Environmental performance of rainwater harvesting strategies in Mediterranean buildings

Purpose: The rapid urbanization and the constant expansion of urban areas during the last decades have locally led to increasing water shortage. Rainwater harvesting (RWH) systems have the potential to be an important contributor to urban water self-sufficiency. The goal of this study was to select an environmentally optimal RWH strategy in newly constructed residential buildings linked to rainwater demand for laundry under Mediterranean climatic conditions, without accounting for water from the mains. Methods: Different strategies were environmentally assessed for the design and use of RWH infrastructures in residential apartment blocks in Mediterranean climates. The harvested rainwater was used for laundry in all strategies. These strategies accounted for (i) tank location (i.e., tank distributed over the roof and underground tank), (ii) building height considering the number of stories (i.e., 6, 9, 12, and 15), and (iii) distribution strategy (i.e., shared laundry, supply to the nearest apartments, and distribution throughout the building). The RWH systems consisted of the catchment, storage, and distribution stages, and the structural and hydraulic calculations were based on Mediterranean conditions. The quantification of the environmental performance of each strategy (e.g., CO2eq. emissions) was performed in accordance with the life cycle assessment methodology. Results and discussion: According to the environmental assessment, the tank location and distribution strategy chosen were the most important variables in the optimization of RWH systems. Roof tank strategies present fewer impacts than their underground tank equivalents because they enhance energy and material savings, and their reinforcement requirements can be accounted for within the safety factors of the building structure without the tank. Among roof tanks and depending on the height, a distribution strategy that concentrates demand in a laundry room was the preferable option, resulting in reductions from 25 to 54 % in most of the selected impact categories compared to distribution throughout the building. Conclusions: These results may set new urban planning standards for the design and construction of buildings from the perspective of sustainable water management. In this sense, a behavioral change regarding demand should be promoted in compact, dense urban settlements.Peer ReviewedPostprint (author's final draft

Potencial d'aprofitament de recursos pluvials en zones urbanes al barri La Plana - Santa Bàrbara - Vallpineda del municipi de Sitges

Aquest estudi es centra en l'anàlisi de l'aprofitament d'aigües pluvials en sisteme

Urban rainwater runoff quantity and quality : a potential endogenous resource in cities?

Unidad de excelencia María de Maeztu MdM-2015-0552Rainwater harvesting might help to achieve self-sufficiency, but it must comply with health standards. We studied the runoff quantity and quality harvested from seven urban surfaces in a university campus in Barcelona according to their use (pedestrian or motorized mobility) and materials (concrete, asphalt and slabs). An experimental rainwater harvesting system was used to collect the runoff resulting from a set of rainfall events. We estimated the runoff coefficient and initial abstraction of each surface and analyzed the physicochemical and microbiological properties, and hydrocarbon and metal content of the samples. Rainfall intensity, surface material and state of conservation were essential parameters. Because of low rainfall intensity and surface degradation, the runoff coefficient was variable, with a minimum of 0.41. Concrete had the best quality, whereas weathering and particulate matter deposition led to worse quality in asphalt areas. Physicochemical runoff quality was outstanding when compared to superficial and underground water. Microorganisms were identified in the samples (>1 CFU/100 mL) and treatment is required to meet human consumption standards. Motorized traffic mostly affects the presence of metals such as zinc (31.7 μg/L). In the future, sustainable mobility patterns might result in improved rainwater quality standards

Potencial d'aprofitament de recursos pluvials en zones urbanes al barri La Plana - Santa Bàrbara - Vallpineda del municipi de Sitges

Aquest estudi es centra en l’anàlisi de l’aprofitament d’aigües pluvials en sistemes urbans, concretament al barri de LaPlana - Sta. Bàrbara - Vallpineda de Sitges, en base als escenaris proposats que contemplen diferents criteris i paràmetres. La metodologia utilitzada que conjuga els resultats potencials de l’oferta amb els de la demanda d’aigua al barri permet la determinació del nivell d’autosuficiència hídrica del sistema. Els resultats mostren una alta autosuficiència del 90% en quant es s’apliquen estratègies de gestió hídrica ecoeficients i mesures domèstiques per a reduir la demanda domèstica del sector. A més, la tipologia de coberta inclinada i un major règim pluviomètric anual, s’ha observat afavoreixen l’augment d’aquest índex. Per tant, es considera apropiat realitzar un eficient aprofitament de l’aigua de pluja, com a recurs endogen local, donats els beneficis econòmics, ambientals i socials que comporta en una situació de dèficit hídric com la del municipi de Sitges

Enviromental assessment of rainwater harvesting strategies in urban areas from a life cycle perspective

En el context de la transició cap a la sostenibilitat urbana un dels majors reptes que encaren les societats modernes és l’aprovisionament d'aigua, un recurs que és reconegut cada vegada més com a valuós mentre la quantitat i qualitat disponibles en disminueixen. La creixent evidència d'escassetat d'aigua a nivell mundial promou la necessitat de treballar en possibles sinèrgies entre les diferents fonts d’aigua existents i a diferents escales per tal de desenvolupar una xarxa més integrada, eficient i equitativa. Aquesta tesi es centra en l’aprofitament de l’aigua de pluja com a recurs endogen local amb el potencial per aconseguir un metabolisme més circular capaç de tancar els fluxos d'aigua i de complir amb els objectius d’autosuficiència hídrica en entorns urbans. Aquesta estratègia pot ajudar a reduir les infraestructures de captació i tractament necessàries per l'aigua potable, així com les de gestió i tractament d'aigües residuals, a la vegada que permet un major control del d’avingudes i inundacions en entorns urbans. No obstant actualment hi ha una manca de coneixement al voltant de quina és l’estratègia més adequada per a recollir aigües pluvials aplicable a cada escala urbana per una banda, i per l’altra la quantitat i qualitat del l’aigua d’escolament tampoc ha estat abordada en detall sota les condicions climàtiques i ambientals pròpies de les zones Mediterrànies (més concretament a Espanya). L'objectiu d'aquesta tesi és donar resposta a aquestes preguntes mitjançant el plantejament, l’avaluació i la validació del potencial i les avantatges de l’aprofitament d’aigües pluvials amb el menor impacte possible per tal d’assolir una millora en el cicle urbà de l’aigua en regions Mediterrànies. Per tal d'avaluar l'ecoeficiència de diverses estratègies de captació d'aigües pluvials en barris de nova construcció i determinar així l'estratègia òptima ambientalment, la infraestructures necessàries per la recollida, emmagatzematge i subministrament han estat dissenyades i avaluades des de la perspectiva de l’Anàlisi de Cicle de Vida (ACV). A més, diverses variables que afecten directament aquests sistemes han estat seleccionades i avaluades convenientment; entre elles s’inclou el model de densitat urbana, l'escala d’estudi , la ubicació del tanc dins de l'edifici, l'alçada d’aquest i per últim l’estratègia de subministrament d'aigua. Els resultats determinen l’impacte ambiental de cada escenari al llarg del cicle de vida de les infraestructures i indiquen l'opció ambientalment òptima per la recollida d'aigües pluvials a diferents escales. L'avaluació de la quantitat i qualitat potencial de d’aquest recurs en un entorn urbà s'ha desenvolupat per mitjà d'un estudi de cas experimental. Per a dur-lo a terme, set superfícies de captació diferents van ser seleccionats dins del campus de la UAB per cadascuna de les quals va ser adaptada una instal·lació de recollida i emmagatzematge de pluvials al llarg d’un període de 22 mesos de campanya experimental . La selecció de les diferents superfícies de captació es va realitzar d'acord amb dos criteris : el material de la superfície i el seu tipus d'ús . L'avaluació de la quantitat consistir en el càlcul dels models de regressió d'escolament - precipitació , l'estimació de la coeficient d’escolament (RC) global i l'abstracció inicial, mentre que les avaluacions de qualitat comprenen una varietat significativa dels paràmetres fisicoquímics i microbiològics. Els resultats van ser analitzats des d'un enfocament estadístic per validar la seva significança i correlació. Els criteris ambientals resultants d’aquesta tesi estan pensats per ajudar a definir les estratègies òptimes i determinar els usos de l'aigua de pluja amb els que millor s’aconsegueix la transició cap a la sostenibilitat de les zones urbanes, així com el redisseny més ecoeficient de les xarxes d'aigua urbana en el context del canvi climàtic. Aquests resultats poden servir d'orientació en la planificació i disseny urbà mitjançant la integració de criteris ambientals en els processos de presa de decisions.In the context of transition towards urban sustainability one of the major challenges facing modern societies is the provision of water, a resource that is increasingly recognized as a valuable resource while the quantity and quality available is decreasing. The growing evidence of water scarcity worldwide enhance the need to work on synergies among the different existing water sources and urban scales in order to develop more integrated, efficient and equitable water networks. In this sense, this dissertation focuses on the use of rainwater as a local endogenous resources to achieve a more circular metabolism able to close water flows and capable of accomplish urban water self-sufficiency. This can help to reduce the collection and treatment infrastructure needs for drinking water as well as the management and treatment of wastewater while having a greater control of floods in urban environments. However, there is still a lack of knowledge on which is the most adequate rainwater harvesting (RWH) strategy for each urban scale on one hand, while on the other the quantity and quality of runoff has yet not been addressed under the local climatic and environmental conditions of Mediterranean areas (more specifically in Spain). The aim of this research was to answer this question by investigating, evaluating and validating the potential and advantages of using rainwater to achieve, with the lower impact possible, the improvement of the water cycle in urban areas located within the Mediterranean climate. In order to evaluate the eco-efficiency of several RWH strategies for newly built neighbourhoods and to determine the environmentally optimum strategy, the necessary rainwater collection, storage and distribution infrastructures were designed and then environmentally assessed through a Life Cycle Assessment (LCA) approach. In addition, several variables that directly affect RWH infrastructures were selected and conveniently assessed; these include the urban density model, the building scale, the tank location within the building, the building height and at last the water supplying strategy. The results evaluate the environmental performance of each scenario and indicate the most environmentally friendly option for rainwater harvesting at different scales. The assessment of the potential RWH quantity and quality in an urban environment was developed by means of an experimental case study. To develop it, seven different catchment surfaces were selected within the UAB campus for which an experimental RWH installation was adapted and run over a period of 22 months of experimental campaign. The selection of catchment areas was done according to two criteria: surface material and type of use of the surface. The quantity assessment consisted of the calculation of the runoff –rainfall regression models, the estimation of the global RC and of the initial abstraction, while quality assessments comprised a significant variety of physicochemical and microbiological parameters. From a statistical approach all results were tested for significance and correlated. The resulting environmental criteria are thought so to define the optimal strategies and uses of rainwater that best leads towards the sustainability of urban areas as well as the most eco-efficient redesign of urban water grids in the context of climate change. These results may provide useful guidance in urban planning and design by integrating environmental criteria into the decision-making processes

Enviromental assessment of rainwater harvesting strategies in urban areas from a life cycle perspective

En el context de la transició cap a la sostenibilitat urbana un dels majors reptes que encaren les societats modernes és l'aprovisionament d'aigua, un recurs que és reconegut cada vegada més com a valuós mentre la quantitat i qualitat disponibles en disminueixen. La creixent evidència d'escassetat d'aigua a nivell mundial promou la necessitat de treballar en possibles sinèrgies entre les diferents fonts d'aigua existents i a diferents escales per tal de desenvolupar una xarxa més integrada, eficient i equitativa. Aquesta tesi es centra en l'aprofitament de l'aigua de pluja com a recurs endogen local amb el potencial per aconseguir un metabolisme més circular capaç de tancar els fluxos d'aigua i de complir amb els objectius d'autosuficiència hídrica en entorns urbans. Aquesta estratègia pot ajudar a reduir les infraestructures de captació i tractament necessàries per l'aigua potable, així com les de gestió i tractament d'aigües residuals, a la vegada que permet un major control del d'avingudes i inundacions en entorns urbans. No obstant actualment hi ha una manca de coneixement al voltant de quina és l'estratègia més adequada per a recollir aigües pluvials aplicable a cada escala urbana per una banda, i per l'altra la quantitat i qualitat del l'aigua d'escolament tampoc ha estat abordada en detall sota les condicions climàtiques i ambientals pròpies de les zones Mediterrànies (més concretament a Espanya). L'objectiu d'aquesta tesi és donar resposta a aquestes preguntes mitjançant el plantejament, l'avaluació i la validació del potencial i les avantatges de l'aprofitament d'aigües pluvials amb el menor impacte possible per tal d'assolir una millora en el cicle urbà de l'aigua en regions Mediterrànies. Per tal d'avaluar l'ecoeficiència de diverses estratègies de captació d'aigües pluvials en barris de nova construcció i determinar així l'estratègia òptima ambientalment, la infraestructures necessàries per la recollida, emmagatzematge i subministrament han estat dissenyades i avaluades des de la perspectiva de l'Anàlisi de Cicle de Vida (ACV). A més, diverses variables que afecten directament aquests sistemes han estat seleccionades i avaluades convenientment; entre elles s'inclou el model de densitat urbana, l'escala d'estudi , la ubicació del tanc dins de l'edifici, l'alçada d'aquest i per últim l'estratègia de subministrament d'aigua. Els resultats determinen l'impacte ambiental de cada escenari al llarg del cicle de vida de les infraestructures i indiquen l'opció ambientalment òptima per la recollida d'aigües pluvials a diferents escales. L'avaluació de la quantitat i qualitat potencial de d'aquest recurs en un entorn urbà s'ha desenvolupat per mitjà d'un estudi de cas experimental. Per a dur-lo a terme, set superfícies de captació diferents van ser seleccionats dins del campus de la UAB per cadascuna de les quals va ser adaptada una instal·lació de recollida i emmagatzematge de pluvials al llarg d'un període de 22 mesos de campanya experimental . La selecció de les diferents superfícies de captació es va realitzar d'acord amb dos criteris : el material de la superfície i el seu tipus d'ús . L'avaluació de la quantitat consistir en el càlcul dels models de regressió d'escolament - precipitació , l'estimació de la coeficient d'escolament (RC) global i l'abstracció inicial, mentre que les avaluacions de qualitat comprenen una varietat significativa dels paràmetres fisicoquímics i microbiològics. Els resultats van ser analitzats des d'un enfocament estadístic per validar la seva significança i correlació. Els criteris ambientals resultants d'aquesta tesi estan pensats per ajudar a definir les estratègies òptimes i determinar els usos de l'aigua de pluja amb els que millor s'aconsegueix la transició cap a la sostenibilitat de les zones urbanes, així com el redisseny més ecoeficient de les xarxes d'aigua urbana en el context del canvi climàtic. Aquests resultats poden servir d'orientació en la planificació i disseny urbà mitjançant la integració de criteris ambientals en els processos de presa de decisions.In the context of transition towards urban sustainability one of the major challenges facing modern societies is the provision of water, a resource that is increasingly recognized as a valuable resource while the quantity and quality available is decreasing. The growing evidence of water scarcity worldwide enhance the need to work on synergies among the different existing water sources and urban scales in order to develop more integrated, efficient and equitable water networks. In this sense, this dissertation focuses on the use of rainwater as a local endogenous resources to achieve a more circular metabolism able to close water flows and capable of accomplish urban water self-sufficiency. This can help to reduce the collection and treatment infrastructure needs for drinking water as well as the management and treatment of wastewater while having a greater control of floods in urban environments. However, there is still a lack of knowledge on which is the most adequate rainwater harvesting (RWH) strategy for each urban scale on one hand, while on the other the quantity and quality of runoff has yet not been addressed under the local climatic and environmental conditions of Mediterranean areas (more specifically in Spain). The aim of this research was to answer this question by investigating, evaluating and validating the potential and advantages of using rainwater to achieve, with the lower impact possible, the improvement of the water cycle in urban areas located within the Mediterranean climate. In order to evaluate the eco-efficiency of several RWH strategies for newly built neighbourhoods and to determine the environmentally optimum strategy, the necessary rainwater collection, storage and distribution infrastructures were designed and then environmentally assessed through a Life Cycle Assessment (LCA) approach. In addition, several variables that directly affect RWH infrastructures were selected and conveniently assessed; these include the urban density model, the building scale, the tank location within the building, the building height and at last the water supplying strategy. The results evaluate the environmental performance of each scenario and indicate the most environmentally friendly option for rainwater harvesting at different scales. The assessment of the potential RWH quantity and quality in an urban environment was developed by means of an experimental case study. To develop it, seven different catchment surfaces were selected within the UAB campus for which an experimental RWH installation was adapted and run over a period of 22 months of experimental campaign. The selection of catchment areas was done according to two criteria: surface material and type of use of the surface. The quantity assessment consisted of the calculation of the runoff -rainfall regression models, the estimation of the global RC and of the initial abstraction, while quality assessments comprised a significant variety of physicochemical and microbiological parameters. From a statistical approach all results were tested for significance and correlated. The resulting environmental criteria are thought so to define the optimal strategies and uses of rainwater that best leads towards the sustainability of urban areas as well as the most eco-efficient redesign of urban water grids in the context of climate change. These results may provide useful guidance in urban planning and design by integrating environmental criteria into the decision-making processes

Urban rainwater runoff quantity and quality : a potential endogenous resource in cities?

Unidad de excelencia María de Maeztu MdM-2015-0552Rainwater harvesting might help to achieve self-sufficiency, but it must comply with health standards. We studied the runoff quantity and quality harvested from seven urban surfaces in a university campus in Barcelona according to their use (pedestrian or motorized mobility) and materials (concrete, asphalt and slabs). An experimental rainwater harvesting system was used to collect the runoff resulting from a set of rainfall events. We estimated the runoff coefficient and initial abstraction of each surface and analyzed the physicochemical and microbiological properties, and hydrocarbon and metal content of the samples. Rainfall intensity, surface material and state of conservation were essential parameters. Because of low rainfall intensity and surface degradation, the runoff coefficient was variable, with a minimum of 0.41. Concrete had the best quality, whereas weathering and particulate matter deposition led to worse quality in asphalt areas. Physicochemical runoff quality was outstanding when compared to superficial and underground water. Microorganisms were identified in the samples (>1 CFU/100 mL) and treatment is required to meet human consumption standards. Motorized traffic mostly affects the presence of metals such as zinc (31.7 μg/L). In the future, sustainable mobility patterns might result in improved rainwater quality standards

Environmental performance of rainwater harvesting strategies in Mediterranean buildings

SostenipraUnidad de excelencia María de Maeztu MdM-2015-0552Purpose: The rapid urbanization and the constant expansion of urban areas during the last decades have locally led to increasing water shortage. Rainwater harvesting (RWH) systems have the potential to be an important contributor to urban water self-sufficiency. The goal of this study was to select an environmentally optimal RWH strategy in newly constructed residential buildings linked to rainwater demand for laundry under Mediterranean climatic conditions, without accounting for water from the mains. Methods: Different strategies were environmentally assessed for the design and use of RWH infrastructures in residential apartment blocks in Mediterranean climates. The harvested rainwater was used for laundry in all strategies. These strategies accounted for (i) tank location (i.e., tank distributed over the roof and underground tank), (ii) building height considering the number of stories (i.e., 6, 9, 12, and 15), and (iii) distribution strategy (i.e., shared laundry, supply to the nearest apartments, and distribution throughout the building). The RWH systems consisted of the catchment, storage, and distribution stages, and the structural and hydraulic calculations were based on Mediterranean conditions. The quantification of the environmental performance of each strategy (e.g., CO₂eq. emissions) was performed in accordance with the life cycle assessment methodology. Results and discussion: According to the environmental assessment, the tank location and distribution strategy chosen were the most important variables in the optimization of RWH systems. Roof tank strategies present fewer impacts than their underground tank equivalents because they enhance energy and material savings, and their reinforcement requirements can be accounted for within the safety factors of the building structure without the tank. Among roof tanks and depending on the height, a distribution strategy that concentrates demand in a laundry room was the preferable option, resulting in reductions from 25 to 54 % in most of the selected impact categories compared to distribution throughout the building. Conclusions: These results may set new urban planning standards for the design and construction of buildings from the perspective of sustainable water management. In this sense, a behavioral change regarding demand should be promoted in compact, dense urban settlements

Environmental performance of rainwater harvesting strategies in Mediterranean buildings

Purpose: The rapid urbanization and the constant expansion of urban areas during the last decades have locally led to increasing water shortage. Rainwater harvesting (RWH) systems have the potential to be an important contributor to urban water self-sufficiency. The goal of this study was to select an environmentally optimal RWH strategy in newly constructed residential buildings linked to rainwater demand for laundry under Mediterranean climatic conditions, without accounting for water from the mains. Methods: Different strategies were environmentally assessed for the design and use of RWH infrastructures in residential apartment blocks in Mediterranean climates. The harvested rainwater was used for laundry in all strategies. These strategies accounted for (i) tank location (i.e., tank distributed over the roof and underground tank), (ii) building height considering the number of stories (i.e., 6, 9, 12, and 15), and (iii) distribution strategy (i.e., shared laundry, supply to the nearest apartments, and distribution throughout the building). The RWH systems consisted of the catchment, storage, and distribution stages, and the structural and hydraulic calculations were based on Mediterranean conditions. The quantification of the environmental performance of each strategy (e.g., CO2eq. emissions) was performed in accordance with the life cycle assessment methodology. Results and discussion: According to the environmental assessment, the tank location and distribution strategy chosen were the most important variables in the optimization of RWH systems. Roof tank strategies present fewer impacts than their underground tank equivalents because they enhance energy and material savings, and their reinforcement requirements can be accounted for within the safety factors of the building structure without the tank. Among roof tanks and depending on the height, a distribution strategy that concentrates demand in a laundry room was the preferable option, resulting in reductions from 25 to 54 % in most of the selected impact categories compared to distribution throughout the building. Conclusions: These results may set new urban planning standards for the design and construction of buildings from the perspective of sustainable water management. In this sense, a behavioral change regarding demand should be promoted in compact, dense urban settlements.Peer Reviewe

Development of urban solar infrastructure to support low-carbon mobility

The provision of an adequate network of urban infrastructures is essential to create clean and energy-efficient urban mobility systems. However, the urban infrastructure to support sustainable mobility can produce a substantial environmental burden if no life cycle environmental criteria are applied in its design and management. This paper demonstrates the potential to support energy-efficient and CO2-free pedestrian and electric bike (e-bike) mobility through the ecological design (eco-design) of urban elements. An eco-design approach is applied to reconceptualize a conventional pergola toward an eco-product (solar pergola). The solar pergola generates surplus photovoltaic electricity that provides a multifunctional character. According to the end-use of this energy, different scenarios are analyzed for robust decision-making. The deployment of solar pergolas can contribute to save from 2,080kg to over 47,185kg of CO2 eq. and from 350,390MJ to over 692,760MJ eq. in 10 years, depending on the geographic emplacement (solar radiation and electricity grid system). These savings are equivalent to charging 2-9 e-bikes per day using clean energy. Instead of maximizing infrastructure deployment to shift to environmentally friendly modes of mobility, the implementation of multifunctional urban elements represents a key area of action in the context of smart city development