The need to satisfy the increasing demand for building materials and the challenge of reusing plastic to help improve the critical environmental crisis has led to the recycling of plastic waste, which is further exploited and transformed into new and creative materials for the construction industry. This study looked into the use of low-density recycled polyethylene (LDPE) to produce non-conventional plastic sand cobbles. LDPE waste was melted in order to obtain enough fluid consistency which was then mixed with sand in a 25/75 plastic-sand ratio respectively, such a mixture helped producing cobbles of 10 cm × 20 cm × 4 cm. Water absorption, weight, and density measurements were performed on both commercial and non-conventional plastic sand cobbles. Moreover, compression, bending, and wear resistance were also conducted as part of their mechanical characterization. Plastic sand cobbles showed lower water absorption and density values than commercial cobbles. The mechanical properties evaluated showed that plastic sand cobbles have a higher modulus of rupture and wear resistance than commercial cobbles. In addition, plastic sand cobbles meet the Colombian Technical Standard in lightweight traffic for pedestrians and vehicle, officially known as Norma Técnica Colombiana (NTC), with 25.5 MPa, 16.3 MPa, and 12 mm compression resistance, modulus of rupture and footprint length in wear resistance respectively. Finally, a market study was conducted to establish a factory to produce this type of cobbles in Ibague, Colombia. Not only the study showed positive financial indicators, which means that it is feasible running a factory to manufacture plastic sand cobbles in the city of Ibague, but it also concluded that nonconventional plastic sand cobbles could be explored to provide a comprehensive alternative to LDPE waste.

Owing to the ongoing accumulation of industrial by-products, the management and disposal of waste have emerged as a significant issue. Employing these industrial wastes as an alternative to replace cement holds potential as a promising solution for conserving energy and reducing CO₂ emissions. In this study, pig and beef bone powder were used as cement replacements in concrete, and the mechanical properties were studied. Bone powders were prepared from random bones collected from local slaughterhouses, butchers, and restaurants. The pig bone powder (PBP) and beef bone powder (BBP) were prepared by direct fire contact, oven-calcined for 4 h at 300 °C, crushed, and sieved to size 0.4 to 2 mm. A concrete mix design was formulated for a target compressive strength of 21 MPa at 28 days of curing. This design included three different levels of cement replacement with each type of bone powder (10%, 15%, and 20% by mass). These mixes were then evaluated and compared to a control mix without any bone powder replacement (PB-0). This study evaluated the mechanical properties via compressive strength and flexural testing. The results showed that the workability of the mixtures decreased with the increase in bone powder content. Bone powder functions as a pozzolanic substance, engaging in a chemical reaction with the calcium hydroxide in concrete to produce compounds that exhibit cement-like properties; however, an increase in bone powder content worsened the mechanical properties. The most promising results were obtained for a 10% replacement percentage of BBP and PBP, obtaining strengths of 21.15 MPa and 22.78 MPa, respectively. These are both above the design strength, with PBP concrete even exceeding the strength of PB-0 (21.75 MPa). These results showed a good agreement with the standard values and allow to use these wastes as a replacement for cement, becoming a sustainable solution to the exploitation of quarry materials and, in turn, to the problem of contamination by biological waste from the meat industry.

Effective management of agricultural waste is an important contribution to environmental sustainability and economic development, especially considering the significant volume of agricultural residues produced worldwide. Rice is a widely cultivated crop in Colombia, and its high production results in a high amount of wastes, which is often underutilized due to a lack of knowledge regarding its potential value-added applications. On the other hand, the construction industry has become increasingly aware of the necessity to develop materials with reduced environmental impact. Therefore, this study explores the application of the Analytic Hierarchy Process (AHP) to evaluate various alternatives for utilizing rice waste in construction materials; the alternatives were evaluated based on criteria tailored to the needs of local agricultural communities in the Tolima region of Colombia. The findings highlight the potential of rice husk ash (RHA) as an environmentally responsible alternative in the construction sector, offering a viable solution for waste management while contributing to the economic development of small-scale farmers.

In Colombia, most commercial drying processes are frequently performed through the burning of wood and fossil fuels with high costs and environmental damage. Nevertheless, solar drying is a technique that could also be used to reduce many of the problems present in traditional drying techniques. Finding low-cost technology to install a solar dryer in a vulnerable community of women is an appropriate alternative; the transfer of knowledge on this technique could lead to greater empowerment of women and prevent gender inequality. This study evaluated the color and water activity of the mango (Mangifera indica L.) after a drying process in a greenhouse dryer. Furthermore, this study showed the relevance of implementing this technique in a community of women affected by the military conflict in Colombia. Results showed that a solar dryer achieved drying times of around 23–26 h, reaching water activity values below the 0.5 threshold which, according to international standards, has been considered as a food safety value. In addition, the color of the dry mango is slightly affected through this drying technique, providing a more acceptable consumer product. The application of the solar dryer has proven to be an easy-to-use and environmentally friendly method. On the other hand, it is also an opportunity to improve, with a low-cost investment, the living conditions of vulnerable communities.

Los países en desarrollo y aquellos con tradición agrícola tienen entre sus prioridades gubernamentales el diseño e implementación de planes de mejora para aumentar la productividad en este sector. La priorización de esos planes tiende a basarse en la evaluación de indicadores de producción, dejando de lado aspectos logísticos clave como transporte, manipulación, embalaje, entre otros. Por esta razón, este trabajo propone una metodología multicriterio, basada en el método de expertos y el método de planificación del desarrollo tecnológico en cadenas agroindustriales propuesto por ISNAR, que estiman el índice de potencial logístico (LPi) y el índice de nivel de competitividad (LCi). El análisis conjunto de ambos indicadores permitió priorizar los productos en una matriz denominada matriz de priorización. La metodología fue validada en un caso de estudio a través de la priorización de productos hortícolas y frutales en cinco zonas del Tolima - Colombia para asignar recursos con el fin de implementar estrategias logísticas.

Cocoa production has emerged as an effective agricultural strategy to reduce conflict in Colombia, transitioning from coca to cocoa cultivation. While this shift has provided economic benefits, it has also resulted in the generation of substantial cocoa by-products. Although there are various alternative methods of utilizing these by-products, many farmers are unaware of them, and others lack the necessary tools to determine which alternative is the best to pursue. This study sought to explore sustainable options for cocoa waste utilization through the application of the Analytic Hierarchy Process (AHP). By employing technological surveillance, viable options for reusing cocoa residues were identified. The AHP results indicate that pellet production is a promising alternative for rural communities. It is also a potential source of energy that could address the community’s need for alternative energy sources. Initially, other energy production alternatives were not explored. However, in response to the AHP findings, this study also explored the use of cocoa waste combined with animal manure for energy generation through anaerobic digestion.