High-rate algal pond for removal of pharmaceutical compounds from urban domestic wastewater under tropical conditions. Case study: Santiago de Cali, Colombia.

This study evaluated the capacity of a pilot-scale high-rate algal pond (HRAP) to remove pharmaceutical compounds (PCs) from domestic wastewater in the city of Santiago de Cali, Colombia. The compounds analyzed included antiepileptics, hypolipidemic drugs, tranquilizers and analgesics, and anti-inflammatory drugs. The HRAP operated under a continuous water flow of 0.2 m3d-1 and a 3-day hydraulic retention time (HRT). Removal efficiencies were high (>70%) for fenofibric acid, ibuprofen, and paracetamol; medium (30-70%) for gabapentin, lamotrigine, fenofibrate, gemfibrozil, diclofenac, ketoprofen, naproxen, and pentoxifylline; and low (<30%) for carbamazepine and its metabolite 10,11-Dihidro-10,11-dihidroxicarbamazepine (CBZ-Diol). The findings herein are similar to other studies, but were obtained with a shorter HRT. These results show that tropical environmental conditions favor photodegradation and contribute to the development of microalgae and the biodegradation process. Twenty microalgae species were identified, with the phylum Chlorophyta as the most abundant, particularly due to its natural introduction. The removal of the PCs also reflected a percentage reduction (>50%) in the ecological hazard posed by most of the compounds, although it is important to note that the hazard from gemfibrozil and ibuprofen remained high even after treatment, indicating the need for complementary treatment.

Study of the occurrence and ecosystem danger of selected endocrine disruptors in the urban water cycle of the city of Bogotá, Colombia.

Endocrine disruptors have been studied for their high occurrence in different environments including aquatic; however, in the context of developing countries, their occurrence, magnitude and potential threat have little information. This study involved the analysis of various components of the urban water cycle in the city of Bogotá, Colombia. As a result, it was found that the compounds with the highest occurrence are plasticizers such as phthalates and bisphenol A, whereas among the drugs, carbamazepine presented the highest concentrations (0.68-31.45 µg L-1); the analysis of the threat coefficient (HQ) showed the importance of bis(2-ethylhexyl) phthalate (BEHP) and estrone (E1) that can reach surface waters from domestic and industrial discharges.

The occurrence of emerging compounds in real urban wastewater before and after the COVID-19 pandemic in Cali, Colombia.

The COVID-19 pandemic is considered one of the most significant global disasters in the last years. The rapid increase in infections, deaths, treatment, and the vaccination process has resulted in the excessive use of pharmaceuticals that have entered the environment as micropollutants. Considering the prior information about the presence of pharmaceuticals found in the wastewater of Cali, Colombia, which was collected from 2015 to 2022. The data monitored after the COVID-19 pandemic showed an increase in the concentration of analgesics and anti-inflammatory drugs of up to 91%. This increase was associated with the consumption of pharmaceuticals for mild symptoms, such as fever and pain. Moreover, the increase in concentration of pharmaceuticals poses a highly ecological threat, which was up to 14 times higher than that reported before of COVID-19 pandemic. These results showed that the COVID-19 had not only impacted human health but also had an effect on environmental health.

Tratamiento de lixiviados utilizando humedales construidos y determinación de conductividades hidráulicas en clima tropical / Treatment of leachate using constructed wetlands and determination of hydraulic conductivities in a tropical climate

RESUMEN Los humedales construidos en los últimos años han sido ampliamente usados en la depuración de una gran variedad de aguas residuales, por ser una alternativa que ofrece múltiples ventajas, en comparación con otros sistemas de tratamiento. Este estudio evaluó la eficiencia de seis sistemas de humedales, construidos de flujo subsuperficial horizontal (HCFSSH), a escala piloto, para la remoción de materia orgánica (DQO), nutrientes (N-NO3-, P-PO43-) y plomo (Pb+2), además de la incidencia del tiempo de operación sobre la conductividad hidráulica (Ks) para tratar lixiviados del Relleno Sanitario "El Ojito", del municipio de Popayán, Cauca. Tres humedales fueron plantados con Heliconia psittacorum (HCFSSH-H. p) y tres con Cyperus haspan (HCFSSH-C. h); el medio de soporte utilizado fue grava, operados con un caudal de 0.012m3/día y un tiempo de retención hidráulico de 4 días; las unidades recibieron efluente de una laguna de oxidación. Los resultados mostraron remociones medias de: DQO (51,67 y 64,00%), N-NO3- (45,33 y 48,17%), P-PO43- (53,67 y 62,67%) y Pb+2 (5,74 y 14,75%) para los HCFSSH-H. p y HCFSSH-C. h, respectivamente y valores de conductividad hidráulica, entre 700 y 1000m/día. El sistema de humedales mostró ser eficiente para el tratamiento secundario de lixiviado de rellenos sanitarios maduros, obteniendo eficiencias de remoción, significativamente mayores, en los HCFSSH-C.h.

ABSTRACT In recent years, constructed wetlands have been widely used for the purification of wastewater, representing an alternative method that offers multiple advantages when compared to other treatment systems. The present study assessed the efficiency of six horizontal subsurface flow constructed wetlands (HSSFCW) at pilot scale for the removal of organic matter (COD), nutrients (N-NO3-, P-PO43-) and lead (Pb2+). The study also looked at the operating time on hydraulic conductivity (Ks) to treat leachate from the "El Ojito" Sanitary Landfill in the municipality of Popayán, Cauca. Three wetlands were planted with Heliconia psittacorum (HSSFCW-H. p), and three with Cyperus haspan (HSSFCW-C. h). The support medium used was gravel. They were operated at a flow of 0.012m3/day, and a hydraulic retention time of 4 days. The units received effluent from the oxidation pond. The results showed mean removals of COD (51.67 and 64.00%), N-NO3- (45.33 and 48.17%), P-PO43- (53.67 and 62.67%) and Pb+2 (5.74 and 14.75%) for HSSFCW-H. p and HSSFCW-C. h respectively. Hydraulic conductivity values were between 700 and 1000m/day. The wetland system proved to be efficient for the secondary treatment of leachate from mature landfills, obtaining removal efficiencies significantly higher in HSSFCW-C. h.