http://yetl.yabesh.ir/yetl1/handle/yetl/18997 Mon, 13 Apr 2026 21:44:13 GMT 2026-04-13T21:44:13Z http://localhost:80/yetl1/bitstream/id/184314/ http://yetl.yabesh.ir/yetl1/handle/yetl/18997 http://yetl.yabesh.ir/yetl1/handle/yetl/4310080 Effects of Bioretention Soil Mixtures on Metal Speciation and Toxicity to Aquatic Communities Kelly DeGuzman; Thorsten Knappenberger; Yaniv Olshansky; Eve Brantley; Anand D. Jayakaran Heavy metal concentrations in stormwater runoff are regulated and monitored because these pollutants can be toxic to aquatic communities. When evaluating stormwater toxicity to aquatic organisms, a heavy metal’s bioavailability and speciation should be considered in addition to the total metal concentration. The influent and effluent of four bioretention soil mixtures (BSMs) from 10 storms were evaluated for speciation shifts of typical heavy metals and changes to stormwater toxicity to find out if any of the BSMs were more adept at decreasing pollutant bioavailability. Visual MINTEQ 3.1 was used for metal speciation, and the Windward Environmental Biotic Ligand Model (BLM) (v 3.41.2.45) was used to predict toxic concentrations of heavy metal species. No noticeable speciation shifts were noted within bioretention cell (BRC) effluent for cadmium, copper, lead, and zinc. A multiple-factor analysis (MFA) indicated that the four BSMs do not differ from one another in reducing the BLM-identified toxic limit (relative toxicity) of stormwater effluent for the BLM-selected aquatic organisms. BRCs are most effective at reducing the toxicity of stormwater when the stormwater contains high pollutant concentrations. BRCs may increase the effluent stormwater’s toxicity at low pollutant concentrations through Cu export from compost. Wed, 01 Jan 2025 00:00:00 GMT http://yetl.yabesh.ir/yetl1/handle/yetl/4310080 2025-01-01T00:00:00Z http://yetl.yabesh.ir/yetl1/handle/yetl/4310079 Modeling the Resilience Performance of Houston’s Wastewater Treatment Plant under Wet Weather Conditions Lu Liu; Jarrett Morrison; Lauren Stadler; Andrew Shaw; Jeseth Delgado Vela; Dylan Christenson With increasing severity of wet weather events due to a changing climate, many municipal wastewater treatment plants are grappling with challenges in maintaining effective flow and effluent management. Compounded by aging wastewater infrastructure, it is imperative to enhance the resilience of wastewater systems to cope with the increasing intensity of wet weather events. This study employs a robust modeling framework using the Benchmark Simulation Model 2 and provides an analysis of the resilience performance of a wastewater treatment plant in Houston, Texas, in response to synthetic storms of varying intensities. It was shown that increased severity in wet weather results in decreased resilience performance with ammonia removal as the performance metric. Potential sewer overflows are identified in the absence of equalization basins under all synthetic storm scenarios. Furthermore, the sewershed, characterized by a high population density and low economic capacity, renders communities within it more susceptible to the adverse effects of potential sewer overflows. While effluent ammonia concentration remains within permissible limits due to the dilution effect, the substantial discharge of untreated ammonia loads into the receiving river may pose risks to the expansion of the hypoxic zone in the Gulf of Mexico. Our study addresses a critical gap in the quantitative assessment of US wastewater systems’ resilience performance under varying severities of wet weather. Overall, it highlights the urgent need to evaluate the resilience of existing wastewater systems, particularly in the context of evolving climate conditions and aging infrastructure. Wed, 01 Jan 2025 00:00:00 GMT http://yetl.yabesh.ir/yetl1/handle/yetl/4310079 2025-01-01T00:00:00Z http://yetl.yabesh.ir/yetl1/handle/yetl/4310078 Characterizing Stormwater Basin Conditions Using Tracked BMP Inspection and Rating Reports from the Virginia Department of Transportation Jacob D. Nelson; Savannah L. Lynn; Jonathan L. Goodall Studies have rarely used stormwater best management practice (BMP) condition rating data to quantify changes in condition ratings and characterize condition issues, making it challenging to implement proactive maintenance practices. To help address this knowledge gap, we answer the following questions pertaining to a widely used stormwater BMP: detention and retention basins. (1) How often do basin condition ratings change over time? (2) What are specific site and structural condition issues identified during condition inspections? (3) What issues and site characteristics correspond with basins that experience a rapid decline in condition rating, meaning a decrease in two or more condition rating levels within a single year? We do this by characterizing basin condition ratings and associated issues using information included in more than 5,500 basin inspection reports, each containing more than 200 questions, stored in the Virginia Department of Transportation (VDOT) asset management system. On average, between 5.6 and 8.3 issues were recorded per visit for D-rated and E-rated basins compared with 0.03 to 1.8 issues for A-rated and B-rated basins. Of the 901 basins with three consecutive years of inspections, 41% and 35% had condition ratings that changed from 2020 to 2021 and from 2021 to 2022, respectively. The most common issues associated with rapid condition rating decline included major corrosion on the low flow orifice trash/debris rack, control structure, and pipe. Rapidly declining condition ratings were observed in 67% of VDOT’s nine independent management districts, suggesting rapid declines occur independently of management practices. Higher median elevation and percent slope attributes and lower median population were correlated with basins experiencing rapid condition rating decline. Using these results as context, we discuss considerations for improving BMP inspection data quality and opportunities for supporting proactive BMP management practices that can benefit other agencies managing a large portfolio of stormwater assets. Stormwater asset management systems can be leveraged to track changes in the conditions of best management practices by collecting, storing, and processing detailed asset inspection reports. This study showed that detention/retention basin condition ratings can change within a single year’s time and that rapidly declining condition ratings, meaning ratings that decline by two or more levels within a single year, can occur independently of management practices. Inspector certification, automatic system-issued ratings, inspection report auditing, and controlled vocabulary during data entry of inspection reports should be considered to reduce bias and improve the quality of condition rating data in support of proactive maintenance. Wed, 01 Jan 2025 00:00:00 GMT http://yetl.yabesh.ir/yetl1/handle/yetl/4310078 2025-01-01T00:00:00Z http://yetl.yabesh.ir/yetl1/handle/yetl/4310077 Disposition of Uranium and Other Heavy Metals in the Groundwater in the Baran District of Rajasthan, India Ashu Rani; Ramet Meena; Kiran Parashar; Shobhana Sharma; Ankit Sharma; Nepal Chandra Mondal; Sushil Kumar Sharma People are vulnerable to chemical and radiological risks when consuming water tainted with heavy metals. Because many people living in the Baran district of Rajasthan, India, rely on groundwater for drinking, they are more susceptible to heavy metal toxicity. The main aim of the study was to analyze the change in concentrations of metal content in groundwater samples before and after the monsoon season, which may be due to various human activities, pesticides, fertilizers, industrial effluents, and vehicles. In this context, 200 groundwater samples from 100 villages throughout 8 tehsils in the Baran district of Rajasthan, India, were examined for heavy metals, such as copper (Cu), zinc (Zn), iron (Fe), lead (Pb), cobalt (Co), and aluminum (Al), as well as uranium, before and after the monsoon. The light-emitting diode (LED) fluorimetry technique was used to analyze uranium concentration in groundwater, and an atomic absorption spectrometer was employed to access heavy metals. As per the safe limits recommended by various protection organizations, the health risks associated with heavy metals were examined and correlated with uranium content. According to the research, Pb, Al, and Co concentrations in the Baran district vary before and after the monsoon season. The U, Fe, and Pb concentrations were found to have a weakly positive correlation during the premonsoon season. Furthermore, following the monsoon season, U contents increased in about 89% of samples; the highest increase was 5.4 ppb. Conversely, uranium and other atoms (i.e., Cu, Zn, Co, Fe, and Al) had a mild negative association in the pre- and postmonsoon periods, which could be attributed to the various origin metals in the region and groundwater. However, a noteworthy association was discovered among U, Pb, and Al following the monsoon. Pearson’s correlation analysis was used to categorize types of correlations between heavy metals. Wed, 01 Jan 2025 00:00:00 GMT http://yetl.yabesh.ir/yetl1/handle/yetl/4310077 2025-01-01T00:00:00Z