Impact of rainwater harvesting systems on nutrient and sediment concentrations in roof runoff

2013 ◽  
Vol 14 (2) ◽  
pp. 220-229 ◽  
Author(s):  
Kathy M. DeBusk ◽  
William F. Hunt

Rainwater harvesting (RWH) systems have the unique ability to contribute to stormwater management goals via mitigation of runoff volumes and peak flow rates. Additionally, collecting and storing runoff via RWH systems can potentially provide water quality benefits due to physical and chemical processes that occur within the storage tank. This study quantified the water quality improvement provided by storing rooftop runoff via RWH systems at four sites in Raleigh, North Carolina, USA. Roof runoff and extraction spigot samples were analyzed for total suspended solids (TSS), nitrogen species and total phosphorus. Roof concentrations were significantly greater than spigot concentrations for all constituents except TSS, indicating the ability of RWH systems to significantly lower nutrient concentrations of incoming roof runoff. Lack of significant TSS reduction was likely attributable to low, ‘irreducible’ concentrations of TSS in the roof runoff. The use of additional filtration components prior to the extraction spigot could aid in lowering spigot TSS concentrations. The findings presented herein contend that stormwater benefits associated with RWH are not only limited to hydrologic mitigation, but also include reductions in concentrations of nitrogen and phosphorus species. Thus, it is recommended that pollutant removal credit be assigned to these systems when used as stormwater control measures.

2014 ◽  
Vol 15 (1) ◽  
pp. 134-141 ◽  
Author(s):  
J. P. Kohlitz ◽  
M. D. Smith

Health risks from drinking rainwater are relatively small in the developing world context, but action is needed to ensure water safety. Water safety plans (WSPs) use an approach to manage water quality that has shown signs of success with public and communal water supplies, but relatively little research has been done to investigate the application of WSPs to self-supply systems. The aim of this paper is to investigate the primary issues surrounding appropriate water quality management of domestic rainwater harvesting (DRWH) systems in Fiji and consider how the principles of WSPs can be applied in this context. A qualitative research design was followed, utilising semi-structured interviews with 34 rural households and six key informants, sanitary inspections of DRWH systems and thematic data analysis. A number of challenges, including limited government resources and the limited knowledge and casual attitudes of rural rainwater consumers, constrain the practicality of adopting conventional WSPs at the household level, but steps for improvement can be taken.


2016 ◽  
Vol 17 (2) ◽  
pp. 452-460 ◽  
Author(s):  
Yonghwan Kim ◽  
Anh Dzung Dao ◽  
Mikyeong Kim ◽  
Viet-Anh Nguyen ◽  
Mooyoung Han

2021 ◽  
Author(s):  
H. S. Lim ◽  
E. Segovia ◽  
A. D. Ziegler

Abstract This study examined the effects of two substrates (SOIL and COMMERCIAL) and grass on the green roof runoff quality in Singapore. Ten events were sampled over a 9-month period. Rainfall and green roof runoff from grass and bare experimental configurations were tested for total organic carbon (TOC), nitrogen and phosphorus nutrients (N, NH4+-N and PO43−-P), cations/anions and trace metals (Fe, Cu, Zn, Cd and Pb). All configuration units neutralised acid rainfall and removed metals except Fe despite their proximity to an industrial area. Concentrations decrease over the monitoring period for most water quality variables. The COMMERCIAL (COM) configurations elevated Cl− (3.8–10.8 ppm), SO42− (1.5–32.4 ppm), NO3−-N (7.8–75.6 ppm) and NH4+-N (22.0–53.1 ppm) concentrations in the runoff. Concentrations of NO3−-N (4.5–67.7 ppm) and NH4+-N (14.7–53.0 ppm) remained high at the end of the monitoring period for the COMgrass configuration, even with dilution from monsoon rainfall, making it suitable as an irrigation water source and a fertiliser substitute. The SOIL substrate retained N-nutrients, TOC and trace metals with concentrations comparable or below rainfall inputs. This substrate is suitable for widespread green roof applications in Singapore and other tropical cities. We recommend substrate testing before their approval for use on green roofs and encourage the long-term monitoring of these systems.


2011 ◽  
Vol 695 ◽  
pp. 93-96
Author(s):  
Ree Ho Kim ◽  
Jung Hun Lee ◽  
Sang Ho Lee ◽  
Hana Kim

Pollutants in rainwater often cause problems such as non-point source pollutant and deterioration of collected water quality in rainwater harvesting systems. Fiber filter media have been developed to resolve these problems by removing pollutants in rainwater by filtration and ion-exchange mechanisms. They have been also successfully applied for the treatment of first-flush rainwater. However, little information is available on the long-term efficiency and the lifetime of the fiber filter media. In this study, new and used fiber filter media were compared in terms of their filterability and ion-exchange capability. The used filter media samples were taken from a first flush filter in a rainwater harvesting system located in an elementary school in Kyonggi-Do. They were used from 2005 to 2010 without any replacement or cleaning. Water quality parameters of an inflow and outflow in the first flush filter were analyzed to quantify the on-site treatment efficiency of the used media. It was shown that the turbidity was removed by approximately 60% and COD was partly removed. The removal efficiency of particles by the used media was similar to that by the new media. Nevertheless, the removal efficiencies of nitrogen and phosphorous by the used media were substantially reduced when compared with the new media. This suggests that the fiber filter media should be periodically replaced to maintain high removals of nutrients. On the other hand, they can be used for more than 6 years if their primary purpose is to removal particles.


2001 ◽  
Vol 52 (2) ◽  
pp. 235 ◽  
Author(s):  
Lester J. McKee ◽  
Bradley D. Eyre ◽  
Shahadat Hossain ◽  
Peter R. Pepperell

Water quality was monitored on a spatial and temporal basis in the subtropical Richmond River catchment over two years. Nutrient concentrations varied seasonally in a complex manner with highest concentrations (maximum =3110 µg N L – 1 and 572 µg P L –1 ) associated with floods. However, median (444 µg N L – 1 and 55 µg P L – 1 ) concentrations were relatively low compared with other parts of the world. The forms of nitrogen and phosphorus in streams varied seasonally, with greater proportions of inorganic nitrogen and phosphorus during the wet season. Minimum nutrient concentrations were found 2—3 months after flood discharge. With the onset of the dry season, concentration increases were attributed to point sources and low river discharge. There were statistically significant relationships between geology and water quality and nutrient concentrations increased downstream and were significantly related to population density and dairy farming. In spite of varying geology and naturally higher phosphorus in soils and rocks in parts of the catchment, anthropogenic impacts had the greatest effects on water quality in the Richmond River catchment. Rainfall quality also appeared to be related both spatially and seasonally to human activity. Although the responses of the subtropical Richmond River catchment to changes in land use are similar to those of temperate systems of North America and Europe, the seasonal patterns appear to be more complex and perhaps typical of subtropical catchments dominated by agricultural land use.


2016 ◽  
Vol 16 (5) ◽  
pp. 1388-1397 ◽  
Author(s):  
Elena E. Neibaur ◽  
Elizabeth P. Anderson

Rainwater harvesting (RWH) is increasingly utilized today by populations to alleviate water supply issues, particularly in rural, dry environments. Limited research has considered, simultaneously, the numerous factors that contribute to sustainability – for example, social acceptance, water quality, and maintenance needs – of RWH. This research aimed to improve the understanding of factors influencing the sustainability of rainwater harvesting systems for domestic use (DRWHS) through examination of social, water quality, and technical feasibility components. We conducted 50 household surveys and 17 rainwater quality analyses in San Jose Xacxamayo, a rural, semi-arid community in Puebla, Mexico. Results showed that DRWHS are socially accepted primarily because of the presence of existing local skills and knowledge, as well as critical need for water. Results from most of the water quality parameters measured were within World Health Organization (WHO) guidelines for human consumption, with the exception of pH, total coliform, and heterotrophic plate count, which required water treatment prior to consumption. Technical feasibility was the main barrier to the sustainability of DRWHS; highly seasonal rainfall and small roof sizes (averaging 70 m2) resulted in households unable to meet annual water needs. Increasing roof sizes and providing water treatment could ensure DRWHS sustainability in the studied community.


Author(s):  
Never Mujere ◽  
William Moyce

Climate change affects water resources through changes in evaporation, groundwater recharge, temperature, runoff and rainfall. Such changes affect the mobilization of nutrients, distribution and mobility of pollutants in freshwater systems. The direct and indirect climate change impacts on water quality comprise biological, physical and chemical changes. Biological changes include pathogenic microbes in water. Physical changes include increased water temperature, reduced river and lake ice cover, more stable vertical stratification and less mixing of water of deep-water lakes, and changes in water discharge, affecting water level and retention time. Chemical changes include increased nutrient concentrations, water color and decreased oxygen content. However, few scientific works have been recently published on the impacts of climate change on water quality modification. This chapter fills a real gap because there has been no comprehensive review on climate change and river water quality to date. It focuses on the expected water quality impacts of climate change.


Author(s):  
Never Mujere ◽  
William Moyce

Climate change affects water resources through changes in evaporation, groundwater recharge, temperature, runoff and rainfall. Such changes affect the mobilization of nutrients, distribution and mobility of pollutants in freshwater systems. The direct and indirect climate change impacts on water quality comprise biological, physical and chemical changes. Biological changes include pathogenic microbes in water. Physical changes include increased water temperature, reduced river and lake ice cover, more stable vertical stratification and less mixing of water of deep-water lakes, and changes in water discharge, affecting water level and retention time. Chemical changes include increased nutrient concentrations, water color and decreased oxygen content. However, few scientific works have been recently published on the impacts of climate change on water quality modification. This chapter fills a real gap because there has been no comprehensive review on climate change and river water quality to date. It focuses on the expected water quality impacts of climate change.


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