RFI - Attachment F - Engineering Report

                                                                                                                                       1
                                                                                                               Technical Papers




SOLID AND NUTRIENT POLLUTANT
REMOVAL BY AN ENGINEERED
STORMWATER FILTRATION MEDIA
Field evaluation of a radial cartridge media filter
M Wicks, J Lenhart, J Pedrick


Abstract                                      (Wicks et al., 2011) using a granular           suspended solids, together with
This paper provides a summary of              perlite, zeolite and carbon filtration          both soluble and particulate fractions
the results associated with a 20-month        media blends. Similar to blended                of both phosphorus and nitrogen
                                              filtration media, activated alumina             at mean concentrations that can be
field study conducted at the Mitchell
                                              media employs both physical as well             compared to the Australia context,
Community College test site located in
                                              as chemical filtration characteristics to       to validate the performance of the
the town of Mooresville, North Carolina,
                                              promote adsorption of pollutants such           activated alumina in the RFCS.
USA. The study was conducted to
                                              as dissolved phosphorus (Ma, 2011). The
demonstrate the effectiveness of a radial                                                         The RCFS, as seen in Figure 1,
                                              legislated removal requirements of both
cartridge filtration system (RCFS) using                                                      is typically comprised of a vault that
                                              phosphorus and nitrogen have become
an activated alumina media, treating                                                          houses rechargeable, media-filled filter
                                              commonplace in Australia, for example
stormwater runoff with respect to the                                                         cartridges. Stormwater entering the
                                              the Queensland Planning Policy (DSDIP,
removal of solid and nutrient pollutants.                                                     system percolates horizontally through
                                              2014) for the treatment of stormwater
                                                                                              these media-filled cartridges, where
  Testing of the RCFS was conducted           from development sites.
                                                                                              pollutant removal processes occur. Once
for a suite of pollutants, including Total
                                                 Although the stormwater treatment            filtered through the media, the treated
Suspended Solids (TSS), Total Phosphorus
                                              objectives for TSS, TP and TN have              stormwater is directed to a collection pipe
(TP) and Total Nitrogen (TN) in accordance
                                              been commonplace in Australia, reliable         and/or discharged to the receiving water.
with an approved Project Plan.
                                              and transferrable data from robust
                                                                                                 The Mitchell Community College
   Results from the study indicated           field assessments in other regions
                                                                                              testing site is located in the town of
that the RCFS, operating at 0.5L/s            can seldom be accomplished due to
                                                                                              Mooresville, North Carolina; it is owned
per cartridge, successfully treated           variations in climatic conditions, particle
                                                                                              and operated by Mitchell Community
stormwater runoff with significant            size distribution of solids and soluble
                                                                                              College and is used for parking. The site
reductions for solid and nutrient             fractions of nutrients. For example,
                                                                                              is 68% impervious and the total drainage
pollutants that were observed between         Wong and Walker (2009) found that
                                                                                              area for the site is 4,370m2. A view of the
influent and effluent sampling locations      the particle size distributions range
                                                                                              finished parking lot located on site can
using the Efficiency Ratio (ER) calculation   on Australian roadways were between
                                                                                              be seen in Figure 2. Stormwater runoff
(TSS 90%, TP 86%, and TN 56%) and             approximately 2 and 500 microns.
                                                                                              from the contributing drainage area
Summation of Load (SOL) efficiency
                                                 This research provides information for       is directed to the RCFS for treatment
calculation methods (TSS 91%, TP 87%,
                                              a range of particle size distributions for      before eventually discharging.
and TN 50%). These results demonstrate
that the radial cartridge filter system was                                                 OVERFLOW RISER AND HOOD
able to successfully meet the current                        INLET ENERGY DISSIPATER

load-based objectives from the NSW
DECC (2007) and QLD Single State
Planning Policy (2014) for all relevant
pollutants, including TSS, TP and TN.

Keywords: BMP, stormwater, TP, TN,
TSS, activated alumina, media filter
cartridge.

Introduction
This field trial complements previous
studies undertaken on the RCFS
utilising alternative filtration media
in both North America and Australia.                                                                                  OUTLET SUMP
RCFS have previously demonstrated               INLET PIPE                                                CONDUIT

significant removal of both phosphorus                                        INLET SUMP

and nitrogen (about 44%) on a SOL basis       Figure 1. Diagram of an RFCS system.



                                                                                                               SEPTEMBER 2014 water