Ž . The aim of this study was to determine the temporal variation in the concentrations of arseni... more Ž . The aim of this study was to determine the temporal variation in the concentrations of arsenic As , beryllium Be ,
Journal of Environmental Science and Health, Part A, 1999
To determine the temporal variation in the levels of polychlorinated dibenzo‐p‐dioxins (PCDDs) an... more To determine the temporal variation in the levels of polychlorinated dibenzo‐p‐dioxins (PCDDs) and dibenzofurans (PCDFs) in vegetation grown near an old municipal solid waste incinerator (Montcada, Barcelona, Spain), 24 herbage samples were collected at the same sampling points in which samples had been taken one year before. While in the previous survey PCDD/F concentrations ranged from 1.07 to 3.05 ng
Desalination becomes in many parts of the world and also in Europe a promising option to combat w... more Desalination becomes in many parts of the world and also in Europe a promising option to combat water stress in water scarce regions. However, also the question of sustainability and environmental impacts of this technology is in focus of numerous studies and discussions. Especially, the focus is set on high energy demand and disposal of generated brine. In this study, the conventional desalination technology in Europe reverse osmosis (RO) has been compared to the newly developed membrane based technology Memstill® by means of life cycle assessment (LCA). The objective is to define clearly conditions when the environmental impacts are lowest. The results reveal not only the strong dependency of the energy supply and demand but also the potential to reduce the environmental impacts while combining with alternative renewable energy supply. The reverse osmosis can be combined with renewable energies and Memstill® with cogeneration or waste heat. The global warming potential can even be reduced by 98% when RO is combined with wind energy instead of using the electricity grid mix of Spain. Memstill® is especially favourable to RO for feed water with higher salt content due to its almost salt concentration independent energy demand.
ABSTRACT In this paper ten control strategies are tested, starting from a default tuning of the c... more ABSTRACT In this paper ten control strategies are tested, starting from a default tuning of the controllers, to evaluate its results in terms of general plant performance indicators such as the effluent quality index (EQI) and the operating cost index (OCI). Using the Benchmark simulation No 1 (BSM1), many simulations are done to determine the most sensitive parameter of the proportional-integral (PI) controllers implemented. The most sensitive parameter is selected by evaluating the influence of the proportional gain (Kp) and the integral time (Ti) in the general performance of the plant when they are changed into the proposed ranges. From the simulation study, Ti is selected as the most sensitive parameter. A comparison between the results in terms of EQI vs OCI graphics, varying Kp and Ti and the results varying only Ti, shows similar behaviours on the plant performance for all strategies.
ABSTRACT This paper presents the application of different control strategies applied for wastewat... more ABSTRACT This paper presents the application of different control strategies applied for wastewater treatment plants (WWTP). The main purpose is to evaluate its effectiveness/cost trade-off attending a set of criteria. The study has been performed by using the Benchmark Simulation Model No. 2 (BSM2) and the evaluation criteria have been selected taking into account the most relevant indicators provided by this benchmark scenario. More specifically, five strategies have been implemented and compared with the default closed loop control strategy (DCL) of BSM2 and between them. Results show that the control strategies that use the ammonia cascade controller provide better results in most of the evaluated criteria than the control strategies implemented by using only the oxygen controller. Ammonia controller improves the results in terms of effluent quality and operational costs due to the reported aeration energy savings. As a conclusion of this study the control strategy that uses the ammonia and carbon controllers has been selected as the most recommended for implementation.
Life cycle assessment (LCA) methodology is used to evaluate the environmental profile of a produc... more Life cycle assessment (LCA) methodology is used to evaluate the environmental profile of a product or process from its origin to its final destination. In this paper we used LCA to evaluate the current situation of a wastewater treatment plant and identify improvement alternatives. Currently, the highest environmental impacts are caused by the stages of the plant with the highest energy consumption, the use of biogas from anaerobic digestion (95% burned in torch) and the final destination of the sludge (98.6% for agricultural use and 1.4% for compost). We propose four alternatives for biogas applications and five alternatives for sludge applications and compare them to the current situation. The alternatives were incorporated in a decision support system to identify and prioritize the most positive environmental option. Using biogas to produce electricity or a combination of electricity and heat provided the best environmental options since the energy produced would be enough to supply all the stages of the plant, thus reducing their environmental impact. The best environmental option for the final destination of the sludge is to combine the current situation (fertilizer replacement) with use of the sludge in a cement plant (as a replacement for fuel and raw material).
The aim of this study was to calculate the incremental lifetime-risk to dioxins and furans (PCDD/... more The aim of this study was to calculate the incremental lifetime-risk to dioxins and furans (PCDD/Fs) for the population living in the surroundings of a municipal solid waste incinerator (MSWI), as well as to establish the potential reduction on human health risks as a consequence of the adaptation to the EU legislation on pollutant emissions from the MSWI stack. Analytical and modelled results were obtained. PCDD/F concentrations in environmental media were determined by means of a simple-compartment-multimedia model (air -soilvegetation model). Predicted and measured PCDD/F concentrations in soils and vegetation were compared, and the effects of MSWI emissions in the environmental media were determined. Human health risks due to PCDD/F emissions from the MSWI were also estimated based on I-TEQ measured and modelled in various environmental media. Cancer risks due to PCDD/F emissions of the plant were 1.07E À 07 and 3.08E À 09, before and after installation of the clean air system, respectively. On the other hand, cancer risks due to other PCDD/F emission sources in the area were 5.54E À 06 and 1.86E À 06. Total PCDD/F cancer risks (including those from diet) for the population living in the vicinity of the MSWI were 1.3E À 04 and 4.25E À 05, respectively (67.6% of reduction). Hazard ratio for total PCDD/F exposure (including diet) decreased during the last 5 years from 1.16 to 0.38. The above data show that other emission sources of PCDD/Fs also have a notable environmental impact on the area under direct influence of the MSWI. D
The incremental lifetime risks due to polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/F... more The incremental lifetime risks due to polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) for the residents living in the surroundings of a municipal solid waste incinerator (MSWI) have been assessed. Two dierent pathways of exposure to PCDD/Fs, ingestion through the diet and exposure from MSWI emissions, were compared. Monte-Carlo simulations were carried out to obtain variability and uncertainty propagation The joint analysis of uncertainty and variability included a sensitivity analysis that identi®ed the contribution to variance by dierent inputs. In general terms, PCDD/F ingestion through the diet contributed with more than 99% of the total risk, whereas direct exposition to PCDD/F emissions from the MSWI was less than 1% The results show that the median (50% percentile) of non-carcinogenic risk due to PCDD/Fs in the population living in the surroundings of the MSWI was 0.72 and the ratio of the 95th percentile and ®fth percentile was about 2. With respect to the total carcinogenic risk, the median increment in individual lifetime was 7:90 Â 10 À5 , while the ratio between the 95th percentile and the ®fth percentile was about 1.5. In this analysis, a sequential structural decomposition of the relationships between the input variables has been used to partition the variance in the output (risk) in order to identify the most in¯uential contributors to overall variance among them. Ó
The incremental lifetime risks due to polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/F... more The incremental lifetime risks due to polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) for the residents living in the surroundings of a municipal solid waste incinerator (MSWI) have been assessed. Two dierent pathways of exposure to PCDD/Fs, ingestion through the diet and exposure from MSWI emissions, were compared. Monte-Carlo simulations were carried out to obtain variability and uncertainty propagation The joint analysis of uncertainty and variability included a sensitivity analysis that identi®ed the contribution to variance by dierent inputs. In general terms, PCDD/F ingestion through the diet contributed with more than 99% of the total risk, whereas direct exposition to PCDD/F emissions from the MSWI was less than 1% The results show that the median (50% percentile) of non-carcinogenic risk due to PCDD/Fs in the population living in the surroundings of the MSWI was 0.72 and the ratio of the 95th percentile and ®fth percentile was about 2. With respect to the total carcinogenic risk, the median increment in individual lifetime was 7:90 Â 10 À5 , while the ratio between the 95th percentile and the ®fth percentile was about 1.5. In this analysis, a sequential structural decomposition of the relationships between the input variables has been used to partition the variance in the output (risk) in order to identify the most in¯uential contributors to overall variance among them. Ó
The vegetation and soil levels of the 17 polychlorinated dibenzo-p-dioxin and dibenzofuran (PCDD/... more The vegetation and soil levels of the 17 polychlorinated dibenzo-p-dioxin and dibenzofuran (PCDD/F) toxic congeners were calculated by means of a vegetation and a soil model, respectively. Both models predicted the levels of the 17 PCDD/F congeners in quite good agreement with the observed results although the soil model was more accurate than the vegetation model. Four different pathways of contribution to the vegetation concentrations were taken into account: vapour-phase absorption, dry particle deposition, wet particle deposition and uptake by root. The most important pathway was the vapour-phase absorption and the less was the uptake by root. In the soils model four pathways were considered: background soil concentration, dry particle deposition, wet particle deposition and uptake by root. After the background concentration, the most important pathway was the wet deposition. Ó
Ž . The aim of this study was to determine the temporal variation in the concentrations of arseni... more Ž . The aim of this study was to determine the temporal variation in the concentrations of arsenic As , beryllium Be ,
Journal of Environmental Science and Health, Part A, 1999
To determine the temporal variation in the levels of polychlorinated dibenzo‐p‐dioxins (PCDDs) an... more To determine the temporal variation in the levels of polychlorinated dibenzo‐p‐dioxins (PCDDs) and dibenzofurans (PCDFs) in vegetation grown near an old municipal solid waste incinerator (Montcada, Barcelona, Spain), 24 herbage samples were collected at the same sampling points in which samples had been taken one year before. While in the previous survey PCDD/F concentrations ranged from 1.07 to 3.05 ng
Desalination becomes in many parts of the world and also in Europe a promising option to combat w... more Desalination becomes in many parts of the world and also in Europe a promising option to combat water stress in water scarce regions. However, also the question of sustainability and environmental impacts of this technology is in focus of numerous studies and discussions. Especially, the focus is set on high energy demand and disposal of generated brine. In this study, the conventional desalination technology in Europe reverse osmosis (RO) has been compared to the newly developed membrane based technology Memstill® by means of life cycle assessment (LCA). The objective is to define clearly conditions when the environmental impacts are lowest. The results reveal not only the strong dependency of the energy supply and demand but also the potential to reduce the environmental impacts while combining with alternative renewable energy supply. The reverse osmosis can be combined with renewable energies and Memstill® with cogeneration or waste heat. The global warming potential can even be reduced by 98% when RO is combined with wind energy instead of using the electricity grid mix of Spain. Memstill® is especially favourable to RO for feed water with higher salt content due to its almost salt concentration independent energy demand.
ABSTRACT In this paper ten control strategies are tested, starting from a default tuning of the c... more ABSTRACT In this paper ten control strategies are tested, starting from a default tuning of the controllers, to evaluate its results in terms of general plant performance indicators such as the effluent quality index (EQI) and the operating cost index (OCI). Using the Benchmark simulation No 1 (BSM1), many simulations are done to determine the most sensitive parameter of the proportional-integral (PI) controllers implemented. The most sensitive parameter is selected by evaluating the influence of the proportional gain (Kp) and the integral time (Ti) in the general performance of the plant when they are changed into the proposed ranges. From the simulation study, Ti is selected as the most sensitive parameter. A comparison between the results in terms of EQI vs OCI graphics, varying Kp and Ti and the results varying only Ti, shows similar behaviours on the plant performance for all strategies.
ABSTRACT This paper presents the application of different control strategies applied for wastewat... more ABSTRACT This paper presents the application of different control strategies applied for wastewater treatment plants (WWTP). The main purpose is to evaluate its effectiveness/cost trade-off attending a set of criteria. The study has been performed by using the Benchmark Simulation Model No. 2 (BSM2) and the evaluation criteria have been selected taking into account the most relevant indicators provided by this benchmark scenario. More specifically, five strategies have been implemented and compared with the default closed loop control strategy (DCL) of BSM2 and between them. Results show that the control strategies that use the ammonia cascade controller provide better results in most of the evaluated criteria than the control strategies implemented by using only the oxygen controller. Ammonia controller improves the results in terms of effluent quality and operational costs due to the reported aeration energy savings. As a conclusion of this study the control strategy that uses the ammonia and carbon controllers has been selected as the most recommended for implementation.
Life cycle assessment (LCA) methodology is used to evaluate the environmental profile of a produc... more Life cycle assessment (LCA) methodology is used to evaluate the environmental profile of a product or process from its origin to its final destination. In this paper we used LCA to evaluate the current situation of a wastewater treatment plant and identify improvement alternatives. Currently, the highest environmental impacts are caused by the stages of the plant with the highest energy consumption, the use of biogas from anaerobic digestion (95% burned in torch) and the final destination of the sludge (98.6% for agricultural use and 1.4% for compost). We propose four alternatives for biogas applications and five alternatives for sludge applications and compare them to the current situation. The alternatives were incorporated in a decision support system to identify and prioritize the most positive environmental option. Using biogas to produce electricity or a combination of electricity and heat provided the best environmental options since the energy produced would be enough to supply all the stages of the plant, thus reducing their environmental impact. The best environmental option for the final destination of the sludge is to combine the current situation (fertilizer replacement) with use of the sludge in a cement plant (as a replacement for fuel and raw material).
The aim of this study was to calculate the incremental lifetime-risk to dioxins and furans (PCDD/... more The aim of this study was to calculate the incremental lifetime-risk to dioxins and furans (PCDD/Fs) for the population living in the surroundings of a municipal solid waste incinerator (MSWI), as well as to establish the potential reduction on human health risks as a consequence of the adaptation to the EU legislation on pollutant emissions from the MSWI stack. Analytical and modelled results were obtained. PCDD/F concentrations in environmental media were determined by means of a simple-compartment-multimedia model (air -soilvegetation model). Predicted and measured PCDD/F concentrations in soils and vegetation were compared, and the effects of MSWI emissions in the environmental media were determined. Human health risks due to PCDD/F emissions from the MSWI were also estimated based on I-TEQ measured and modelled in various environmental media. Cancer risks due to PCDD/F emissions of the plant were 1.07E À 07 and 3.08E À 09, before and after installation of the clean air system, respectively. On the other hand, cancer risks due to other PCDD/F emission sources in the area were 5.54E À 06 and 1.86E À 06. Total PCDD/F cancer risks (including those from diet) for the population living in the vicinity of the MSWI were 1.3E À 04 and 4.25E À 05, respectively (67.6% of reduction). Hazard ratio for total PCDD/F exposure (including diet) decreased during the last 5 years from 1.16 to 0.38. The above data show that other emission sources of PCDD/Fs also have a notable environmental impact on the area under direct influence of the MSWI. D
The incremental lifetime risks due to polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/F... more The incremental lifetime risks due to polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) for the residents living in the surroundings of a municipal solid waste incinerator (MSWI) have been assessed. Two dierent pathways of exposure to PCDD/Fs, ingestion through the diet and exposure from MSWI emissions, were compared. Monte-Carlo simulations were carried out to obtain variability and uncertainty propagation The joint analysis of uncertainty and variability included a sensitivity analysis that identi®ed the contribution to variance by dierent inputs. In general terms, PCDD/F ingestion through the diet contributed with more than 99% of the total risk, whereas direct exposition to PCDD/F emissions from the MSWI was less than 1% The results show that the median (50% percentile) of non-carcinogenic risk due to PCDD/Fs in the population living in the surroundings of the MSWI was 0.72 and the ratio of the 95th percentile and ®fth percentile was about 2. With respect to the total carcinogenic risk, the median increment in individual lifetime was 7:90 Â 10 À5 , while the ratio between the 95th percentile and the ®fth percentile was about 1.5. In this analysis, a sequential structural decomposition of the relationships between the input variables has been used to partition the variance in the output (risk) in order to identify the most in¯uential contributors to overall variance among them. Ó
The incremental lifetime risks due to polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/F... more The incremental lifetime risks due to polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) for the residents living in the surroundings of a municipal solid waste incinerator (MSWI) have been assessed. Two dierent pathways of exposure to PCDD/Fs, ingestion through the diet and exposure from MSWI emissions, were compared. Monte-Carlo simulations were carried out to obtain variability and uncertainty propagation The joint analysis of uncertainty and variability included a sensitivity analysis that identi®ed the contribution to variance by dierent inputs. In general terms, PCDD/F ingestion through the diet contributed with more than 99% of the total risk, whereas direct exposition to PCDD/F emissions from the MSWI was less than 1% The results show that the median (50% percentile) of non-carcinogenic risk due to PCDD/Fs in the population living in the surroundings of the MSWI was 0.72 and the ratio of the 95th percentile and ®fth percentile was about 2. With respect to the total carcinogenic risk, the median increment in individual lifetime was 7:90 Â 10 À5 , while the ratio between the 95th percentile and the ®fth percentile was about 1.5. In this analysis, a sequential structural decomposition of the relationships between the input variables has been used to partition the variance in the output (risk) in order to identify the most in¯uential contributors to overall variance among them. Ó
The vegetation and soil levels of the 17 polychlorinated dibenzo-p-dioxin and dibenzofuran (PCDD/... more The vegetation and soil levels of the 17 polychlorinated dibenzo-p-dioxin and dibenzofuran (PCDD/F) toxic congeners were calculated by means of a vegetation and a soil model, respectively. Both models predicted the levels of the 17 PCDD/F congeners in quite good agreement with the observed results although the soil model was more accurate than the vegetation model. Four different pathways of contribution to the vegetation concentrations were taken into account: vapour-phase absorption, dry particle deposition, wet particle deposition and uptake by root. The most important pathway was the vapour-phase absorption and the less was the uptake by root. In the soils model four pathways were considered: background soil concentration, dry particle deposition, wet particle deposition and uptake by root. After the background concentration, the most important pathway was the wet deposition. Ó
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