Jiadong Zhang, V. Prodanovic, A. Lintern, Kefeng Zhang
Constructed wetlands are a type of green infrastructure commonly used for urban stormwater treatment. Previous studies have shown that the various design characteristics have an influence on the outflow heavy metal concentrations. In this study, we develop a Bayesian linear mixed model (BLMM) and a Bayesian linear regression model (BLRM) to predict the outflow concentrations of heavy metals (Cd, Cu, Pb and Zn) using an inflow concentration (Cin) and five design variables, namely media type, constructed wetland type (CWT), hydraulic retention time, presence of a sedimentation pond (SedP) and wetland-to-catchment area ratio (Ratio). The results show that the BLMM had much better performance, with the mean Nash–Sutcliffe efficiency between 0.51 (Pb) and 0.75 (Cu) in calibration and between 0.28 (Pb) and 0.71 (Zn) in validation. The inflow concentration was found to have significant impacts on the outflow concentration of all heavy metals, while the impacts of other variables on the wetland performance varied across metals, e.g., CWT and SedP showed a positive correlation to Cd and Cu, whereas media and Ratio were negatively correlated with Pb and Zn. Results also show that the 100-fold calibration and validation was superior in identifying the key influential factors.
{"title":"Development of the data-driven models for accessing the impact of design variables on heavy metal removal in constructed wetlands","authors":"Jiadong Zhang, V. Prodanovic, A. Lintern, Kefeng Zhang","doi":"10.2166/bgs.2021.024","DOIUrl":"https://doi.org/10.2166/bgs.2021.024","url":null,"abstract":"\u0000 Constructed wetlands are a type of green infrastructure commonly used for urban stormwater treatment. Previous studies have shown that the various design characteristics have an influence on the outflow heavy metal concentrations. In this study, we develop a Bayesian linear mixed model (BLMM) and a Bayesian linear regression model (BLRM) to predict the outflow concentrations of heavy metals (Cd, Cu, Pb and Zn) using an inflow concentration (Cin) and five design variables, namely media type, constructed wetland type (CWT), hydraulic retention time, presence of a sedimentation pond (SedP) and wetland-to-catchment area ratio (Ratio). The results show that the BLMM had much better performance, with the mean Nash–Sutcliffe efficiency between 0.51 (Pb) and 0.75 (Cu) in calibration and between 0.28 (Pb) and 0.71 (Zn) in validation. The inflow concentration was found to have significant impacts on the outflow concentration of all heavy metals, while the impacts of other variables on the wetland performance varied across metals, e.g., CWT and SedP showed a positive correlation to Cd and Cu, whereas media and Ratio were negatively correlated with Pb and Zn. Results also show that the 100-fold calibration and validation was superior in identifying the key influential factors.","PeriodicalId":9337,"journal":{"name":"Blue-Green Systems","volume":null,"pages":null},"PeriodicalIF":4.6,"publicationDate":"2021-12-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45243089","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Bioretention systems maintain the natural water cycle and help to mitigate climatic extremes impact on urban areas by retarding, storing, and evaporating stormwater runoff. Although bioretention systems have been operated for more than 25 years, systematic investigations on the hydrological functionality and pollutant retention performance of older systems are rare. We employed laboratory and field experiments to investigate three long-term operated bioretention systems in Germany with the following objectives: (i) physico-chemical substrate characterisation; (ii) an event-based influent and effluent trace metal concentration monitoring covering 22 months and (iii) the calculation of metal retention rates. Regarding the pollution status, we found significantly increased trace metal contents in the soil substrate mainly as a function of the drainage area type and the inflow regime. Nonetheless, all measured metal seepage concentrations fall below the German legislative trigger values. Our current findings demonstrate no risk of groundwater degradation even for old bioretention systems suggesting bioretention as a powerful and sustainable tool for stormwater management. Further research requires the handling of soil substrates modified by stormwater infiltration showing enhanced trace metal contents and a certain amount of technogenic sediments.
{"title":"Seepage metal concentrations beneath long-term operated bioretention systems","authors":"Arne Reck, Mogens Thalmann, E. Paton, B. Kluge","doi":"10.2166/bgs.2021.014","DOIUrl":"https://doi.org/10.2166/bgs.2021.014","url":null,"abstract":"Bioretention systems maintain the natural water cycle and help to mitigate climatic extremes impact on urban areas by retarding, storing, and evaporating stormwater runoff. Although bioretention systems have been operated for more than 25 years, systematic investigations on the hydrological functionality and pollutant retention performance of older systems are rare. We employed laboratory and field experiments to investigate three long-term operated bioretention systems in Germany with the following objectives: (i) physico-chemical substrate characterisation; (ii) an event-based influent and effluent trace metal concentration monitoring covering 22 months and (iii) the calculation of metal retention rates. Regarding the pollution status, we found significantly increased trace metal contents in the soil substrate mainly as a function of the drainage area type and the inflow regime. Nonetheless, all measured metal seepage concentrations fall below the German legislative trigger values. Our current findings demonstrate no risk of groundwater degradation even for old bioretention systems suggesting bioretention as a powerful and sustainable tool for stormwater management. Further research requires the handling of soil substrates modified by stormwater infiltration showing enhanced trace metal contents and a certain amount of technogenic sediments.","PeriodicalId":9337,"journal":{"name":"Blue-Green Systems","volume":null,"pages":null},"PeriodicalIF":4.6,"publicationDate":"2021-11-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41688221","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Global warming – mainly caused by carbon emissions – is a major global challenge for human sustainable development. Carbon emission reduction and resource recovery from sludge treatment are critical to the carbon neutralisation of future wastewater treatment plants. This paper analyses the key elements of carbon emissions during sludge treatment and disposal, namely energy source carbon emissions, fugitive carbon emissions and carbon compensation. Of the four mainstream process routes analysed in this work, anaerobic digestion + dry incineration is identified as the route with the highest potential for reducing carbon emissions in the future. Finally, based on a review of current international research hotspots, the future development directions for sludge treatment and resource recovery are discussed. This paper thus provides a comprehensive understanding of the current sludge treatment processing routes and serves as a reference for process route selection and future research on carbon neutralisation.
{"title":"Sludge treatment and resource recovery towards carbon neutrality in China: current status and future perspective","authors":"Ying Xu, Rui Liu, Dong-fang Yang, Xiaohu Dai","doi":"10.2166/bgs.2021.115","DOIUrl":"https://doi.org/10.2166/bgs.2021.115","url":null,"abstract":"\u0000 Global warming – mainly caused by carbon emissions – is a major global challenge for human sustainable development. Carbon emission reduction and resource recovery from sludge treatment are critical to the carbon neutralisation of future wastewater treatment plants. This paper analyses the key elements of carbon emissions during sludge treatment and disposal, namely energy source carbon emissions, fugitive carbon emissions and carbon compensation. Of the four mainstream process routes analysed in this work, anaerobic digestion + dry incineration is identified as the route with the highest potential for reducing carbon emissions in the future. Finally, based on a review of current international research hotspots, the future development directions for sludge treatment and resource recovery are discussed. This paper thus provides a comprehensive understanding of the current sludge treatment processing routes and serves as a reference for process route selection and future research on carbon neutralisation.","PeriodicalId":9337,"journal":{"name":"Blue-Green Systems","volume":null,"pages":null},"PeriodicalIF":4.6,"publicationDate":"2021-11-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"67819432","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Elhadi Mohsen Hassan Abdalla, I. Selseth, T. Muthanna, H. Helness, K. Alfredsen, Terje Gaarden, E. Sivertsen
Lined permeable pavements (LPPs) are types of sustainable urban stormwater systems (SUDs) that are suitable for locations with low infiltration capacity or shallow groundwater levels. This study evaluated the hydrological performance of an LPP system in Norway using common detention indicators and flow duration curves (FDCs). Two hydrological models, the Storm Water Management Model (SWMM)-LID module and a reservoir model, were applied to simulate continuous outflows from the LPP system to plot the FDCs. The sensitivity of the parameters of the SWMM-LID module was assessed using the generalized likelihood uncertainty estimation methodology. The LPP system was found to detain the flow effectively based on the median values of the detention indicators (peak reduction = 89%, peak delay = 40 min, centroid delay = 45 min, T50-delay = 86 min). However, these indicators are found to be sensitive to the amount of precipitation and initial conditions. The reservoir model developed in this study was found to yield more accurate simulations (higher NSE) than the SWMM-LID module, and it can be considered a suitable design tool for LPP systems. The FDC offers an informative method to demonstrate the hydrological performance of LPP systems for stormwater engineers and decision-makers.
{"title":"Hydrological performance of lined permeable pavements in Norway","authors":"Elhadi Mohsen Hassan Abdalla, I. Selseth, T. Muthanna, H. Helness, K. Alfredsen, Terje Gaarden, E. Sivertsen","doi":"10.2166/bgs.2021.009","DOIUrl":"https://doi.org/10.2166/bgs.2021.009","url":null,"abstract":"\u0000 Lined permeable pavements (LPPs) are types of sustainable urban stormwater systems (SUDs) that are suitable for locations with low infiltration capacity or shallow groundwater levels. This study evaluated the hydrological performance of an LPP system in Norway using common detention indicators and flow duration curves (FDCs). Two hydrological models, the Storm Water Management Model (SWMM)-LID module and a reservoir model, were applied to simulate continuous outflows from the LPP system to plot the FDCs. The sensitivity of the parameters of the SWMM-LID module was assessed using the generalized likelihood uncertainty estimation methodology. The LPP system was found to detain the flow effectively based on the median values of the detention indicators (peak reduction = 89%, peak delay = 40 min, centroid delay = 45 min, T50-delay = 86 min). However, these indicators are found to be sensitive to the amount of precipitation and initial conditions. The reservoir model developed in this study was found to yield more accurate simulations (higher NSE) than the SWMM-LID module, and it can be considered a suitable design tool for LPP systems. The FDC offers an informative method to demonstrate the hydrological performance of LPP systems for stormwater engineers and decision-makers.","PeriodicalId":9337,"journal":{"name":"Blue-Green Systems","volume":null,"pages":null},"PeriodicalIF":4.6,"publicationDate":"2021-11-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43151636","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Peng Liu, Zihan Li, Zifan Che, Hu Xinran, M. Ying, H. Ren, Xu-xiang Zhang
Enteric viruses are known to be prevalent in municipal wastewater, but information on the health risks arising from wastewater reuse is limited. This study quantified six common enteric viruses in raw wastewater and determined the effectiveness of different secondary and tertiary treatment processes at reducing their abundances in three full-scale wastewater treatment plants in China. In the raw wastewater, polyomavirus BK and norovirus GII (Nov GII) exhibited the highest abundance among the detected DNA and RNA viruses, respectively, with concentrations >5 log10 copies/L. Viruses in the raw wastewater were mainly removed by the secondary treatment processes, with log reduction values ranging from 1 to 2. The tertiary treatment processes of both chlorination and ultraviolet irradiation facilitated the additional reduction of viruses. The quantitative microbial risk assessment was applied to estimate the health risks of adenovirus (Adv) and Nov GII when reusing the treated wastewater for irrigation of public green spaces and crops. Estimated disabled-adjusted life-years of Adv and Nov GII for both reuses were higher than the risk threshold (10−6) required by the WHO in the actual scenarios. More effective treatment technologies should be implemented to remove viruses for safe reuse of the treated wastewater.
{"title":"Prevalence of common enteric viruses in municipal wastewater treatment plants and their health risks arising from wastewater reuse","authors":"Peng Liu, Zihan Li, Zifan Che, Hu Xinran, M. Ying, H. Ren, Xu-xiang Zhang","doi":"10.2166/bgs.2021.012","DOIUrl":"https://doi.org/10.2166/bgs.2021.012","url":null,"abstract":"\u0000 Enteric viruses are known to be prevalent in municipal wastewater, but information on the health risks arising from wastewater reuse is limited. This study quantified six common enteric viruses in raw wastewater and determined the effectiveness of different secondary and tertiary treatment processes at reducing their abundances in three full-scale wastewater treatment plants in China. In the raw wastewater, polyomavirus BK and norovirus GII (Nov GII) exhibited the highest abundance among the detected DNA and RNA viruses, respectively, with concentrations >5 log10 copies/L. Viruses in the raw wastewater were mainly removed by the secondary treatment processes, with log reduction values ranging from 1 to 2. The tertiary treatment processes of both chlorination and ultraviolet irradiation facilitated the additional reduction of viruses. The quantitative microbial risk assessment was applied to estimate the health risks of adenovirus (Adv) and Nov GII when reusing the treated wastewater for irrigation of public green spaces and crops. Estimated disabled-adjusted life-years of Adv and Nov GII for both reuses were higher than the risk threshold (10−6) required by the WHO in the actual scenarios. More effective treatment technologies should be implemented to remove viruses for safe reuse of the treated wastewater.","PeriodicalId":9337,"journal":{"name":"Blue-Green Systems","volume":null,"pages":null},"PeriodicalIF":4.6,"publicationDate":"2021-11-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43816158","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-09-25DOI: 10.22541/au.163255049.94952987/v1
S. Spraakman, J. Martel, J. Drake
Bioretention is a type of green stormwater infrastructure for the urban environment that mimics a natural hydrologic system by reducing peak flows and runoff volumes and encouraging infiltration and evapotranspiration. This study examines the complete water balance of a bioretention system located in Vaughan, Ontario, Canada, between 2018 and 2019. The water balance was further broken down by event size, where the event size was determined by rainfall frequency analysis. Recharge was the largest component of the water balance overall (86 % of inflow), as well as by event size. Evapotranspiration was the next largest water balance component (7 % of inflow overall), and was a significant component of inflow (21 %) when considering only small events (50 % probability of recurrence). Evapotranspiration is a slow but consistent process, averaging 2.3 mm/day overall and 2.9 mm/day during the growing season. Climate change is likely to bring more wet days and higher temperatures, which will impact the bioretention water balance by increasing evapotranspiration and inflow. Design standards for retention targets should be updated based on the most recent rainfall frequency analyses to adjust for changing climate conditions.
{"title":"How much water can bioretention retain, and where does it go?","authors":"S. Spraakman, J. Martel, J. Drake","doi":"10.22541/au.163255049.94952987/v1","DOIUrl":"https://doi.org/10.22541/au.163255049.94952987/v1","url":null,"abstract":"Bioretention is a type of green stormwater infrastructure for the urban\u0000environment that mimics a natural hydrologic system by reducing peak\u0000flows and runoff volumes and encouraging infiltration and\u0000evapotranspiration. This study examines the complete water balance of a\u0000bioretention system located in Vaughan, Ontario, Canada, between 2018\u0000and 2019. The water balance was further broken down by event size, where\u0000the event size was determined by rainfall frequency analysis. Recharge\u0000was the largest component of the water balance overall (86 % of\u0000inflow), as well as by event size. Evapotranspiration was the next\u0000largest water balance component (7 % of inflow overall), and was a\u0000significant component of inflow (21 %) when considering only small\u0000events (50 % probability of recurrence). Evapotranspiration is a slow\u0000but consistent process, averaging 2.3 mm/day overall and 2.9 mm/day\u0000during the growing season. Climate change is likely to bring more wet\u0000days and higher temperatures, which will impact the bioretention water\u0000balance by increasing evapotranspiration and inflow. Design standards\u0000for retention targets should be updated based on the most recent\u0000rainfall frequency analyses to adjust for changing climate conditions.","PeriodicalId":9337,"journal":{"name":"Blue-Green Systems","volume":null,"pages":null},"PeriodicalIF":4.6,"publicationDate":"2021-09-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68201158","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Lidia Cano Pecharroman, Christopher Williams, N. G. Nylen, M. Kiparsky
Traditional, limited purpose grey infrastructure has failed to address the world's interrelated water challenges. Improving water security will increasingly require more integrated responses. This paper examines large-scale green infrastructure (LSGI), planned natural or hybrid systems that materially affect water security at the watershed scale, as one such response. This paper examines key challenges for governing and financing LSGI, which hinder its broader use. We report on four case studies located in the United States where LSGI is being employed to improve water security. Through analysis of these case studies and related literature, we identify three themes important for LSGI governance: cost sharing, performance monitoring, and legitimization. First, we hypothesize that formal cost sharing based on the multiple benefits LSGI provides could enable wider adoption, but find that in these examples cost sharing is limited and informal. Second, our research suggests that expanding performance monitoring to encompass key secondary benefits could help clarify how the benefits and burdens of a project are distributed across stakeholders, facilitate cost sharing, and enhance project legitimacy. Finally, LSGI will require further legitimization – developing a broader perception that LSGI is an appropriate alternative or complement to grey infrastructure – to develop as a viable contributor to water security.
{"title":"How can we govern large-scale Green infrastructure for multiple water security benefits?","authors":"Lidia Cano Pecharroman, Christopher Williams, N. G. Nylen, M. Kiparsky","doi":"10.2166/bgs.2021.015","DOIUrl":"https://doi.org/10.2166/bgs.2021.015","url":null,"abstract":"\u0000 Traditional, limited purpose grey infrastructure has failed to address the world's interrelated water challenges. Improving water security will increasingly require more integrated responses. This paper examines large-scale green infrastructure (LSGI), planned natural or hybrid systems that materially affect water security at the watershed scale, as one such response. This paper examines key challenges for governing and financing LSGI, which hinder its broader use. We report on four case studies located in the United States where LSGI is being employed to improve water security. Through analysis of these case studies and related literature, we identify three themes important for LSGI governance: cost sharing, performance monitoring, and legitimization. First, we hypothesize that formal cost sharing based on the multiple benefits LSGI provides could enable wider adoption, but find that in these examples cost sharing is limited and informal. Second, our research suggests that expanding performance monitoring to encompass key secondary benefits could help clarify how the benefits and burdens of a project are distributed across stakeholders, facilitate cost sharing, and enhance project legitimacy. Finally, LSGI will require further legitimization – developing a broader perception that LSGI is an appropriate alternative or complement to grey infrastructure – to develop as a viable contributor to water security.","PeriodicalId":9337,"journal":{"name":"Blue-Green Systems","volume":null,"pages":null},"PeriodicalIF":4.6,"publicationDate":"2021-09-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45635033","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Élections parlementaires en Bulgarie, 4 avril 2021","authors":"Dobrin Kanev","doi":"10.3917/blue.001.0064","DOIUrl":"https://doi.org/10.3917/blue.001.0064","url":null,"abstract":"","PeriodicalId":9337,"journal":{"name":"Blue-Green Systems","volume":null,"pages":null},"PeriodicalIF":4.6,"publicationDate":"2021-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"91054672","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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