC and DOC compared to the grate ash leachate. The grate ash leachate toxicity was similar to that previously reported in literature, therefore, confirming that used setup was both comparable and reliable.

Influence of Landfill Operation and Tropical Seasonal Variation on Leachate Characteristics: Results from Lysimeter Experiment

This study demonstrates the influence of lysimeter operational condition and tropical seasonal variation of leachate characteristics generated from municipal solid waste (MSW) deposited in landfill lysimeter at KUET campus, Bangladesh. Three different situations of landfill were considered here as well as both the open dump lysimeter-A having a base liner and sanitary landfill lysimeter-B and C at two different types of cap liner were simulated. The leachate characteristics, leachate generation and climatic influence parameter had been continually monitored, from June 2008 to May 2010. This period covers both dry and rainy season. The leachate generation followed the rainfall pattern and the open dump lysimeter-A without top cover was recorded to have the highest leachate generation. Moreover, the open dump lysimeter-A had lower concentration and load of total kjeldahl nitrogen (TKN), ammonia nitrogen (NH4-N) and dissolved organic carbon (DOC), while chemical oxygen demand (COD) and biological oxygen demand (BOD5) concentration were higher compared with sanitary lysimeter-B and C. On the other hand, sanitary lysimeter-B, not only had lowest leachate generation, but also produced reasonably low COD and BOD5 concentration compared with open dump lysimeter-A. Based on evaluated results, it was also concluded that metal concentrations which were comparatively higher in leachate of open dump lysimeter were Ca and K, however, the heavy metal concentrations of Cd, Cu, Zn and Mn, and those apparently lower were metals of Na, Mg and Fe as well as heavy metals of Cr, Pb and Ni. However, significant release of heavy metals under open dump lysimeter was observed compared to sanitary lysimeter. Moreover, meaningful correlation between DOC and leaching of Cu and Pb was observed. Result reveals that lysimeter operational mode had direct effect on leachate quality. Finally, it can be concluded that the knowledge of leachate quality will be useful in planning and providing remedial measures of proper liner system in landfill design and leachate treatment.

Analysis and Selection of Appropriate Aggregation Function for Calculating of Leachate Pollution Index of Landfill Lysimeter

A technique to quantify the leachate pollution potential of solid waste landfills on a comparative scale using an index known as the leachate pollution index (LPI) developed. The LPI is a quantitative tool by which the leachate pollution data of the landfill sites can be reported uniformly. It is an increasing scale index and has been formulated based on Delphi technique. The formulation process involved selecting variables, deriving weights for the selected pollutant variables, formulating their sub-indices curves and finally representing the pollutant variables to arrive at LPI. The aggregation function is one of the most important steps in calculating any environmental index. If aggregation function is ambiguous, the result will raise an unnecessary alarm, indicating a comparatively less polluted environmental situation as mere contaminated. Similarly, if the aggregation function is eclipsed a false sense of security may be created, indicating a highly polluted environmental situation as less polluted. In this paper, the concept of LPI is briefly described. In order to select the most appropriate aggregation function, various possible aggregation functions are described and used to calculate LPI values for pilot scale landfill lysimeter at KUET campus, Khulna, Bangladesh. Based on obtained results, it is concluded that the weighted linear sum aggregation function is the best possible aggregation function for calculating LPI. Sensitivity analysis of the six short-listed aggregation functions is performed to substantiate this conclusion.

Pilot-Scale Simulation of Landfill Bioreactor and Controlled Dumping of Fresh and Partially Stabilized Municipal Solid Waste in a Tropical Developing Country

Four pilot-scale lysimeters were used to study the benefits of landfill operation with and without leachate recirculation in tropical weather conditions. Young and old landfills were simulated by filling lysimeters with a segregated fraction of fresh municipal solid waste (MSW) and MSW mined from an open dump site, respectively, and periodically monitoring leachate quantity and quality and biogas quality. For each substrate, one lysimeter was operated as a bioreactor with leachate recirculation and another lysimeter was operated as a controlled dump, for a period of 10 months. Densities between 652 and 825 kg/m3 could be achieved with fresh and mined MSW. Despite such compaction during waste placement, bioreactor technology helps in leachate management, especially in the case of the young landfill lysimeter operated in tropical weather. The benefits of leachate recirculation in the young landfill lysimeter were evident from the significant decrease in chemical oxygen demand (COD) (86%), biochemical oxyge...

Co-disposal of electronic waste with municipal solid waste in bioreactor landfills

Three pilot scale lysimeters were adopted to evaluate the stability pattern and leaching potential of heavy metals from MSW landfills under the E-waste co-disposed condition. One lysimeter served as control and solely filled with MSW, whereas the other two lysimeters were provided with 10% and 25% of E-waste scraps (% by weight), respectively. The reactors were monitored over a period of 280 days at ambient settings with continuous leachate recirculation. Stabilization pattern of carbon appears to be more than 50% in all the three lysimeters with irrespective of their operating conditions. Iron and zinc concentrations were high in leachate during bioreactor landfill operation and correlating with the TCLP leachability test results. In contrast, Pb concentration was around <0.6 mg/L, but which showed maximum leaching potential under TCLP test conditions. But, no heavy metal accumulation was found with leachate recirculation practices in lysimeters. Mobility of the metal content from the E-waste was found to be amplified with the long term disposal or stabilization within landfills. The results showed that the TCLP test cannot be completely reliable tool for measuring long-term leachability of toxic substances under landfill condition; rather landfill lysimeter studies are necessary to get the real scenario.

Biological stability of municipal solid waste from simulated landfills under tropical environment

Biological stability of the Municipal Solid Waste (MSW) is assessed under tropical climatic condition using landfill lysimeters. Various landfill operating conditions and two different substrates were employed. Solid waste samples collected during different time intervals of landfill operation assessed for volatile solids (VS), organic carbon (OC), specific oxygen uptake rate (SOUR), and water extractable components. Organic carbon achieved faster stabilization than the nitrogen content in MSW within the various landfill operating conditions. At the end of 960 days of lysimeter operation, the MSW from different landfills were aerobically and anaerobically stable and results comparable with compost. Further, bioreactor landfill given better biological stability and high methane content than other landfill operating conditions with continuous leachate treatment is compelling benefit.

Evaluation of an Alternative Method of Leachate Collection System Design

The current practice of leachate collection and removal system LCRS design for sanitary landfills has limitations because of the uncertainties associated with a key design parameter, leachate production rate. The traditional techniques for determining leachate generation are accurate only to within one order of magnitude. One of the drawbacks is the inability of these techniques to account for short-term fluctuations in leachate generation rate caused by heavy rainfall events or leachate recirculation events. This paper presents a rational method to account for fluctuations in leachate generation by incorporating a correction factor to leachate generation rates determined from traditional techniques. The correction factor known as the peak leachate factor PLF is developed from landfill lysimeter and pilot scale test cell studies. It is defined as the ratio between peak and average daily leachate generation rate, and is proposed to be used in conjunction with the output from a leachate generation model such as the hydrologic evaluation of landfill performance model to generate a design leachate generation rate. The potential of applying PLF in the design of a LCRS in full scale landfills is evaluated by studying the scale up possibility of the hydrological behavior of laboratory lysimeters to a field scale landfill test cell. The results demonstrated that the hydrologic behavior of the field test cell is similar to that of the lysimeters. The results indicated that various categories of landfill cells will require the adoption of PLFs depending on the type of waste landfilled and climatic conditions and operational characteristics of the landfills. PLF could be an important design parameter for LCRS in landfills cells, especially those operated with continuous leachate recirculation or located in tropical climates subjected to frequent high intensity rainfall events.