Abstract Water scarcity and climate change led to changes in water management, especially in urban areas. RainWater Harvesting (RWH) is a promising technique that allows the collection and reuse of ...rainwater, as well as protecting sewage systems from overload. This article reviews the current state of RWH in Europe, including advantages, implementation, potential efficiency, usage requirements, quality, and treatment processes. The main findings include the importance of RWH as a sustainable water management technique, the historical background and renewed interest in RWH systems in recent years, the positive impact of RWH on reducing energy consumption and greenhouse gas emissions, the versatility of rainwater usage, and the potential cost savings and benefits in various regions. RWH systems are gaining popularity in Europe, particularly in Germany, Austria, and Switzerland. Climate change and precipitation patterns affect rainwater availability and quality. RWH can be used for various purposes, including drinking, but requires proper purification for health safety. It is also being implemented in new locations like airports and large buildings. RWH systems have a high potential to overcome undesired results of climate change. Among that, numerous aspects still need to be considered in the future that allow the application of RWH systems on a larger scale.
The development of rainwater utilization strategies has relied on rainwater harvesting (RWH) systems for centuries to alleviate the pressure on water resources. However, there are still significant ...knowledge gaps regarding the changes in water quality in RWH systems during long-term storage in non-rainy seasons. This study evaluated the water quality processes in RWH systems through static rainwater storage experiments for approximately 60 days. The results revealed that nutrients in rainwater accumulated in sediment during storage. Disturbance and redox conditions at the rainwater-sediment interface contribute to the release of sedimentary facies materials. The rainwater showed distinct DO stratification, with the biochemical reactions of sedimentary facies being the primary factor driving oxygen consumption. ORP and turbidity showed positive correlations with COD (r = 0.582; 0.572), TOC (r = 0.678; 0.681), TN (r = 0.452; 0.439), and NH4+-N (r = 0.502; 0.553) (P < 0.05). The regulation of water quality and extension of the usage cycle were identified as critical factors influenced by DO. In addition, bacteria share similar ecological niche preferences. These findings provide scientific evidence for the high-quality reuse of rainwater in decentralized RWH systems during long-term storage in non-rainy seasons.
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•DO stratification in RRWH is driven by biochemical reactions of sedimentary facies.•Disturbance and redox conditions contribute to release of sedimentary facies materials.•Sediment accretion exacerbates rainwater quality deterioration during storage.•Bacteria communities exhibit similar ecological niche preferences in RRWH.
Rainwater harvesting is an ancient practice currently used for flood and drought risk mitigation. It is a well-known solution with different levels of advanced technology associated with it. This ...study is aimed at reviewing the state of the art with regards to rainwater harvesting, treatment, and management. It focuses on the environmental and social benefits of rainwater harvesting and links them to the Sustainable Development Goals. The review identifies characteristics of laws and regulations that encourage this practice and their current limitations. It presents methodologies to design a rainwater harvesting system, describes the influence of design variables, and the impact of temporal and spatial scales on the system’s performance. The manuscript also analyzes the most advanced technologies for rainwater treatment, providing insights into various processes by discussing diverse physiochemical and biological technology options that are in the early stages of development. Finally, it introduces trends and perspectives which serve to increase rainwater harvesting, water reuse, and effective management.
Studies in Real−Time Control (RTC) Rainwater Harvesting Systems (RWH) have to date been limited to the control of single storages, leaving the potential benefits of operating multiple storages in a ...coordinated manner largely untested. In this study, we aimed to design an optimization‐based RTC strategy that can operate multiple storages in a coordinated manner to achieve multiple objectives. We modeled the long‐term performance of this coordinated approach (i.e., termed as coordinated control) across a range of storage sizes and compared it with a strategy that optimized the operation of each storage individually, ignoring the state of other stores within the system. Our results show that coordinated control delivered a synergy benefit in achieving better baseflow restoration, with almost no detriment to the water supply and flood protection (overflow reduction) performance. The efficiency achieved through coordinated control allows large storages to compensate for smaller, underperforming systems, to achieve higher overall performance. Such a finding suggests a general control principle in building coordination among multiple storages, which can potentially be adapted to mitigate flooding risks, and also applied to other stormwater control measures. This also opens up a new opportunity for practitioners to construct a future “smart rainwater grid” using a network of distributed storages, in combination with centralized large storages, to manage urban stormwater in a range of contexts and for a range of environmental objectives.
Plain Language Summary
“Smart tanks” based on Real−Time Control (RTC) technology is increasingly applied in rainwater harvesting systems to address water shortages, urban flooding and streams depleted of flow. However, most uses of this technology have been applied to single tanks, without testing the potential of a network controlled in a coordinated manner to better address the environmental problems. To understand the effect of such coordination, we designed a control strategy accordingly and modeled its performance using a customized model. We found that a network of smart tanks can, in most cases, deliver a synergy benefit in restoring streamflow compared to systems that only work on their own. More importantly, this coordination allows large tanks to compensate for smaller, underperforming tanks, to achieve higher overall performance. It suggests a general control principle in building coordination among multiple storages, which can potentially be adapted to mitigate flooding risks, and also applied to other stormwater control measures. It opens up a smart future for managing urban water in a range of contexts and for a range of environmental objectives.
Key Points
Multiple rainwater storages can be operated in a coordinated manner by Real−Time Control (RTC) technology for multiple objectives
This coordinated RTC delivers synergy benefits in restoring baseflow
Large storages compensate for small underperforming storages within the network
► Investigates the effectiveness of stormwater harvesting and payback periods for large rainwater tanks using recorded daily rainfall data. ► Analysis revealed that two tanks (considered in the case ...study) have payback periods of 21 years and 19 years. ► Relationships between different percentage increase in yearly water prices and payback periods are presented. ► Several hypothetical scenarios to optimise the size and connected roof area of the tanks were presented. ► Difference in optimisation results for rainfalls in a real average year and a theoratical annual average assumption are presented.
Rainwater tanks for larger roof areas need optimisation of tank size, which is often not carried out before installation of these tanks. This paper presents a case study of rainwater tank evaluation and design for large roof areas, located in Melbourne, Australia, based on observed daily rainfall data representing three different climatic regimes (i.e. dry average, and wet years). With the aim of developing a comprehensive Decision Support Tool for the performance analysis and design of rainwater tanks, a simple spreadsheet based daily water balance model is developed using daily rainfall data, contributing roof area, rainfall loss factor, available storage volume, tank overflow and irrigation water demand. In this case study, two (185
m
3 and 110
m
3) underground rainwater tanks are considered. Using the developed model, effectiveness of each tank under different climatic scenarios are assessed. The analysis shows that both the tanks are quite effective in wet and average years, however less effective in dry years. A payback period analysis of the tanks is preformed which reveals that the total construction cost of the tanks can be recovered within 15–21 years time depending on tank size, climatic conditions and future water price increase rates. For the tanks, a relationship between water price increase rates and payback periods is developed. The study highlights the need for detailed optimisation and financial analysis for large rainwater tanks to maximise the benefits.
Numerous studies have focused on the spectral characteristics and seasonal variations of dissolved organic matter (DOM) in rainwater. However, the relationship between the optical indices of DOM and ...nutrients in rainwater from different ecological areas of large reservoirs is poorly understood. A one-year monitoring study was conducted between March 2019 and February 2020 in the Danjiangkou Reservoir in Henan Province, China, to compare the composition, spectral characteristic parameters, and relationship between the optical indices of DOM and nutrients in rainwater under different ecological environments. The study showed that the average value of a300 in all samples was 5.29 ± 2.16 m-1 and showed a seasonal trend of higher in spring and winter and lower in summer and autumn as well as a regional difference of agricultural area > urban area > reservoir area. A three-dimensional fluorescence with parallel factor analysis (EEM-PARAFAC) revealed four components of the rainwater: C1 and C2 as UV humic-like substances, and C3 and C4 as protein-like substances. The protein-like components of rainwater from agricultural areas had a high fluorescence intensity, whereas the UV humic-like components of rainfall from urban and reservoir areas had a high fluorescence intensity. Analysis of the fluorescence indices showed that rainwater DOM humification was low and had a strong endogenous character in the Danjiangkou Reservoir. The redundancy analysis revealed that NO3−-N, DTN, and SO42− mainly influenced the DOM optical indices of rainwater in urban areas, EC, DTN, and DOC had the highest interpretation of the DOM optical indices of rainwater in agricultural areas, and SO42−, DOC, and DTN had the highest interpretation of the DOM optical indices of rainwater in the reservoir. Overall, understanding the characteristics of rainfall DOM fluorescence and the relationships with nutrients in different ecological regions provides important information for comprehending biogeochemical processes in reservoirs.
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•Concentration of dissolved organic matter (DOM) in rainwater exhibited seasonal variations and regional differences.•Rainwater DOM consists of humic-like and protein-like substances.•Low humification and aromaticity of DOM in rainwater, but high microbial contribution.•Atmospheric nutrients are closely coupled with rainwater DOM.
Purpose: study the methodology for designing a rainwater harvesting system and evaluate its technical and economic viability for supplying water for washing vehicles in the garage of the State ...University of Rio de Janeiro (UERJ), Maracanã campus. Theoretical framework: water supply in urban areas faces complex challenges, due to changes in minimum flows, pollution of water sources, demand growth, variability and uncertainties in the rainfall regime. Rainwater harvesting systems have become an alternative to supply non-potable demand, reducing the need for consumption by the public supply system. Method: evaluation of rainfall in the region of Tijuca, Rio de Janeiro, to meet the demand for water for washing vehicles through a rainwater harvesting system. The calculations of the catchment area and volume of the reservoirs used data, with a historical series between 2009 and 2018, statistical adjustment of the Gumbel frequency distribution and a ten-year recurrence period. Results and conclusion: An average percentage of 61 to 75% of demand was met, depending on rainfall variations and the capacity of the reservoir adopted. Average monthly savings of between US$ 200 and US$ 300 were found, corresponding to a period of 4 to 24 months for cushioning investments in the implementation of the system. Research implications: The research contributes with data that reinforce the importance and efficiency of correctly sized systems, as an alternative source to meet non-potable demands. Originality/value: the article presents a specific methodology for sizing the main elements in a system (catchment area and reservoir volume) and configures excellent technical and economic viability in the proposed use.
A study of precipitation (rainwater) chemistry during the two consecutive summer monsoon seasons of 2013 and 2014 at a high altitude station (2200m asl) at eastern Himalaya region (Darjeeling); a ...typical metropolitan urban location (Kolkata), and a rural environment near the Bay of Bengal (Falta) was conducted. The volume-weighted mean (VWM) concentration shows that total ionic composition was maximum over Kolkata (391μeql−1) followed by Falta (204μeql−1) and Darjeeling (64μeql−1). 85% rain samples were alkaline over Kolkata, whereas, 55 and 65% samples were acidic over Falta and Darjeeling respectively. Ca2+ was the most potential species to completely neutralize the acidity over Kolkata, whereas, NH4+ was the potential species to partially neutralize the acidity over Falta and Darjeeling. The deposition fluxes of anthropogenic and dust species over Kolkata was remarkably higher than Falta and Darjeeling. Anthropogenic and dust chemical species in rainwater were found to be dominant over Kolkata and Falta when the air masses passes from the polluted continental region. Rainwater acidity over Darjeeling was highest when air masses arrived from the Arabian Sea compared to air masses from the Bay of Bengal. Positive matrix factorization model was used for the source apportionment of the ionic species scavenged by rain. Comparable contributions of marine, dust, and anthropogenic sources were identified as major source over Kolkata. The major contributions were identified from marine and fossil fuel burning over Falta, whereas, marine, biomass/coal burning, ammonia from agricultural activities and domestic wastes were identified as the major sources over Darjeeling.
•First-time precipitation chemistry was conducted in eastern Himalayan region•Precipitation events over eastern Himalayan region were mostly acidic•Major precipitation events were alkaline over metropolitan urban atmosphere at IGP•Anthropogenic species were scavenged more over urban metropolis
Rainwater harvesting (RWH) coupled with gravity-driven membrane (GDM) filtration was used to simultaneously treat rainwater and recover energy. A pilot GDM could obtain a relatively stable level of ...permeate flux (~4.0 L/(m2·h)) under a set water head (ΔH = 0.4 m) over 140 days of operation. An increase water head (ΔH = 0.6 m) did not achieve a sharp increase in stabilized flux (~2.4 L/(m2·h)) over 20 days of operation until the end. It was found that GDM filtration could produce a permeate that was almost free of particles. However, only a small amount of organic matter and trace metals (i.e., Cr, Al, Fe, Cu, Al, Mn and Ca) were removed, as demonstrated by excitation-emission matrix (EEM) and energy dispersive spectrometry (EDS) analysis. Additionally, the bacterial abundance within the permeate ((8.45 ± 0.11) × 102 cells/mL) decreased compared to that within the GDM tank ((1.85 ± 0.14) × 105 cells/mL), revealing that the rejected bacteria might enhance biofilm formation. The presence of extracellular polymeric substances (EPS), adenosine triphosphate (ATP) and assimilable organic carbon (AOC) indicated a high level of microbial activity within the biofilm, which was also demonstrated by the porous cake layer morphology observed by scanning electron microscopy (SEM) and results from confocal laser scanning microscopy (CLSM) imaging of the biofilm. NH3-N was removed by Nitrospira within the biofilm, which was identified by microbial community analysis. Overall, this novel approach has the potential to improve municipal water availability and stormwater management practices.
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•Rainwater harvesting coupled with gravity-driven membrane (GDM) filtration was used for roofing rainwater reuse.•A relatively stable level of permeate flux was achieved under a setting roofing rain water energy.•GDM filtration could free of particles and remove a small amount of organic matter and trace metals.•Biofilm in GDM filtration exhibits high biologically active and improve rainwater quality.
This article aimed to carry out a systematic review of rainwater harvesting and storage systems (RWHSS) between 2012 and 2022. This study used the guidelines of the Preferred Reporting Items for ...Systematic Reviews and Meta-Analyses statement (PRISMA) as reviewing method. The systematic review process involved four stages: identification, screening, eligibility and inclusion. To carry out this research, the Scopus, ScienceDirect and Springer Link digital databases were consulted using the keywords “rainwater”, “storage”, “harvesting”, “rural”, “treatment”; initially obtaining 581 results, after filtering the information through PRISMA, 15 articles were obtained to carry out the analysis of the results linked to the questions raised in this work. The results showed that all the RWHSS have four main components: 1) Catchment area, 2) gutters, 3) pipes and 4) storage system. Regarding the most used material in the system's catchment area, it is galvanized metal with 25.71% of the studies and for the construction of the cistern, it is concrete with 41.66%. The quality of the rainwater collected in the RWHSS varies according to some factors such as the material, maintenance, weather conditions, etc. The main rainwater quality parameters considered by the authors at the time of implementing and using an RWHSS were identified, and compliance of the parameters with the WHO standard values was also evaluated. The main parameters considered by the authors were: pH (66.66%), turbidity (53.33%), E. Coli (53.33%), lead (40%) and nitrates (40%).
•Rainwater collection and storage systems are capable of supplying drinking water.•The most used material for rainwater collection is galvanized metal.•The most used materials in the construction of the cistern are concrete.•The main rainwater quality parameters analyzed are pH, turbidity, E. Coli, lead, nitrates.
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