RFI - Attachment F - Engineering Report

   4. Nutrient Species Comparison with Local Data
There is limited information available relating to the categorisation of nutrients, into their
constituent species, within runoff from carparks and roads in Australia. However, a literature
search did reveal a range of EMCs for Ammonia which could be used for comparative
purpose. These are referenced below.

Morison P (2001) reported on the Ammonia EMC in runoff from the St Martins carpark which
was in the order of 1 mg/L.

The recommended typical EMC values for nutrients in runoff from various land uses, provided
in Fletcher T et al (2004), do not include a species breakdown for either Total Phosphorus or
Total Nitrogen. Other data, referencing Ammonia EMCs in runoff from urban catchments in
Sydney and the Illawarra, suggest a mean range of between 0.02 and 0.54 mg/L while similar
EMCs measured in Hornsby returned mean Ammonia EMC ranges of between 0.01 and 0.11
mg/L. Similarly, Ammonia EMCs in runoff from urban catchments in Grafton were found to be
between 0.02 and 0.41 mg/L (Fletcher T et al, 2004).

The Contech Engineered Solutions (2012) product evaluation identified an EMC range of
between 0.05 mg/L and 0.72 mg/L with a mean of 0.27 mg/L for the Ammonia in runoff from
the Mitchell Community College carpark.

Consequently it would appear that the Ammonia EMCs measured in runoff from the Mitchell
Community College carpark are similar to those reported in runoff from the St Martins carpark
and other urban catchments in the Sydney, Illawarra and Grafton regions of NSW as reported
in Fletcher T et al (2004).


DISCUSSION


Based on the information provided in Contech Engineered Solutions (2012) product
evaluation of the StormFilter® installed, within the Mitchell Community College carpark, it is
our opinion that the sampling and monitoring of the system has been undertaken with
sufficient scientific rigour to meet the objectives of the project. Further, the sampling
methodology and testing procedures used by Contech Engineered Solutions are consistent
with the Australian and New Zealand Guidelines, NQWMS (2000).

With regards to compatibility with Australian conditions:

       Pollutant concentrations in the influent appear lower than those that may be expected
        under Australian conditions. Consequently the Efficiency Ratios determined may be
        expected to be higher if the same StormFilter® treatment system were installed on a
        similar carpark in Australia;
       The use of a storage tank, upstream of the treatment system, allows the required
        treatment volume of runoff to be released to the treatment system at a flow rate
        comparable to the Treatable Flow Rate of the cartridge filter system. Consequently
        comparisons between rainfall intensities is not thought necessary as the storage
        volume within the detention tank and the size of the outlet orifice control the flow rate



HES – StormFilter® System Peer Review                                                         Page 4