Mitigating the Risks of Urban Stormwater Harvesting

(2008 – 2010)

The aim of this research project was to determine the performance of innovative stormwater recycling systems and to assess the short and long term risks of utilising recycled stormwater for crop irrigation.  Furthermore, this project assessed the health risks associated with the use of untreated, as compared with treated, roof runoff.

The stormwater/roof runoff treatment systems were tested at the Centre for Education and Research of Environmental Strategies (CERES) in Melbourne, Australia – a perfect location to demonstrate successful partnerships between community groups and businesses, also to illustrate the success of large stormwater harvesting strategies for irrigation use by over 220,000 visitors annually.

Paved surface runoff system

Description. Two stormwater treatment systems (1) envissTM Sentinel pits and (2) RootZone vertical reed bed filter are fed in parallel by stormwater runoff from a large car park and roof.  The treated water is then gravity fed to a large lined storage pond, from where it is pumped to a small enclosed tank used for irrigation of the large organic vegetable garden.  These vegetables are consequently sold at the fresh produce market held on site.

Monitoring. Whilst in-and-outflows from each system were monitored on a regular basis, water quality samples were also collected during wet weather events to characterise (a) the overall level of pollution in the runoff from a typical carpark/roof catchment, (b) the treatment performance of the two stormwater recycling systems and (c) the level of pollution fed into the stormwater storage pond.  Routine ‘grab’ sampling tested the quality of the irrigation water.  Furthermore, soil and vegetable ‘grab’ samples from the organic vegetable garden were tested on a regular basis.

Roof runoff system

Description. This section of the project builds on a previous one, which was funded by Round 3 of the Smart Water Fund (project entitled: ‘Smart Water Not Mains Water’).  The previous funds were awarded to CERES to help fund the installation and setup (but not the monitoring) of the roof harvesting system at the CERES site.  For this project, the runoff was split into two separate rainwater tanks, where one included the use of an envissTM system before storage of the roof runoff.

Monitoring. The water levels in each tank were monitored weekly, as well as the amount of water pumped from each tank for reuse.  This monitoring will help quantify the level of water supply substitution each system is achieving, as well as the total amount of potable water saved.  ‘Grab’ water quality samples were also collected routinely from outlets of each of the two tanks.

Research Team:
Dr David McCarthy, Prof Ana Deletic, Prof Tim Fletcher, Peter Poelsma, Justin Lewis and Joanne O’Toole.

Project Partners:
This project has been funded by Monash University, CERES (a community environment park in East Brunswick, Victoria) and Envirostream Solutions (envissTM, a company providing novel treatment solutions for stormwater harvesting) in conjunction with the Smart Water Fund (a funding scheme aiming to secure Victoria’s water future).

Key Industry Reports:
McCarthy D.T., Deletic A. and Fletcher T.D. (2008) New technologies for mitigating risks of stormwater reuse – Report 1: Design, construction and installation of treatment systems. Monash University, Australia.

McCarthy D.T., Deletic A. and Fletcher T.D. (2009) New technologies for mitigating risks of stormwater reuse – Report 2: Design of monitoring system and installation of necessary equipment. Monash University, Australia.

McCarthy D.T., Poelsma P.J. and Deletic A. (2011) New technologies for mitigating risks of stormwater reuse – Report 4: Collect samples from road runoff system and vegetable garden. Monash University, Australia.

Magyar M., McCarthy D.T. and Deletic A. (2010) New technologies for mitigating risks of stormwater reuse – Report 5: Collection of water samples from Roof Runoff for six months and analysis of data. Monash University, Australia.

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