A stochastic approach for assessing the chronic environmental risk generated by wet-weather events from integrated urban wastewater systems

Wet-weather discharges from urban areas with a combined wastewater system represent a threat for surface waters. In fact, when the system capacity is reached during medium/big rain events, a mixture of stormwater and untreated wastewater is discharged through combined sewer overflows (CSOs) or bypass (BP) of wastewater treatment plants (WWTP). The discharged pollutant loads are highly variable in time and space, making it difficult to correctly monitor and assess the environmental risks for a specific catchment. The present work proposes a methodology to assess the chronic impact of wet-weather discharges from integrated urban wastewater systems (IUWS) by using a stochastic approach. Monitoring data from the literature were used to characterize the discharges and to predict the risk posed by (micro-)pollutants on a yearly basis in an archetype IUWS. Calculated risks from wet-weather discharges are compared against those posed by WWTP effluent. The results show that CSOs pose a higher risk to surface waters compared to WWTP effluent and bypass, with polycyclic aromatic hydrocarbons being the category of micropollutants of major concern for CSOs. Conversely, WWTP effluent discharges are responsible for most of the risk associated with pharmaceuticals. A sensitivity and uncertainty analysis highlighted the importance of performing an accurate estimation of the recipient flow rate, which can provide a better risk estimation than focusing only on the characterization of the discharged concentrations. In climate change scenarios, where recipient flow rate reduction and overflow volume increment is expected, the risk caused by wet-weather discharges may increase for all micropollutant categories, including pharmaceuticals.Environmental chronic risk generated by wet-weather discharges compared to final effluent was stochastically assessed, also from a climate-change perspective, stressing their growing contribution for many (micro-)pollutants

Assessing the contribution of wet-weather discharges on micropollutants release by urban catchments

Wet-weather discharges from integrated urban wastewater systems (IUWS) represent a threat for surface waters. When the system capacity is reached during medium/large rain events, a mixture of stormwater and untreated wastewater is discharged to surface water through Combined Sewer Overflows (CSOs) or Bypass (BP) of Wastewater Treatment Plants (WWTP). The loads of contaminants discharged by CSOs and BP are highly variable in time and space (Petrie, 2021), making it difficult to correctly monitor and assess the environmental risk for a specific catchment. The present work aims at assessing the impact of 12 micropollutants present in wet-weather discharges on receiving surface water, by using an archetype IUWS, defined through a stochastic approach. Monitoring data from literature were retrieved and elaborated to characterize the discharges and to predict the risk posed by micropollutants on a yearly horizon. The calculated risk from wet- weather discharges was compared against that posed by WWTP effluent (EFF)

An integrated modelling framework to assess cascade water reuse in urban areas

In the recent years water scarcity has been an increasing problem for many countries worldwide. For this reason, there is currently a strong focus on increasing reclaimed wastewater reuse, especially for agriculture purposes (Fernandes and Cunha Marques, 2023). Besides, the cost of energy from conventional resources is increasing, thus the energy sector is moving towards more distributed and efficient use of heat sources across urban areas. Typical applications are heat pumps using local groundwater reservoirs and subsequently discharging in the nearby surface water bodies/artificial channels (recipients). Furthermore, for a better quality of these recipients and for a better performance of wastewater treatment plants (WWTP), stormwater can be collected in separated sewers discharging only the urban runoff to the recipient. In this context, water is subjected to multiple uses, with potential cross-contaminations across different compartments, posing a risk for the environment. Hence, there is a strong need for tools capable of supporting stakeholders towards a wiser and safer use of water resources, to ensure long-term resilience, stability, sustainability and security of the society with regard to water use. An integrated model was developed to simulate the fate and associated risk of hazardous contaminants in a cascade water reuse system

Covid-19 patient management in outpatient setting: A population-based study from southern italy

Evidence on treatments for early-stage COVID-19 in outpatient setting is sparse. We explored the pattern of use of drugs prescribed for COVID-19 outpatients’ management in Southern Italy in the period February 2020–January 2021. This population-based cohort study was conducted using COVID-19 surveillance registry from Caserta Local Health Unit, which was linked to claims databases from the same catchment area. The date of SARS-CoV-2 infection diagnosis was the index date (ID). We evaluated demographic and clinical characteristics of the study drug users and the pattern of use of drugs prescribed for outpatient COVID-19 management. Overall, 40,030 patients were included in the analyses, with a median (IQR) age of 44 (27–58) years. More than half of the included patients were asymptomatic at the ID. Overall, during the study period, 720 (1.8%) patients died due to COVID-19. Azithromycin and glucocorticoids were the most frequently prescribed drugs, while oxygen was the less frequently prescribed therapy. The cumulative rate of recovery from COVID-19 was 84.2% at 30 days from ID and it was lower among older patients. In this study we documented that the drug prescribing patterns for COVID-19 treatment in an outpatient setting from Southern Italy was not supported from current evidence on beneficial therapies for early treatment of COVID-19, thus highlighting the need to implement strategies for improving appropriate drug prescribing in general practice