Brenda Lizeth Monzón-Reyes

The coffee agroindustry is one of the main economic activities in rural communities of developing countries. However, its processing generates wastewater with high organic loads and emerging contaminants such as caffeine. In the absence of proper sanitation infrastructure, these discharges are often combined with municipal wastewater, increasing the risk of water pollution and threatening both environmental and community health. In this context, sustainable and low cost treatment alternatives are requerid to mitigate these impacts, particularly in rural settings. This study evaluated the performance of a full-scale hybrid system consisting of a settler tank followed by constructed wetland cells (SF-CW and SSF-CW) planted with ornamental species (Eichhornia crassipes, Alocasia odora, Hedychium coronarium, Heliconia psittacorum and Zantedeschia aethiopica). Monitoring was carried out from February to July 2024, including caffeine analysis by UV-Vis spectrophotometry during both the coffee harvesting and processing season and periods when only rural domestic wastewater was treated. The system achieved an average caffeine removal efficiency of over 99% during the coffee processing season. The ornamental plants adapted well to the operational conditions, showing high resilience and stable growth, as well as potential ornamental and commercial value. This work provides full-scale operational evidence of the potential of ornamental constructed wetlands as a practical and replicable solution for treating rural wastewater mixed with coffee-processing effluents, while simultaneously delivering environmental protection, social benefits, and local economical opportunities for rural communities.

Mentions of microplastics (MPs) are increasingly frequent, for they are present in all environments, including wastewater. Knowing their possible harmful effects on the food chain, the fact that they appear in crops is concerning. The ways by which they are transported and stored, as well as their final destination, are still unclear. The issue of MPs in wastewater and how they are carried into agricultural crops are little-known facts. This study aims to evaluate whether horizontal subsurface flow wetlands with ornamental plants (Hippeastrum hybridum hort and Heliconia bihai marginata) can retain microplastics present in domestic wastewater while at the same time recirculating water for irrigation of the Phaseolus vulgaris crop. On average, the ornamental plants Hippeastrum hybridum hort and Heliconia bihai marginata removed contaminants such as COD, NH₄⁺, TN, NO₂⁻, TP, PO₄³⁻, and TSS, with an efficiency of 84% and 98%, respectively. The presence of MPs was identified via FTIR analysis and visual characterization in domestic wastewater, treated wastewater, and well water; the quality of the fruit for human consumption was determined using safety tests for Escherichia coli and Salmonella.

The lack of access to centralized technologies and economic resources in rural communities makes wastewater management a critical challenge. Decentralized systems such as constructed wetlands offer sustainable solutions by leveraging natural processes for effluent treatment. However, their success and sustainability require active community participation. Currently, there is little evidence of community involvement in the implementation, maintenance, and management of constructed wetlands. Existing strategies for community collaboration in environmental and sanitation projects were analyzed through a literature review covering research conducted in the last 20 years. Only peer-reviewed research in English and Spanish was considered. Based on the findings, a triple helix model integrating academia, government, and society is proposed, compiling the most functional strategies from initial awareness raising to maintenance and dissemination. A case study of community participation is presented under this approach in the Salvador Díaz Mirón rural community, Veracruz, Mexico. The results of this study provide key information for effective strategies designed to manage constructed wetlands, emphasizing that their success depends on both the technology and the genuine commitment of communities to their operation and long-term sustainability. Furthermore, these findings can serve as a reference for decision-makers and project planners seeking to integrate participatory models into decentralized sanitation and water resource conservation.

The development of sustainable infrastructure is essential to address the challenges of climate change and reduce CO₂ emissions. The use of alternative materials, such as agro-industrial ashes and silica fume, emerges as a promising option to enhance the durability of concrete and diminish its environmental impact. These materials can partially replace conventional cement, contributing to the construction of more sustainable infrastructure without compromising performance, even under adverse environmental conditions. In this study, we present an analysis of the use of sugarcane bagasse ash (SBA) and silica fume (SF) as a 15% cement replacement. The behavior of these materials was investigated under coastal conditions, analyzing climatic variables and degrading gases such as CO₂, CH₄, and N₂O. Electrochemical techniques were employed to measure corrosion rate and potential, in addition to conducting carbonation and compressive strength tests. The mixtures with a 15% addition of SBA and SF showed improvements compared to conventional mixes. SBA reduced the corrosion rate by 25% and increased compressive strength by 12% after 150 days, while SF enhanced carbonation resistance by 20% and compressive strength by 25%. The incorporation of SBA and SF provides significant durability in coastal environments, contributing to the sustainability of infrastructure exposed to adverse weather conditions.