Jellyfish Compliance with SQIDEP · MCU15/0122

Australian Journal of Water Research
ISSN: 2203-9482 (Print) ISSN: 2203-9490 (Online)

3.2 Treatment Performance
Measured concentrations representing inflows to the treatment device and outflows from the device
was used for determining the treatment performance. Treatment performance was evaluated for TSS,
TN and TP as these are the most common stormwater quality parameters. The estimated treatment
performance is shown in Table 5.

Table 5. Concentration Reduction Efficiency and Efficiency Ratio
   Date                 TSS (mg/L)                     TN (mg/L)                      TP (mg/L)
 sampled
               Inflow    Outflow     CRE      Inflow    Outflow     CRE      Inflow    Outflow      CRE
28/06/2014    180           13       92.8       1.3        1.3        0.0      0.24      0.24        0.0
16/08/2014    170            2       98.8       2.8        0.5       82.1      0.41      0.03       92.7
27/08/2014    19             2       89.5       1.1        0.5       54.5     0.093      0.05       46.2
25/09/2014    26             4       84.6       3.1        1.1       64.5      0.17      0.06       64.7
13/10/2014    25             4       84.0       1.9        1.9        0.0      0.17      0.12       29.4
27/10/2014    51            10       80.4        6         2.3       61.7      0.53      0.17       67.9
06/11/2014    74             8       89.2       3.2        1.6       50.0      0.31      0.08       74.2
 Average      78             6                  2.8        1.3                 0.27      0.11
        Average CRE                  88.5                            44.7                           53.6
        Median CRE                   89.2                            54.5                           64.7
Note:
    1.   CRE – Concentration reduction efficiency. CRE is the percentage reduction in concentration
         with respect to inflow concentration for individual events.
    2.   Concentrations less than Practical Quantification Limit (PQL) was replaced by 50% of
         detection limit for performance calculations.

It is commonly known that the average of a small sample set can be far from the true mean of a
population. In this respect, median values could be a true representative of performance indicators. This
is particularly true when a data set is log-normally distributed rather than normally distributed. As
evident in Table 5, median of the percentage concentration reduction efficiencies for TSS, TN and TP
are 89.2%, 54.5% and 64.7%, respectively. Average values (mean) for the same parameters are less
than 10% difference from the median except for TP. This indicates consistency in treatment
performance of the Jellyfish® Filter for all the events investigated.


4. Comparison of Treatment Performance with Previous Studies
Demonstrating the validity of the data obtained and estimated performance is critical in field
monitoring. Accordingly, the data obtained and estimated performance was compared with treatment
performance reported in previous studies.


4.1 Comparison of Rainfall Data
It was considered important to demonstrate that the range of rainfall events monitored is within the
range of rainfall typical to local conditions. At the same time, it was also important to compare the
events monitored with the events monitored by the UoF (2011) study. Accordingly, the events
monitored in this study are plotted with typical Brisbane events from 2004 (selected as a representative
year) and events monitored in UoF (2011) study as shown in Figure 4. Phase 1 of the study undertaken
confirmed that 2004 represents a rainfall year with average annual rainfall depth and hence can be
considered as a representative year (Egodawatta et al. 2014). As evident in Figure 4, events monitored
in this study are well within the envelope created by the other two sets of rainfall data, thus confirming
the representativeness of the monitored events in this study.




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