The objective of this study was to develop a forecast model to determine the rate of generation of municipal solid waste in the municipalities of the Cuenca del Cañón del Sumidero, Chiapas, Mexico. Multiple linear regression was used with social and demographic explanatory variables. The compiled database consisted of 9 variables with 118 specific data per variable, which were analyzed using a multicollinearity test to select the most important ones. Initially, different regression models were generated, but only 2 of them were considered useful, because they used few predictors that were statistically significant. The most important variables to predict the rate of waste generation in the study area were the population of each municipality, the migration and the population density. Although other variables, such as daily per capita income and average schooling are very important, they do not seem to have an effect on the response variable in this study. The model with the highest parsimony resulted in an adjusted coefficient of 0.975, an average absolute percentage error of 7.70, an average absolute deviation of 0.16 and an average root square error of 0.19, showing a high influence on the phenomenon studied and a good predictive capacity.

At an international level, enormous volumes of construction and demolition wastes are generated: 170 million tons/year in the USA, 500 million tons/year in the European Union (EU) and 12 million tons/year in Mexico. Alternative uses for these heterogeneous materials, such as the manufacture of sustainable bricks, are potential solutions to this growing environmental issue. Based on previous studies, and in compliance with Mexican standards, four different types of secondary materials were utilized in the composition of a sustainable brick matrix. Temperature and solar radiation used for drying purposes were determined, as well as weight loss, resistance and initial maximum absorption. In order to characterize the resulting matrix, observations were made with a scanning electron microscope, and the chemical composition of the samples was determined by detecting basic compounds using mapping through SEM-EDS microanalysis, connected to the SEM unit. Finally, thermogravimetric analyses were performed to correlate mechanical and chemical behavior, and resistance to high temperatures of the mixtures. The results obtained showed that all-in-one (AiO) is the most appropriate material for brick manufacturing, Opuntia ficus-indica mucilage improves physical properties, such as increased compressive strength and reduced water absorption, while wood residues, clay minerals and illite enhance mechanical properties.

This work demonstrates the reaction of ozone on the amino acids comprising the covering layer of resistant micro-organisms. A secondary aim was to check the byproducts generated when ozone was applied to synthetic samples (such as Vibrio cholerae NO 01 WFCC-449, Salmonella typhi ATTC-6539, faecal coliforms and Ascaris suum). The ozone was applied at a concentration of 18.4 mgO₃/min at pH 3, for different lengths of time. In the case of bacteria, results showed that, at 8 minutes, the number was reduced to the level of the Official Mexican Standards set for treated water destined for irrigation purposes (1,000 MPN/100 mL). Excellent correlation coefficients (0.95 to 0.99) were obtained for microbial concentrations versus ozone contact time. Destruction times required for 100% removal of the initial bacteria population varied between 2 and 14 minutes, while Ascaris suum required 1 hour. When Gram-negative bacteria die due to the effects of ozone, cellular lysis and the liberation of endotoxins (biodegradable) were observed. The ozonation of amino acids in the shell of Ascaris suum eggs, leads to the formation of aldehydes, such as formaldehyde and acetaldehyde, in low concentrations (0.0003 and 0.0005 μg/mL respectively). These levels are not hazardous to human health.

In this paper, a proposal was presented to improve the MSW collection service in the municipality of Reforma, in Chiapas, Mexico. Specific field work was developed and various spatial analysis techniques were applied in the GIS environment. The application of a multivariate analysis technique (Grouping Analysis) allowed the study area to be clustered into three waste collection sectors with common characteristics, which were the basis for generating three collection route scenarios. Scenario 1 corresponds to the current situation, where 478 waste collection points are served, with an average travel distance of 60.30 km and a collection time of 8.00 h. Scenario 2 was generated through the “maximize coverage” algorithm and vehicle route modeling in ArcGis 10.8. In this scenario, 1220 waste collection points are served, with an average travel distance of 143.21 km and an average collection time of 12.38 h. Scenario 3 was created using the “minimize facilities” algorithm, as well as collection modeling in ArcGis 10.8. Using this algorithm, impedances (distances) were automatically minimized so that 697 waste collection points could be served, with an average travel distance of 100.00 km and an average collection time of 9.66 h. In terms of improvement, scenario 3 gives the best results, because it minimizes distances and average travel times.

The main aim of this research was to compare a bio-coagulant, organic coagulant, and a conventional coagulant applied to the treatment of leachates. Coagulant options were Stage 1 FeCl3, Stage 2 Polyamine, and Stage 3 Opuntia ficus mucilage (OFM). Optimal conditions for maximum chemical oxygen demand (COD) removal were determined by experimental data and Response Surface Methodology. The application of Multiple Criteria Decision Analysis using Multi-Criteria Matrix (MCM) was explored by evaluating the Coagulation–Flocculation processes. Maximum COD removal (%) and the best MCM scores (on a scale from 0 to 100) were: Stage 1: 69.2±0.9 and 48.50, Stage 2: 37.8±1.1 and 79.0, and Stage 3: 71.1±1.7, and 81.5. Maximum COD removal using FeCl3 and OFM was not statistically different (p 0.15 < 0.05). OFM extraction process was evaluated (yield 0.70 ± 1.17%, carbohydrate content 32.6 ± 1.18%). MCM allows the evaluation of additional technical aspects, besides oxygen COD removal, as well as economic aspects, permitting a more comprehensive analysis. Significant COD removals indicate that the use of OFM as a coagulant in the treatment of stabilized leachate was effective. Opuntia ficus cladodes, a residue, were used to treat another residue (leachates).