Propuesta metodológica para la toma de decisiones entre rehabilitación y clausura de sitios de disposición final

Ponència presentada al IX Simposio Iberoamericano de Ingeniería de Residuos, Panamá, del 20 al 24 de setembre de 2021En México, los residuos sólidos urbanos (RSU) generados se deposita preferentemente en rellenos sanitarios (RESA); sin embargo, en número, solo el 13% de los sitios de disposición final (SDF) son RESA y el 87% son sitios no controlados (SNC). Los SNC implican riesgos para la salud y al ambiente. La SEMARNAT ha buscado que los SDF del país cumplan con la NOM-083-SEMARNAT-2003; y para ello ha elaborado con otras instituciones, manuales y guías; sin embargo, aplicar estos documentos, representa un gran gasto para los municipios que tienen SNC. El objetivo de este trabajo fue proponer una metodología para evaluar a nivel preliminar SNC, que con menores costos y tiempo, apoye en la toma de decisión entre clausura o rehabilitación. Para ello, la propuesta comprende: ubicación de SDF y análisis histórico del área afectada mediante Mapa Digital de INEGI, Google Mapas y Google Earth Pro; análisis del cumplimiento de la NOM-083-SEMARNAT-2003 con el Sistema de Información Geográfica para el Manejo de RSU (SIGMIRSU) y la aplicación de una Tabla de Verificación a responsables del SDF; así como la elaboración de recomendaciones. Se eligieron como casos de estudio el SDF de Xalatlaco, Estado de México y el SDF de Tlalpujahua, Michoacán. La aplicación de la metodología para la evaluación a nivel preliminar, evidenció que el SDF de Xalatlaco requiere de atención urgente y debe ser revisado de cerca con la Secretaría del Medio Ambiente; y que el SDF de Tlalpujahua, tiene posibilidades de ser rehabilitado para operar conforme a la NOM-083-SEMARNAT-2003.In Mexico, the municipal solid waste (MSW) generated is preferably deposited in sanitary landfills (SL); however, in number, only 13% of the final disposal sites (FDS) are SL and 87% are uncontrolled sites (UNS). The UNS pose risks to health and the environment. SEMARNAT has sought that the country's SDF comply with NOM-083-SEMARNAT-2003; and for this it has prepared with other institutions, manuals and guides; However, applying these documents represents a great expense for municipalities that have UNS. The objective of this work was to propose a methodology to evaluate UNS at a preliminary level, which with lower costs and time, supports decision-making between closure or rehabilitation. For this, the proposal includes: FDS location and historical analysis of the affected area using INEGI's Digital Map, Google Maps and Google Earth Pro; analysis of compliance of NOM-083-SEMARNAT-2003 with the Geographic Information System for MSW Management (SIGMIRSU) and the application of a Verification Table to those responsible for the SDF; as well as that the development of recommendations. The FDS of Xalatlaco, State of Mexico and the SDF of Tlalpujahua, Michoacán were chosen as case studies. The application of the methodology for the evaluation at a preliminary level, showed that the SDF of Xalatlaco requires urgent attention and should be closely reviewed with the Ministry of the Environment; and the SDF of Tlalpujahua, has the possibility of being reactivated to operate according to NOM-083-SEMARNAT2003

The treatment with the probiotic Shewanella putrefaciens Pdp11 of sepecimens of Solea senegalensis exposed to high stocking densities to enhance their resistance to disease

Aquaculture industry exposes fish to acute stress events, such as high stocking density, and a link between stress and higher susceptibility to diseases has been concluded. Several studies have demonstrated increased stress tolerance of fish treated with probiotics, but the mechanisms involved have not been elucidated. Shewanella putrefaciens Pdp11 is a strain isolated from healthy gilthead seabream (Sparus aurata L.) and it is considered as probiotics. The aim of this study was to evaluate the effect of the dietary administration of this probiotics on the stress tolerance of Solea senegalensis specimens farmed under high stocking density (PHD) compared to a group fed a commercial diet and farmed under the same conditions (CHD). In addition, during the experiment, a natural infectious outbreak due to Vibrio species affected fish farmed under crowding conditions. Changes in the microbiota and histology of intestine and in the transcription of immune response genes were evaluated at 19 and 30 days of the experiment. Mortality was observed after 9 days of the beginning of the experiment in CHD and PHD groups, it being higher in the CHD group. Fish farmed under crowding stress showed reduced expression of genes at 19 day probiotic feeding. On the contrary, a significant increase in immune related gene expression was detected in CHD fish at 30 day, whereas the gene expression in fish from PHD group was very similar to that showed in specimens fed and farmed with the conventional conditions. In addition, the dietary administration of S. putrefaciens Pdp11 produced an important modulation of the intestinal microbiota, which was significantly correlated with the high number of goblet cells detected in fish fed the probiotic diet.S

Changes in intestinal microbiota and gene expression of immune system parameters caused by dietary administration of alginate and Shewanella putrefaciens Pdp11 in Senegalese sole (Solea senegalensis Kaup, 1858) specimens

Dietary administration of sodium alginate single or mixed with Pdp11 modulated the intestinal microbiota diversity of sole juveniles. Both treatments promoted a change in the species present in the gut in comparison with control group. In addition, oral administration of alginate promoted the appearance of an intestinal microbiota highly influenced by the prebiotic presence. Synbiotic administration of alginate with Pdp11 promoted a more pronounced decreasing in the similarity index and in the species richness. Both treatments modulated the expression of genes related with immune system functions

Modulation of the intestinal microbiota and expression of gene of senegalese sole (Solea senegalensis, Kaup 1858) after dietary administration of oxytetracycline.

Oxitetracycline and probiotics (Pdp11) administration to sole juveniles showed important changes in the species composition of intestinal microbiota that established a relationship between these species and gene expression