Wastewater surveillance represents an alternative approach to regulating contamination and the early detection of infectious agents and outbreaks of diseases of public health importance. This study evaluated domestic wastewater effects on recreational waters in estuarine and seawater bodies in Guayas and Santa Elena provinces in Ecuador, South America. Fecal indicator bacteria (thermotolerant coliforms) served as key indicators for evaluation. Physical, chemical, and microbiological quality markers following the Ecuadorian environmental quality standard and the discharge of effluents to the water resource were analyzed. Samples were collected from 44 coastal sites and 2 oxidation lagoons during the dry and rainy seasons of 2020 and 2021, respectively. SARS-CoV-2 RNA was detected in samples with higher E. coli concentrations using reverse transcription quantitative PCR to detect the genes N and ORF1ab. All samples analyzed for SARS-CoV-2 showed Ct ˂ 40 for at least one gene. Four samples showed at least 20 genome copies of gene N per reaction. These were at an artisanal fishing port, an estuarine area (Palmar), a recreational bay, and an oxidation lagoon. A moderate correlation was found between SARS-CoV-2 RNA, thermotolerant coliform and E. coli (p-value ≤ 0.0037), and a strong and positive correlation between thermotolerant coliform and E. coli. (p-value ≤ 0.00001), highlighting the utility of these established parameters as a proxy of the virus. Significant differences were found in the concentrations of thermotolerant coliforms between seasons (p-value = 0.016) and sites (p-value = 0.005). The highest levels of coliforms were found in the dry season (63000 MPN/100 mL) in Anconcito and during the rainy season (14000 MPN/100 mL) at Esterillo in Playas County. It is recommended that the decentralized autonomous governments of the surveyed provinces in Ecuador implement urgent corrective actions and establish medium-term mechanisms to minimize a potential contamination route. Additional parameters must be included in the monitoring, such as Enterococcus and intestinal parasites, due to their public health implications. In the oxidation lagoons, maintenance actions must be carried out, including the dissolution of sediments, an increase in water retention times, and in situ treatment of the sludge, to improve the system’s performance.

Microplastics (MPs) have emerged as a major pollutant in aquatic ecosystems, primarily originating from industrial activities and plastic waste degradation. Understanding their transport dynamics is crucial for assessing environmental risks and developing mitigation strategies. This study employs Computational Fluid Dynamics (CFD) simulations to model the trajectory of MPs in section B of the Salado Estuary in the city of Guayaquil, Ecuador, using ANSYS FLUENT 2024 R2. The transient behavior of Polyethylene Terephthalate (PET) particles was analyzed using the Volume of Fluid (VOF) multiphase model, k-omega SST turbulence model, and Discrete Phase Model (DPM) under a continuous flow regime. Spherical PET particles (5 mm diameter, 1340 kg/m³ density) were used to establish a simplified baseline scenario. Two water velocities, 0.5 m/s and 1.25 m/s, were selected based on typical flow rates reported in similar estuarine systems. Density contour analysis facilitated the modeling of the air-water interface, while particle trajectory analysis revealed that at 0.5 m/s, particles traveled 18–22.5 m before sedimentation, whereas at 1.25 m/s, they traveled 50–60 m before reaching the bottom. These findings demonstrate that higher flow velocities enhance MP transport distances before deposition, emphasizing the role of hydrodynamics in microplastic dispersion. While limited to one particle type and idealized conditions, this study underscores the potential of CFD as a predictive tool for assessing MP behavior in aquatic environments, contributing to improved pollution control and remediation efforts.

Wastewater surveillance represents an alternative approach for the diagnosis and early detection of infectious agents of public health importance. This study aimed to evaluate SARS-CoV-2 and other quality markers in oxidation lagoons, estuarine areas and seawater at Guayas and Santa Elena in Ecuador. Sample collections were conducted twice at 42 coastal sites and 2 oxidation lagoons during dry and rainy seasons (2020-2021). Physico-chemical and microbiological parameters were evaluated to determine organic pollution. Quantitative reverse transcription PCR was conducted to detect SARS-CoV-2. Results showed high levels of Escherichia coli and low dissolved oxygen concentrations. SARS-CoV-2 was detected in sea-waters and estuaries with salinity levels between 34.2-36.4 PSU and 28.8 °C-31.3 °C. High amounts of fecal coliforms were detected and correlated with the SARS-CoV-2 shedding. We recommend to decentralized autonomous governments in developing countries such as Ecuador to implement corrective actions and establish medium-term mechanisms to minimize a potential contamination route. HIGHLIGHTS: SARS-CoV-2 RNA was detected in estuaries, bays and the wastewater treatment systems in Playas and Santa Elena. High levels of fecal coliforms were detected along shorelines. Water quality parameters revealed a negative impact on the beaches studied associated with human activities.

Microplastics (MPs) have emerged as a major pollutant in aquatic ecosystems, primarily originating from industrial activities and plastic waste degradation. Understanding their transport dynamics is crucial for assessing environmental risks and developing mitigation strategies. This study employs Computational Fluid Dynamics (CFD) simulations to model the trajectory of MPs in section B of the Salado Estuary in the city of Guayaquil, Ecuador, using ANSYS FLUENT 2024 R2. The transient behavior of Polyethylene Terephthalate (PET) particles was analyzed using the Volume of Fluid (VOF) multiphase model, k-omega SST turbulence model, and Discrete Phase Model (DPM) under a continuous flow regime. Spherical PET particles (5 mm diameter, 1340 kg/m³ density) were introduced at water velocities of 0.5 m/s and 1.25 m/s. Density contour analysis facilitated the modeling of the air-water interface, while particle trajectory analysis revealed that at 0.5 m/s, particles traveled 18–22.5 meters before sedimentation, whereas at 1.25 m/s, they traveled 50–60 meters before reaching the bottom. These findings demonstrate that higher flow velocities enhance MP transport distances before deposition, emphasizing the role of hydrodynamics in microplastic dispersion. This study underscores the potential of CFD as a predictive tool for assessing MP behavior in aquatic environments, contributing to improved pollution control and remediation efforts.

According to the evolution of unmanned aerial vehicles (UAV), several investments have been increasing every year, especially in the field of aerodynamic characteristics. This paper deals with the prediction of pressure and velocity fields on a UAV with internal propulsion system using computational fluid dynamics. The main objective is to evaluate the effect of the air flow past the aircraft and how this affects the aerodynamic performance by means of obtaining lift and drag forces. The airfoil of this aircraft is the 2415-3S, which was developed in previous research [1]. Since the computational domain is three-dimensional and complex, a hybrid mesh was developed and validated with a convergence study. Both the computational domain and the numerical solution were developed with commercial CAD and CFD software respectively. Air, incompressible and steady was simulated with a Reynolds number of 2.74 × 10 ⁵ . The selected turbulence model was Spalart-Allmaras which has been designed specifically for aerospace applications involving wall-bounded flows. Lift, drag and moment coefficients as well as pressure and velocity contours were obtained at different angles of attack. Experimental results will be obtained in future work to be compared to numerical ones and achieve the validation.

In Ecuador, extensive coconut (Cocos nucifera) harvesting generates large quantities of waste, including husks, shells, and fibers, posing environmental and economic challenges. This study explores the densification of coconut waste (CW) into pellets and briquettes to address these issues. The process involved raw material collection, pre-treatment, drying, grinding, sieving, mixing, pelletizing, and briquetting, using cassava starch (CS) as a binder. Two CW-to-CS compositions were tested for each type of fuel. Key physical and combustion properties, such as higher heating value, moisture, volatile matter, fixed carbon, ash content, bulk density, and friability, were analyzed. Results showed that the PCA91 pellet sample (90% CW, 10% CS) achieved the best performance with a higher heating value of 15,350 J/g and 11.54% moisture content. Similarly, the BCA91 briquette sample (90% CW, 10% CS) demonstrated better performance with a heating value of 14,950 J/g and 13.75% moisture content. Most samples met the heating value and bulk density requirements of the Swedish SS187120 and Colombian NTC 2060 standards, although some fell short on ash, volatile matter, and fixed carbon content. Adjusting the CW-to-CS ratio could optimize biofuel properties, balancing energy output and stability, highlighting coconut waste’s potential as a sustainable biofuel.