Municipal Waste Landfill Site Research Articles

Spatial Distribution of Salmonella in Soil near Municipal Waste Landfill Site

Due to the heterogeneous origin of municipal waste, different substrates support the growth of many microorganisms, including those hazardous to humans. In consequence, landfills collecting these refuses are regarded as serious sources of infectious material contaminating the environment. In this study, we aimed to assess how waste may be related to the presence of Salmonella spp. in soil within a landfill and its surroundings. The numbers of these pathogens were estimated in soil samples collected at 17 different stands established in the municipal waste landfill of Barycz (near Kraków, Poland) and the surrounding area. The analysis showed that in all soil samples, Salmonella spp. did not exceed 270 cfu g−1 in dry soil (i.e., the active landfill sector). Salmonella spp. was found in 57% of the tested soil samples in spring, 88% in summer, 45% in autumn, and was not detected in winter. A spatial distribution visualized by graphical maps allowed determination of the influence of the active sector on the surrounding areas. The graphical maps showed the impact of seasons on the spread of Salmonella spp. in the soil near the landfill. Detection and estimation of Salmonella spp. distribution in soil within the landfill area distinctly confirms the hazardous impact of collected wastes on hygienic characteristics of the soil.

VOLATILE ORGANIC COMPOUNDS FROM GREEN WASTE ANAEROBIC DEGRADATION AT LAB-SCALE: EVOLUTION AND COMPARISON WITH LANDFILL GAS

The chemical composition of volatile organic compounds (VOCs) in landfill gas from municipal waste (MW) landfills primarily depends on the type of degrading waste. To provide first insights into the relationship between VOC chemistry (in landfill gas) and specific waste components, a lab-scale experiment on anaerobic digestion (AD) of green waste (GW) was carried out. The composition of the released C4+ VOCs was semi-quantitatively determined and indirectly compared to that generally expected for the overall MW landfill gas. The generated biogas from degrading GW during AD time showed up to 29 different VOCs, mainly including terpenes, followed by alkanes, alkenes, cyclics, aromatics, and halogenated compounds. O- and S-substituted compounds were sporadically detected. Overall, speciation and total concentration of VOCs fluctuated over AD time, likely due to changes in microbial populations and metabolism, as well as substrate depletion, during the AD evolution. As expected, VOC speciation in the GW biogas was lower than that of the typical MW landfill gas, since the latter is generated by a large variety of organic and synthetic waste components following different sequential degradation processes. These results highlighted that, when disposed of at MW landfill sites, the specific GW component may (i) potentially concur to the overall odour charge and toxic effects of MW landfill gas and (ii) detrimentally impact the energy exploitation of MW landfill gas by releasing terpenes, aromatics, and halogenated compounds.

Study of Biogas Composition on Operational and Non-Operational Landfill Sites from Poland

An assessment of the variability of biogas components captured in an active and closed municipal waste landfill sites differing of amount deposited waste, activity period with their passive degassing, was presented in the article. The results of research did not show significant differences between components of LFG from studied landfill sites. But was confirmed that the two landfill sites including used landfill site, became at the last phase degradation of waste and advantage the anaerobic processes at the low value below 0.02 of CH4/O2 indicator. It was demonstrated by the very low average methane content below 1%, and significant higher of oxygen above 19%. This confirm that only way of biogas utilization is to burn it in flare on the landfill sites.

Groundwater quality testing in the area of municipal waste landfill sites in Dąbrowa Górnicza (southern Poland)

Abstract Groundwater quality assessment for pollution can be undertaken with the use of indicators that will confirm or deny the negative impact of potential pollution sources. Based on water quality monitoring data from the Lipówka I and Lipówka II municipal landfill sites in Dąbrowa Górnicza from the last five years, the water quality in the area was assessed using the Nemerow Pollution Index (NPI) method. Seven parameters were assessed – pH, electrical conductivity, and the concentrations of chlorides, sulphates, ammonium ions, boron and iron. The limits for class III water quality were used as the reference level. The results of the NPI calculations show that the highest indices were obtained for the piezometers PZ5 and T5 located in the outflow of the water from the Lipówka I landfill site. The highest values of the Nemerow index were obtained for ammonium ions and reached a value of over 36 in the PZ5 piezometer and 17 in the T5 piezometer. The other parameters did not indicate a significant impact of the landfill sites on the quality of groundwater. The highest values of the indicators were observed in 2017. It is worth noting that, apart from the large differences in the content of ammonium ions, the values of the Nemerow indices for the electrical conductivity specifically for the PZ5 piezometer are twice as high as for the other piezometers and four times higher than for boron. The Nemerow index is a useful and easy method of assessing the quality of groundwater. It can even be used for a small number of parameters.

Assessment of GHG Interactions in the Vicinity of the Municipal Waste Landfill Site—Case Study

Landfills have been identified as one of the major sources of greenhouse gas (GHG) emissions and as a contributor to climate change. Landfill facilities exhibit considerable spatial and temporal variability of both methane (CH4) and carbon dioxide (CO2) rates. The present work aimed to evaluate the spatial distribution of CH4 and CO2 and their δ13C isotopic composition originating from a municipal landfill site, to identify its contribution to the local GHG budget and the potential impact on the air quality of the immediate surroundings in a short-term response to environmental conditions. The objective was met by performing direct measurements of atmospheric CO2 and CH4 at the selected monitoring points on the surface and applying a binary mixing model for the determination of carbon isotopic ratios in the vicinity of the municipal waste landfill site. Air samples were collected and analysed for isotopic composition using flask sampling with a Picarro G2201-I Cavity Ring-Down Spectroscopy (CRDS) technique. Kriging and Inverse distance weighting (IDW) methods were used to evaluate the values at unsampled locations and to map the excess of GHGs emitted from the landfill surface. The large off-site dispersion of methane from the landfill site at a 500 m distance was identified during field measurements using isotopic data. The mean δ13C of the landfill biogas emitted to the surrounded atmosphere was −53.9 ± 2.2‰, which corresponded well to the microbial degradation processes during acetate fermentation in the waste deposits. The calculated isotopic compositions of CO2 (δ13C = −18.64 ± 1.75‰) indicate the domination of biogenic carbon reduction by vegetation surrounding the landfill. Finally, amounts of methane escaping into the air can be limited by the appropriate landfill management practices (faster covers active quarter through separation layer), and CH4 reduction can be achieved by sealing the cover on the leachate tank.

Emission and Neutralization of Methane from a Municipal Landfill-Parametric Analysis

An attempt was made to estimate the annual production of CH4 at a municipal waste landfill site in Poland. As a matter of fact, the extent of the unorganized emission of CH4 from the landfill surface was approached based on the adopted mathematical model. The Ward agglomeration method for cluster analysis and the Pearson coefficient were employed to evaluate the distance-based similarity measure and to optimize methods for estimating methane emissions from a landfill as well as to verify the input parameters for the model. In order to calculate the content of biodegradable organic parts in the waste, morphological tests of the landfilled waste were performed. Physical quantities, measurements and the actual amount of the landfilled waste as well as the volume of CH4 neutralized in a collective flare were implemented in the model, respectively. The model-based findings and experimental outcome demonstrated stable gas production in the landfill with a high CH4 content. On the other hand, a rather low efficiency of the landfill passive degassing installation indicated the necessity to design and develop its active counterpart with the prospective application of the generated biogas for energy production in a cogeneration system.

Seasonal characterization and quantification of municipal solid waste: Energy content and statistical analysis

Determining the seasonal and annual quantities and compositions of the municipal solid waste and assessing the present management conditions of three urban communities in the northwest of Iran were the core objectives of this study. Our findings revealed that the average daily per capita of municipal waste generation was 0.489–0.841 kg/cap-day. Organic and food waste comprised the largest part (56.46%) of the total generated waste in the studied cities, whereas paper and cardboard, plastics, metals, rubber, textiles, glass, woods, and other waste constituted 5.99, 12.62, 1.05, 0.95, 7.71, 1.63, 1.23, and 12.36%, respectively. More than 21% of the total generated waste was directly recyclable. Bulk density of the waste was determined as 182.53 kg/m3. In addition, the moisture content and the chemical characteristics (food and organic fraction) of the generated waste including the amounts of carbon, nitrogen, phosphorous, ash, and C/N ratio were 67.44, 50.86, 1.67, 0.41, 34.91, and 30.61%, respectively. Waste composition in different seasons followed a variable pattern. In the present conditions, all the three studied cities were sending their waste to the municipal waste landfill sites that were actually used as a dump for waste. Hence, great concerns were raised from the public health and environmental viewpoints such as ground water, soil, and air pollution at the final disposal sites in the area. Implementation of source reduction, separation and recycling program, closing dump sites, and investing for new landfill sites according to the scientific and environmental approaches, were proposed.

The study on the SWOT analysis of renewable energy sector on the example of the Pomorskie Voivodeship (Poland)

SWOT analysis of renewable energy in Poland on the example of Pomorskie Voivodeship has been described. The current state of and development prospects for renewable energy in the Pomorskie Voivodeship have been presented. In this region, there are 40 wind installations of total power of 424 MW, 108 hydropower plants of total power of 34 MW, one power plant co-firing biomass with coal. There is 102 million dm3/year of bio ethanol and 159 million dm3/year of biodiesel produced. There are five biogas plants located at municipal waste landfill sites and four biogas plants at sewage treatment works as well as nine agricultural biogas plants. A few hundred solar collectors and heat pumps have been installed in the Voivodeship. The conducted SWOT analysis shows that the further development of renewable energy sector in Poland is strongly depended form the following: the Act on renewable energy sources, simpler legal regulations, more effective financial support for new investments, introduction of guaranteed certificate prices, education of the public, and investors and decision-makers in the filed of renewable energy sector development.

Bacterial community diversity in municipal waste landfill sites.

Little is known about the bacterial diversity of landfills and how environmental factors impact the diversity. In this study, PCR-based 454 pyrosequencing was used to investigate the bacterial communities of ten landfill leachate samples from five landfill sites in China. A total of 137 K useable sequences from the V3-V6 regions of the 16S rRNA gene were retrieved from 205 K reads. These sequences revealed the presence of a large number of operational taxonomic units (OTUs) in the landfills (709-1599 OTUs per sample). The most predominant bacterial representatives in the landfills investigated, regardless of geographic area, included Gammaproteobacteria, Firmicutes, and Bacteroidetes. The phyla Fusobacteria and Tenericutes were also found for the first time to be predominant in the landfills. The phylum Fusobacteria predominated (51.5 and 48.8%) in two semi-arid landfills, and the phylum Tenericutes dominated (30.6%) at one humid, subtropical landfill. Further, a large number of Pseudomonas was detected in most samples, comprising the dominant group and accounting for 40.9 to 92.4% of the total abundance. Principal component analysis (PCA) and cluster analysis based on OTU abundance showed that the abundant taxa separated the bacterial community. Canonical correlation analysis (CCA) suggested that precipitation and landfilling age significantly impact on the bacterial community structure. The bacterial community function (e.g., cellulolytic bacteria, sulfate-reducing bacteria (SRB), sulfate-oxidizing bacteria, and xenobiotic organic compound (XOC)-degrading bacteria) was also diverse, but the pattern is unclear.

Archaeal community diversity in municipal waste landfill sites.

Despite the pivotal role of archaea in methane production in landfills, the identity, ecology, and functional diversity of these microorganisms and their link to environmental factors remain largely unknown. We collected 11 landfill leachate samples from six geographically distinct landfills of different ages in China and analyzed the archaeal community by bar-coded 454 pyrosequencing. We retrieved 121,797 sequences from a total of 167,583 sequences (average length of 464 bp). The archaeal community was geographically structured, and nonabundant taxa primarily contributed to the observed dissimilarities. Canonical correlation analysis (CCA) suggested that the total phosphorous (TP), nitrate, and conductivity are important drivers for shaping the archaeal community. The hydrogenotrophic methanogens Methanomicrobiales and Methanobacteriales greatly dominated 9 of 11 samples, ranging from 83.7 to 99.5 %. These methanogens also dominated the remaining two samples, accounting for 70.3 and 58.8 %, respectively. Interestingly, for all of the studied Chinese landfills, 16S rRNA analysis indicated the predominance of hydrogenotrophic methanogens.

Phytoremediation of 1,4-Dioxane-Containing Recovered Groundwater

The results of a pilot-scale phytoremediation study are reported in this paper. Small plots of trees established on a closed municipal waste landfill site were irrigated with recovered groundwater containing 1,4-dioxane (dioxane) and other volatile organic compounds (VOCs). The plots were managed to minimize the leaching of irrigation water, and leaching was quantified by the use of bromide tracer. Results indicated that the dioxane (2.5 μg/L) was effectively removed, probably via phytovolatilization, and that a full-scale phytoremediation system could be used. A system is now in place at the site in which the recovered groundwater can be treated using two different approaches. A physical treatment system (PTS) will be used during the winter months, and a 12 ha phytoremediation system (stands of coniferous trees) will be used during the growing season. The PTS removes VOCs using an air-stripper, and destroys dioxane using a photo-catalytic oxidation process. Treated water will be routed to the local sewer system. The phytoremediation system, located on the landfill, will be irrigated with effluent from the PTS air-stripper containing dioxane. Seasonal use of the phytoremediation system will reduce reliance on the photo-catalytic oxidation process that is extremely energy consumptive and expensive to operate.

The microbial ecology of anaerobic cellulose degradation in municipal waste landfill sites: evidence of a role for fibrobacters

Cellulose is reputedly the most abundant organic polymer in the biosphere, yet despite the fundamental role of cellulolytic microorganisms in global carbon cycling and as potential sources of novel enzymes for biotechnology, their identity and ecology is not well established. Cellulose is a major component of landfill waste and its degradation is therefore a key feature of the anaerobic microbial decomposition process. Here, we targeted a number of taxa containing known cellulolytic anaerobes (members of the bacterial genus Fibrobacter, lineages of Clostridium clusters I, III, IV and XIV, and anaerobic fungi of the Neocallimastigales) in landfill leachate and colonized cellulose 'baits' via PCR and quantitative PCR (qPCR). Fibrobacter spp. and Clostridium clusters III, IV and XIV were detected in almost all leachate samples and cluster III and XIV clostridia were the most abundant (1-6% and 1-17% of total bacterial 16S rRNA gene copies respectively). Two landfill leachate microcosms were constructed to specifically assess those microbial communities that colonize and degrade cellulose substrates in situ. Scanning electron microscopy (SEM) of colonized cotton revealed extensive cellulose degradation in one microcosm, and Fibrobacter spp. and Clostridium cluster III represented 29% and 17%, respectively, of total bacterial 16S rRNA gene copies in the biofilm. Visible cellulose degradation was not observed in the second microcosm, and this correlated with negligible relative abundances of Clostridium cluster III and Fibrobacter spp. (≤ 0.1%), providing the first evidence that the novel fibrobacters recently detected in landfill sites and other non-gut environments colonize and degrade cellulose substrates in situ.

Study of the VOC emissions from a municipal solid waste storage pilot-scale cell: Comparison with biogases from municipal waste landfill site

The emission of volatile organic compounds (VOCs) from municipal solid waste stored in a pilot-scale cell containing 6.4 tonnes of waste (storage facility which is left open during the first period (40 days) and then closed with recirculation of leachates during a second period (100 days)) was followed by dynamic sampling on activated carbon and analysed by GC–MS after solvent extraction. This was done in order to know the VOC emissions before the installation of a methanogenesis process for the entire waste mass. The results, expressed in reference to toluene, were exploited during the whole study on all the analyzable VOCs: alcohols, ketones and esters, alkanes, benzenic and cyclic compounds, chlorinated compounds, terpene, and organic sulphides. The results of this study on the pilot-scale cell are then compared with those concerning three biogases from a municipal waste landfill: biogas (1) coming from waste cells being filled or recently closed, biogas (2) from all the waste storage cells on site, and biogas (3) which is a residual gas from old storage cells without aspiration of the gas. The analysis of the results obtained revealed: (i) a high emission of VOCs, principally alcohols, ketones and esters during the acidogenesis; (ii) a decrease in the alkane content and an increase in the terpene content were observed in the VOCs emitted during the production of methane; (iii) the production of heavier alkanes and an increase in the average number of carbon atoms per molecule of alkane with the progression of the stabilisation/maturation process were also observed. Previous studies have concentrated almost on the analysis of biogases from landfills. Our research aimed at gaining a more complete understanding of the decomposition/degradation of municipal solid waste by measuring the VOCs emitted from the very start of the landfill process i.e. during the acidogenesis and acetogenesis phases.

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).

Microbial Air Quality in Offices at Municipal Landfills

The purpose of this study was to evaluate the influence of two municipal landfills on the microbiological air quality in offices on landfill sites. The evaluation was based on the concentration levels of airborne bacteria and fungi and the identification of isolated strains. Air samples were collected with a six-stage Andersen impactor. The concentrations of bacterial aerosol ranged from 1.0 × 103 to 7.2 × 104 colony forming units (CFU)/m3 indoors, and from 7.0 × 10 to 4.0 × 104 CFU/m3 outdoors. The corresponding fungal aerosol ranges were from 2.3 × 102 to 7.3 × 103 CFU/m3 indoors and from 2.0 × 102 to 1.2 × 104 CFU/m3 outdoors. The concentration levels were affected by the season of the year. The study showed that both indoor and outdoor air were heavily contaminated with bacteria and fungi. The proximity of the unpaved transport route and the weighing of refuse loads contributed to the increase of bacterial and fungal aerosol concentrations significantly. The air in the offices was characterized not only by elevated concentrations of bacteria and fungi but also by high frequencies of gram-negative bacteria, along with fungal species characteristic of landfills. The quantitative and qualitative changes in the composition of the bacterial and fungal aerosol posed a possible health risk to office workers at municipal waste landfill sites.

Selective determination of gas dialysable components in complex sample solutions using triangle programmed coulometric titration in continuous flow systems

A precisely and sensitively working coulometric flow titration procedure was developed to determine ammonium/ammonia and sulphide/hydrogen sulphide in leachate from a municipal waste landfill site. The selectivity of coulometric titration with electrogenerated hypobromite could be essentially improved by the combination with a continuously and quantitatively working thin layer gas dialysis cell, which was integrated in the flow titration setup in one measuring device. During the flow titrations both ammonium/ammonia and sulphide/hydrogen sulphide were quantitatively separated from the sample solutions. Both the commonly used biamperometric and the chemiluminescence flow detection could be applied to follow the titration course. By triangle-programmed coulometric titration ammonium/ammonia were detected in a linear range from 10 −3 to 10 −6 M (relative standard deviation (RSD) = 1%, n = 6, confidence level α = 0.05) using biamperometric detection and from 5 × 10 −4 to 10 −6 M (RSD = 3%, n = 6, α = 0.05) using chemiluminescence detection. Sulphide/hydrogen sulphide could be determined in a linear range from 5 · 10 −4 to 2 · 10 −6 M (RSD = 4%, n = 6, α = 0.05). Up to 30 flow titrations could be implemented per hour.

Capacities and limits of three different technologies for the biological treatment of leachate from solid waste landfill sites

AbstractLeachate from a municipal waste landfill site was treated using an activated sludge bioreactor, a fluidized bed biofilm reactor and a packed‐bed column reactor (trickling filter).The leachate contained high organic matter (2.0–2.6 g/l of COD), high ammonium (300–700 mg/l) and sulphide (200–800 mg/l) concentrations, as well as low metal concentrations.The continuously operating reactors were employed to study the effects of TOC loading on the removal of TOC as well as on the nitrification and denitrification processes.Among the three biological treatment technologies investigated, the fluidized bed biofilm reactor was best with respect to removing ammonia and TOC. More than 90% of TOC and 99% of ammonia were removed when TOC loading was less than 0.5 kg/m3 × d. At a TOC loading of 4 kg/m3 × d, the removal of TOC and ammonia was 80% and 99%, respectively.In contrast, the treatment of leachate with the packed‐bed reactor was successful in TOC removing only at TOC loading less than 0.3 kg/m3 × d (TOC elimination decreased from 86% at 0.06 kg/m3 × d to 60% at 0.3 kg/m3 × d). However, the reactor was active in nitrification even at a higher TOC loading (more than a 98% ammonia elimination at a TOC loading of 0.5 kg/m3 × d).Leachate was processed in the activated sludge reactor when TOC loading was less than 0.5 kg/m3 × d (with a removal of TOC and ammonia up to 83% and 99%, respectively). The activated sludge reactor was also effective in TOC removal at a higher TOC loading (e.g. a 74% TOC removal at a TOC loading of 1 kg/m3 × d), but for ammonia elimination, the activity continuously decreased (less than 60% ammonia removal at a TOC loading of 1 kg/m3 × d).Overloading in the activated sludge system was indicated by a high concentration of ammonia and nitrite in the effluent. In the packed bed reactor, overloading was characterized by a progressively incomplete TOC removal. No significant overloading was found in the fluidized bed reactor up to a TOC loading of 4 kg/m3 × d.