Water Quality Improvement and Pollutant Removal by Two Regional Detention Facilities with Constructed Wetlands in South Texas

A Compact, Low-Cost, and Low-Power Turbidity Sensor for Continuous In Situ Stormwater Monitoring

Turbidity stands as a crucial indicator for assessing water quality, and while turbidity sensors exist, their high cost prohibits their extensive use. In this paper, we introduce an innovative turbidity sensor, and it is the first low-cost turbidity sensor that is designed specifically for long-term stormwater in-field monitoring. Its low cost (USD 23.50) enables the implementation of high spatial resolution monitoring schemes. The sensor design is available under open hardware and open-source licences, and the 3D-printed sensor housing is free to modify based on different monitoring purposes and ambient conditions. The sensor was tested both in the laboratory and in the field. By testing the sensor in the lab with standard turbidity solutions, the proposed low-cost turbidity sensor demonstrated a strong linear correlation between a low-cost sensor and a commercial hand-held turbidimeter. In the field, the low-cost sensor measurements were statistically significantly correlated to a standard high-cost commercial turbidity sensor. Biofouling and drifting issues were also analysed after the sensors were deployed in the field for more than 6 months, showing that both biofouling and drift occur during monitoring. Nonetheless, in terms of maintenance requirements, the low-cost sensor exhibited similar needs compared to the GreenSpan sensor.

Water quality performance assessment of two stormwater detention basins located in the recharge zone of a karst aquifer

Stormwater detention basins are used to minimize peak discharges and improve water quality mainly through sedimentation; however, limited studies have evaluated the water quality performance of detention basins located over karst aquifers. Karst aquifers are vital sources of drinking water for many regions of the world and their recharge areas are susceptible to contamination from surface water resources. In this study, an analysis of two stormwater detention basins (namely, Kyle and TPC) located in the recharge zone of one of the most prolific karst aquifers in the world (Edwards Aquifer, San Antonio, Texas), were conducted over a period of one year to quantify the water quality and hydrologic performance of the basins. Automated samples were collected during the storm events and analyzed for nitrate (NO3--N), nitrite (NO2--N), ammonia (NH3-N), total dissolved nitrogen (TDN), phosphorus (PO43-), total suspended solids (TSS), total dissolved solids (TDS), total carbon (TC), total organic carbon (TOC), and chemical oxygen demand (COD). Both basins reduced NH3-N, TSS and COD concentrations significantly while NO3--N and PO43- concentrations exhibited a net export. Furthermore, TPC showed greater reductions in NO2--N, TOC and TC concentrations compared to Kyle. Higher TSS removal was observed at TPC due to differences in retention time. A volume reduction of 44% and 64% was observed in TPC and Kyle, respectively. The results of this study demonstrate that stormwater detention basins located over the Edwards Aquifer effectively remove particulate pollutants while also being a potential source of dissolved pollutants such as nitrate. Overall, the results presented here have important implications for operation and maintenance of stormwater basins constructed over recharge zones of Edwards Aquifer.

Comparative life cycle assessment of the linear and circular wine industry chains: a case study in Inner Mongolia, China

Environmental issues and the sustainability of the wine industry receive widespread public attention, but few studies address the environmental impact of the circular wine industry chain. Therefore, we applied the life cycle assessment (LCA) method to a wine enterprise in Inner Mongolia, China, to conduct a cradle-to-gate assessment and comparative analysis on the linear and circular wine industry chain scenarios. The results show that the circular industry chain (S2) has better environmental benefits; the total value of each environmental impact category of S2 is reduced by more than 80% compared with that of the linear industry chain (S1). The global warming potential of S1 is decreased from 4.88 kg CO2eq to 0.919 kg CO2eq for S2. Viticulture is the primary source of environmental problems in all life cycle stages of both scenarios, and electricity and diesel consumption are the key factors affecting the results. Our study shows that the optimization of S2 significantly improves resource efficiency and energy utilization and alleviates the environmental burden through proper waste recycling. Finally, we proposed optimization suggestions based on S2. This study provides scientific guidance for promoting the wine industry to build a circular industry chain and optimize the industrial structure, thus promoting the sustainable development of the industry.

Natural wetlands efficiency assessment in removing sugarcane fields' drainage contaminants: a case study in Khuzestan, Southwest Province of Iran

The present study investigated the efficiency of a real-scale natural wetland (Naseri Wetland) in the qualitative treatment of agricultural drainage of Khuzestan sugarcane for 1 year (2019-2020). This study divides the wetland length into three equal parts in W1, W2, and W3 stations. The efficiency of the wetland in removing contaminants such as Cr, Cd, BOD₅, TDS, TN, and TP is evaluated by field sampling, laboratory analysis, and t-test. Results indicate that the highest mean difference in Cr, Cd, BOD, TDS, TN, and TP are observed between W0 and W3. At W3, the farthest station from the entry point, the highest removal efficiency is obtained for each factor. Removal percentage of Cd, Cr, and TP in all seasons is equal to 100% up to station 3 (W3), and BOD5 and TN are 75% and 65%, respectively. Also, the results show a gradual rise in TDS along the wetland's length due to high evaporation and transpiration in the area. Naseri Wetland reduces the Cr, Cd, BOD, TN, and TP compared to the initial level. This decrease is more significant at W2 and W3, and it is worth mentioning that W3 has the most considerable reduction. With increasing distance from the entry point, the effect of timing of 1.10, 1.26, 1.30, and 1.60 on removing heavy metals and nutrients is high. The highest efficiency is observed for each retention time at W3.

Reduction in Nitrogen Exports from Stormflow after Conversion of a Dry Detention Basin to a Stormwater Wetland

Stormwater control measures such as dry detention basins and wetlands are often used to reduce the discharge of urban runoff and nutrients to streams, but differences in nutrient treatment may vary between practices. The goal of this study was to compare the nitrogen treatment efficiency of a dry detention basin before and after it was converted into a stormwater wetland. Inflow and outflow from a detention basin in Greenville, North Carolina was sampled during 13 storms and the stormwater wetland was sampled during 10 storms. Total dissolved nitrogen (TDN), NO3−, NH4+, chloride, dissolved organic carbon (DOC), and physicochemical properties were evaluated. Inflow and outflow from the detention basin had identical median concentrations of TDN (0.47 mg L−1). The median TDN concentration for wetland outflow (0.18 mg L−1) was 63% lower relative to inflow (0.49 mg L−1). The hydraulic residence time of stormwater in the wetland was more than 10 times greater relative to the dry basin. There was a significant (p < 0.001) reduction in dissolved oxygen and oxidation reduction potential and an increase in median DOC concentrations in wetland outflow relative to inflow. Most of the reduction in TDN within the wetland was attributed to loss of NO3− (80% reduction), possibly due to denitrification. Conversion of dry detention basins to wetlands may provide significant benefits with regards to reducing TDN transport associated with urban runoff.