The Takakura technique converts food waste into compost. This project explored the potential use of composting in offices and workplaces. The method involves using small boxes containing a fermentation substrate where food waste is added. Two Takakura composting boxes (TCBs) were placed in the kitchens of the Chemistry Department and the Environmental Engineering buildings at the Instituto Tecnológico de Costa Rica, Costa Rica. Food waste from both buildings, comprising the food waste of 45 staff members, were composted from June to December 2015. All types of food, except grease, oil, raw meat, and bones, were processed. The mass and volume of food added to the boxes were quantified daily. A chemical analysis of the compost was also performed. A speech was given to educate the staff members about the system. A survey, before and after the speech, was developed to evaluate the knowledge and tolerance towards composting in closed spaces. A total mass of 88.29 kg, equivalent to 232 L of residues, was processed, from which 17.37 kg (37 L) of compost was obtained. This represented a mass and volume reduction of 80% and 84%, respectively. Compost analysis gave a C/N ratio of 14.7/1, indicative of maturity. Most of the staff members (92%) agreed to the separation of waste at the source. However, 37% suggested allocating the box outside the building. The survey, after the speech, showed that educating staff is necessary before installing boxes at a workplace.

This study describes the quality of drinking water sampled over 2 years (2018 and 2019) from 20 ASADAS (Spanish acronym for Administrative Associations for Water and Sewer Systems) in Costa Rica. The analysis included Rotavirus (RV), somatic coliphages, fecal coliforms, and Escherichia coli. The ASADAS were categorized into three regions as temperate rainy (region 1), tropical rainy (region 2), and tropical rainy and dry (region 3) according to biogeographic classification. The concentrations of fecal coliforms and E. coli were higher in samples from surface water sources from the ASADAS in region 3 compared to regions 1 and 2. RV-positive samples (24/296) were detected in drinking-water samples from regions 2 and 3 during dry and transition seasons, with higher concentrations more frequently in the dry season. In addition, somatic coliphages were detected in samples from the three regions, with higher concentrations in region 2. Furthermore, a statistically significant relationship was found between somatic coliphages and diarrheal cases, classified as outbreaks or alerts in the region. Thus, the results confirmed that somatic coliphages are a good indicator of the presence of diarrhea cases in a specific region.

Spent coffee grounds (SCG) are produced in large quantities during coffee brewing, contributing to environmental concerns. Additionally, cationic dyes from textile, paper, and leather wastewater pose a major pollution issue. This study explores SCG as an adsorbent for methylene blue (MB) dye. A novel comparison of SCG cleaning methods with warm water, accelerated solvent extraction (ASE), supercritical fluid extraction (SFE), and ultrasound-induced cavitation (US) is presented. In addition, the chemical modifications of SCG using acetylation, acid (HNO₃), and base (KOH) treatment that have not been reported before are presented. ATR-FTIR confirmed the inclusion of functional groups, for example, the nitro group in SCG treated with HNO₃, and an increase in carboxylic groups in the samples treated with KOH and HNO₃. SEM analysis revealed a consistent porous texture across samples, with SCG-SFE, SCG-US, and SCG-HNO₃ showing smaller pores, and SCG-ASE displaying elongated cavities. Adsorption isotherm tests followed the Freundlich and Langmuir models, indicating favorable adsorption. The Langmuir maximum adsorption capacity (q_max) varied among cleaning methods from 65.69 mg/g (warm water) to 93.32 mg/g (SFE). In contrast, in base- and acid-treated SCG, a three- to four-fold increase in adsorption capacity was observed, with q_max values of 171.60 mg/g and 270.64 mg/g, respectively. These findings demonstrate that SCG washed with warm water and chemically treated achieves adsorption capacities comparable to other biosorbents reported in the literature. Therefore, SCG represents a promising, low-cost, and sustainable material for removing cationic dyes from wastewater, contributing to waste valorization and environmental protection.