How has the COVID-19 pandemic impacted wastewater-based epidemiology?

Wastewater-based epidemiology (WBE) was one of the areas of scientific knowledge that developed significantly with the COVID-19 pandemic, with robust worldwide application to monitor the circulation of the SARS-CoV-2 virus in urban communities at different scales and levels. This mini-review assesses how the COVID-19 pandemic may have influenced the WBE based on the investigation of 1305 scientific reports published (research, review, and conference papers) up to the end of 2022, considering the research objects, funding sources, actors, and countries involved. As a result, 71 % of all WBE-based publications occurred since the beginning of the pandemic, with 62 % addressing SARS-CoV-2, demonstrating the migration of WBE's relative importance in studies on drug abuse, pharmaceuticals consumption, and other disease-causing organisms to the constitution of a tool to support the monitoring of the coronavirus. Before the pandemic, WBE was a tool used for epidemiological surveillance of several diseases (54 % of studies), drug abuse (30 %), and pharmaceutical consumption (9 %). With the pandemic, these research topics lost to space, constituting only 37 % of the area's studies, and SARS-CoV-2 became the central object of studies. In addition, there has been a 4.7 % expansion of developing country participation in sewage surveillance publications and greater diversification of collaborators and funders, especially from government, businesses, and the water industry. International research partnerships had a reduction of 8 %, consequently, there was an increase in local and regional partnerships. With the COVID-19 pandemic, funding for research in WBE became approximately 6.5 % less dependent on traditional research funds. The future of WBE involves different approaches, including different focuses of research and technological advancements to improve the sensitivity, precision, and applicability of these investigations. The new WBE research arrangements are promising, although the post-pandemic challenges are likely to be in maintaining them and overcoming the trend toward a lack of diversity in study subjects.

20-Month monitoring of SARS-CoV-2 in wastewater of Curitiba, in Southern Brazil.

The COVID-19 pandemic resulted in the collapse of healthcare systems and led to the development and application of several approaches of wastewater-based epidemiology to monitor infected populations. The main objective of this study was to carry out a SARS-CoV-2 wastewater based surveillance in Curitiba, Southern Brazil Sewage samples were collected weekly for 20 months at the entrance of five treatment plants representing the entire city and quantified by qPCR using the N1 marker. The viral loads were correlated with epidemiological data. The correlation by sampling points showed that the relationship between the viral loads and the number of reported cases was best described by a cross-correlation function, indicating a lag between 7 and 14 days amidst the variables, whereas the data for the entire city presented a higher correlation (0.84) with the number of positive tests at lag 0 (sampling day). The results also suggest that the Omicron VOC resulted in higher titers than the Delta VOC. Overall, our results showed that the approach used was robust as an early warning system, even with the use of different epidemiological indicators or changes in the virus variants in circulation. Therefore, it can contribute to public decision-makers and health interventions, especially in vulnerable and low-income regions with limited clinical testing capacity. Looking toward the future, this approach will contribute to a new look at environmental sanitation and should even induce an increase in sewage coverage rates in emerging countries.

Scaling-up of the adsorption process of ammonia nitrogen onto expanded vermiculite using fixed-bed columns.

Expanded vermiculite was used as an adsorbent to remove ammonia nitrogen from landfill leachate. Bench and pilot-scale adsorption experiments were performed with leachate collected from a closed sanitary landfill located in Curitiba, southern Brazil. At the bench-scale, two different heights of vermiculite and three different flow rates were tested using a fixed-bed column. These tests produced an average uptake capacity of 33.4 mg g-1 for the ammonia nitrogen concentration of 2,560 mg L-1. The Yan model was used to determine the breakthrough and the exhaustion times due to the best fit of the data to this model. At the pilot-scale, the flow rate was determined from the shortest length of the mass transfer zone obtained from bench-scale experiments. Tests were performed using one stainless-steel column filled with 26.2 kg of expanded vermiculite, which resulted in a bed height of 1.6 m. A leachate flow rate of approximately 350 L d-1 was applied to achieve the required contact time of 8.3 h. At this scale, an average uptake capacity of 18.1 mg g-1 was obtained for the ammonia nitrogen concentration of 1,193 mg L-1. It is worth mentioning that the flow rate and the concentration of the adsorbate in the feeding solution are fundamental to improve the operational time of the fixed-bed column. The main goal of this research was the determination of operating conditions to scale-up the adsorption process of ammonia nitrogen onto expanded vermiculite. The contact time was a key parameter to reach this goal.

Biosorption of nickel(II) and copper(II) ions from synthetic and real effluents by alginate-based biosorbent produced from seaweed Sargassum sp.

In this study, the alginate-based biosorbent produced from seaweed Sargassum sp. was used in biosorption of Ni2+ and Cu2+ ions from synthetic solutions and real electroplating effluents. Biosorption kinetics, isotherms, pH effect, thermodynamic parameters, and sorption/desorption cycles were also evaluated. Kinetic studies show the sorption equilibrium can be obtained within 180 min for Ni2+ ions and 360 min for Cu2+ ions, and the adsorption kinetics data are well described by the pseudo-second order and diffusion in spherical adsorbents. Langmuir model can be well used to describe the biosorption isotherm data. The maximum sorption capacity (qmax) and Langmuir constant (b) were up to 1.147 mmol g-1 and 1.139 L mmol-1 for Ni2+ ions and 1.640 mmol g-1 and 4.645 L mmol-1 for Cu2+ ions. The calculated thermodynamic parameters (ΔG°, ΔH°, and ΔS°) showed that the biosorption of Ni2+ and Cu2+ ions are predominantly a chemical phenomenon of endothermic nature, favorable, and spontaneous at the temperature ranges of 293-313 K. Partial desorption of the Ni2+ and Cu2+ ions on the biosorbent was achieved using acidic and saline eluents, allowing the biosorbent to be used in new sorption/desorption cycles. EDX analysis suggests an ion exchange mechanism between calcium ions on the biosorbent and target metals. Biosorption of Ni2+ and Cu2+ from real electroplating effluents with high concentrations of light metals becomes highly competitive, decreasing the amount of Ni2+ and Cu2+ ions biosorbed due to the ionic strength effect.