Ramon Farreny

Roof selection for rainwater harvesting: Quantity and quality assessments in Spain

Roofs are the first candidates for rainwater harvesting in urban areas. This research integrates quantitative and qualitative data of rooftop stormwater runoff in an urban Mediterranean-weather environment. The objective of this paper is to provide criteria for the roof selection in order to maximise the availability and quality of rainwater. Four roofs have been selected and monitored over a period of 2 years (2008-2010): three sloping roofs - clay tiles, metal sheet and polycarbonate plastic - and one flat gravel roof. The authors offer a model for the estimation of the runoff volume and the initial abstraction of each roof, and assess the physicochemical contamination of roof runoff. Great differences in the runoff coefficient (RC) are observed, depending mostly on the slope and the roughness of the roof. Thus, sloping smooth roofs (RC>0.90) may harvest up to about 50% more rainwater than flat rough roofs (RC=0.62). Physicochemical runoff quality appears to be generally better than the average quality found in the literature review (conductivity: 85.0 ± 10.0 μS/cm, total suspended solids: 5.98 ± 0.95 mg/L, total organic carbon: 11.6 ± 1.7 mg/L, pH: 7.59 ± 0.07 upH). However, statistically significant differences are found between sloping and flat rough roofs for some parameters (conductivity, total organic carbon, total carbonates system and ammonium), with the former presenting better quality in all parameters (except for ammonium). The results have an important significance for local governments and urban planners in the (re)design of buildings and cities from the perspective of sustainable rainwater management. The inclusion of criteria related to the roofs slope and roughness in city planning may be useful to promote rainwater as an alternative water supply while preventing flooding and water scarcity.

Environmental analysis of rainwater harvesting infrastructures in diffuse and compact urban models of Mediterranean climate

PurposeAt present, many urban areas in Mediterranean climates are coping with water scarcity, facing a growing water demand and a limited conventional water supply. Urban design and planning has so far largely neglected the benefits of rainwater harvesting (RWH) in the context of a sustainable management of this resource. Therefore, the purpose of this study was to identify the most environmentally friendly strategy for rainwater utilization in Mediterranean urban environments of different densities.Materials and methodsThe RWH systems modeled integrate the necessary infrastructures for harvesting and using rainwater in newly constructed residential areas. Eight scenarios were defined in terms of diffuse (D) and compact (C) urban models and the tank locations ((1) underground tank, (2) below-roof tank, (3) distributed-over-roof tank, and (4) block tank). The structural and hydraulic sizing of the catchment, storage, and distribution subsystems was taken into account using an average Mediterranean rainfall, the area of the harvesting surfaces, and a constant water demand for laundry. The quantification of environmental impacts was performed through a life cycle assessment, using CML 2001 Baseline method. The necessary materials and processes were considered in each scenario according to the lifecycle stages (i.e., materials, construction, transportation, use, and deconstruction) and subsystems.Results and discussionThe environmental characterization indicated that the best scenario in both urban models is the distributed-over-roof tank (D3, C3), which provided a reduction in impacts compared to the worst scenario of up to 73% in diffuse models and even higher in compact ones, 92% in the most dramatic case. The lower impacts are related to the better distribution of tank weight on the building, reducing the reinforcement requirements, and enabling energy savings. The storage subsystem and the materials stage contributed most significantly to the impacts in both urban models. In the compact density model, the underground-tank scenario (C1) presented the largest impacts in most categories due to its higher energy consumption. Additionally, more favorable environmental results were observed in compact densities than in diffuse ones for the Global Warming Potential category along with higher water efficiencies.ConclusionsThe implementation of one particular RWH scenario over another is not irrelevant in drought-stress environments. Selecting the most favorable scenario in the development of newly constructed residential areas provides significant savings in CO2 emissions in comparison with retrofit strategies. Therefore, urban planning should consider the design of RWH infrastructures using environmental criteria in addition to economic, social, and technological factors, adjusting the design to the potential uses for which the rainwater is intended.Recommendations and perspectivesAdditional research is needed to quantify the energy savings associated with the insulation caused by using the tank distributed over the roof. The integration of the economic and social aspects of these infrastructures in the analysis, from a life cycle approach, is necessary for targeting the planning and design of more sustainable cities in an integrated way.

Transition towards Sustainable Cities: Opportunities, Constraints, and Strategies in Planning. A Neighbourhood Ecodesign Case Study in Barcelona

Despite covering only 2.7% of the worlds total surface area, the worlds cities are responsible for 75% of the worlds energy consumption and 80% of greenhouse-gas emissions. For this reason, the redesign of cities is essential in the transition towards sustainability. However, planning and designing sustainable neighbourhoods is not a simple task, given that there is no agreement on what the sustainable settlement should be, nor on how this should be achieved. Furthermore, planners have to strive to achieve a balance between financial, environmental, and social goals, and must deal with multiple actors and stakeholders and with site-specific characteristics. The aim of this work is to describe the key determining factors—both opportunities and constraints—found in the process of designing and planning a neighbourhood, based on a case study in the city of Barcelona. In this practical experiment, led by the authors, the ecodesign methodology was applied on an urban scale in the neighbourhood of Vallbona, Barcelona, which occupies an area of 32.6 ha and will host 2120 dwellings. From this neighbourhood ecodesign exercise, it was found that territorial (urban form, urban fabrics, and density; availability of local resources), financial, legal, and political (local governments wishes and leadership) determinants are the most important. It is concluded that there is no single path to achieve urban sustainability, since the design of neighbourhoods in different locations will lead to different results.

Carbon dioxide emissions of Antarctic tourism

Abstract The increase of tourism to the Antarctic continent may entail not only local but also global environmental impacts. These latter impacts, which are mainly caused by transport, have been generally ignored. As a result, there is a lack of data on the global impacts of Antarctic tourism in terms of energy consumption and carbon dioxide emissions. This paper presents and applies a methodology for quantifying CO2 emissions, both for the Antarctic vessel fleet as a whole and per passenger (both per trip and per day). The results indicate that the average tourist trip to Antarctica results in 5.44 t of CO2 emissions per passenger, or 0.49 t per passenger and day. Approximately 70% of these emissions are attributable to cruising and 30% to flying, which highlights the global environmental relevance of local transport for this type of tourism.

Storm tank against combined sewer overflow: Operation strategies to minimise discharges impact to receiving waters

The pollution reduction opportunities of a drainage basin, located in Barcelona (Spain), were analysed as a case study in order to assess strategies for optimised management of sewerage networks in the Mediterranean region. The analysis results show that the introduction of a large storm tank against combined sewer overflow significantly reduces the negative impacts associated with discharges during rainy weather. The total annual mass into the receiving waters is reduced by 45%, measured in terms of suspended solid and chemical oxygen demand. The performance of large storm tanks can be optimised taking advantage of the natural sedimentation of the retained rainwater. At optimum stratification conditions, the annual regulation capability can be increased by 15% compared to the traditional operating conditions. Apparently, the environmental impacts associated with the materials used in the construction of the tank will also be reduced per unit volume of regulated water with the increasing annual regulation capacity.

Introduction to the Eco-Design Methodology and the Role of Product Carbon Footprint

Eco-design is used as a tool in the manufacturing and services sectors for improving the sustainability of products by integrating environmental aspects into the design stage, where most of the product impacts are determined. Laws (e.g., EU eco-design directive) and international schemes (e.g., ISO 14006) have encouraged the use of eco-design by companies; in addition, the literature has reported advances in methodology and widespread case studies in different economic sectors. This chapter aims to show a combined design for environment (DfE) and life cycle assessment (LCA) methodology for the implementation of eco-design by companies. The steps and tools of the methodology, as well as the most common strategies, are described. Product carbon footprint (PCF) plays an important role in the methodology in two main ways. First, PCF is one of the indicators that can be calculated with LCA, which has become a common environmental indicator used by companies, not only as quantitative data of the current environmental performance but also as a benchmark for further improvements. Second, PCF is used as a strategy for environmental communication to consumers through eco-labeling. The main strength of the carbon footprint is that stakeholders (business and consumers) are aware of and understand its meaning due to the presence of carbon emissions and global warming in mass media and public science studies.

Indicators for commercial urban water management: the cases of retail parks in Spain and Brazil

The use of planning and management tools for water management in urban environments is a promising area. This paper focuses on the description of two indicators, Water Intensity of a Purchase (WIP) and Potential Water Self-Sufficiency (PWSS) from rainwater harvesting, for the expanding sector of Retail Parks (RP). The WIP measures the water that is consumed per average customer and purchase, whereas the PWSS quantifies the potential capacity of the system to satisfy its water demand from rainwater. These tools have been checked in two case studies in Spain and Brazil. The results show a WIP of 8.0 and 22.9 litres, respectively, which measures the (in)efficiency of water use. This water demand, mainly of low quality, is met with the potable water supply network, while stormwater runoff is lost to sewage. The PWSS results, 3.0 for Spain and 1.4 for Brazil, indicate that RP could satisfy their needs with rainwater and even have a surplus of water. The combined use of both WIP and PWSS can be useful for the planning, design, evaluation and monitoring of RP.