An assessment of the uncertainties of methane generation in landfills.

The accurate estimation of methane generation in landfills is crucial for effective greenhouse gas management and energy recovery, requiring site-specific assessments due to the inherent variability in waste composition and properties before and after disposal. This study investigates the uncertainties associated with methane generation predictions by employing a combination of stoichiometric methods, Biochemical Methane Potential (BMP) assays, and Bayesian inference. Fresh and aged (1-year-old and 5-year-old) samples collected in the tropical Saravan dump site in Gilan, Iran, were used to evaluate the waste's methane generation potential and degradation rate in the field.

Pseudomonas aeruginosa: One Health approach to deciphering hidden relationships in Northern Portugal.

Aims: Antimicrobial resistance in Pseudomonas aeruginosa represents a major global challenge in public and veterinary health, particularly from a One Health perspective. This study aimed to investigate antimicrobial resistance, the presence of virulence genes, and the genetic diversity of P. aeruginosa isolates from diverse sources.

Biogas production in a tropical landfill: Long-term monitoring results and analysis of variables of influence.

The use of landfill gas for power production is a very attractive option in tropical sanitary landfills mainly in developing countries, where the waste composition, water content, and the climate conditions are favorable to a fast depletion of waste organic matter and a robust short term biogas production response. In this paper, the results of long-term monitoring and methane extraction activities in a tropical landfill are presented, and the obtained results are analyzed taking into account the structure of the prokaryotic communities and the fugitive emissions through the temporary covers. It is shown that waste depletion by aerobic processes and fugitive emissions are probable related to the drop in the efficiency of the extraction system verified in the field and that the performance of the temporary covers is of paramount importance when implementing good practices of waste management in sanitary landfills.

Analysis of column reactor results with organic decay by native organic microbiota and varying permeability.

Field bio-remediation techniques (FBRT) can be a low cost method to avoid the removal of top layers of soil which are rich in organic matter and bio diversity. The use of native microorganisms in FBRT is preferable because non-indigenous species can transfer their genetic material to the environment with negative impacts on the local ecological equilibrium. Petroleum Produced Water (PPW) is an important pollutant source in onshore production areas.

Lead concentrations in whole blood, serum, saliva and house dust in samples collected at two time points (12 months apart) in Santo Amaro, BA, Brazil.

Unlabelled: Whole Blood Lead Level (BLL) is the main marker used to verify lead contamination. The present study explores how BLL is associated with lead concentrations in serum, saliva and house dust. Samples were collected twice from Santo Amaro, BA, Brazil, a region that was contaminated by a lead smelter in the past; a time interval of 12 months was allowed between the two collections.

Concentrate: forage ratio in the diet of dairy cows does not alter milk physical attributes.

This study aimed to evaluate the effect of concentrate-to-forage ratio (C:F) on the performance, blood profile, and milk physicochemical characteristics of mid-lactation cows fed a corn silage-based diet. Twenty four Holstein cows, with BW 575 ± 70 kg, body condition score (BCS) 3.1 ± 0.

A study of the routes of contamination by lead and cadmium in Santo Amaro, Brazil: a response to the comments of Andrade Lima.

This text is part of the discussion about the case of contamination by heavy metals in Santo Amaro, Brazil and the routes of contamination still active in the city. It is presented the point of view of the authors about the questions raised in the text of Prof. Andrade Pinho, presented in this journal issue, as well as the replies considered pertinent by the authors.

A study of the routes of contamination by lead and cadmium in Santo Amaro, Brazil.

The problem of contamination by cadmium and lead in Santo Amaro, Brazil, has been studied since 1970 and the severity of this contamination case has been demonstrated by many authors. This study evaluates the persistence of the superficial soil contamination around the metallurgical plant and attempts to correlate the lead and cadmium concentrations to the past atmospheric emissions from the lead plant and with the presence of lead debris under urban road surface and in the backyards of homes. Past emissions still play an important role in soil contamination.

The natural rehabilitation of an anthropogenically acidified tropical Lake: two decades of monitoring.

The rehabilitation of a pond after approximately 20 years of strong acidified conditions due to industrial and domestic waste deposition in its catchment basin is reviewed. We describe in this study the acidification process that occurred in a tropical pond in Northeast Brazil (Dunas Lake), the rehabilitation plan for the pond and the subsequent monitoring conducted over two decades. After the contamination assessment by the late 80s, a rehabilitation plan was carried out in the early 90s, in which the contaminated soil and water have been removed and reduced, respectively.

An attempt to perform water balance in a Brazilian municipal solid waste landfill.

This paper presents an attempt to model the water balance in the metropolitan center landfill (MCL) in Salvador, Brazil. Aspects such as the municipal solid waste (MSW) initial water content, mass loss due to decomposition, MSW liquid expelling due to compression and those related to weather conditions, such as the amount of rainfall and evaporation are considered. Superficial flow and infiltration were modeled considering the waste and the hydraulic characteristics (permeability and soil-water retention curves) of the cover layer and simplified uni-dimensional empirical models.

A laboratory study on the MSW mechanical behavior in triaxial apparatus.

Shear strength characterization of MSW materials is a mandatory task when performing analyses related to landfill design and landfill geometry improvements. Despite the considerable amount of research focusing on MSW mechanical behavior there remain certain aspects which are not completely understood and deserve attention in particular the case of the undrained behavior of MSW. This paper presents the results of a comprehensive laboratory testing program using a large-scale triaxial apparatus at the Federal University of Bahia, Salvador, Brazil.

Evaluation of the geotechnical properties of MSW in two Brazilian landfills.

The characteristics of municipal solid waste (MSW) play a key role in many aspects of waste disposal facilities and landfills. Because most of a landfill is made up of MSW, the overall stability of the landfill slopes are governed by the strength parameters and physical properties of the MSW. These parameters are also important in interactions involving the waste body and the landfill structures: cover liner, leachate and gas collection systems.

Municipal solid waste effective stress analysis.

The mechanical behavior of municipal solid waste (MSW) has attracted the attention of many researchers in the field of geo-environmental engineering in recent years and several aspects of waste mechanical response under loading have been elucidated. However, the mechanical response of MSW materials under undrained conditions has not been described in detail to date. The knowledge of this aspect of the MSW mechanical response is very important in cases involving MSW with high water contents, seismic ground motion and in regions where landfills are built with poor operation conditions.

Methane generation in tropical landfills: simplified methods and field results.

This paper deals with the use of simplified methods to predict methane generation in tropical landfills. Methane recovery data obtained on site as part of a research program being carried out at the Metropolitan Landfill, Salvador, Brazil, is analyzed and used to obtain field methane generation over time. Laboratory data from MSW samples of different ages are presented and discussed; and simplified procedures to estimate the methane generation potential, Lo, and the constant related to the biodegradation rate, k are applied.