Potential for Potable Water Savings in Buildings by Using Stormwater Harvested from Porous Pavements

Financial Feasibility of Harvesting Rainwater from Permeable Pavements: A Case Study in a City Square

The objective of this study was to carry out the financial feasibility analysis of harvesting rainwater from permeable pavements in a city square. A case study was carried out in a square close to the beach in the city of Florianópolis, Brazil. Questionnaires were applied to pedestrians who circulate within the area. The square is to be implemented to promote sustainability and improve the user’s quality of life. From the rainfall data and the average daily water demand for irrigation of the square vegetation, the volume of rainwater to be harvested from the permeable pavement was calculated. The rainwater demand was estimated as 662 L/day. The implementation and operation costs of the pavement and irrigation systems were evaluated. The potential for potable water savings was 89.8%. The payback period was estimated as 347 months. This study showed that rainwater collected from permeable pavements is financially feasible and represents a promising technique.

Comprehensive Benefit Evaluation of Pervious Pavement Based on China’s Sponge City Concept

Sponge cities provide broad hydrological functions to alleviate urban flooding and other water-related problems in China. Conventional impervious paving cannot meet contemporary sustainable city goals. The permeable paving technology offers primary benefits such as increasing stormwater infiltration, drainage, purification, groundwater recharge, and microclimatic amelioration. Few studies have evaluated the embracive range of benefits and the social functions holistically. This study aimed to develop a comprehensive benefit evaluation system to cover a broad range of indicators. Nineteen indicators were selected based on the literature review, field studies, and research experience. Organized in a three-tiered hierarchical structure, they were divided into environmental, economic, and social benefits. A grey intuitionistic fuzzy comprehensive evaluation model was built by combining intuitionistic fuzzy analysis with a grey comprehensive evaluation. The computational tools could determine the differential weights of indicators and benefit scores. Taking an example of a permeable pavement project in Quanzhou City, the comprehensive benefits were assessed and validated using our evaluation model. The results show that (1) the comprehensive benefits of the project met the economic feasibility criteria with advantages over conventional paving; (2) the environmental benefits were prominently expressed; (3) the social benefits were assessed and confirmed. The results verified the feasibility and applicability of the quantitative-qualitative model. The method could permit the integrated and systematic benefit assessment of permeable paving designs. It also provides guidance and reference to evaluate the performance of permeable pavements and their comprehensive range of benefits. The findings could reference choosing and refining designs, optimizing the benefits, and promoting a science-oriented development of permeable paving.

Permeable Pavements as a Means to Save Water in Buildings: State of the Art in Brazil

Permeable pavements have been the subject of numerous studies in recent decades. The possibility of dissipating stormwater more smoothly and generating numerous benefits to the environment and users makes the use of permeable pavements an excellent possibility of integration into sustainable and resilient water management systems in cities. In Brazil, numerous studies on the quantity and quality of infiltrated water, permeability of the coating, clogging, environmental burden, and feasibility, among other characteristics, have been researched. Within this theme, the Federal University of Santa Catarina (UFSC) has contributed with ten papers in the research of permeable pavements in the last six years, which address various topics about the effectiveness and applicability of permeable pavements. This paper reviews the studies conducted at UFSC on permeable pavements and discusses the different results within the main issues found. In general, the selected documents addressed seven themes in the studies: potential for potable water savings, clogging, quantity and quality of the water infiltrated into the pavement, Life Cycle Assessment (LCA) and its variants, and hydraulic and structural design details. More specifically, many selected papers assess the potential use of stormwater harvested through permeable pavements in non-potable uses of buildings. The possibility of aligning the benefits of green infrastructure with the rational use of water expands the advantages of the system and can help prevent future water scarcity, as well as reduce the environmental impacts of paving.

Stormwater Harvested from Permeable Pavements as a Means to Save Potable Water in Buildings

The main objective of this work is to analyse the potential for potable water savings in university buildings by using stormwater collected from permeable pavements. Six buildings located on the campus of the Federal University of Santa Catarina (UFSC) were selected to obtain monthly water consumption patterns and parking lot areas. The same six buildings were then evaluated considering their location in eight different cities in Brazil, with different rainfall patterns. Simulations using the computer programme Netuno were run to obtain the potential for potable water savings in each building and city combined. The structural design of permeable pavements was also assessed using two methods available in the literature, that is, the American Association of State Highway and Transportation Officials (AASHTO) and Brazilian Portland Cement Association (ABCP). The hydrological-hydraulic design of the permeable pavement was also carried out. The designed thicknesses were compared with the thicknesses obtained using the computer programme Permeable Design Pro. The potential for potable water savings between 18.4% and 84.8% was obtained, depending on the city, building and non-potable water demand considered. For the structural design, the thicknesses obtained by using both methods were similar; however, it was observed that the AASHTO method better represents the pavement model. Regarding the hydrological-hydraulic design, the differences obtained show that the simplification performed for the pavement drainage was in favour of safety. In conclusion, the use of permeable pavements in stormwater harvesting systems is promising, aligning the drainage aid, structural capacity and potential for saving potable water.

Environmental assessment of a permeable pavement system used to harvest stormwater for non-potable water uses in a building

The objective of this work is to present and to apply a method to environmentally evaluate a permeable pavement system used to harvest stormwater for non-potable water uses in a building. Two pavement systems were compared through life cycle assessment (LCA). The first system consists of a permeable pavement; in this case, the stormwater filtered by the pavement is used for non-potable water purposes in a building. The second system consists of a flexible pavement (impermeable), with no stormwater harvesting, and with conventional water supply in the building. The method was applied in a case study in a public building in southern Brazil. Water consumption surveys were made and the potential for potable water and electricity savings in the building were estimated. In the inventory, input and output data related to each stage of the life cycle of the systems were gathered and quantified. In the impact assessment, it was found that, for both pavement systems, the most significant damages were related to the implementation and end-of-life stages. The permeable pavement system presented a lower potential for environmental impacts in most midpoint categories evaluated, and also lower overall potential impact in the endpoint approach. The results also showed that the categories with the greatest environmental impact for both systems were fine particulate matter formation and global warming. The method proposed can be used as a basis for guiding planning and decision-making to improve water infrastructure management through stormwater harvesting in urban centres.

Reduction of Environmental Impacts Due to Using Permeable Pavements to Harvest Stormwater

While rainwater harvesting can provide additional water resources, this approach is largely undertaken using water from roofs. More recently, the potential for using stormwater harvested from permeable pavements was recognised as a potential additional water resource. The objective of this study was to estimate the reduction of environmental impacts caused by traditional drainage systems and centralised water utilities if permeable pavement systems were used to harvest stormwater for nonpotable purposes in buildings. The lifecycle environmental impacts and costs associated with the proposed pavements and hydraulic systems were assessed. The city of Glasgow was chosen as a case study. We used the Netuno computer programme to estimate the potential for potable water savings considering the use of stormwater for nonpotable purposes and the SimaPro software to perform a lifecycle assessment (LCA). With the implementation of permeable pavements and stormwater utilisation, great reductions in lifecycle emissions (i.e., CO2-, SO2-, and PM2.5-equivalent emissions) were observed. The proposed system also proved to be economically feasible, i.e., a payback period equal to 16.9 years. The results show the economic and environmental feasibility of permeable pavements when used on a large scale, proving to be an important strategy to reduce water and environmental stresses caused by centralised water utilities and traditional drainage systems.

The Use of Permeable Interlocking Concrete Pavement to Filter Stormwater for Non-Potable Uses in Buildings

A reduction in potable water demand in buildings could be made by using non-potable water for certain uses, such as flushing toilets. This represents a sustainable strategy that results in potable water savings while also using an underutilised resource. This work assesses the use of permeable interlocking concrete pavement to filter stormwater that could be used for non-potable purposes in buildings. Two pavement model systems were tested. One of the model systems presents a filter course layer with coarse sand and the other model system has no filter course layer. In order to evaluate the filtering capacity, the model systems were exposed to rain events. The amount of water infiltrated through the layers was measured to represent the potential quantity available for use. Stormwater runoff samples were collected from a parking lot paved with impermeable interlocked blocks and then, these were tested in both model systems. Water samples were subjected to quality tests according to the parameters recommended by the Brazilian National Water Agency. The model system with no filter course showed filtering capacity higher (88.1%) than the one with a filter course layer (78.8%). The model system with a filter course layer was able to reduce fecal coliforms (54.7%), total suspended solids (62.5%), biochemical oxygen demand (78.8%), and total phosphorus concentrations (55.6%). Biochemical oxygen demand (42.4%) and total phosphorus concentrations (44.4%) increased in the model system with no filter course layer. In conclusion, one can state that the filter course layer used in permeable interlocking concrete pavement can contribute to decreasing pollutants and can improve stormwater quality. The use of permeable interlocking concrete pavement showed to be a potential alternative for filtering stormwater prior to subsequent treatment for non-potable uses in buildings.

Life cycle energy assessment and economic feasibility of stormwater harvested from pervious pavements

Pervious pavements are one of the most used construction techniques among the Sustainable Urban Drainage Systems (SUDS). The objective of this article is to analyse the energy life cycle and the life cycle cost of stormwater harvesting systems using pervious pavements models in order to compare and evaluate the differences and verify what influences the profitability and sustainability. The method proposed started with the definition of pervious pavement models based on literature review. The main characteristic of the models analysed was the use of porous asphalt with different underlying layers, i.e. thickness and material. The hydrological-hydraulic design of the pavements was also assessed. The potential for potable water savings due to harvesting stormwater from a parking lot was estimated for a public building in Florianópolis, southern Brazil. The models were compared to identify what most influences the potable water savings, the profitability and the sustainability of the systems. The maximum potable water savings found were 42%. It was also observed that the overall consumption of the building has been decreasing over the years, and the yearly rainfall has increased, which leads to a higher potential. In the current water consumption pattern, none of the systems evaluated was profitable or presented sustainability, evaluated herein as negative energy balance. However, it was verified that if analysed comparatively with non-pervious pavement, it was profitable to use stormwater harvested from the pervious pavement. Thus, it can be concluded that stormwater harvesting systems in combination with pervious pavements are promising, serving as SUDS and saving money for users. It is also noticeable that the use of porous asphalt is not recommended when aiming for systems with low embedded energy.

Measurement of Permeability and Comparison of Pavements

Permeable pavements have the ability to reduce surface runoff by allowing water to infiltrate into the underlying soil. The potential of permeable pavements to assist in managing stormwater and improve water quality has gained attention as an option, other than conventional impermeable concrete for paving purposes. This study examined the permeability of three different pavement systems, including the JW Eco-technology pavement (JW), which has not previously been installed or studied in the U.S., standard impermeable concrete (IC), and pervious concrete (PC). Each pavement type was installed in triplicate. Devices based on the ASTM C1701/C1701M and ASTM C1781/C1781M constant-head methods, the National Center for Asphalt Technology (NCAT) falling-head permeameter, and two new square frames, SF-4 and SF-9, modified to fit the JW pavement, were utilized for permeability measurement on several locations of each pavement system. The results showed that the JW Eco-technology pavement had comparable permeability to the commonly used PC pavement in each method used. In addition, there was a strong correlation between the permeability measurements of NCAT method and SF-4, and between the ASTM standard and SF-9. The square frames used in this study showed their effectiveness and efficiency in performing permeability measurements. It was also found that the permeability obtained had a pronounced difference in values between the falling head and the constant head methods, with an average ratio ranging from 4.08–6.36.

Permeable Pavements Life Cycle Assessment: A Literature Review

The number of studies involving life cycle assessment has increased significantly in recent years. The life cycle assessment has been applied to assess the environmental performance of water infrastructures, including the environmental impacts associated with construction, maintenance and disposal, mainly evaluating the amount of greenhouse gas emissions, as well as the consumption of energy and natural resources. The objective of this paper is to present an overview of permeable pavements and show studies of life cycle assessment that compare the environmental performance of permeable pavements with traditional drainage systems. Although the studies found in the literature present an estimate of the sustainability of permeable pavements, the great heterogeneity in the evaluation methods and results is still notable. Therefore, it is necessary to homogenize the phases of goal and scope, inventory analysis, impact assessment and interpretation. It is also necessary to define the phases and processes of the evaluation, as well as the minimum amount of data to be considered in the modelling of life cycle assessment, in order to avoid heterogeneity in the functional units and other components. Thus, more consistent results will lead to a real evaluation of the environmental impacts caused by permeable pavements. Life cycle assessment studies are essential to guide planning and decision-making, leading to systems that consider increasing water resources and reducing natural disasters and environmental impacts.

Water Supply Basins of São Paulo Metropolitan Region: Hydro-Climatic Characteristics of the 2013–2015 Water Crisis

São Paulo metropolitan region experienced an acute water crisis between 2013 and 2015. According to the Brazilian and international press, it was due to climatic, anthropogenic, and water management factors. This paper assesses the hydro-climatic characteristics of the crisis by focusing on the Alto-Tietê basin and the headwater of the Piracicaba-Capivari-Jundiaí (PCJ) basin that supply 70% of the water consumed in the metropolis. Based on 16 rain-gauge stations, 5 runoff-gauge stations, and several statistical analyses carried over the 1951–2015 period, this assessment shows that the 2013–2015 hydro-climatic crisis resulted from a large number of days without rain in the north of the Alto-Tietê basin and to less intense precipitation events in the headwaters of the PCJ basin during the austral spring 2013 and the year 2014. It also defines a return period of 98 years for observed river flows in 2014. Despite the rare nature of this hydrological drought, the need for efficient water saving policies is brought forward.

Application of stormwater collected from porous asphalt pavements for non-potable uses in buildings

This study assessed the potential for potable water savings in a building by using stormwater filtered by a porous asphalt pavement located in a parking lot. Stormwater is meant to be used for non-potable purposes (flushing toilets and urinals). Two models of porous pavement systems were constructed, both with porous asphalt mixture over a different combination of porous granular layers. The models were assessed for their filtering capacity; samples of stormwater runoff were collected in a parking lot located near the building where filtered stormwater is meant to be used. The models showed to be capable of filtering some pollutants. However, additional water treatment would be necessary to obtain the quality required for non-potable uses. Then one model was selected for a theoretical analysis on using it in a parking lot. The potential for potable water savings was analysed considering four scenarios as a function of daily local rainfall data. The thickness of the temporary stormwater reservoir layer was calculated in order to meet the design rainfall adopted, and the stormwater tank capacity was estimated using the Netuno computer programme. As a result, using a 45,000-litre stormwater tank, potable water savings of at least 53% would be obtained if filtered stormwater were used to flush toilets and urinals. This indicates that porous pavements show a great potential for filtering stormwater runoff to be used in buildings.

The effect of different surface materials on runoff quality in permeable pavement systems

To investigate the effect of different permeable pavement surface materials on the removal of pollutants from urban storm-runoff, six commonly surface materials (porous asphalt, porous concrete, cement brick, ceramic brick, sand base brick, and shale brick) were selected in this study and the research was carried out by column experiments. Except the concentrations of total suspended solids (TSS), chemical oxygen demand (COD), ammonia nitrogen (NH₄-N), nitrate nitrogen (NO₃-N), total nitrogen (TN), and total phosphorus (TP) in the influent and effluent that were measured, the removal mechanism of pollutants was discussed further. The results indicate that the surface materials influence the removal efficiency of pollutants greatly and have different effects on certain pollutant. Furthermore, the physical interception and adsorption would be the main mechanism for the removal of pollutants from runoff. For example, for all surface materials, the average removal efficiency of TSS is nearly about 90.0% because of physical interception. Due to the amount of iron oxide, the removal efficiency of COD, NO₃-N, and TN of shale brick was 88.2, 35.1, and 17.5%, respectively. NH₄-N and TN can be easily removed by porous asphalt due to the high content of organic matter. By lacking of useful adsorption sites, all the surface materials had little effect on the removal of TP from runoff. This research could offer useful guidelines for the better design of permeable pavement system and promote the insight into the removal mechanism of pollutants in permeable pavement system. Graphical abstract Different types of materials for the different types of pollutants in the runoff purification capacity were significantly different, overall, shale brick and porous asphalt Shale bricks and porous asphalt have a better purification effect according to the six kinds of materials.

Urban rainwater runoff quantity and quality - A potential endogenous resource in cities?

Rainwater 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.