Stormwater Filtration Performance for the Ecosol Storm Pit (Class 2): Statistical Analysis of Field Data

Fereydoon Pooya Nejad,Aaron C Zecchin

doi:10.3390/w12102723

Abstract

An independent field performance evaluation for a secondary stormwater filtration device, named the Ecosol Strom Pit (Class 2), was performed between May 2017 and July 2019 in an urban catchment in Queensland, Australia. During the testing period, a total of 37 rainfall events were recorded, of which between 15 and 21 events were evaluated as qualifying for the purposes of characterizing the removal efficiency performance of the device. A statistical analysis of the event mean concentrations (EMCs) of the flow streams through the device indicate a statistically significant difference between the influent and effluent streams. A variety of pollutant removal evaluation metrics, including concentration-based and total load-based metrics, were utilized in this study to characterise the efficacy of the device. Two new approaches are proposed for facilitation the analysis: a nonlinear regression approach to more effectively deal with nonlinear patterns in the influent and effluent data and the regression of concentration (ROC), which is an added concentration-based metrics. In summary, the removal efficiencies of the Ecosol Storm Pit (Class 2) were evaluated to be 72–74% for total suspended solids (TSS), 45–50% for total phosphorus (TP), 41–45% for total nitrogen (TN), 27–32% for total heavy metals (THM), 79–85% for total petroleum hydrocarbons (TPH), and 80–88% for total recoverable hydrocarbons (TRH).

Highlights

Within current day Australia, larger scale urban developments require the incorporation of water-sensitive urban design (WSUD) objectives and principles to minimize the impact urban development has on the natural water cycle by protecting natural ecosystems and their water quality [1]
With support in the industry growing for more certainty around performance claims for stormwater filtration devices and methods, Stormwater Australia and key industry stakeholders, in consultation with practitioners, developed the “Stormwater Quality Improvement Device Evaluation Protocol”
All event sampling was independently completed by Moreton Environmental and the data independently analyzed by The University of Adelaide

Summary

Introduction

Within current day Australia, larger scale urban developments require the incorporation of water-sensitive urban design (WSUD) objectives and principles to minimize the impact urban development has on the natural water cycle by protecting natural ecosystems and their water quality [1].WSUD best environmental management practices typically require planners and developers to apply a “fit for purpose” approach to stormwater treatment measures, which often requires a treatment train approach, as no individual treatment measure adequately treats the full range of pollutants contained within the run-off from typical urban developments. Within current day Australia, larger scale urban developments require the incorporation of water-sensitive urban design (WSUD) objectives and principles to minimize the impact urban development has on the natural water cycle by protecting natural ecosystems and their water quality [1]. The objectives of the field study were to verify the pollutant removal capabilities of the Ecosol Storm Pit (Class 2). The Ecosol Storm Pit (Class 2) is a unique compact at-source or in-line secondary stormwater filtration system, designed to carry out multiple treatment processes on stormwater runoff within the one compact underground device [2]. The unit consists of a primary treatment inlet litter basket, designed to capture and retain all particles larger than 200 microns, as well as a unique patented multi-barrier media filter for secondary treatment.

Methods

Discussion

Conclusion