Municipal Solid Waste Landfill Research Articles

Long-term Performance of Textured HDPE Geomembranes in Municipal Solid Waste Landfills

The effect of texturing (co-extrusion using a blowing agent) on the long-term performance of geomembranes immersed in synthetic municipal solid waste (MSW) leachate is examined over an approximately 8-year period. Antioxidant depletion of the textured part is shown to be much faster than that of the smooth edge. Likewise, the degradation in the tensile break properties at 85°C is faster for the textured part than for the smooth edge portion and smooth equivalent. The updated estimates for antioxidant depletion time based on data at four different temperatures (40, 55, 75, and 85°C) over 98 months of data collection are compared with predictions based on 34 months of data and the implications are discussed. Nominal failure was reached at 75°C, and this combined with data at 85°C allows prediction of the time between depletion of Std-OIT and nominal failure at lower temperatures. The effect of salt concentration in incubation fluid on the time to degradation is examined. Finally, the paper comments on the uses of textured versus smooth geomembrane.

Release potential, neglected leakage and reduction countermeasures of COD and Ammonia in MSWLs

In order to eliminate the impact of the industrial revolution on the environment and improve the water ecological environment, pollutant discharge reduction is imperative. With the acceleration of global discharge reduction process, the huge pollutant release potential and potential environmental effects of municipal solid waste landfills gradually appear, but its release amount and intensity have not been quantitatively revealed. We propose a coupling method of parameter stochastic simulation and physical process model simulation to estimate the hidden leakage of large-scale regional municipal solid waste landfills, and provide a methodology for estimating the hidden leakage of landfills in other countries and even in the whole world by taking China, which has the largest amount of waste generation among developing countries, as an example. Prior to the implementation of stringent construction quality control and assurance management requirements, the average annual leachate generation potential over the entire life cycle of 2600 landfills in China was estimated to be 4.66 × 108 m3, in which the concentrations of COD and NH3-N are 5.38 × 102–6.48 × 104 mg/L and 6.10–3.50 × 103 mg/L, respectively, and the total amounts are 5.21 × 103–7.81 × 108 t and 8.09 × 102–6.65 × 107 t, respectively. About 14 % of these pollutants may leak into the environmental media through the landfill liner with the average number of holes of 21.5/ha. For different regions, the overall release, discharge and leakage of COD and NH3-N in East China account for 35.70 %, 36.68 % and 29.60 % respectively, making it the region with the highest potential for discharge and risk of leakage. Meanwhile, the implementation of mandatory regulations related to leachate generation and control has led to a significant reduction in the leakage of pollutants. For instance, comprehensively detecting and repair of holes in the impermeable liner has reduced the number of holes to 2/ha, resulting in a reduction of >90 % in the leakage of pollutants.

Renewable natural gas: A case study of Minnesota

Renewable natural gas (RNG) often generates usable energy from waste products, reduces methane emissions, and creates new revenue streams. However, not all RNG projects are financially or technically feasible. We assessed the total RNG potential of currently available local waste feedstocks in the state of Minnesota and analyzed the financial and technical limitations for project development. We found that under ideal production conditions the RNG potential from municipal solid waste, dairy and hog farm manure, and municipal wastewater solids in the state could replace approximately 7.5% of current Minnesota natural gas use. We find that technical and financial factors such as project size, financing, and distance to an existing pipeline further reduce the number of feasible RNG project sites in Minnesota. Virtual pipelines – trucking RNG short distances to pipeline injection stations – improved the modeled profitability of 124 out of 175 projects (71%) by decreasing transmission costs. No projects are financially feasible without state or federal renewable fuel credit programs because direct sale of RNG alone does not cover project costs. Dairy manure projects have the lowest levelized cost of energy, the highest total revenue, and the shortest payback period compared to municipal solid waste landfill and wastewater treatment plant projects of similar size. This difference is because manure anaerobic digestion projects are eligible for larger credits under renewable fuel credit programs than municipal solid waste landfills and wastewater treatment plants, but this credit system limits end-use of the RNG to vehicle fuel. Our contribution helps provide an outline for the magnitude of current natural gas use in Minnesota replaceable via RNG projects.

Advancing towards circular economy: Environmental benefits of an innovative biorefinery for municipal solid waste management

Inadequate municipal solid waste (MSW) disposal represents a current global challenge, contributing to environmental and societal issues. Instead of viewing waste as a problem, an alternative would be integrate it back into the production chain through a circular economic perspective. In response, an innovative and integrated biorefinery (2IB) has been implemented to effectively manage MSW, without the need for pre-treatment or source separation. This paper aims to evaluate the environmental performance of the 2IB using the life cycle assessment (LCA) method, comparing the results with a MSW landfilling alternative. The ReCiPe-LCA method is applied, and nine impact categories are calculated. Focusing on net emissions, the results show that 2IB yields higher environmental benefits than sanitary landfill in eight out of nine impact categories. For each 1 tonne of MSW treated, the 2IB causes from 2.6 to up to 8.9 times lower global warming, fossil depletion, photochemical oxidant formation, and freshwater eutrophication, 18.9 times lower metal depletion, 22.3 times lower human toxicity, 42.5 times lower terrestrial acidification, and 161 times lower particular matter formation. However, the sanitary landfill leads to two times lower water depletion compared to the 2IB. These findings advocate for prioritizing the 2IB over the sanitary landfill in propositions for public policies focused on MSW management. This work contributes by providing technical information on the 2IB that can be evaluated under methods other than LCA, besides showing its environmental advantages that would boost better decisions towards MSW disposal from a circular economy perspective.

Health risk assessment and characterization of PM2.5 bound bioaerosols at the municipal solid waste landfill site of Nagpur, India

Landfill being the reservoir of organic waste, serves as the most important source in the generation and emission of bioaerosols in the environment, and these bioaerosols have a significant impact on the environment and public health. In India, there are limited studies on the characterization of culturable bacteria and fungi in the bioaerosols originating from landfills. Therefore, the present study aimed to quantify and identify the bioaerosols and study their characteristics at a landfill site in Nagpur, India. The study describes the seasonal variation of PM2.5, PM2.5-associated bacteria and fungi in the landfill air, their molecular identification, antibiotic resistance, pathogenicity, dispersion and health risk assessment during winter and pre-monsoon seasons at the landfill site and surrounding residential sites in upwind and downwind directions. The study showed PM2.5 concentration was highest in the winter season (265.56 μg/m3) followed by the pre-monsoon season (173.1 μg/m3) at the landfill site. The culturable bioaerosol level was also significantly higher in winter (11056 CFU/m3) in comparison to pre-monsoon season (2244 CFU/m3) at the landfill site. Upon isolating and characterizing the microorganisms in the bioaerosols, some of the bacterial isolates, like Bacillus, Staphylococcus gallinarum, and Streptomyces speibonae were found to be resistant to chloramphenicol, netillin, nitrofurantoin, streptomycin etc. About 30% of the bacterial isolates were found to show β-hemolytic virulence activity. This indicated the presence of multi-drug resistant and potentially pathogenic bacteria in the bioaerosols over the landfill. The health risk assessment in adults indicated that the workers at the landfill site were at risk of bacterial aerosol in the winter season (hazard quotient i.e., HQ>1). The impact of bioaerosols on children needs to be investigated in the further studies and regular monitoring of bioaerosols is suggested to avoid any morbidity. To the best of our knowledge, this is the first study on the characterization of microorganisms from the bioaerosols over an open landfill site in India.

Mechanical and Durability Studies about the use of Municipal Solid Waste Landfill in Concrete

The best way to keep the required format of the manuscript is to overwrite these instructions with its text. Papers should be written in English. Manuscripts s Landfilling is the most common and cheapest method of waste management practice in India. Municipal Solid Waste Landfills (MSWL) became a nuisance affecting the health, hygiene, sanitation and aesthetics of the surrounding area. Aggregates occupy almost 70% of concrete, so replacing waste materials with them could be a rewarding choice. In the current work, an experimental investigation is being carried out to test the addition of MSWL as a substitution with fine aggregate for concrete production. Out of the different aged samples available at the dumpsite, the most aged sample is chosen for experimental investigations according to the basic physical properties. Concrete mixes, with 0%, 4%, 5%, 7% and 10% partial replacement of fine aggregate with MSWL are tested for mechanical properties such as compressive strength, split tensile strength, flexural strength, and non-destructive test and have proved to be a partial substitute for fine aggregate. Durability studies such as water absorption, acid attack and sulphate attack also gave better experimental proof for the sustainable reuse of this waste material. The research reveals 5% replacement is the optimum considering all the test result values. The paper leads to advanced research for the suitability of the material in the construction industry.

Analysis of the State of the Municipal Solid Waste Landfill in Ivano-Frankivsk, Ukraine, the Composition of the Leachate, and Promising Technologies for its Treatment

Analysis of the State of the Municipal Solid Waste Landfill in Ivano-Frankivsk, Ukraine, the Composition of the Leachate, and Promising Technologies for its Treatment

A comprehensive investigation of geoenvironmental pollution and health effects from municipal solid waste landfills

This study investigates human health risks associated with heavy metals (HMs) occurrence in municipal solid waste (MSW) landfills. For testing of selected MSW landfills steps were involved, including site characterization, soil sampling and chemical testing, statistical analysis, as well as health risk assessment, carcinogenic and non-carcinogenic effects. For the Polish landfill (Radiowo) the average HMs concentrations were found in the following order: Zn (52.74 mg/kg DM) > Pb (28.32 mg/kg DM) > Cu (12.14 mg/kg DM) > Ni (4.50 mg/kg DM) > Cd (3.49 mg/kg DM), while for the Czech landfill (Zdounky): Zn (32.05 mg/kg DM) > Cu (14.73 mg/kg DM) > Ni (4.73 mg/kg DM) > Pb (0.10 mg/kg DM) = Cd (0.10 mg/kg DM). Strong positive correlations between selected HMs demonstrated identical origins. Principal component analysis (PCA) performed for the Radiowo landfill transferred the soil parameters into three principal components (PCs), accounting for 87.12% of the total variance. The results of the PCA analysis for the Zdounky landfill revealed three PCs responsible for 95.16% of the total variance. The exposure pathways of HMs for landfills were in the following order: ingestion > dermal absorption > inhalation. For both landfills, the values of hazard quotient were lower than 1, indicating no potential negative health effects. In terms of the hazard index (HI), for both landfills, no adverse human health effects occur (HI < 1). The incremental lifetime cancer risk (ILCR) values indicated negligible or acceptable carcinogenic risk of HMs (average ILCR in the range from 5.01E−10 to 5.19E−06).

Pb(ΙΙ), Cd(ΙΙ), and Mn(ΙΙ) adsorption onto pruning-derived biochar: physicochemical characterization, modeling and application in real landfill leachate

The aim of this study was to systemically evaluate how different pyrolysis temperatures (400, 550, and 700 °C) and particle sizes (1–2 mm and 63–75 µm) were influenced biochar evolution, made from urban pruning waste, during pyrolysis process and to establish their relationships with biochar potential for removal of lead (Pb), cadmium (Cd), and manganese (Mn) from real municipal solid waste landfill leachate. The effects of pH (2–7), contact time (30–300 min) and adsorbent dosage (0.1–5 g L−1) on heavy metals removal were also examined. The results showed that physicochemical properties of biochar were greatly influenced by pyrolysis temperature. Particle size, however, showed little influence on biochar characteristics (p > 0.05). The yield, volatile matter, hydrogen and oxygen contents, and surface functional groups decreased consistently with increasing pyrolysis temperature. An increase in the pH, electrical conductivity, ash, fixed carbon, and specific surface area values was also found. In biochar samples formed at high temperatures (i.e., 550 and 700 °C), Fourier transform infrared spectroscopy-FTIR studies confirmed the increase in aromaticity. Field emission scanning electron microscopy-FESEM images showed differences in the microporous structure and lower size pores at higher temperatures. Biochar pyrolyzed at 700 °C with a particle size of 63–75 µm (i.e., Lv700-63) showed the highest removal efficiency performance. Pb and Cd ions were completely removed (100%) by 0.2 g L−1 Lv700-63 at 7.0 pH and contact times of 120 and 90 min, respectively. The maximum percentage removal of Mn was 86.20% at optimum conditions of 0.2 g L−1 Lv700-63 dosage, 7.0 pH, and 180 min contact time. The findings suggests that the surface complexation, π-electron coordination, and cation exchange were the dominant mechanisms for the Pb, Cd, and Mn removal onto Lv700-63.

Laboratory tests for evaluation of shear strength and tensile effect generated by fibers present in Muribeca’s landfills of municipal solid waste

Understanding the geotechnical behavior of a municipal solid waste landfill (MSW) requires the filtering of several studies. Regarding the mechanical behavior, there are several discussions about the conditions for the stability maintenance of these structures. This stability depends a priori on the resistance of the compacted material to remain itself stable in a way that it does not generate ruptures or slips. Of various materials compacted found in the MSW landfills, high percentages of fibers (such as plastic, fabric and wood) are verified, these materials have a great influence on the mechanical behavior of the structure. These fibers in turn produce in general an increase in the geotechnical parameters: cohesion (c), friction angle (ϕ) and tensile (ζ), which consequently increase the degree of stability of the landfill. In this context, the present work performed evaluations of the effect of fiber tensile and shear strength in samples of Muribeca’s MSW landfills, the analyzes were performed by laboratory tests using a specimen of aged residues collected in the field, with a deposition age of 10 years. With the collected sample, direct shear tests were performed on 3 different sample proportions of fibers: 0%, 16.17% and 32.33%, in two conditions of test: flooded and non-flooded. From the results obtained in the tensile angles (ζ) in the condition of flooded of 10.2° and 5.0°, for the percentages of 16.17% and 32.33%, respectively.

A review of existing methods for predicting leachate production from municipal solid waste landfills.

Landfilling is one of the predominant methods of municipal solid waste (MSW) disposal worldwide, while the generation of leachate, a kind of toxic wastewater, is among the primary factors behind landfill instability and environmental contamination problems. Precise prediction of leachate production is crucial to landfill safety evaluation and design. This paper presents a comprehensive review of methods for predicting leachate production from MSW landfills. Firstly, compositional characteristics of MSW and leachate generation mechanism are analysed. Factors influencing leachate production are summarised based on the generation mechanism, including the components of MSW, climatic conditions, landfill structure, and environmental factors. Then, we classified the existing methods for predicting leachate production into four categories: water balance formula, water balance model, empirical formula, and artificial intelligence model methods. Advantages, disadvantages, and applicability of different leachate production prediction methods are compared and analysed. Furthermore, limitations in the existing leachate production prediction methods for MSW landfills and scope for future research are discussed.

Assessment of the influence of the toxic effect of municipal solid waste on the ecological state of the soil

Introduction. Тhe municipal solid waste of pollution negatively affects on the state of the environment, since during their storage on the territory of landfills and the adjacent territory, accumulation of heavy metals (HM) can change the biological indicators of soil conditions: microbiological, biochemical, and phytotoxic.&#x0D; The aim of the study was to assess the influence of the toxic effect of the municipal waste landfill “Azov” in the Rostov region on the ecological state of the soil. &#x0D; Materials and methods. It was explored the influence of municipal solid waste landfill “Azov” of the Rostov region on the ecological condition of the ordinary chernozem in the landfill and adjacent territory (140, 260, 380, and 540 m). The content of heavy metals in the soil, such as chromium (Cr), strontium (Sr), zinc (Zn), vanadium (V), copper (Cu), nickel (Ni), cobalt (Co), lead (Pb), and arsenic (As) were defined. The ecological state is assessed by sensitive and informative-biological indicators of soil pollution: the abundance of bacteria of the genus Azotobacter, the total prevalence of soil bacteria, the activity of catalase, dehydrogenases. &#x0D; Results. Soils were found to contaminate with arsenic by MAC / TAC (exceeding the MAC by 7 times at the landfill and exceeding the MAC by 4 to 6 times in the territory). Pollution with heavy metals according to German MACs with chromium exceeded by 1.4 times). The highest concentration of heavy metals prevailed in the body of the landfill. Depending on distance from the landfill the concentration of heavy metals in the soil decreased. HM contamination leads to negative consequences for the ecological state of ordinary chernozem: the total number of bacteria decreases (until to 95% of the control), the number of the genus Azotobacter decreases (up to 95% of the control), the activity of catalase (up to 25% of the control) and dehydrogenase decreases (up to 30% of control) and increased soil phytotoxicity (up to 60% of control). It can be concluded that the exploitation of the landfill leads to a deterioration of the environmental situation on the territory of the landfill and beyond.&#x0D; Limitations. The ecotoxic effect of HMs on soils less buffered to pollution will be higher than on the chernozems studied in the article.&#x0D; Conclusion. The Landfill “Azov” was found to impact on the microbiological, biochemical, and phytotoxic parameters of the soil negatively. This problem connects with influence of heavy metals which get into the soil of during the operation of the landfill. The most sensitive and informative biological indicators are total number of bacteria and length of radish roots.

Characterization of Leachate and Evaluation of Groundwater Pollution in the Vicinity of the Municipal Solid Waste Landfill in Srinagar, Jammu &amp; Kashmir

Abstract: The most popular way for disposing of municipal solid waste (MSW) throughout India, including Kashmir, is through landfills. However, the discharge of leachate from these facilities has seriously contaminated groundwater. An evaluation was conducted on the groundwater quality near the Srinagar landfill site (Achan). In order to investigate the potential effects of leachate percolation on groundwater quality, samples of leachate and groundwater were taken from the Srinagar dump site and its surrounding areas. Groundwater and leachate samples were used to measure the concentration of various physio-chemical parameters (pH, EC, TDS, COD, BOD, Ca2+, Mg2+, Na+, K+, Cl-, SO42-, NO3-, NH4+, PO43-, Phenol), as well as microbiological parameters (total coliform and faecal coliform) and heavy metals (Cd, Cr, Cu, Fe, Ni, Pb, Zn, and Hg). The relatively elevated levels of NH4+, EC, TDS, BOD, phenol, Cd, and Mg, Cr were above the limits of Indian standard and WHO for drinking water. In addition to this , these also represent heavy pollutant indicators as per the Single Point Pollution Index as well by the Nemero index, as these elements crossed the upper most limit for both these pollution indeces. Assessing the water contamination in depth and distance wise, closer to landfill and shallow wells were characterized as the most polluted and had some additive contaminants ( Cl- ,SO4, Ca , Ni ). This is an indication of pollution transfer and the leachate movement. The presence of total coliform and faecal coliform although in small counts warns for the groundwater quality and thus renders the associated aquifer unreliable for domestic water supply. There is no natural or other possible reason for high concentration of these pollutants, thus it can be concluded that leachate has significant impact on groundwater quality in the area. In the present study, also an attempt has been made to investigate physico-chemical properties, fertilizing potential and heavy metal polluting potentials of the three types of composts including municipal soild waste compost, green waste compost and mixed waste compost. Each of these types were given a treatment with effective micro organisms (EM) to understand the quality of compost so formed by the composting process by its analysis (Laboratory as well as statistical) and the quality of composts was found out using Quality control Indices such as Fertilizing Index and Clean Index. Parameters like, pH, EC, TOC, total nitrogen, total phosphorous, total potassium, C/N ratio, and heavy metals like zinc, copper, cadmium, nickel, lead, and chromium were analyzed and it was found that all the parameters were within the permissible limits prescribed by FCO-2000. Further Fertility Index and Clean Index were determined for the samples and it was found that proper segregation of the solid waste is important from composting point of view because mixed waste affects the quality of compost. From the calculated values for the compost prepared from untreated MSW, FI (3.40) and CI (2.8), for the treated MSW Compost, FI as 3.47 and CI as 3.0, for the untreated mixed waste FI (3.27) and CI (3.0) and for the treated mixed waste FI (3.47), CI (3.2) The determined values indicates that all these compost types belongs to marketable Class D (medium fertilizing potential and medium heavy metal content).The fertility index value was estimated as 2.0 and the Clean Index value as 3.06 for the untreated green waste while for treated green waste FI(2.73) and CI(3.7), which indicates that both compost types belongs to restricted use Class RU-1 (Should not be allowed to market due to low fertilizing potential. However, these can be used as soil conditioner)

Groundwater Chemical Status Assessment in the Area of the Waste Landfill in Chorzów—Southern Poland

In this study, the spatiotemporal variation of water pollution near a municipal solid waste landfill in Chorzow (southern Poland) was investigated. For this purpose, analyses of electrolytic conductivity, sulfates, chlorides, nitrates, ammonium ion, and boron were performed. The landfill water pollution index (LWPI) and Nemerow Pollution Index (NPI) were calculated on the basis of groundwater monitoring results for the study area. The results indicated very high pollution in each piezometer. The value of the LWPI index for the piezometer located at the groundwater outflow from the landfill exceeded 320, and values exceeding five indicate a high risk to groundwater. In the case of the NPI index, the value reached nearly 44, which also indicates a high risk. The structure of both indices allows for the assessment of the level of threat to groundwater in areas of pollution sources. However, the NPI index highlights the contribution of parameters other than main ions to total water pollution. The use of indexes in assessing the quality of groundwater around pollution hotspots is very helpful in waste management, as it allows for determining the degree of threat to water, and thus can help in implementing additional preventive solutions.

Climate variability impacts on methane recovery in a municipal solid waste landfill: A case study in a humid tropical climate region

Climate variability impacts on methane recovery in a municipal solid waste landfill: A case study in a humid tropical climate region

Comparative study of steam, organic Rankine cycle and supercritical CO2 power plants integrated with residual municipal solid waste gasification for district heating and cooling

Among the different waste-to-energy solutions, gasification is considered a promising option and an alternative to landfilling of residual municipal solid waste (RMSW). Therefore, the potential of RMSW air gasification in combination with three different power cycles for district cooling and heating applications is investigated. The model of a fluidized bed air gasifier developed in Aspen Plus is integrated with the models of steam turbine (ST), organic Rankine cycle (ORC), and supercritical CO2 (sCO2) Brayton cycle power plants for the combined cooling, heating, and power production in district networks.The results of the numerical study show that the ST power plant provides higher electrical power compared to the other systems, while sCO2 exhibits better thermal power and the maxima combined energy conversion efficiency. In between, ORCs prove to be a reliable and flexible solution for varying RMSW compositions and temperature levels of the district network. The size of the district network strongly varies with scenarios and in the best case, more than 1,400 residential buildings can be connected to the trigeneration plant considering 20 ktons/year of RMSW input to the gasifier.

Reliability of Municipal Solid Waste Landfills within the Eurocode Framework

Municipal solid waste (MSW) landfill slope failures can have significant consequences for the economy, environment, and human health. One potential cause of slope failure is insufficient reliability, resulting from inadequate design. The usual practice in the design of MSW landfills involves utilizing established geotechnical codes, such as Eurocode 7 (EC7), to perform slope stability assessments. Considering the substantial heterogeneity of MSW relative to soil, questions arise regarding the justification of such an approach in the design of MSW landfills. This study examines the suitability of applying EC7 in MSW landfill design, analyzing the stability and reliability of landfill slopes across various heights, front slope angles, design approaches, and consequence classes. This study finds that, in most cases considered, EC7 does not ensure an adequate level of reliability for MSW landfill slopes. Therefore, it is suggested that EC7 should be complemented with specific guidelines for incorporating MSW in geotechnical analyses to achieve the desired structural reliability. Adopting this strategy will not only enhance the reliability of landfill design but also promote the development of solutions that are economically and environmentally sustainable.

Identification of microplastics in raw and treated municipal solid waste landfill leachates in Hong Kong, China

Plastics are indispensable in modern society but also pose a persistent threat to the environment. In particular, microplastics (MPs) have a substantial environmental impact on ecosystems. Municipal solid waste landfill leachates are a source of MPs, but leakage of MPs from leachates has only been reported in a few studies. As a modern city, Hong Kong has a remarkably high population density and a massive plastic waste generation. However, it depends on conventional landfilling for plastic waste management and traditional thermal ammonia stripping for leachate treatment. Yet, the MP leakage from landfill leachates in Hong Kong has not been disclosed. This is the first study that aimed to identify, quantify, and characterise MPs in raw and treated leachates, respectively, from major landfill sites in Hong Kong. The concentrations of MPs varied from 49.0 ± 24.3 to 507.6 ± 37.3 items/L among the raw leachate samples, and a potential correlation was found between the concentration of MPs in the raw leachate sample from a given landfill site and the annual leachate generation of the site. Most MPs were 100–500 μm fragments or filaments and were transparent or yellow. Regarding the polymeric materials among the identified MPs, poly(ethylene terephthalate) and polyethylene were the most abundant types, comprising 45.30% and 21.37% of MPs, respectively. Interestingly, leachates treated by ammonia stripping contained higher concentrations of MPs than raw leachate samples, which demonstrated that the traditional treatment process may not be sufficient regarding the removal of emerging pollutants, such as MPs. Overall, our findings provide a more comprehensive picture of the pollution of MPs in landfill leachates in Hong Kong and highlight the urgent need for adopting the consideration of MPs into the conventional mindset of waste management systems in Hong Kong.

Effects of operating conditions on the in situ control of sulfur-containing odors by using a novel alternative landfill cover and its transformation mechanism.

Sulfur-containing gases are main sources of landfill odors, which has become a big issue for pollution to environment and human health. Biocover is promising for treating landfill odors, with advantages of durability and environmental friendliness. In this study, charcoal sludge compost was utilized as the main effective component of a novel alternative landfill cover and the in situ control of sulfur-containing odors from municipal solid waste landfilling process was simulated under nine different operating conditions. Results showed that five sulfur-containing odors (hydrogen sulfide, H2S; methyl mercaptan, CH3SH; dimethyl sulfide, CH3SCH3; ethylmercaptan, CH3CH2SH; carbon disulfide, CS2) were monitored and removed by the biocover, with the highest removal efficiencies of 77.18% for H2S, 87.36% for CH3SH, and 92.19% for CH3SCH3 in reactor 8#, and 95.94% for CH3CH2SH and 94.44% for CS2 in reactor 3#. The orthogonal experiment showed that the factors influencing the removal efficiencies of sulfur-containing odors were ranked from high to low as follows: temperature > weight ratio > humidity content. The combination of parameters of 20% weight ratio, 25°C temperature, and 30% water content was more recommended based on the consideration of the removal efficiencies and economic benefits. The mechanisms of sulfur conversion inside biocover were analyzed. Most organic sulfur was firstly degraded to reduced sulfides or element sulfur, and then oxidized to sulfate which could be stable in the layer as the final state. In this process, sulfur-oxidizing bacteria play a great role, and the distribution of them in reactor 1#, 5#, and 8# was specifically monitored. Bradyrhizobiaceae and Rhodospirillaceae were the dominant species which can utilize sulfide as substance to produce sulfate and element sulfur, respectively. Based on the results of OUTs, the biodiversity of these sulfur-oxidizing bacteria, these microorganisms, was demonstrated to be affected by the different parameters. These results indicate that the novel alternative landfill cover modified with bamboo charcoal compost is effective in removing sulfur odors from landfills. Meanwhile, the findings have direct implications for addressing landfill odor problems through parameter adjustment.

Neurobehavioral deficits, histoarchitectural alterations, parvalbumin neuronal damage and glial activation in the brain of male Wistar rat exposed to Landfill leachate

Concerns about inappropriate disposal of waste into unsanitary municipal solid waste landfills around the world have been on the increase, and this poses a public health challenge due to leachate production. The neurotoxic effect of Gwagwalada landfill leachate (GLL) was investigated in male adult Wistar rats. Rats were exposed to a 10% concentration of GLL for 21 days. The control group received tap water for the same period of the experiment. Our results showed that neurobehavior, absolute body and brain weights and brain histomorphology as well as parvalbumin interneurons were severely altered, with consequent astrogliosis and microgliosis after 21 days of administrating GLL. Specifically, there was severe loss and shrinkage of Purkinje cells, with their nucleus, and severe diffused vacuolations of the white matter tract of GLL-exposed rat brains. There was severe cell loss in the granular layer of the cerebellum resulting in a reduced thickness of the layer. Also, there was severe loss of dendritic arborization of the Purkinje cells in GLL-exposed rat brains, and damage as well as reduced populations of parvalbumin-containing fast-spiking GABAergic interneurons in various regions of the brain. In conclusion, data from the present study demonstrated the detrimental effects of Gwagwalada landfill leachate on the brain which may be implicated in neuropsychological conditions.