Leachate Management Research Articles

Potential pollution risks of historic landfills on low‐lying coasts and estuaries

Historically, it was common practice to dispose of landfill waste in low‐lying estuarine and coastal areas where land had limited value due to flood risk. Such ‘historic landfills’ are frequently unlined with no leachate management and inadequate records of the waste they contain. Globally, there are 100,000s such landfills, for example, in England there are >1200 historic landfills in low‐lying coastal areas with many in close proximity to designated environmental sites or in/near areas influencing bathing water quality; yet, there is a very limited understanding of the environmental risk posed. Hence, coastal managers are more likely to select conservative management policies, for example, hold‐the‐line, when alternative more sustainable policies, for example, managed realignment, may be preferred. Some historic coastal landfills have already started to erode and release waste, and with the anticipated effects of climate change, erosion events are likely to become more frequent. Strategies to mitigate the risk of contaminant release from historic landfills such as excavation and relocation or incineration of waste would be prohibitively expensive for many countries. Therefore, it will be necessary to identify which sites pose the greatest pollution risk in order that resources can be prioritized, and to develop alternative management strategies based on site specific risk. Before such management strategies can be achieved there remain many unknowns to be addressed including the extent of legacy pollution in coastal sediments, impacts of saline flooding on contaminant release and the nature, behavior and environmental impact of solid waste release in the coastal zone. WIREs Water 2018, 5:e1264. doi: 10.1002/wat2.1264This article is categorized under: Engineering Water > Sustainable Engineering of Water Science of Water > Water and Environmental Change

Electrical Resistivity Tomography Techniques for Identifying Groundwater Pollution Due To Leachate flows at Putri Cempo Landfill

Landfill developed with open dumping system and below the adequate standard potentially lead to new problems like those found at Putri Cempo Landfill in Surakarta City. They include leachate, which easily flows in runoff, seeps through soil and land surface, and infiltrate into groundwater that supplies the surrounding residential wells. A research on leachate spread pattern from landfills to their surrounding areas thereby becomes necessary particularly in terms of environmental pollution potential from underground, which is latent and difficult to monitor. The aims of this research were (1) to identify the areas that experienced groundwater pollution due to leachate flows, (2) to identify the distribution of resistivity in these areas, and (3) to develop a model for leachate management. This research used Electrical Resistivity Tomography (ERT) survey for identifying the distribution of resistivity in polluted areas. It also used groundwater quality analysis for validating the interpretation of the ERT survey results. The results of the research showed that there was an anomaly in the subsurface layer. Materials with resistivity values of 0.25-1.20 ohmm were found in various depths within 0-8 m below the surface. These values were much lower than the resistivity of the main materials found at the measurement site, i.e. 4.9-13.1 ohmm. Accordingly, this anomaly signified the existing influence of pollution. The pollution along the geoelectrical sounding line had uneven distribution and centric pattern at several points that indicated the accumulation sites of leachate. The proposed leachate management model included the constructions of base lining (liner), leachate collection channel, geomembrane-composed final cap, and leachate treatment.

Heavy Metal Contamination of Ground Water from an Unlined Landfill in Bulawayo, Zimbabwe.

Background.Developing countries such as Zimbabwe deal with challenges in solid waste management such as insufficient waste recycling, hazardous wastes that are not separated for safe disposal, and landfills that are not properly engineered to prevent groundwater pollution. For these reasons, landfills in developing countries pose serious environmental and public health hazards.Objectives.The objective of this study was to assess heavy metal release and groundwater pollution from an unlined landfill in Bulawayo, Zimbabwe. The purpose of the study was to explore environmental and public health risks posed by improperly managed landfills in developing countries.Methods.We assessed levels of metal release from Richmond landfill in the city of Bulawayo, Zimbabwe by measuring lead, cadmium, chromium and copper levels in landfill soil, leachate and plants. We also monitored metal levels in groundwater from boreholes located in a residential area in the vicinity and downgradient of the landfill within a range of 800–2135 m. Soil was characterized at the landfill to assess potential sources of heavy metals.Results.All metals that were assessed were present in landfill soil and in leachate. There was high metal accumulation in weeds that were growing at the landfill, indicating mobility and bioavailability of the metals. Groundwater from nearby boreholes had high levels of lead (Pb) and cadmium (Cd) which were negatively correlated to distance from the landfill (p<0.01), indicating contamination from the landfill. The Pb and Cd levels exceeded World Health Organization standards for drinking water quality, posing health hazards to the communities who rely on the water. Solid waste at the landfill consisted of soft plastics (33%), hard plastics (18.6%), metals (3%), paper (8%), electronic waste (0.8%), organics (15.3%) and various other types (21.3%).Discussion.A combination of factors may be attributed to groundwater contamination. These include the co-disposal of metallic and electronic wastes at the landfill, lack of membrane lining at the landfill, inadequate leachate management and the porous geo-physical characteristics of the sub-surface at the landfill site.Conclusions.Our study highlights adverse environmental and public health consequences of co-disposal of metals and electronic wastes at improperly engineered municipal landfills. This is a ‘wake-up’ call for policy makers in developing countries to improve solid waste management.

The use of electrical resistivity tomography and borehole to characterize leachate distribution in Laogang landfill, China.

Leachate is a polluting liquid which may cause harmful effects on human health or the environment without a tightly control manner. The leachate management is an important part of the design and operation of bioreactor landfills. To detect the leachate distribution in Laogang Landfill, China, the measurement of electrical resistivity tomography (ERT) was carried out in three areas with different ages. ERT method proved to be an effective non-invasive geophysical method in bioreactor landfills, and the physical properties of waste samples obtained by boreholes were tested in a laboratory. The correlation between the resistivity and the moisture content was described by Archie's law. The result shows that the moisture content of fresh waste is inhomogeneous, while that of aged waste increases with depth. A pseudo 3D model of the moisture content was proposed to improve the understanding of leachate distribution and exhibit the accuracy of the ERT method.

Investigation of landfill leachate treatability for reuse in agricultural purposes

Leachates from landfills are one of the environmental challenges in developing countries, such as Iran that also will face water scarcity in the near future. Landfill leachate management to decrease the negative impact on water resources is indispensable. On the one hand, depending on the age of landfill, high ammonia concentration leachates could be a resource for use in agricultural purposes and on the other, treated leachate can be used as a valuable resource for agronomic irrigation. In order to investigate this hypothesis, landfill leachate was provided from the Sari municipal landfill in the north of Iran (COD = 7,045 mg/l; BOD5/COD = 0.36) and the performance of different combinations of biological, chemical and membrane processes were evaluated according to Iran's Agricultural Water Standard (IAWS). The treatment processes consisted of sequencing batch reactor (SBR), Fenton's process/SBR, and membrane/SBR/Fenton. Results indicated in addition to access IAWS, the treated leachate through Membrane/SBR/Fenton's process could be used as a nitrogen source for agricultural purposes. The removal efficiency of primary parameters, including COD, BOD5, turbidity, and color were 89%, 96%, 99% and 98%, respectively.

Characterization of Lakhodair Landfill Leachate

Leachate is the water contained in the solid waste dumped in a landfill and comes out during its decomposition but continues to ooze out even after stabilization of the solid waste and many years after the closure of the landfill. It contains a number of toxic and hazardous compounds, and is likely to contaminate the environmental sinks. Moreover, this leachate varies in its flows and characteristics over different phases of a landfill life. Leachate management is one of the major concerns and tough task associated with the landfill operation, and comprises monitoring and predicting landfill leachate and the variation in its flows and composition, associated risk assessment and hazard rating, and designing the most accurate treatment system before disposing it into environmental sinks. This study has analyzed the characteristics of a newly designed landfill site on modern lines at Lakhodair, Lahore, finding it to be slightly alkaline and high in organic matter (BOD5, COD), Na, K and a few heavy metals (Ni and Cr) of the sixteen pollution indicators (EC, turbidity, hardness, TDS, TSS, BOD5, COD, Na, K, Cl, Ni, Cr, Pb, Mn, Cu, Zn), which indicates it can easily be treated with simple physic-chemical methods; such as coagulation/flocculation, sedimentation, filtration, and biological treatment, and brought into some reuse such as irrigation.

Remediation of leachate by composite NZVI-activated carbon in packed column

Improper solid waste management at final disposal site can cause in environtmental problem. The surrounding water bodies could be affected by leachate from the solid waste decomposition process because leachate contains high concentration of BOD 5 , COD, ammonia, hydrocarbon suspended solid, and heavy metals. This problem has affected a final disposal site (named Sukawinatan) in Palembang, Indonesia, which did not implement leachate management system. This paper propose a method to reduce BOD 5 , COD, Ammonia concentrations of the leachate in by applying composite nano zero valent iron (NZVI) – activated carbon for the remediation system of the surrounding area of Sukawinatan final disposal. The performance of the method was evaluated in this study using laboratory porous column apparatus. The results showed that the composite NZVI-activated carbon can be used to reduce concentration of pollutants from water bodies. The removal efficiency of this method on BOD 5 , COD and ammonia are 94.81 %, 92.81 % dan 95.58 % respectively.

An eco-friendly approach for minimizing pollution of metal from municipal solid waste leachate in India

Municipal solid waste (MSW) leachate management has become an important issue worldwide. The present study evaluated the potential of indigenous fungi for biosorption of Cd2+ from leachate. Three isolates—Trichoderma harzianum, Aspergillus niger and Aspergillus flavus were selected based on their ability to exclude the Cd2+ at the preliminary stage. Among these, Trichoderma harzianum was found to be an excellent fungus for cadmium absorption. The highest biosorption rate for Cd2+ was achieved under the conditions: temperature 45 °C (64.87%), pH 6.0 (64.78%) and spore concentration [105 cfu ml−1] (64.41%). The obtained data indicated that the developed fungal consortium is very efficient and effective for cadmium removal (72.41%), thereby demonstrating that it is a promising solution for removing toxic metals from MSW leachate.

A comparison of the toxicity of landfill leachate exposure at the seed soaking and germination stages on Zea mays L. (maize)

To compare the toxicity of landfill leachate exposure at the early stages of seed soaking and germination on maize, a field experiment was conducted to evaluate the physiological aspects of growth, yield and potential clastogenicity of root-tip cells. The maizes were treated with leachate at levels of 2%, 10%, 20%, 30% or 50% (V/V). First, the change of physiological indexes, including chlorophyll (Chl), Malondialdehyde (MDA) and Reactive oxygen species (ROS) levels, combined with yield all showed that soaking with leachate, but not germination, generated a greater ecological risk on maize. After a soaking treatment of maize with 50% leachate, the Chl, MDA and ROS levels during a vigorous growth period were 47.3%, 149.8% and 309.7%, respectively, of the control, whereas the yield decreased to 68.6% of the control. In addition, our results demonstrated that the leachate at lower levels could promote growth. This is mainly embodied in that the yield of maize treated with 10% leachate at the soaking stage increased to 116.0% of the control. Moreover, the cytological analysis experiment also demonstrated that the ecological risk of leachate still exists in both cases. Furthermore, the gray relational analysis showed that the ear row number and tassel branch number were the major factors affecting the yield of maize treated with 50% leachate at the stages of soaking and germination, respectively. In general, these results are helpful in understanding the phytotoxicity of leachate, which provides additional reference data for risk assessment and management of leachate.

The Effect of Particle size Distribution on Hydraulic Permeability in a Waste Mass

In the waste management hierarchy, the least preferable option is waste disposal. Nonetheless, disposal is an integral part of any waste management system. In a landfill, during waste degradation processes leachate is formed that can potentially cause clogging of bottom drainage layers. To ensure stability of landfill construction, the physical properties of its components have to be controlled. In a landfill, waste presents the largest structural element and often controls both the stability and integrity of the lining system. The hydrology of precipitation, evaporation, runoff and the hydraulic performance of the capping and liner materials are important controls of the moisture content. It is important to understand the hydrology of a landfill site as it affects sustainability of landfill leachate management system. The water balance also depends on waste characteristics and waste particle size distribution. Waste characteristics are closely related to the waste composition in a landfill. The aim of the study is to determine the hydraulic permeability in a landfill depending on the particle size distribution of municipal solid waste disposed. Samples were taken from a landfill operating for five years. The samples were sorted to obtain fractions with differing particle sizes. The largest fraction of the waste was within the size-range of 20–100mm. The permeability test was conducted using the column test. The paper presents the results of the test indicating higher permeability with larger waste particle size.

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.

Experimental determination of nanofiltration models: application to nitrate removal

Nowadays, nitrate contamination of groundwater is a growing problem both in developed and developing countries. Such contamination comes mainly from the intensive use of nitrogen fertilizers in agriculture. Other possible sources of water contamination by nitrates are improper discharges of industrial effluents, the inadequate management of leachate from landfill of municipal solid waste and effluents from intensive farming. The maximum permissible concentration of nitrates in the water for public consumption in the EU countries is 50 mg/L, although the World Health Organization established a value of 25 mg/L to be considered a quality water. This problem of nitrate contamination, widespread in countries of the European Union, is very important in Spain, where there are some regions with a high presence of aquifers with nitrate concentrations significantly higher than the established limits. Among the possible treatments for nitrate removal from contaminated waters, nanofiltration (NF) is a technically proven process that eliminates nitrates without causing a significant imbalance in the rest of dissolved salts. In this work, the removal of nitrates from water using a commercial NF membrane is studied. Synthetic feeds with levels of nitrate concentration higher than the ones usually found in contaminated aquifers have been considered. On the other hand, the experimental results have been fitted to the solution-diffusion model, having found mathematical expressions that can be used to predict membrane performance for feed concentrations higher than 100 mg/L. The model considers the concentration on the surface of the membrane, estimated by the film theory model. It has been proved that concentration polarization cannot be neglected for this application. The tested membrane allows nitrate decontamination of water (concentration below the legal limit) in one pass for values of feed concentration up to 100 mg/L, with a transmembrane pressure of 5 bar.

Phycoremediation of landfill leachate with chlorophytes: Phosphate a limiting factor on ammonia nitrogen removal.

The potential of microalgae to bioremediate wastewater has been reported in numerous studies but has not been investigated as extensively for landfill leachate, which may be attributed to its complex nature and toxicity.In this study we explored if microalgal phycoremediation could constitute an alternative biological treatment option for landfill leachate management in regions with temperate climatic conditions. The aim of this study was to assess the performance of microalgae species at relatively low temperature (15 °C) and light intensity (14:10 h, light: dark, 22 μmol m−2 s−1) for reduction in energy inputs. Four chlorophyte strains originating from the North-West of Ireland were selected and used in batch experiments in order to evaluate their ability to reduce total ammonia nitrogen, oxidised nitrogen and orthophosphate in landfill leachate. The Chlamydomonas sp. strain SW15aRL isolated from raw leachate achieved the highest level of pollutant reduction whereby a decrease of 51.7% of ammonia nitrogen was observed in 10% raw leachate (∼100 mg l−1 NH4+-N) by day 24 in experiments without culture agitation. However, in the experiment conducted with 10% raw leachate supplemented with phosphate, a decrease of 90.7% of ammonia nitrogen was obtained by day 24 while also achieving higher biomass production. This series of experiments pointed to phosphorus being a limiting factor in the microalgae based phycoremediation of the landfill leachate.The effective reduction of ammonia nitrogen in landfill leachate can be achieved at lower temperature and light conditions. This was attained by employing native species adapted to such conditions and by improving nutrient balance.

THE APPLICATION OF DRASTIC MODEL IN WASTE RURAL LANDFILL SITE SELECTION (CASE STUDY: VILLAGES OF KARUN COUNTY)

THE APPLICATION OF DRASTIC MODEL IN WASTE RURAL LANDFILL SITE SELECTION (CASE STUDY: VILLAGES OF KARUN COUNTY)

Managing the leachate at the regional landfill in Kikinda

In developed, industrial countries, there is 1.2kg waste per capita, waste being collected and disposed of in regulated, sanitary landfills, which have systems for the protection of groundwater and air from pollutants, in Serbia, the largest number of landfills does not meet even the basic safety criteria for environmental protection. Several municipalities in Serbia began with the organization of the regional waste management system and within that frame, the construction of regional landfills which meet European standards in terms of environmental protection. The paper presents a method of management and use of leachate at the regional waste landfill 'ASA', Kikinda.

Municipal Solid Waste Landfills Construction and Management-A Few Concerns

In Bangalore city, one of the major problems is municipal solid management (MSW) due to ever increasing waste quantity along with its changing waste characteristics. Municipal solid waste includes non-hazardous waste generated in house, institutions, commercial and business establishments in an urban area. As city grow and produce more municipal solid waste and their waste collection systems become more efficient, due the environmental impact from dump site becomes increasingly intolerable. A report on waste management prepared for the Government of India (1998) by a sub-committee of the Supreme Court describes this as a serious situation. The municipal bodies in Bangalore have been unable to manage the rapid changes that have led to both increased waste quantities and changes in the waste composition this leading to an over-loading of the service. MSW rules do not permit to dump mixed waste in direct land filling and hence, the waste needs to be segregated in order to collect and reuse all recyclable and the organic matter needs to be stabilized. The generated and collected MSW needs to be processed/ treated with only non-biodegradable MSW and the rejects of the processing facility being dumped in landfill. Leachate emanating from solid waste deposited in landfill possess dissolved or an entrained environmentally harmful substances. Generally, environmental impacts and economic damages of poor leachate management practices on groundwater and receiving surface waters are not clearly understood. With this context, this study, the concept of leachate pollution index, a tool for quantifying the leachate pollution potential and water quality index for surrounding water bodies of Mavallipura landfill site in Bangalore has been applied. It has been found that the leachate generated from the Mavallipura landfill site has high contamination potential to the surrounding water bodies. The results revealed that quality of ground water resources in Mavallipura landfill is deteriorating largely, as a result of the poor practice of solid waste management. Hence, an effective remedial plan needs to be prepared for the sustainable water quality maintenance of the area.

Environmental Impact Assessment of Improper Dumping of Municipal Solid Waste in Salem City, Tamilnadu, India

Salem City is one of the hundred cities selected under the Smart Cites Mission Program by the Government of India and positioned at sixth place out of twelve selected Smart Cities in Tamil Nadu State with an area of 100 sq.km and a population of 8,51,577. It generates around 335 MT per day of Municipal Solid Waste (MSW) at a rate of 393 gram per capita per day. At present the entire solid waste generated from the city has been dumped in an unscientific manner in Erumapalayam Landfill area of 28 acres which is located 12 km away from the city. The open dumping of Salem City MSW in the landfill area due to without liners and without a leachate management facility causes groundwater pollution and as well as saturation of an existing landfill site. Hence, in the present study an attempt has been made to quantify the impacts on land and water environments due to improper disposal of Salem city MSW in and around the Erumapalayam Landfill through an Environmental Impact Assessment (EIA) study. From the detailed investigation of the water quality analysis of ground water in and around the dumping yard, it was found that the ground water was not suitable for drinking at places within 1000m radius of the landfill and this was exclusively due to the infiltration of leachate from the dumping yard which caused the ground water pollution. Similarly, the Environmental Impact Assessment study on soil environment revealed that the top soil layer is not polluted due to the improper dumping of MSW in the landfill area at present, nevertheless if the prevailing situation continues, it will affect the soil fertility in the near future.

Effect of feed pattern of landfill leachate on water reduction in constructed wetland in Southeast Asia

To improve landfill management in Southeast Asia, reduction of landfill leachate volume with low cost and easy operation is required. The present study attempted to utilize constructed wetland (CW) for reduction of landfill leachate by evapotranspiration. The objective of this study is to evaluate the influence of operation and season on evapotranspiration of CW applied to landfill leachate treatment in tropical regions. The pilot-scale CW planted with cattail was constructed in Sainoi landfill site, Thailand. CW could siginificantly reduce the leachate volume by the evapotranspiration in daytime than nighttime. Frequent inflow of horizontal subsurface flow (HSSF) during daytime resulted in active evapotranspiration. Evapotranspiration of CW in HSSF with high frequency of inflow showed the similar that in free water surface (FWS). Throughout the year including both rainy and dry seasons, evapotranspiration of CW were significantly higher than the evaporation volume which is regarded as water reduction by existing landfill leachate treatment, i.e. stabilization pond. CW should be served as the techonology for appropriate management of landfill leachate in Southeast Asia.

Management of landfill leachate: The legacy of European Union Directives

Landfill leachate is the product of water that has percolated through waste deposits and contains various pollutants, which necessitate effective treatment before it can be released into the environment. In the last 30years, there have been significant changes in landfill management practices in response to European Union (EU) Directives, which have led to changes in leachate composition, volumes produced and treatability. In this study, historic landfill data, combined with leachate characterisation data, were used to determine the impacts of EU Directives on landfill leachate management, composition and treatability. Inhibitory compounds including ammonium (NH4-N), cyanide, chromium, nickel and zinc, were present in young leachate at levels that may inhibit ammonium oxidising bacteria, while arsenic, copper and silver were present in young and intermediate age leachate at concentrations above inhibitory thresholds. In addition, the results of this study show that while young landfills produce less than 50% of total leachate by volume in the Republic of Ireland, they account for 70% of total annual leachate chemical oxygen demand (COD) load and approximately 80% of total 5-day biochemical oxygen demand (BOD5) and NH4-N loads. These results show that there has been a decrease in the volume of leachate produced per tonne of waste landfilled since enactment of the Landfill Directive, with a trend towards increased leachate strength (particularly COD and BOD5) during the initial five years of landfill operation. These changes may be attributed to changes in landfill management practices following the implementation of the Landfill Directive. However, this study did not demonstrate the impact of decreasing inputs of biodegradable municipal waste on leachate composition. Increasingly stringent wastewater treatment plant (WWTP) emission limit values represent a significant threat to the sustainability of co-treatment of leachate with municipal wastewater. In addition, the seasonal variation in leachate production poses a risk to effective co-treatment in municipal WWTPs, as periods of high leachate production coincide with periods of maximum hydraulic loading in WWTPs.

Recovery of nitrogen and water from landfill leachate by a microbial electrolysis cell–forward osmosis system

A microbial electrolysis cell (MEC)–forward osmosis (FO) system was previously reported for recovering ammonium and water from synthetic solutions, and here it has been advanced with treating landfill leachate. In the MEC, 65.7±9.1% of ammonium could be recovered in the presence of cathode aeration. Without aeration, the MEC could remove 54.1±10.9% of ammonium from the leachate, but little ammonia was recovered. With 2M NH4HCO3 as the draw solution, the FO process achieved 51% water recovery from the MEC anode effluent in 3.5-h operation, higher than that from the raw leachate. The recovered ammonia was used as a draw solute in the FO for successful water recovery from the treated leachate. Despite the challenges with treating returning solution from the FO, this MEC–FO system has demonstrated the potential for resource recovery from wastes, and provide a new solution for sustainable leachate management.