Municipal Waste Landfill Research Articles

The Lost Value of Groundwater and its Influence on Environmental Decision Making

A critical aspect in establishing environmental policies lies in the proper assessment of the value of the resource being affected. Standard risk assessment analyses calculate the cost of pollution as consisting, solely, of the cost to remediate a site. This traditional definition is extended here to include the lost value of groundwater. These concepts and their impact on decision-making analyses are illustrated through the case of municipal waste landfills. Based on data from existing polluting sites, a simple cost-benefit probabilistic analysis is conducted first, which equates, as is the practice, the cost of pollution to that of remediation. This leads rationally to selection of the lowest-protection technology. Using plausible arguments the reduction in value of groundwater from potable high-quality water to irrigation water, which is what is returned after remediation, is argued. The arguments consist of: (a) the ratio of the subsidized prices of drinking to irrigation water reflects the relative value of the use of water; (b) the amount paid for remediation, in each case, represents, at a minimum, the value of the water recovered; and (c) the lost value of groundwater equals the value of drinking water minus the value of irrigation water. Incorporation of this lost value of groundwater is sufficient to drastically alter the conclusions of the decision-making analysis and make the highest level technology the most rational and profitable alternative. The broader point of this article lies in that proper accounting of environmental costs is necessary in order to alter environmental policies and practices.

Treatment process adapted to stabilized leachates: Lime precipitation–prefiltration–reverse osmosis

Leachates are generated from municipal waste landfills under the action of water percolating through the landfilled waste. These leachates contain high amounts of inorganic and organic matter and must imperatively be treated before being discharged into the environment. Reverse osmosis is the most widely used method for treating these leachates, since it produces a permeate in compliance with the increasingly strict reject requirements and a retentate containing high concentrations of organic material and inorganic salts. However, the efficiency of this process at the industrial scale is limited mainly because of membrane fouling and the high osmotic pressures involved. A suitable pretreatment is required to overcome these limitations. This paper presents the development and optimization of an innovative combination of processes for the treatment of landfill leachates. This process combination consists in a chemical precipitation of the leachate using lime, followed by a standard filtration on a rotary drum vacuum precoat filter which separates the precipitated phase from the liquid phase before the final step of reverse osmosis. Coupling these processes makes it possible (i) to decrease the salinity of the effluent by 15–30% through precipitation of the metals and carbonates, thereby facilitating RO operation by decreasing the osmotic pressure, (ii) to eliminate by co-precipitation the humic acids responsible for irreversible membrane fouling, (iii) to generate a sludge that is stable, chemically inert, relatively dry (50% siccity) and that can be easily stored on an adequate site. At the industrial scale, it makes it possible to decrease the working pressures as well as the concentrate volumes (or residues) generated and at the same time increase the conversion rate of RO process. It can also make it possible to reduce the frequency of membrane cleaning and the consumption of cleaning chemicals.

UTILIZATION OF SEWAGE SLUDGE FROM ACID CASEIN PRODUCTION FOR SOIL FERTILIZATION

Organic biodegradable waste composes a fair part of farm and vital activity waste. The disposal of this waste in municipal waste landfills pollutes the environment and soil. Therefore, the European Union and other countries look for alternatives to manage biodegraded waste. This paper seeks to analyse the properties of sludge that forms in the sewage treatment plants of the acid casein production, examines experience in managing and applying sludge. The results of an experiment show that sewage sludge from the acid casein production is suitable as a soil fertilizer for growing lettuce (Lactuca sativa L.) and garden cress (Lepidium sativum L.). After soil was fertilized with this sludge, the germination of lettuce and garden cress as well as the biomass of experimental alimentary plants increased. A suitable ratio of soil and sludge mixture was determined (for lettuce ‐ 1:1, for garden cress ‐ 3:1). Potassium sulphate which was added to a soil‐sludge mixture improved the values of fertility parameters of alimentary plants.

Utilization of sewage sludge from acid casein production for soil fertilization

Abstract Organic biodegradable waste composes a fair part of farm and vital activity waste. The disposal of this waste in municipal waste landfills pollutes the environment and soil. Therefore, the European Union and other countries look for alternatives to manage biodegraded waste. This paper seeks to analyse the properties of sludge that forms in the sewage treatment plants of the acid casein production, examines experience in managing and applying sludge. The results of an experiment show that sewage sludge from the acid casein production is suitable as a soil fertilizer for growing lettuce (Lactuca sativa L.) and garden cress (Lepidium sativum L.). After soil was fertilized with this sludge, the germination of lettuce and garden cress as well as the biomass of experimental alimentary plants increased. A suitable ratio of soil and sludge mixture was determined (for lettuce ‐ 1:1, for garden cress ‐ 3:1). Potassium sulphate which was added to a soil‐sludge mixture improved the values of fertility parame...

Investigative studies for the use of an inactive asbestos mine as a disposal site for asbestos wastes

Although, according to European legislation the use of Asbestos Containing Materials is forbidden, many buildings in Greece still contain asbestos products, which must be removed at some point in the near future. Therefore, suitable disposal sites must be found within Greece, so that the unverified disposal of asbestos waste in municipal waste Landfills is brought to an end. In the present work, an innovative approach to the disposal problem of asbestos wastes in Greece has been examined, through a risk assessment analysis of the inactive asbestos mine of Northern Greece and an evaluation of its suitability as a disposal site for asbestos wastes in the future. According to the research carried out, two areas (Site 1 and Site 2) inside the mine area are suitable for the construction of a disposal site for asbestos wastes. The geological investigations showed that in Site 1 and Site 2 ultrabasic rocks of ophiolite complex were prevalent, which have been intensely serpentinized and converted into the fibrous shape of serpentine (asbestos). Concentrations of hazardous substances such as heavy metals in the soil of Site 1 and Site 2 oscillate at low levels, with the exception of the concentrations of nickel and chrome which are high. The investigative work also included the collection of meteorological data and the monitoring of the water level of the artificial lake, which has developed inside the open mine. The main aim is to safely dispose asbestos wastes inside the mine, to minimize any pollution of the wider vicinity of the mine, as well as to engage in restoration activities.

Organometals of tin, lead and mercury compounds in landfill gases and leachates from Bavaria, Germany

Organo-Sn, -Pb and -Hg compounds were monitored in gases and leachates of 11 municipal waste landfills and one hazardous waste landfill from Bavaria, Germany, with the objectives to estimate the methylation of Sn, Pb and Hg and to assess the risk of their release into the adjacent environment. In the gases, tetramethyl Sn predominated (>80% of total gaseous Sn) with concentrations up to 160 microg Sn m(-3). Dimethyl-Hg and tetramethyl-Pb were only occasionally detected with concentrations up to 2.9 and 2.1 microg m(-3) as Hg or Pb, respectively. In all leachates, trimethyl-Sn dominated with a maximum concentration of 2100 ng Sn L(-1). No organo-Pb compounds were found, and monomethyl-Hg was detected in only one leachate. The concentrations of trimethyl-Sn were up to 100-fold higher in the condensate water than in leachates, and the concentrations of organo-Sn compounds were lower in the adjacent groundwater than in the corresponding leachates. The high abundance of methylated Sn species in the gases and leachates indicates Sn methylation, suggesting the landfill as a source for organo-Sn compounds. In comparison, methylation of Hg and Pb was of little importance, probably due to low Hg concentrations and low rates of Pb methylation in the landfill. The risks of organo-Sn compounds release to the adjacent air is low due to flaring of landfill gases. However, there is probable release of organo-Sn compounds, especially trimethyl-Sn, to the adjacent groundwater.

Bioreactivity of leachate from municipal solid waste landfills — assessment of toxicity

With the UK producing 400 million tonnes of waste each year, the problem of waste disposal is recognised as one of the most serious environmental problems facing the nation. Of this, over 35 million tonnes is municipal waste, largely derived from households, but also includes some commercial and industrial waste. There are strong national and international concerns about the possible adverse health effects of living in the vicinity of municipal waste landfills. An understanding of the ranges of toxicity of landfill emissions is crucial to determine the degree of concern we should have about the potential effects they could have upon nearby populations and the surrounding environment. Leachates from three different types of landfills have been collected and screened for their potential to induce toxicity. Bioreactivity was measured by a plasmid DNA scission assay (PSA), and 2',7'-dichlorodihydrofluorescin fluorescence (DCFH). The results indicate that leachates cause damage to plasmid DNA in a dose-dependent manner and that toxicity varies between different types of landfills as well as within individual waste sites. Overall, the data implies that the complex chemistry involved in leachate formation has yet to be delineated in terms of the toxicological response.

Seasonal variation of particulate organic compounds in atmospheric PM 10 in the biggest municipal waste landfill of Algeria

The average composition and seasonal variations of atmospheric organic particulates with respect to n-alkanes, n-alkanoic acid, polycyclic aromatic hydrocarbon (PAHs), and nitrated polycyclic aromatic hydrocarbons (N-PAHs) were determined at the biggest municipal waste landfill in Algeria located in Oued Smar, 13 km east of downtown Algiers. Samplings were carried out from August 2002 to February 2003, and organic compounds adsorbed in air particles having an aerodynamic diameter lower than 10 μm (PM 10) were characterized using gas chromatography coupled with mass spectrometric detection (GC/MSD). Total concentrations ranged from 828 to 11,068 ng per cubic meter of air for n-alkanes, from 1714 to 21,710 ng per cubic meter of air for n-alkanoic acids, from 13 to 212 ng per cubic meter of air for PAHs and from 93 to 205 pg per cubic meter of air for N-PAHs. n-Alkanoic acids accounted for 85 and 56% of the total organic composition of the aerosol measured in summer and winter, respectively, were the biggest fraction. The distribution profiles and the diagnostic ratios of some marker compounds allowed to identify the combustion and microbial activity as the major sources of particulate organic pollutants associated with direct emission. The year-time dependence of organic fraction content of aerosol in Oued Smar appeared to be related to average meteorological conditions as well as variability of rate and nature of materials wasted into the landfill.

Species Alterations Caused by Nitrogen and Carbon Addition in Nutrient-deficient Municipal Waste Landfills

The ultimate target of restoring waste landfills is revegetation. The most effective method for increasing species richness and biomass in nutrient limited waste landfills is the use of fertilizers. The aim of the present study was to investigate the effects of nitrogen fertilizer, and the addition of carbon through sawdust, sucrose and litter, on vegetation dynamics at a representative municipal waste landfill in South Korea: Kyongseodong. A total of 288 permanent plots <TEX>$(0.25m^2)$</TEX> were established and treated with nitrogen fertilizer (5, 10 and <TEX>$20Ng/m^2$</TEX>), sawdust <TEX>$(289g/m^2)$</TEX> sucrose <TEX>$(222g/m^2)$</TEX> and litter <TEX>$(222g/m^2)$</TEX>. The aboveground biomass was significantly enhanced by nitrogen fertilizer at 5 and <TEX>$10Ng/m^2$</TEX>, compared with the control plots. The total cover of all plant species increased significantly on plots treated with 5 and <TEX>$20Ng/m^2$</TEX>, as well as on those treated with sawdust and sucrose, compared with the control plots. The higher species richness after nitrogen fertilization of 10 to <TEX>$20Ng/m^2$</TEX>, and the sawdust and sucrose treatment demonstrated that this was an appropriate restoration option for nutrient deficient waste landfills. This study demonstrated positive nutrient impacts on plant biomass and species richness, despite the fact that municipal waste landfills are ecosystems that are highly disturbed by anthropogenic and internal factors (landfill gas and leachate). Adequate N and C combined treatments will accelerate species succession (higher species richness and perennial increase) for restoration of waste landfills.

VOLATILE ORGANIC COMPOUNDS MEASUREMENT IN THE BOUNDARY OF WASTE TREATMENT FACILITIES

Concentrations of the principal volatile organic compounds, such as benzene, toluene, ethylbenzene, m,p,o-xylene, styrene, and chlorobenzene were measured at the solid waste treatment plants classified into four categories; municipal waste incinerator, municipal waste landfill site, industrial waste incinerator and industrial waste landfill site. The average concentration of VOCs in industrial waste treatment facilities was 33.43 ppb and was significantly higher than that measured at municipal waste treatment facilities (4.71 ppb). The average toluene concentrations measured at incinerators (13.05 ppb) were a little higher than those measured at landfill sites (11.54 ppb). The contribution of the waste treatment facilities to the concentration of benzene (0.35 ppb) and o-xylene (0.15 ppb) in the industrial area was relatively small. However, toluene measured in the industrial waste treatment facilities was the most abundant VOCs with the average concentration of 21.37 ppb. As a result of analyses of fingerprint, in cases of IISH and ILUS, a variety of compounds other than major VOCs were detected in high level. On the Pearson correlation analysis, the correlation was generally positive and some pairs of these VOCs were very strongly correlated (correlation coefficient > 0.75).

Development of quality objectives for contaminated sites: state of the art and new perspectives

Local soil contamination, mainly associated with industrial facilities (both in operation and after closure), uncontrolled (industrial and/or municipal) waste landfills, mining and diffused leaching underground storage tanks and pipelines, is an actual and relevant environmental priority in Europe. Different approaches have been applied in the European countries during the past few years to develop the quality objectives for contaminated sites according to the following three categories: the limit value criterion for soil and groundwater; the absolute risk analysis for a given contaminated site; and the comparative (or relative) risk analysis among different potentially contaminated sites. The present paper gives, together with a synthetic state of the art of the contaminated site management situation at different EU countries, a view on the current experience, problems and regulatory requirements in Italy on these possible soil and groundwater quality approaches, also with comparative considerations to other significant European and international strategies.

Description of the EVIAVE methodology for environmental diagnosis of municipal waste landfills

In Europe, a Council Directive passed in 1999 provided for the regulation of waste disposal in landfills. This was a specific piece of legislation aimed at environmental control of new and currently operational installations. As a result, it has become necessary to adapt currently operational release points to make them compatible with the new legislation. This new situation has obliged the different environmental organisations to carry out a stocktaking of release points in order to draw up a conditioning plan or a closing plan in accordance with the directive. The present study describes a new methodology by which environmental diagnosis of landfill sites may be carried out, involving the formulation of environmental indexes that give information about the potential environmental problems of currently operational landfills. The indexes provide information related to the location, design and operation in order to help draw up action plans for the conditioning or closure of the landfill site and to prioritise the order of actions required.

Landfill leachate treatment with sequencing batch reactor and membrane bioreactor

Landfill leachate from a composting field of a Finnish municipal waste landfill was treated with sequencing batch reactor (SBR) and a submerged membrane bioreactor (MBR) fed batchwise. The average quality of the leachate was 475 mg/l suspended solids, 1240 mg/l BOD7, 10 mg/l phosphorus, and 210 mg/l ammonium nitrogen. Hydraulic retention times in SBR varied from four to nine days and in MBR from two to five days. Solids retention times in SBR were from 10 to 40 days and in MBR from 35 to over 60 days. The sludge concentration in SBR varied from 6.6 to 10 g/l and in MBR from 7.3 to 9.3 g/l in normal conditions. In SBR, suspended solids concentration in effluent was up to 89% smaller than influent suspended solids concentration. However, sometimes bulking reduced the efficiency. The preliminary results with MBR start-up showed that it is free from bulking problems and compared to feed concentration the retention was over 99% of suspended solids. It also increased the retentions of both BOD7 and ammonium nitrogen to >97% and reduced variations. Phosphorus retention was >88%.

Landfill leachate treatment methods: A review

Landfilling of municipal waste is still a major issue of the waste management system in Europe. The generated leachate must be appropriately treated before being discharged into the environment. Technologies meant for leachate treatment can be classified as follows (i) biological methods, (ii) chemical and physical methods. Here we review briefly the main processes currently used for the landfill leachates treatments.

Airborne Emissions of Mercury from Municipal Solid Waste. II: Potential Losses of Airborne Mercury before Landfill

Waste distribution and compaction at the working face of municipal waste landfills releases mercury vapor (Hg0) to the atmosphere, as does the flaring of landfill gas. Waste storage and processing before its addition to the landfill also has the potential to release Hg0 to the air if it is initially present or formed by chemical reduction of HgII to Hg0 within collected waste. We measured the release of Hg vapor to the atmosphere during dumpster and transfer station activities and waste storage before landfilling at a municipal landfill operation in central Florida. We also quantified the potential contribution of specific Hg-bearing wastes, including mercury (Hg) thermometers and fluorescent bulbs, and searched for primary Hg sources in sorted wastes at three different landfills. Surprisingly large fluxes were estimated for Hg losses at transfer facilities (∼100 mg/hr) and from dumpsters in the field (∼30 mg/hr for 1,000 dumpsters), suggesting that Hg emissions occurring before landfilling may constitute a significant fraction of the total emission from the disposal/landfill cycle and a need for more measurements on these sources. Reducing conditions of landfill burial were obviously not needed to generate strong Hg0 signals, indicating that much of the Hg was already present in a metallic (Hg0) form. Attempts to identify specific Hg sources in excavated and sorted waste indicated few readily identifiable sources; because of effective mixing and diffusion of Hg0, the entire waste mass acts as a source. Broken fluorescent bulbs and thermometers in dumpsters emitted Hg0 at 10 to >100 μg/hr and continued to act as near constant sources for several days.

Approches du bilan hydrique de deux centres de stockage des déchets ménagers dans les pays en développement : cas de Go Cat (Vietnam) et Essaouira (Maroc)

Waste management in developing countries is a growing concern because of its impact on Man and on the environment. The traditional method, known as “landfilling”, is still the most widespread for solid waste disposal, because of its relatively low cost. In the developing countries, the insufficiency of financial and technical means too often causes the municipalities and the population to dump waste into uncontrolled sites. This study has been carried out within the frame program of the French Agency for Environment and Energy Management (ADEME), dealing with the landfilling of municipal waste in developing countries. The major objective is the definition of a methodology for designing and operating municipal waste landfilling facilities, suitable for developing countries. This paper presents the first results obtained on three sites, i.e. the lanfilling facility of Essaouira (Kingdom of Morocco), under mediterranean climate, the facility of Nkolfoulou, located near the city of Yaoundé (Republic of Cameroon), under equatorial climate, and the facility of Go Cat, located by Hô Chi Minh-City, in Vietnam, under wet tropical climate. Waste management in developing countries is a growing concern because of its impact on Man and on the environment. The traditional method, known as “landfilling”, is still the most widespread for solid waste disposal, because of its relatively low cost. In the developing countries, the insufficiency of financial and technical means too often causes the municipalities and the population to dump waste into uncontrolled sites. This study has been carried out within the frame program of the French Agency for Environment and Energy Management (ADEME), dealing with the landfilling of municipal waste in developing countries. The major objective is the definition of a methodology for designing and operating municipal waste landfilling facilities, suitable for developing countries. This paper presents the first results obtained on three sites, i.e. the lanfilling facility of Essaouira (Kingdom of Morocco), under mediterranean climate, the facility of Nkolfoulou, located near the city of Yaoundé (Republic of Cameroon), under equatorial climate, and the facility of Go Cat, located by Hô Chi Minh-City, in Vietnam, under wet tropical climate.

Gaseous methyl- and inorganic mercury in landfill gas from landfills in Florida, Minnesota, Delaware, and California

Abstract Municipal waste landfills contain numerous sources of mercury which could be emitted to the atmosphere. Their generation of methane by anaerobic bacteria suggests that landfills may act as bioreactors for methylated mercury compounds. Since our previous study at a single Florida landfill, gaseous inorganic and methylated mercury species have now been identified and quantified in landfill gas at nine additional municipal landfills in several regions of the US. Total gaseous mercury occurs at concentrations in the μg m−3 range, while methylated compounds occur at concentrations in the ng m−3 range at all but one of the landfill sites. Dimethylmercury is the predominant methylated species, at concentrations up to 100 ng m−3, while monomethyl mercury was generally lower. Limited measurements near sites where waste is exposed for processing (e.g. working face, transfer areas) suggest that dimethylmercury is released during these activities as well. Although increasing amounts of landfill gas generated in the US are flared (which should thermally decompose the organic mercury to inorganic mercury), unflared landfill gas is a potentially important anthropogenic source of methylated mercury emissions to the atmosphere.

Standard and alternative landfill capping design in Germany

Abstract Engineered capping systems are in most cases an indispensable and often the only efficient component required by the long-term safety concept for landfills, mine tailings tips and contaminated land. In Germany the composite liner is the main component of standard landfill cappings for municipal and hazardous waste landfills and the compacted clay liner (CCL) for landfills for inert or low-contamination waste. The composite liner is a technically highly effective but very expensive system. Research and experience has given rise to concern about the proper long-term performance of a conventional single CCL as a landfill capping. Therefore, alternative capping systems are discussed and applied for landfills and for the containment of contaminated sites. This paper gives an overview on various alternative engineered cappings and suitable systems for capping reflecting the state of the art and the expert view in Germany. According to the European Council Directive on the landfill of waste an impermeable mineral layer is recommended for the surface sealing of non-hazardous landfills and a composition of artificial sealing liner and impermeable mineral layer for hazardous landfills. In both cases a drainage layer thickness of at least 0.5 m is suggested. These recommendations should be interpreted flexibly and to some extent modified in the light of the experience and results presented in this paper.

Wind tunnel experiments of tracer dispersion downwind from a small-scale physical model of a landfill

Wind tunnel experiments have been carried out on a small-scale physical model of a municipal waste landfill (MWL) in the CRIACIV (Research Centre of Building Aerodynamics and Wind Engineering) “environmental” wind tunnel in Prato (Italy). The MWL model simulates a landfill whose surface is higher than the surrounding surface, applying a 1:200 scaling factor. Modelling an area source such as landfill is a difficult task for numerical models due to turbulence phenomena that modifies the flow near the source increasing ground level concentration (GLC). For the specific task, a new set-up of the wind tunnel has been developed, with respect to previous studies carried out on line and point sources physical models. The tracer used in the experiments was ethylene, suitable for non-buoyant plume conditions, typical for MWL emissions. A detailed result database has been obtained in terms of GLC and concentration profiles as well as flow turbulence and velocity field characterisation.

Wind tunnel experiments of tracer dispersion downwind from a small-scale physical model of a landfill

Wind tunnel experiments have been carried out on a small-scale physical model of a municipal waste landfill (MWL) in the CRIACIV (Research Centre of Building Aerodynamics and Wind Engineering) “environmental” wind tunnel in Prato (Italy). The MWL model simulates a landfill whose surface is higher than the surrounding surface, applying a 1:200 scaling factor. Modelling an area source such as landfill is a difficult task for numerical models due to turbulence phenomena that modifies the flow near the source increasing ground level concentration (GLC). For the specific task, a new set-up of the wind tunnel has been developed, with respect to previous studies carried out on line and point sources physical models. The tracer used in the experiments was ethylene, suitable for non-buoyant plume conditions, typical for MWL emissions. A detailed result database has been obtained in terms of GLC and concentration profiles as well as flow turbulence and velocity field characterisation.