ABSTRACT This research investigated whether pervious concrete is effective in removing dissolved ... more ABSTRACT This research investigated whether pervious concrete is effective in removing dissolved zinc and copper contaminants from stormwater runoff. Pervious concrete cylinders were loaded in the laboratory with simulated runoff, and influent and effluent concentrations and volumes measured. In one set of tests, stormwater was dispensed at typical concentrations (100 mu g/L Zn and 20 mu g/L Cu) simulating ten consecutive storm events of 12 mm (0.5 in.) of rain to test initial removal performance. Another set of cylinders was loaded at forty times the typical concentration to simulate accelerated longterm metal loading indicative of several years of typical use. Cylinders were removed after 15 and 24 accelerated events respectively for further typical concentration performance testing. Performance for the typical concentration tests both pre and post accelerated loading were calculated as a percent metals retained and also as a percent decrease in effluent versus influent concentration. The pre accelerated metal loading results indicate averages of 93% and 91% retained, and 90% and 87% concentration decreases for Zn and Cu respectively. Similar percentages were retained post accelerated metal loadings with slightly lower averages for copper after 24 accelerated loading events, although this was probably due to a higher infiltration rate. Removals were seen to be effected by both physical (water trapping) and by chemical (sorption and complexation) processes.
Transportation Research Board 93rd Annual MeetingTransportation Research Board, 2014
Developed areas with more impervious pavement surfaces usually experience increased levels of sto... more Developed areas with more impervious pavement surfaces usually experience increased levels of stormwater runoff and associated higher pollutant loadings. A common practice to more economically treat these associated pollutants is to design treatment options for the water quality volume of a storm, that is, the first part of a large storm that frequently includes the first flush, where pollutants deposited between events may be dislodged. This theoretical case study includes an add-on strategy for water quality improvement optimization by additionally focusing on the stormwater ‘hotspot’ contributing areas known for having higher pollutant loadings, frequently five to ten times higher. The methodology is developed and then theoretically applied to a series of options for a ferry terminal case, with two innovative designs; a reverse slope to land treatment train and a pervious concrete overlay with sweeping combination. The results are presented in tabular formats which might be usable as comparative multi-criteria decision support tools by decision makers. Further theoretical evaluations of one of the options provide for an additional pictorial decision support tool for environmental uncertainty considerations. The results indicate a significant increase in system or treatment train efficiency even for conservative hotspot factors.
Rivers are a major pathway for the transport of plastics into the ocean. Plastic pollution captur... more Rivers are a major pathway for the transport of plastics into the ocean. Plastic pollution capture devices offer one way to reduce the accumulation of plastic in the environment. This paper provides a framework for selecting a device to reduce plastic pollution in freshwater, synthesizing information of forty prevailing plastic pollution capture devices. We distinguish three major components of plastic pollution technology (booms, receptacles, and watercraft vehicles) and collect details on each technology including its features, limitations, efficiency, reported costs, and maintenance requirements. A framework is developed to aid in device selection by water and waste managers, which highlights the need for a watershed assessment, an understanding of site conditions, the attainment of community buy-in, and a long-term maintenance plan. While plastic pollution capture devices can help reduce the flux of plastic waste from freshwater, management of plastic waste at the source is also needed to ultimately clean our oceans and waterways.
ABSTRACT: Bioretention is an evolving type of Green Stormwater Infrastructure (GSI) designed to a... more ABSTRACT: Bioretention is an evolving type of Green Stormwater Infrastructure (GSI) designed to attenuate peak flows, reduce stormwater volume, and treat stormwater. This article examines the capabilities of a bioretention soil mixture of sand and compost enhanced with aluminum‐based drinking water treatment residuals to reduce nutrients from stormwater runoff. Columns with and without a saturation zone and vegetation were compared to examine their role in removing nitrate and ortho‐phosphate from stormwater. Results show that utilization of a saturation zone can significantly reduce nitrate in effluent water (71% compared to 33% without a saturated zone), even in a newly constructed system. However, ortho‐phosphate reduction was significantly better in the columns without a saturated zone (80%) compared to columns with (67%). Plants did not significantly improve removal. This suggests amendments such as aluminum‐based water treatment residuals for phosphorus removal and a saturation zone for nitrogen removal are needed during the initial establishment period.
The Sustainable Design Guidelines were developed in Phase I of this research program (WA-RD 816.1... more The Sustainable Design Guidelines were developed in Phase I of this research program (WA-RD 816.1). Here the authors are reporting on the Phase II effort that “beta-tested” the Phase I Guidelines on example ferry terminal designs and refinements made to the tool. The specific objectives of this project are to: 1. Cite example Washington State Ferries (WSF) terminal projects that would serve as candidates for assessing the Sustainable Design Guidelines; 2. Compile and analyze site and resource attributes influencing the design needs; 3. Develop a “20% design” for each of the example terminals; 4. Refine the Draft Sustainable Design Guideline; 5. Develop preliminary data on the efficacy of sample stormwater design solutions; and 6. Develop a database tool for GRIP, the proposed Green Rating Integration Platform for WSF. This project represents the second phase in a three-part effort. The final component will develop and potentially demonstrate specific solutions that present unique opportunities will be deployed in Phase III.
ABSTRACT Green roofs have become increasingly common in urban areas to slow and reduce stormwater... more ABSTRACT Green roofs have become increasingly common in urban areas to slow and reduce stormwater runoff from buildings. However, phosphorus has been found to leach from green roofs. Water treatment residuals (WTRs), a waste product in the water treatment process, may help reduce leaching of phosphorus from green roofs. This study evaluated a green roof retrofit that consisted of a WTR filter at the green roof drain to reduce phosphorus in runoff. Samples of rainfall, runoff from a green roof, and runoff from a regular roof were collected every time it rained and analyzed for total phosphorus (TP), phosphate (PO43−), copper (Cu) and zinc (Zn). Samples were taken January–March 2020 and September 2020–March 2021. Phosphate and TP concentrations were significantly lower (p<0.05) with the retrofit during the winter (Jan–March 2020 and 2021) but not during the fall (Sept–December 2020). The change in WTR efficacy may be due to the WTRs drying out during the summer months, although it appears the WTRs are effective once they have been resaturated during the fall wetting period. This study shows that the WTR retrofit may reduce phosphorus leaching as long as the WTRs do not dry out. The WTRs should be replaced each fall in regions that experience dry summer months to maximize efficacy.
ABSTRACT This research investigated whether pervious concrete is effective in removing dissolved ... more ABSTRACT This research investigated whether pervious concrete is effective in removing dissolved zinc and copper contaminants from stormwater runoff. Pervious concrete cylinders were loaded in the laboratory with simulated runoff, and influent and effluent concentrations and volumes measured. In one set of tests, stormwater was dispensed at typical concentrations (100 mu g/L Zn and 20 mu g/L Cu) simulating ten consecutive storm events of 12 mm (0.5 in.) of rain to test initial removal performance. Another set of cylinders was loaded at forty times the typical concentration to simulate accelerated longterm metal loading indicative of several years of typical use. Cylinders were removed after 15 and 24 accelerated events respectively for further typical concentration performance testing. Performance for the typical concentration tests both pre and post accelerated loading were calculated as a percent metals retained and also as a percent decrease in effluent versus influent concentration. The pre accelerated metal loading results indicate averages of 93% and 91% retained, and 90% and 87% concentration decreases for Zn and Cu respectively. Similar percentages were retained post accelerated metal loadings with slightly lower averages for copper after 24 accelerated loading events, although this was probably due to a higher infiltration rate. Removals were seen to be effected by both physical (water trapping) and by chemical (sorption and complexation) processes.
Transportation Research Board 93rd Annual MeetingTransportation Research Board, 2014
Developed areas with more impervious pavement surfaces usually experience increased levels of sto... more Developed areas with more impervious pavement surfaces usually experience increased levels of stormwater runoff and associated higher pollutant loadings. A common practice to more economically treat these associated pollutants is to design treatment options for the water quality volume of a storm, that is, the first part of a large storm that frequently includes the first flush, where pollutants deposited between events may be dislodged. This theoretical case study includes an add-on strategy for water quality improvement optimization by additionally focusing on the stormwater ‘hotspot’ contributing areas known for having higher pollutant loadings, frequently five to ten times higher. The methodology is developed and then theoretically applied to a series of options for a ferry terminal case, with two innovative designs; a reverse slope to land treatment train and a pervious concrete overlay with sweeping combination. The results are presented in tabular formats which might be usable as comparative multi-criteria decision support tools by decision makers. Further theoretical evaluations of one of the options provide for an additional pictorial decision support tool for environmental uncertainty considerations. The results indicate a significant increase in system or treatment train efficiency even for conservative hotspot factors.
Rivers are a major pathway for the transport of plastics into the ocean. Plastic pollution captur... more Rivers are a major pathway for the transport of plastics into the ocean. Plastic pollution capture devices offer one way to reduce the accumulation of plastic in the environment. This paper provides a framework for selecting a device to reduce plastic pollution in freshwater, synthesizing information of forty prevailing plastic pollution capture devices. We distinguish three major components of plastic pollution technology (booms, receptacles, and watercraft vehicles) and collect details on each technology including its features, limitations, efficiency, reported costs, and maintenance requirements. A framework is developed to aid in device selection by water and waste managers, which highlights the need for a watershed assessment, an understanding of site conditions, the attainment of community buy-in, and a long-term maintenance plan. While plastic pollution capture devices can help reduce the flux of plastic waste from freshwater, management of plastic waste at the source is also needed to ultimately clean our oceans and waterways.
ABSTRACT: Bioretention is an evolving type of Green Stormwater Infrastructure (GSI) designed to a... more ABSTRACT: Bioretention is an evolving type of Green Stormwater Infrastructure (GSI) designed to attenuate peak flows, reduce stormwater volume, and treat stormwater. This article examines the capabilities of a bioretention soil mixture of sand and compost enhanced with aluminum‐based drinking water treatment residuals to reduce nutrients from stormwater runoff. Columns with and without a saturation zone and vegetation were compared to examine their role in removing nitrate and ortho‐phosphate from stormwater. Results show that utilization of a saturation zone can significantly reduce nitrate in effluent water (71% compared to 33% without a saturated zone), even in a newly constructed system. However, ortho‐phosphate reduction was significantly better in the columns without a saturated zone (80%) compared to columns with (67%). Plants did not significantly improve removal. This suggests amendments such as aluminum‐based water treatment residuals for phosphorus removal and a saturation zone for nitrogen removal are needed during the initial establishment period.
The Sustainable Design Guidelines were developed in Phase I of this research program (WA-RD 816.1... more The Sustainable Design Guidelines were developed in Phase I of this research program (WA-RD 816.1). Here the authors are reporting on the Phase II effort that “beta-tested” the Phase I Guidelines on example ferry terminal designs and refinements made to the tool. The specific objectives of this project are to: 1. Cite example Washington State Ferries (WSF) terminal projects that would serve as candidates for assessing the Sustainable Design Guidelines; 2. Compile and analyze site and resource attributes influencing the design needs; 3. Develop a “20% design” for each of the example terminals; 4. Refine the Draft Sustainable Design Guideline; 5. Develop preliminary data on the efficacy of sample stormwater design solutions; and 6. Develop a database tool for GRIP, the proposed Green Rating Integration Platform for WSF. This project represents the second phase in a three-part effort. The final component will develop and potentially demonstrate specific solutions that present unique opportunities will be deployed in Phase III.
ABSTRACT Green roofs have become increasingly common in urban areas to slow and reduce stormwater... more ABSTRACT Green roofs have become increasingly common in urban areas to slow and reduce stormwater runoff from buildings. However, phosphorus has been found to leach from green roofs. Water treatment residuals (WTRs), a waste product in the water treatment process, may help reduce leaching of phosphorus from green roofs. This study evaluated a green roof retrofit that consisted of a WTR filter at the green roof drain to reduce phosphorus in runoff. Samples of rainfall, runoff from a green roof, and runoff from a regular roof were collected every time it rained and analyzed for total phosphorus (TP), phosphate (PO43−), copper (Cu) and zinc (Zn). Samples were taken January–March 2020 and September 2020–March 2021. Phosphate and TP concentrations were significantly lower (p<0.05) with the retrofit during the winter (Jan–March 2020 and 2021) but not during the fall (Sept–December 2020). The change in WTR efficacy may be due to the WTRs drying out during the summer months, although it appears the WTRs are effective once they have been resaturated during the fall wetting period. This study shows that the WTR retrofit may reduce phosphorus leaching as long as the WTRs do not dry out. The WTRs should be replaced each fall in regions that experience dry summer months to maximize efficacy.
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