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Humeceptor® Sizing Detailed ReportPCSWMM for Humeceptor®

Project InformationDate 3/08/2018

Project Name Hardi Seven HillsProject Number 180006Location Seven HillsDesigner Name Karina - 02 9267 9312Company SCP Consutling

Stormwater Quality Objective

This report outlines how the Humeceptor® Hydrodynamic Separator can achieve a definedwater quality objective through the removal of total suspended solids (TSS). Attached to thisreport is the Humeceptor® Sizing Summary.

Humeceptor® System Recommendation

The Humeceptor® System model STC 9 achieves the water quality objective removing 81% TSSfor a MUSIC particle size distribution.

The Humeceptor® System

The Humeceptor® Hydrodynamic Separator is sized to treat stormwater runoff by removinghydrocarbons and fine sediments through gravity separation and flotation. Humeceptor®’spatented design provides TSS removal during all rainfall events, including large storms. Significantlevels of pollutants such as heavy metals, hydrocarbons and nutrients are prevented fromentering natural water resources. Extensive research on the operation of Humeceptor®Hydrodynamic Separators has also proven that previously captured sediment is notre-suspended (scoured) even at 500% flow capacity (University of Florida, 2009).

Humeceptor® devices provide a high level of TSS removal for small frequent storm events (<0.5yrARI) that represent the majority of annual rainfall volume and pollutant load. Treatmentcontinues during large infrequent events, however, such events have little impact on theaverage annual TSS removal as they represent a small percentage (typ. <5%) of the total annualrunoff volume and pollutant load.

Humeceptor® is the only Hydrodynamic Separator specifically designed to remove TSS for awide range of particle sizes, including fine sediments (<100 microns), that are often overlooked inthe design of other stormwater treatment devices (GPTs). Effective removal of TSS will also result

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in removal of particulate-bound nitrogen and phosphorous. Field research of the Humeceptor®system confirms removal of greater than 30% TN and TP for units sized to provide 80% TSS removal(Maunsell AECOM, 2008, Associated Earth Sciences, 1999).

SMALL STORMS DOMINATE HYDROLOGY & POLLUTANT EXPORT

“Rainfall runoff pathways, rates and patterns are a key driver of contaminantmobilisation, transport, and interception. In urban catchments, the morefrequent events generate the most significant contaminant loads. A largeproportion (70% to 90%) of contaminants are exported by storm events of 1yr ARIevent and smaller. For example, the sum of flows up to the 1 yr ARI can representmore than 95% of the mean annual runoff volume.”– Engineers Australia, Australian Runoff Quality, 2006

“(Hydrology) curves are relatively independent of the time of concentration ofthe catchment and also (shows) that the incremental benefit of increasing thetreated volume of runoff diminishes beyond a design flow rate of the 2 year ARI.Further, the plot suggests that generally the optimum operating range falls withina design flow rate of between 0.25 and 1.0 year ARI discharges.”

- CSIRO, Urban Stormwater: Best Practice Environmental ManagementGuidelines, 1999

Design Methodology

Each Humeceptor® system is sized using PCSWMM for Humeceptor®, a continuous simulationmodel based on USEPA SWMM. The program calculates hydrology from at least 10 years ofrecent, local, historical rainfall data and specified site parameters. With USEPA SWMM’sprecision, every Humeceptor® unit is designed to achieve a user-defined water qualityobjective.

The TSS removal data presented follows USEPA guidelines to reduce the average annual TSSload. Humeceptor®’s unit process for TSS removal is settling. The settling model calculates TSSremoval by analysing (summary of analysis presented in Appendix 2):

Site parametersContinuous historical rainfall, including duration, distribution, peaks (Figure 1)Inter-event duration (Antecedent Dry Period)Particle size distributionParticle settling velocities (Stokes Law, corrected for drag)TSS load (Figure 2)Hydraulic Residence time of the system

The Humeceptor® System maintains continuous TSS removal for all influent flow rates, even whenbypass flows occur. Figure 3 illustrates the continuous treatment by Humeceptor® throughout thefull range of storm events analysed. It is clear that large events do not significantly impact theaverage annual TSS removal. There is no decline in cumulative TSS removal, indicating scourdoes not occur as the flow rate increases.

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Figure 1. Runoff Volume by Flow Rate for PARRAMATTA N (MASONS DR) – NSW 6612, 1984 to 2006for 0.4394 ha, 80% impervious. Small frequent storm events represent the majority of annualrainfall volume. Large infrequent events have little impact on the average annual TSS removal,as they represent a small percentage of the total annual runoff volume.

Figure 2. Long Term Pollutant Load by Flow Rate for PARRAMATTA N (MASONS DR) – 6612, 1984 to2006 for 0.4394 ha, 80% impervious. The majority of the annual pollutant load is transported bysmall frequent storm events (<0.5 yr ARI). Conversely, large infrequent events carry aninsignificant percentage of the total annual pollutant load.

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Humeceptor® ModelTSS Removal (%)

STC 981

Drainage Area (ha)Impervious (%)

0.439480

Figure 3. Cumulative TSS Removal by Flow Rate for PARRAMATTA N (MASONS DR) – 6612, 1984 to2006. Humeceptor® continuously removes TSS throughout the full range of storm eventsanalysed. Large events do not significantly impact the average annual TSS removal, due to thebuildup and washoff action on 100% impervious catchments with “at source” treatment.Research into the Humeceptor® confirms scour does not occur as the flow rate increases, and isreflected in the graph (University of Florida, 2008).

References

Associated Earth Sciences (1999) “STC900 (STC3) Field Monitoring – Seatac, Washingtion”CSIRO (1999) “Urban Stormwater: Best Practice Environmental Management Guidelines”Engineers Australia (2006) “Australian Runoff Quality”Maunsell AECOM (2008) “Stormwater Quality Monitoring at Treated Drainage Outfalls (PostCleaning) – Main Roads WA”University of Florida (2008) “Multi-Phase Physical Model Testing of a Stormceptor® STC450i” (STC2)

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Appendix 1Humeceptor® Design Summary

Project InformationDate 3/08/2018Project Name Hardi Seven HillsProject Number 180006Location Seven Hills

Designer InformationCompany SCP Consutling

Contact Karina - 02 9267 9312

RainfallName PARRAMATTA N (MASONS DR)

State NSW

ID 6612

Years of Records 1984 to 2006

Latitude 33°47'30"S

Longitude 151°1'5"E

Notes

N/A

Water Quality ObjectiveTSS Removal (%) 80

Drainage AreaTotal Area (ha) 0.4394

Imperviousness (%) 80

The Humeceptor® System model STC 9 achievesthe water quality objective removing 81% TSS for aMUSIC particle size distribution.

Upstream DetentionStorage Discharge(cu-m) (L/s)0.000 00.000

165.000 18.000250.000 74.000

Humeceptor® Sizing Summary

Humeceptor® ModelTSS Removal

%STC 2 65STC 3 75STC 5 75STC 7 76STC 9 81

STC 14 82STC 18 85STC 23 86STC 27 88STC 40 91STC 50 91STC 60 93

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Particle Size DistributionRemoving finer sediment particles (<100 microns) from runoff ensures that more of the pollutants, suchas hydrocarbons and heavy metals, are captured and are not discharged into our natural waterways.The table below lists the particle size distribution used to define the annual TSS removal.

MUSIC

Particle Size Distribution SpecificGravity

SettlingVelocity Particle Size Distribution Specific

GravitySettlingVelocity

µm % m/s µm % m/s1 0.1 1.1 0.0004 500 5 2.65 0.08482 1.9 1.2 0.00044 1 1.5 0.00048 2 1.8 0.0004

16 5 1.8 0.000432 10 2.2 0.000764 25 2.2 0.0027

128 32 2.65 0.0109256 18 2.65 0.0347

Humeceptor® Design NotesHumeceptor® performance estimates are based on simulations using PCSWMM for Humeceptor®.

Design estimates listed are only representative of specific project requirements based on totalsuspended solids (TSS) removal.Only the STC2 and Multiceptor™ units are adaptable to function with a grated inlet and/or inlinepipes.Only the Multiceptor™ models STC 3 to STC 27 may accommodate multiple inlet pipes.

Inlet and outlet invert elevation differences are as follows:

Inlet and Outlet Pipe Invert Elevations DifferencesInlet Pipe

Configuration STC2 STC 3 toSTC 27 STC40 to STC60

Single inlet pipe 75 mm 25 mm 75 mm

Multiple inlet pipes 75 mm 75 mm Only one inletpipe.

Design estimates are based on stable site conditions only, after construction is completed.Design estimates assume that the drainage network is not submerged during zero flows. Forsubmerged applications, please contact your local Humes® Water Solutions representative for anAquaceptor™.

Design estimates may be modified for specific spills controls (Humeceptor® EOS). Please contactyour local Humes® Water Solutions representative for further assistance.

For pricing inquiries or assistance, please contact Humes® Water Solutions, Ph. 1300 361 601

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Appendix 2Summary of Design Assumptions

SITE DETAILS

Site Drainage AreaTotal Area (ha) 0.4394 Imperviousness (%) 80

Surface CharacteristicsWidth (m) 133Slope (%) 2Impervious Depression Storage(mm) 0.508

Pervious Depression Storage (mm) 5.08Impervious Manning’s n 0.015Pervious Manning's n 0.25

Maintenance FrequencySediment build-up reduces the storage volumefor sedimentation. Frequency of maintenance isassumed for TSS removal calculations.Maintenance Frequency (months) 12

Infiltration ParametersHorton’s equation is used to estimate infiltrationMax. Infiltration Rate (mm/h) 61.98Min. Infiltration Rate (mm/h) 10.16

Decay Rate (s-1) 0.00055

Regeneration Rate (s-1) 0.01

EvaporationDaily Evaporation Rate (mm/day) 4.05

Dry Weather FlowDry Weather Flow (L/s) No

Upstream DetentionStage-storage and stage-discharge relationship used to model upstream detention prior to theHumeceptor® System is identified in the table below.

Storage Dischargecu-m L/s0.000 00.000

165.000 18.000250.000 74.000

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PARTICLE SIZE DISTRIBUTIONParticle Size DistributionRemoving finer sediment particles (<100 microns) from runoff ensures that more of the pollutants, such ashydrocarbons and heavy metals, are captured and are not discharged into our natural waterways. Thetable below lists the particle size distribution used to define the annual TSS removal.

MUSIC

Particle Size Distribution SpecificGravity

SettlingVelocity Particle Size Distribution Specific

GravitySettlingVelocity

µm % m/s µm % m/s1 0.1 1.1 0.0004 500 5 2.65 0.08482 1.9 1.2 0.00044 1 1.5 0.00048 2 1.8 0.0004

16 5 1.8 0.000432 10 2.2 0.000764 25 2.2 0.0027

128 32 2.65 0.0109256 18 2.65 0.0347

Figure 1. PCSWMM for Humeceptor® standard design Particle Size Distributions.

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TSS LOADINGTSS Loading Parameters

TSS Loading Function Event Mean Concentration (EMC)

HYDROLOGY ANALYSISPCSWMM for Humeceptor® calculates annual hydrology with the USEPA SWMM and at least 10 years ofrecent, local, historical rainfall data. Performance calculations of the Humeceptor® System are based onthe average annual removal of TSS for the selected site parameters. The Humeceptor® System isspecifically designed to capture fine particles (silts and sands) by focusing on average annual runoffvolume ensuring positive removal efficiency is maintained during all rainfall events, while preventing theopportunity for scour.

Smaller, frequently recurring storms account for the majority (typ. >95%) of rainfall events and mean annualrunoff volume (MARV), as observed in the historical rainfall data analyses presented in this section.

Rainfall StationRainfall Station PARRAMATTA N (MASONS DR)

Rainfall File Name NSW6612.NDC Total Number of Events 2853

Latitude 33°47'30"S Total Rainfall (mm) 15987.3

Longitude 151°1'5"E Average Annual Rainfall(mm) 695.1

Elevation (m) 23 Total Evaporation (mm) 1123.9Rainfall Period of Record (y) 23 Total Infiltration (mm) 3072.0

Total Rainfall Period (y) 23 Percentage of Rainfall that isRunoff (%) 74.4

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Rainfall Event Analysis

Rainfall Depth No. of Events Percentage ofTotal Events Total Volume Percentage of

Annual Volumemm % mm %6.35 2299 80.6 3741 23.412.70 262 9.2 2368 14.819.05 114 4.0 1804 11.325.40 54 1.9 1207 7.631.75 35 1.2 1010 6.338.10 24 0.8 841 5.344.45 16 0.6 665 4.250.80 15 0.5 721 4.557.15 7 0.2 378 2.463.50 2 0.1 120 0.769.85 3 0.1 205 1.376.20 2 0.1 143 0.982.55 1 0.0 79 0.588.90 2 0.1 173 1.195.25 2 0.1 185 1.2

101.60 1 0.0 97 0.6107.95 6 0.2 624 3.9114.30 1 0.0 113 0.7120.65 0 0.0 0 0.0127.00 1 0.0 127 0.8133.35 1 0.0 133 0.8139.70 0 0.0 0 0.0146.05 0 0.0 0 0.0152.40 0 0.0 0 0.0158.75 0 0.0 0 0.0165.10 1 0.0 161 1.0171.45 0 0.0 0 0.0177.80 0 0.0 0 0.0184.15 0 0.0 0 0.0190.50 0 0.0 0 0.0196.85 0 0.0 0 0.0203.20 0 0.0 0 0.0209.55 0 0.0 0 0.0

>209.55 4 0.0 1092 6.8

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Pollutograph

Flow Rate CumulativeMass

L/s %1 54.74 86.69 95.616 98.325 99.236 99.749 99.964 99.981 100.0

100 100.0121 100.0144 100.0169 100.0196 100.0225 100.0256 100.0289 100.0324 100.0361 100.0400 100.0441 100.0484 100.0529 100.0576 100.0625 100.0676 100.0729 100.0784 100.0841 100.0900 100.0