The state of Western Australia recently completed a brand new athletics stadium in Perth where the use of recycled effluent (RE) was made possible through the closeness to Perth's main Waste Water Treatment Plant (WWTP).
Waterman Irrigation already had a system in place for the nearby University of Western Australia, using water from the same source, so the company was contracted to design and supply the complete control system for not only the athletics stadium but also the adjacent basketball stadium surrounds and rugby field
The requirements were as follows:
- Irrigate during the night with water from an underground tank
- Fill the tank with recycled water during the day
- Monitor chlorine levels in the tank and switch to bore water if the levels are too low
- Provide bore water supply as a backup for the nightly irrigation, as flush water after RE irrigation and for use during daytime hours for maintenance functions
- Integrate an iron filter into the system
- Provide variable speed control to the system to provide a steady system pressure even with a different amount of irrigation stations connected
- Provide integration with the existing irrigation system from the University who are using the same main line from the WWTP
- Allow freely adjustable grouping of multiple stations
- Provide Internet-based central control
- Provide hand-held remote control
The resulting control system provided the operators (Venues West) with a simple but sophisticated method of controlling irrigation that met all of the above criteria.
In detail, Waterman Irrigation provided the following:
- Waterman Irrigation 2-wire controller complete with 63-station encoder, wireless router and touchscreen operator interface in a free standing metal enclosure. A total of 55 decoders have been installed to date.
- Fibre-optic link to the University of Western Australia sporting grounds.
- Free standing bore pump controller with variable speed drive and touchscreen operator interface. Bore level transmitter, pressure transmitter and flow transmitter.
- RS 485 communication between the bore pump controller and the irrigation controller.
- Hard-wired link to the multi-stage variable speed control system for the tank pumps.
- Hard-wired link to chlorination system.
- Hard-wired link to the filtration plant.
- Flow meter at the tank outlet.
Software modifications to the standard Waterman program included the following:
- Measure the level in the underground tank at midday and provide accurate fill-time requirements to be used by the Water Corporation.
- Open and close a boundary valve between the University grounds and the athletics stadium so as not to interfere in the University's irrigation program.
- Activate emergency shutdown valves at the tank inlets should the main valve remain open for too long.
- Prevent watering with bore water when the filter is faulty.
- Automatic change-over from RE to bore water should the tank level get too low.
- Prevent RE irrigation when the chlorine level in the tank is too low.
- A freely adjustable operating time for when RE can be used. Bore water will always be used automatically outside these hours.
- Access to the central server at Waterman Irrigation's offices in the Joondalup Business Park.
- A Palm Treo PDA with dedicated Waterman software for hand-held remote control