RFI - Attachment F - Engineering Report

stormwater treatment                                                                                                    refereed paper



Background
This field trial follows a previous research
project undertaken by the School of
Earth and Environmental Sciences,
James Cook University (JCU), as part of
a wider investigation into the impacts of
road runoff on the Kuranda Range Road
watershed, near Cairns (Munksgaard and
Lottermoser, 2008), which discharges
into the sensitive environment of Streets
Creek. JCU reported on the quality of
the watershed’s receiving waters, the
chemical characterisation of the road
runoff and the performance of the system
over four runoff events.
   JCU found that the system “had a
high retention capacity for suspended
                                                     Figure 2. Schematic of the SYSTEM treatment train.
sediment and by implication particulate
metals”. Conversely, they reported that              achieved substantial removal of                protection on the steel components.
the “treatment train” had only a “modest             Total Nitrogen (45%), Total Phosphorus         Given the substantial removal of
retention capability for dissolved (filtered)        (70%), Total Aluminium (71%), Total Nickel     suspended solids, nutrients and total
metals”. In addition, JCU identified that            (73%), Total Lead (60%) and Total Copper       metals, it appears unlikely that the
the treatment train system was, in fact,             (58%). On the other hand, it identified        dissolved copper and zinc, observed
responsible for a significant net export of          potential releases of Suspended Solids         in the outflows, was associated with
zinc. On the basis of their data, nutrient           under 500 microns, as well as dissolved        a release of the under-500 micron
levels in the road runoff were low, and              zinc and copper.                               sediment fraction.
do not constitute a water quality concern
at Streets Creek. However, they also                    One explanation for the above-                It was largely to address these issues
reported significant retention of both TN            mentioned releases is that they could          and better understand the sources of
and TP. The JCU study, which, in their               be related to the anaerobic conditions         these copper and zinc releases that
own words “do[es] not constitute a full              present in either the standing water           Stormwater360 undertook a further field
evaluation of the EnviroPod/StormFilter              within the wet-sump or, in the case of         evaluation of the treatment train system,
treatment system”, found the system                  zinc, corrosion of the exposed galvanised      which is the subject of this evaluation.

  Table 1. Water quality analytical parameters.
  Parameter                             Abbreviation              Analytical Method*        Units      Limit of Reporting     Analysed by
  Electrical Conductivity                       EC                   APHA 2510B            µS/cm                1             Cairns Water
  pH                                            pH                  APHA 4500-H+              -                 0.1           Cairns Water
  Suspended Solids above                                          500 micron sieve &
                                     SS > 500 micron                                        mg/L                1             Cairns Water
  500 microns                                                       APHA 2540B
  Volatile Suspended Solids                                       500 micron sieve &
                                   SS Vol. > 500 micron                                     mg/L          0.1% Dry Solids     Cairns Water
  above 500 microns                                                 APHA 2540E
  Suspended Solids                                               APHA 2540B; equiv.
                                      SS < 500 micron                                       mg/L                1             Cairns Water
  below 500 microns                                               ASTM D-3977-97
  Volatile Suspended Solids
                                   SS Vol. < 500 micron              APHA 2540E             mg/L          0.1% Dry Solids     Cairns Water
  below 500 microns
  Suspended Solids                              SS                    Calculated            mg/L                 -                  -
  Volatile Suspended Solids                SS Vol.                    Calculated            mg/L                 -                  -
  Total Phosphorus                              TP                  APHA 4500-P            mg/L P              0.02           Cairns Water
  Total Nitrogen                                TN                  APHA 4500-N            mg/L N              0.05           Cairns Water
  Total Kjeldahl Nitrogen                   TKN                       Calculated           mg/L N                -                  -
  Ammonia Nitrogen
                                           NH3-N                   APHA 4500-NH3           mg/L N              0.05           Cairns Water
  (Ammonium Nitrogen)
  Nitrate/Nitrite
                                       NO3-/NO2--N                 APHA 4500-NO3           mg/L N              0.01           Cairns Water
  (Total Oxidised Nitrogen)
  Total Organic Carbon                      TOC                     APHA 5310-B             mg/L                1                 ALS
  Dissolved Organic Carbon                  DOC                     APHA 5310-B             mg/L                1                 ALS
  Particle Size Distribution
                                            PSD                 Malvern Mastersizer S      micron              0.05               QUT
  (Laser Diffraction)


2 SEPTEMBER 2011 water                                                                                    technical features