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.

Sugar is the most important food supplement of our daily diet. During the production, sugar mills use a large volume of water and produce a significant amount of wastewater polluted with high organic compounds. Therefore, it is necessary to treat the wastewater before their disposal. For this reason, this article presents the results obtained from the monitoring of a coupled system of aged refuse filled bioreactors (ARFB) in full scale to treat wastewater from a sugar mill. The coupled system consists of two bioreactors (a primary one -ARFB₁- and a rectification one -ARFB₂-) arranged in a series with identical geometries. The ARFB₁-ARFB₂ system was evaluated in two stages. The first stage (maintenance period) for 28 weeks, and second stage (Zafra season) for 29 weeks. The system was fed with sugar mill wastewater (SMW) with a chemical oxygen demand (COD) of 2787 ± 1552 mg/L and 2601 ± 722 mg/L, respectively. As results, we observed a rapid stabilization of the system over 2 months. In addition, we found the ARFB₁-ARFB₂ system achieved an average COD removal of 94.9%, with a final effluent (E2) concentration below the maximum permissible limits of Mexican and international regulations for all analyzed parameters. Finally, the results of this study show that the ARFB₁-ARFB₂ full-scale novel technology is an efficient process for removal of the main contaminants that affect the wastewater from the sugar mills.

In this study, the operation of a final disposal site for municipal solid waste in the state of Chiapas, in Mexico, was evaluated. Several spatial analyses and Geographic Information Technology (GIT) tools were used. It was found that the site’s current operation and location are deficient, partially complying with regulations. The gaseous dispersion is not far-reaching (from 100 to 8725 µg/m³ for landfill gas, and from 0.01 to 0.35 µg/m³ for H₂S) but requires attention to avoid olfactory unpleasantness. Liquid emissions (conservative pollutants) move in the east direction of the final disposal site, which can damage the environmental infrastructure (water supply wells) in the long term. The highest and lowest concentrations were found in years 1 (12,270 mg/m³) and 20 (1080 mg/m³), respectively. Thermal emissions around the dumping site are important due to the formation of microclimatic zones. Temperature differences were found during the analysis period, ranging from 8.37 °C in summer to 2.49 °C in winter, which are due to waste decomposition processes and anthropogenic activities. Finally, the change in land use around the dumping site increased at a rate of 5.82% per year, mainly due to the growth of homes, communication routes, and shopping centers.

This paper shows a watershed prioritization analysis applied to municipal solid waste. The study area was the macrowatershed “Cañón del Sumidero”, in the state of Chiapas, Mexico. Geographic information systems, multi-criteria evaluation techniques, as well as several geomorphometric, land use, vegetation and waste management variables were used. The results indicate that, of the set of watersheds analyzed (4 subwatersheds and 80 microwatersheds), only 14 (2 subwatersheds and 12 microwatersheds) have high priority, since they are severely affected by the mismanagement of solid waste. This is also due to the major presence of urban settlements, which are places with different dynamics in terms of population growth, migration, as well as access to infrastructure and services, such as collection and final disposal of waste. Additionally, the incidence of certain biophysical and geomorphometric variables, such as steep slopes, high rainfall and high drainage density, among others, exacerbate the waste-related problems. The remaining watersheds (2 subwatersheds and 68 microwatersheds) showed moderate or low prioritization values because of the low amount of solid waste produced there. Finally, this work concludes that the regionalization of municipalities and the management of solid waste through decentralized operating agencies can help solve solid waste management problems since this approach would permit to delegate non-primary activities from watershed operating agencies to other specialized waste agencies.

En el presente trabajo se diseñó y construyó un simulador de lluvias utilizando materiales de bajo costo y de fácil transporte, el cual permitió controlar variables como intensidad, uniformidad y duración. Se controló el caudal con una electroválvula mediante un detector de cruce por cero, tarjeta de control y una etapa potencia. Los resultados indicaron que el comportamiento en la distribución espacial de la lluvia fue uniforme con un valor superior a 80%, intensidad de lluvia similares a episodios naturales con una energía cinética superior a 27 J/mm m2, con un control del caudal de 97% de precisión.

In developing countries, achieving greater coverage in the treatment and safe reuse of graywater is a pending task. Therefore, this article presents the results obtained from cafeteria wastewater treatability tests and effluent toxicity tests. For the treatment, a serial system was applied: an aged refuse filled bioreactor (ARFB) and a solar distiller (SD). In the first stage (ARFB), two hydraulic loads (HLs) were tested (200 and 400 L/m³·day), the latter being the best of them, with an average decrease of 95.7% in chemical oxygen demand (COD). In the second stage (SD), the decrease was 62.8%, resulting in a final effluent with 67.7 mg/L COD, which corresponded to a global COD decrease of 97.4%. For the toxicity tests, radish seeds were used in the serial system effluent, obtaining a relative seed germination (RSG) rate of 93.3% compared to 80% obtained in the ARFB effluent. For the percentage germination index (PGI), it was determined that both effluents (ARFB and ARFB-SD) presented a toxicity considered low, especially the ARFB-SD effluent whose PGI value was close to zero (−0.0667). The results obtained showed not only that the ARFB-SD system is efficient in removing the high organic load that can go along with cafeteria wastewater, but also that it can provide an effluent with a very low toxicity level based on the PGI close to zero.