RFI - Attachment F - Engineering Report

 Peer Review: StormFilter® as a stormwater improvement
        device under typical Australian conditions


1. Background


Urban stormwater runoff is a major source of pollutant which can undermine
waterway health. A study by Cordery (1976) demonstrated that urban runoff from
three urban catchments in Sydney resulted in the wash-off of greater pollutant mass
into the waterways than typical sewage effluents subject to secondary treatment.
Sartor and Boyd (1972) found that sediments present in urban runoff carried a large
quantity of pollutants with them. The loadings and concentrations of suspended
solids and nutrients in urban runoff were reported to be much higher than runoff from
typical rural areas (Chew et al., 1997). The concentrations of sediment-bound
contaminants generally vary with particle size, and generally finer particles carry a
larger quantity of contaminants than larger ones (Sartor and Gaboury, 1984).
Shartor et al. (1974) found that in urban runoff although less than 10% of particulates
are in the silt and clay soil size they contain over 50% of the Phosphorus and 25% of
other pollutants. Chew et al. (2004) showed that higher concentrations of heavy
metals are also associated with smaller size particles. Results show that almost 50%
of the heavy metals found on street sediments are associated with particles of 60–
200 µm in size, and 75% are associated with particles finer than 500 µm in size.
Vaze and Chiew (2004) found that about 50% of heavy metals were associated with
particles smaller than 200 µm, and 75% with particles smaller than 500 µm. Hence,
controlling of finer particles has emerged as a priority in urban stormwater
management in Australia similar to other developed countries. In this regard, the
particle size distributions (PSD) of urban runoff sediments have been the basis of
many urban stormwater management guidelines both in Australia and other
countries. New research conducted in Australia and other countries have revealed
that the PSD of urban runoff in Australia are not significantly different from
international results (e.g. USA) when considering similar collection methods and
similar analytical techniques (Drapper, 2014).
This review focuses on StormFilter®, which is a radial cartridge media filter in
relation to its pollutant removal efficiency from typical urban runoff under Australian
conditions.


2. Review of StormFilter®
StormFilter® is a radial cartridge filtration system (RCFS) that uses an activated
alumina media to treat stormwater runoff, particularly to remove solids and nutrients
from urban runoff. Activated alumina is made of aluminium oxide (Al2O3) and has a
very high surface-area-to-weight ratio, due to the many tunnel-like pores within it,
which is ideal to remove pollutants from water. The adsorptive capacity of activated
alumina is quite high, and hence it is widely used in water treatment process as an
adsorptive filter media to enhance the removal of the phosphorus from water (Wang
et al., 2015). In a laboratory experiment of treating river water conducted by Wang et

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