Product specific emissions from municipal solid waste landfills

This paper presents and verifies the computer tool LCA-LAND for estimation of emissions from specific waste products disposed in municipal solid waste landfills in European countries for use in the inventory analysis of LCA. Examples of input data (e.g. distribution of the waste product in different countries, composition of the product and physical/chemical/biological properties of waste product components) and output data (e.g. estimated emissions to atmosphere and water) are given for a fictive waste product made of representative types of components (toluene, cellulose, polyvinylchloride (PVC), copper and chloride). Since waste products from different processes in the product system may be disposed at different landfills where they are mixed with waste originating outside the product system, the estimated emissions from specific waste products cannot be compared with measured emissions from true landfills. Hence, the computer tool is verified in terms of mass balances and sensitivity analyses. The mass balances agree exactly and the sensitivity analyses show that different types of waste product components behave differently in different types of landfills. Emission of e.g. toluene is significantly reduced in the presence of landfill top-cover, landfill gas combustion units and leachate treatment units. Generally, the sensitivity analysis shows good agreement between the relative proportions of various types of emissions (based on properties of the waste and properties of landfills) and good agreement with emission levels that would be expected based on a general understanding of landfill processes.     

The impact of landfilling and composting on greenhouse gas emissions – A review

Municipal solid waste is a significant contributor to greenhouse gas emissions through decomposition and life-cycle activities processes. The majority of these emissions are a result of landfilling, which remains the primary waste disposal strategy internationally. As a result, countries have been incorporating alternative forms of waste management strategies such as energy recovery from landfill gas capture, aerobic landfilling (aerox landfills), pre-composting of waste prior to landfilling, landfill capping and composting of the organic fraction of municipal solid waste. As the changing global climate has been one of the major environmental challenges facing the world today, there is an increasing need to understand the impact of waste management on greenhouse gas emissions. This review paper serves to provide an overview on the impact of landfilling (and its various alternatives) and composting on greenhouse gas emissions taking into account streamlined life cycle activities and the decomposition process. The review suggests greenhouse gas emissions from waste decomposition are considerably higher for landfills than composting. However, mixed results were found for greenhouse gas emissions for landfill and composting operational activities. Nonetheless, in general, net greenhouse gas emissions for landfills tend to be higher than that for composting facilities.     

Bio-pretreatment of municipal solid waste prior to landfilling and its kinetics

The conventional landfilling does not promote sustainable waste management due to uncontrolled emissions which potentially degrade the environment. Pretreatment of municipal solid waste prior to landfilling significantly enhances waste stabilization, reduces the emissions and provides many advantages. Therefore, pretreatment of municipal solid waste methods were investigated. The major objectives of biological pretreatment are to degrade most easily degradable organic matters of MSW in a short duration under controlled conditions so as to produce desired quality for landfill. To investigate the suitable pretreatment method prior to landfilling for developing countries four pretreatment simulators were developed in the laboratory: (i) anaerobic simulator (R₁), (ii) aerobic pretreatment simulator by natural convection of air (R₂), (iii) aerobic pretreatment simulator by natural convection of air with leachate recirculation (R₃) and (iv) forced aeration and leachate recirculation (R₄). During the pretreatment organic matter, elemental composition, i.e., carbon, hydrogen, nitrogen and settlement were determined for bench scale experiments. A two-component kinetic model is proposed for the biodegradation of organic matter. Biodegradation kinetic constants were determined for readily and slowly degradable organic matter. The biodegradation of organic matter efficiency in terms of kinetic rate constants for the pretreatment simulators was observed as R₄ > R₃ > R₂ > R₁. Biodegradation rate constants for readily degradable matter in simulators R₄ and R₃ were 0.225 and 0.222 per day. R₃ and R₄ simulators were more effective in reducing methane emissions about 45% and 55%, respectively, as compared to anaerobic simulator R₁. Pretreatment of MSW, by natural convection of air with leachate recirculation R₃ is sustainable method to reduce the emissions and to stabilize the waste prior to landfilling.     

Influence of supplemental heat addition on performance of pilot-scale bioreactor landfills

Implementation of supplemental heat addition as a means of improving bioreactor landfill performance was investigated. The experimental work was conducted with two pilot-scale bioreactor setups (control cell and heated cell) operated for 280 days. Supplemental heat was introduced by recirculating leachate heated up to 35 °C compared to the control which used similar quantities of leachate at room temperature (21 ± 1 °C). The temporal and spatial effects of recirculating heated leachate on the landfill internal temperature were determined, and performance was assessed in terms of leachate parameters and biogas production. Recirculation of heated leachate helped establish balanced anaerobic microbial consortia that led to earlier (70 days) and greater (1.4-fold) organic matter degradation rates, as well as threefold higher methane production compared to the non-heated control. Despite the significant enhancements in performance resulting from supplemental heat addition, heated leachate recirculation did not significantly impact waste temperatures, and the effects were mainly restricted to short periods after recirculation and mostly at the upper layers of the waste. These findings suggest that improvements in bioreactor landfill performance may be achieved without increasing the temperature of the whole in-place waste, but rather more economically by raising the temperature at the leachate/waste interface which is also exposed to the maximum moisture levels within the waste matrix.     

Comparative life cycle assessments of incineration and non-incineration treatments for medical waste

Background, aim, and scope  Management of the medical waste produced in hospitals or health care facilities has raised concerns relating to public health, occupational safety, and the environment. Life cycle assessment (LCA) is a decision-supporting tool in waste management practice; but relatively little research has been done on the evaluation of medical waste treatment from a life cycle perspective. Our study compares the environmental performances of two dominant technologies, hazardous waste incineration (HWI) as a type of incineration technology and steam autoclave sterilization with sanitary landfill (AL) as a type of non-incineration technology, for specific medical waste of average composition. The results of this study could support the medical waste hierarchy. Materials and methods  This study implemented the ISO 14040 standard. Data on steam autoclave sterilization were obtained from an on-site operations report, while inventory models were used for HWI, sanitary landfill, and residues landfill. Background data were from the ecoinvent database. The comparative LCA was carried out for five alternatives: HWI with energy recovery efficiencies of 0%, 15%, and 30% and AL with energy recovery efficiencies of 0% and 10%. Results  The assumptions on the time frame for landfill markedly affect the impact category scores; however, the orders of preference for both time frames are almost the same. HWI with 30% energy recovery efficiency has the lowest environmental impacts for all impact categories, except freshwater ecotoxicity. Incineration and sanitary landfill processes dominate global warming, freshwater aquatic ecotoxicity, and eutrophication of incineration and non-incineration alternatives, respectively. Dioxin emissions contribute about 10% to human toxicity in HWI without energy recovery alternatives, and a perturbation analysis yielded identical results. As regards eutrophication, non-incineration treatments have an approximately sevenfold higher impact than incineration treatments. Discussion  The differences between short-term and long-term time frame assumptions mainly are decided by heavy metals dissolved in the future leachate. The high heat value of medical waste due to high contents of biomass, plastic, and rubber materials and a lower content of ash, results in a preference for incineration treatments. The large eutrophication difference between incineration and non-incineration treatments is caused by different N element transformations. Dioxin emission from HWI is not the most relevant to human toxicity; however, large uncertainties could exist. Conclusions  From a life cycle perspective, the conventional waste hierarchy, implying incineration with energy recovery is better than landfill, also applies to the case of medical waste. The sanitary landfill process is the key issue in non-incineration treatments, and HWI and the subsequent residues landfill processes are key issues in incineration treatments. Recommendations and perspectives  Integrating the medical waste hierarchy and constructing a medical waste framework require broader technologies to be investigated further, based on a life cycle approach. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

Waste treatment in product specific life cycle inventories

The final disposal of waste in sanitary landfills generates environmental impacts in the form of gaseous emissions and effluents in the seepage water. In product specific Life Cycle Assessments, these environmental impacts resulting from the disposal of the product under study frequently have a strong influence on the overall results. The Sanitary Landfill (SL), like the Municipal Solid Waste Incineration (MSWI), is a complex system with a large variety of different types of waste with varying input composition. A direct determination of the environmental impacts resulting from the landfilling of a single input component, e.g. by measurements, is not possible. The model approach described in this paper shows an operationalized concept for the allocation of the environmental effects caused by the landfill process to special input components. The calculation of the landfill emissions in the model is based on the emission spectrum (landfill gas and seepage water) of an average-sized landfill in Germany and the elementary composition of the single waste fraction under consideration. The resulting reactor landfill module comprises an average split for diffuse and captured landfill emissions, the use of captured landfill gases in a gas engine and a cleaning of captured seepage water in a waste water treatment plant. A short case study demonstrates the calculation of the effects of landfilling of a defined waste fraction (bottle fraction in post-consumer plastic waste).     

Coal Tar‐Containing Asphalt Resource or Hazardous Waste?

Abstract: Coal tar was used in Sweden for the production of asphalt and for the drenching of stabilization gravel until 1973. The tar has high concentrations of polycyclic aromatic hydrocarbons (PAH), some of which may be strongly carcinogenic. Approximately 20 million tonnes of tar-containing asphalt is present in the public roads in Sweden. Used asphalt from rebuilding can be classified as hazardous waste according to the Swedish Waste Act. The cost of treating the material removed as hazardous waste can be very high due to the large amount that has to be treated, and the total environmental benefit is unclear. The transport of used asphalt to landfill or combustion will affect other environmental targets. The present project, based on three case studies of road projects in Sweden, evaluates the consequences of four scenarios for handling the material: reuse, landfill, biological treatment, and incineration. The results show that reuse of the coal tar-containing materials in new road construction is the most favorable alternative in terms of cost, material use, land use, energy consumption, and air emissions.     

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.     

Comparative life cycle assessment of two landfill technologies for the treatment of municipal solid waste

Goal and Scope  The potential environmental impacts associated with two landfill technologies for the treatment of municipal solid waste (MSW), the engineered landfill and the bioreactor landfill, were assessed using the life cycle assessment (LCA) tool. The system boundaries were expanded to include an external energy production function since the landfill gas collected from the bioreactor landfill can be energetically valorized into either electricity or heat; the functional unit was then defined as the stabilization of 600 000 tonnes of MSW and the production of 2.56x10⁸ MJ of electricity and 7.81x10⁸ MJ of heat. Methods  Only the life cycle stages that presented differences between the two compared options were considered in the study. The four life cycle stages considered in the study cover the landfill cell construction, the daily and closure operations, the leachate and landfill gas associated emissions and the external energy production. The temporal boundary corresponded to the stabilization of the waste and was represented by the time to produce 95% of the calculated landfill gas volume. The potential impacts were evaluated using the EDIP97 method, stopping after the characterization step. Results and Discussion  The inventory phase of the LCA showed that the engineered landfill uses 26% more natural resources and generates 81% more solid wastes throughout its life cycle than the bioreactor landfill. The evaluated impacts, essentially associated with the external energy production and the landfill gas related emissions, are on average 91% higher for the engineered landfill, since for this option 1) no energy is recovered from the landfill gas and 2) more landfill gas is released untreated after the end of the post-closure monitoring period. The valorization of the landfill gas to electricity or heat showed similar environmental profiles (1% more raw materials and 7% more solid waste for the heat option but 13% more impacts for the electricity option). Conclusion and Recommendations  The methodological choices made during this study, e.g. simplification of the systems by the exclusion of the identical life cycle stages, limit the use of the results to the comparison of the two considered options. The validity of this comparison could however be improved if the systems were placed in the larger context of municipal solid waste management and include activities such as recycling, composting and incineration.     

Demographic impact of landfill closure on a resident opportunistic gull

The management of mixed municipal waste can have an impact on wildlife and ecosystems. Previous studies have investigated how opportunistic species like gulls can react very fast to new landfills; however, the impact of landfill closure on bird populations is less investigated. Yet, there is a need to understand how fast and to what extent, animal populations can be adapted to new scenarios where the waste will not be deposited in landfill sites anymore. The aim is to determine the influence of landfill closures on apparent survival of a resident Yellow-legged Gull (Larus michahellis) population, used as a model species showing short-distance foraging movements, and with a high dependence on local food subsidies. Complementarily, we built some basic population growth models in order to determine how potential changes in survival (before/after landfill closure) will impact on population growth rate. Using a data set of 4,437 Yellow-legged Gull chicks ringed in four colonies over a period of 13 years, we obtained evidence supporting that the apparent survival was affected by landfill closure, especially if the landfill was located within a buffer of 10 km around the colony. Landfill closure affected the survival of first-year gulls (with a mean decrease of ~ 0.5–0.36), but not of older birds. Consequently, we did not detect a remarkable effect of landfill closures on population growth rate, probably due to the lack of effect on adult survival rates except for one of the surveyed colonies, where we found an annual decline of 7%.     

Quantity,Components, and Value of Waste Materials Landfilled in the United States

The current system of production and consumption needs end‐of‐life disposal to function, but the linkage between upstream production‐consumption with the downstream landfill as terminus is, at best, a tenuous, one‐way relationship, suggesting a partial system failure. A starting point to fix this link is to confront, systematically, the messy “black box” that is mixed waste landfilling, interrogate its contents locally, and determine a baseline that can be used to scale up results. Here, we develop a detailed model characterizing landfilled municipal solid waste (MSW) in the United States across the dimensions of material quantity, quality, location, and time. The model triangulates measurements spanning 1,161 landfills (representing up to 95% of landfilled MSW) and 15,169 solid waste samples collected and analyzed at 222 sites across the United States. We confirm that landfilled quantities of paper (63 million megagrams [Mg]), food waste (35 million Mg), plastic (32 million Mg, textiles (10 million Mg), and electronic waste (3.5 million Mg) are far larger than computed by previous top‐down U.S. government estimates. We estimate the cost of MSW landfill disposal in 2015 (10.7 billion U.S. dollars [USD]) and gross lost commodity value of recyclable material (1.4 billion USD). Further, we estimate landfill methane emissions to be up to 14% greater (mass basis) than the 2015 U.S. inventory. By principally relying on measurements of waste quantity and type that are recorded annually, the model can inform more effective, targeted interventions to divert waste materials from landfill disposal, improve local, regional, and national emission estimates, enhance dissipative loss estimates in material flow analyses, and illuminate the dynamics linking material, energy, and economic dimensions to production, consumption, and disposal cycles.     

垃圾填埋场氧化亚氮排放控制研究进展

填埋是国内外城市生活垃圾处理的一种主要方式.垃圾填埋场是温室气体氧化亚氮(N2O)和甲烷(CH4)的重要排放源.作为一种高效痕量的温室气体,N2O具有极高的潜在增温效应,其每分子潜在的增温作用是二氧化碳(CO2)的296倍.而且N2O能在大气中长期稳定存在,对臭氧层具有较强的破坏作用.本文针对垃圾填埋场N2O排放的控制研究,概述了垃圾填埋处理过程中主要排放源的N2O排放及其影响因素,提出了现阶段适应我国垃圾填埋场N2O排放控制的一系列措施,并展望了垃圾填埋场温室气体N2O排放控制理论和技术的研究方向.     

The microbial metabolic activity on carbohydrates and polymers impact the biodegradability of landfilled solid waste

Biodegradation - Biological waste degradation is the main driving factor for landfill emissions. In a 2-year laboratory experiment simulating different landfill in-situ aeration scenarios, the...     

Evaluating Habitat Manipulations and Rodenticides to Protect Seedlings from Rodent Damage at Restored Landfills in New York

Solid waste landfills have become rather commonplace in urbanized and industrialized regions of the world. If designed, managed, and restored properly, they can be converted to useful land uses. However, restoration of woody vegetation can be difficult when animal damage occurs. Numerous species of voles occur throughout the northern hemisphere and several may become serious pests of restoration plantings at high population density, increasing the expense and difficulty of establishing targeted plant communities. We anticipated that meadow voles (Microtus pennsylvanicus) were responsible for causing the majority of damage to seedlings planted on restored landfill sites in Brooklyn, New York. We evaluated the ability of two habitat manipulations (e.g. mowing, pea gravel barrier) and rodenticides to protect seedlings. We documented substantial damage and deaths of seedlings caused by rodents in the study plots with losses (damaged or dead seedlings combined) ranging from 40 to 73%. These losses occurred regardless of seedling species. Because of the preponderance of voles (71% of all first‐time captures), we suspect that voles are the main species causing seedling damage. Substantial losses of seedlings occurred across treatments, although there were fewest losses with a pea gravel barrier treatment. While the pea gravel treatment reduced seedling losses about 55% compared to control plots, it is clear that additional research is needed to identify more efficient ways to reduce seedling losses to rodents in restoration plantings.     

Comparative study of six different sludges by sequential speciation of heavy metals

The presence of heavy metals in the sludges produced in wastewater treatment plants restricts their use for agricultural purposes. This study looks at different types of sludge (aerobic, anaerobic, unstabilised, sludge from a waste stabilisation pond, sludge from an extended aeration plant and heat treated sludge) and compares the distribution of heavy metals with the treatment that they have undergone. In addition, the total quantity of metals (Cd, Cr, Cu, Ca, K, Fe, Mg, Ni, Na, Pb and Zn) and some agronomic parameters necessary for characterising a sludge as suitable for use as amendment were determined. The BCR method for heavy metal speciation was followed. Principal component analysis (PCA) was applied in order to obtain more information about metal speciation in the sewage sludges. It was confirmed that the concentration of heavy metals did not exceed the limits set out by European legislation and that the stabilisation treatment undergone by the sludges strongly influenced the heavy metal distribution and the phases to which they were associated. The waste stabilisation pond sludge, which has undergone a higher degree of mineralisation than the others, shows a lower metal bioavailability index since practically all the heavy metals in it are associated to the oxidisable and residual fraction. On the other hand the unstabilised sludge, which, along with that exposed to extended aeration, contains the highest accumulations of heavy metals in the most easily assimilable fractions.     

Mixed municipal waste management in the Czech Republic from the point of view of the LCA method

Purpose  

This paper presents the results of a life-cycle assessment (LCA) study for integrated systems (IS) of mixed municipal waste (MMW) management in the Czech Republic. The seven IS categories assessed were: (a) incineration with slag recovery, (b) incineration without slag recovery, (c) landfills with incineration of the landfill gas by flaring, (d) landfills with recovery of the landfill gas, (e) mechanical–biological treatment (MBT) with aerobic treatment, (f) MBT biodrying with co-incineration of refuse-derived fuel, and (g) MBT biodrying with incineration of refuse-derived fuel from a monosource.     

Leachate and gaseous emissions from initial phases of landfilling mechanically and mechanically-biologically treated municipal solid waste residuals

In this study, the behaviour, and leachate and gaseous emissions during the initial phases of landfilling mechanically (M) and mechanically-biologically (MB) treated municipal solid waste residuals in northern climatic conditions was compared using two landfill lysimeters (112 m3). The results demonstrate that the strong acid phase of M residuals degradation lasts at least 2 years, while in the MB residuals the acid phase lasts only a few months. The SCOD and NH4-N concentrations varied 20-100g/l and 600-1800 mg/l in M leachate and 1-4 g/l and 100-400mg/l in MB leachate, respectively. The leaching of SCOD was approximately 40-fold (24.2 and 0.6 kg/t TS) and leaching of NH4-N approximately 5-fold (356 and 60 g/t TS) from the M than MB residuals; thus the effect of biological stabilisation was more marked on the leaching of SCOD than of NH4-N. Moreover gas (methane, carbon dioxide and nitrous oxide) emissions were several-fold higher from the M than MB residuals.     

Sanitary Waste Landfill Effects on an Invasive Wild Pig Population

Being opportunistic omnivores, wild pigs (Sus scrofa) readily feed on edible garbage. Given the presence of substantial volumes of edible food waste, large multi-county and regional municipal sanitary waste landfills constitute attractive forage resources for pigs, providing a year-round anthropogenic source of potentially high-quality forage. Our objective was to assess the effects that a large regional landfill has on the local pigs foraging in that facility's waste disposal cells. The landfill, located on the United States Department of Energy's Savannah River Site (SRS) in South Carolina, USA, became operational in 1998 and pigs began foraging there in 2001. By 2009 >100 pigs/night were observed foraging in the landfill, suggesting landfill establishment may have important consequences for population dynamics, public safety, and disease transmission. We evaluated changes in body mass, fetal litter size, numbers of pigs removed, and wild pig-vehicle collisions (WPVCs) before (1980–2000) and after (2001–2019) pigs began foraging in the landfill on SRS. Body mass during the after period increased to a greater extent for pigs in the vicinity of the landfill compared to pigs on the rest of SRS. Fetal litter size increased for pigs in the vicinity of the landfill, whereas it remained unchanged on the rest of SRS. Our density surrogate (number of pigs harvested) increased around the landfill during the after period by 2.9 times, whereas on the rest of the site it only increased by 53%. No WPVCs occurred adjacent to the landfill before 2001, but WPVCs increased along the 2 major roads bordering the landfill after 2001. Effects of sanitary waste landfills on wild pig populations scavenging there can present unique challenges to population management, control, public safety, and disease transmission. Potential approaches to address these challenges could be exclusion fencing to prevent access to the landfill's waste disposal cells or enhanced placement of waste cell covers to reduce access. © 2021 The Wildlife Society.     

Cellulose hydrolysis by a methanogenic culture enriched from landfill waste in a semi-continuous reactor

This study investigates the hydrolysis of cellulose by a mixed culture enriched from landfill waste in a continuous reactor operated under prolonged residence times to accommodate methanogenic conditions. Chemostat studies of hydrolysis under balance methanogenic conditions are rarely reported, despite the importance of hydrolysis under these conditions in waste management and renewable energy industries. Continuous digestion was studied in a 1.25l digester, fed with a 1% (w/v) slurry of 50mum cellulose in sterilized leachate drawn from a 220l digester operated on a feedstock of mixed municipal solid waste. Unsterilized leachate was used as the inoculum. Stable and rapid hydrolytic conditions were established at residence time of 2.5, 3.5 and 5d with a 1st order hydrolysis rate 0.45+/-0.07d(-1) and high methane yields ranging from 57% to 62% of solubilised cellulose on a COD basis. Biomass yields were between 32% and 35% of solubilised cellulose on a COD basis, over three times that observed with fermentative cultures. This is attributed to the diversity of the microbial population which fully converted solubilised COD to methane, as evident by VFA yields of less than 8% on a COD basis.     

Releasing behavior of copper in recirculated bioreactor landfill

The purpose of this study was to determine the releasing behavior of copper in municipal solid waste (MSW) in landfill with respect to refuse and leachate as an inseparable system. Two simulated bioreactor landfills, one with leachate recirculation and the other without, were operated in room temperature for 320 days. Copper in refuse showed behaviors of staggered migration and retention, which corresponded with the degradation process of landfill obviously. The significant different amounts of Cu²⁺ leached out from refuse into leachate of two landfills were 24.74 mg and 118.53 mg after 320 days’ operation, respectively. It also reflected the releasing behavior of copper in landfill refuse at different stage accordingly. The results confirmed that the refuse in landfill had high potential of secondary pollution after closure.