Intelligent home domestic water and wastewater management system
The 'Intelligent Home' concept at Regent Gardens, South Australia, involved collaboration between A.V. Jennings Pty. Ltd, innovative Australian businesses, and groups within the University of South Australia. The Intelligent Home is a modern semi-detached dwelling, which, among many other features, has incorporated two independent water management systems into its design :
- roof runoff collection system for hot water supply, with mains water only used as make-up water when the raintank is empty
- treatment and re-use of 'greywater' (bathroom and laundry wastewater) via a submerged gravel-based reedbed system, with re-use for toilet flushing, aesthetics and, potentially, for garden irrigation
The Urban Water Resources Group initiated these concepts and provided the follow-up performance monitoring. The reedbed treatment system was extensively monitored during the period of rental tenancy between September 1996 to September 1997. A variety of water-tolerant vegetation was planted to assess species survivability, spreading potential, aesthetics and maintenance needs. Wastewater and effluent samples were regularly taken from eight dedicated sampling locations in the treatment system, with more than 500 separate analyses made for a wide variety of public health and environmental parameters. A University Small Grant awarded in 1996 partly offset the substantial cost of this work. UWRC and, later, final year civil engineering undergraduates undertook many of the analyses in house. Staff and students of the School of Chemical Technology became involved during 1997, refining nutrient analysis methodology and undertaking tracer experiments to ascertain flow paths through the reed bed. ICP analysis was made for selected ion species and metals, including copper, iron, lead and zinc, for both reedbed and raintank systems. Microbial counts and biological oxygen demand were analysed independently by the Australian Water Quality Centre.
The data have conclusively shown that the reedbed system has not only met SA Health Commission public health requirements, but achieved large percentage reductions in most water quality parameters of environmental concern. In contrast, recent examination by the SA Health Commission of other on-site treatment systems (aerobic treatment units and sub-surface sand filters) in the Adelaide Hills showed less than one third of the tested systems complied with the effluent quality requirements, with only five percent meeting all the requirements. Investigators in other Australian states and overseas have made similar findings. It would seem that there is significant room for improvement in small-system technology design and management. The knowledge and experience gained from the Intelligent Home reedbed project readily suggests this technology as a very promising alternative, one ideally suited for small 'cluster-dwelling' type developments in both urban 'broadacres' and rural un-sewered areas.
Intelligent home, Northfield
The initiative for this project came from the School of Building and Planning : its outcome is a “home of the 21st Century” which includes some 300 features which are innovative or, at least, “not normal”. Two of these are water-centred and involve, firstly, the rainwater supply to the hot water system and secondly, the “greywater” treatment/re-use system. Rainwater, collected in a 2 kL tank and pumped to the hot water “head-tank” in the roof of the dwelling, is heated to 65°C thereby destroying roof-originating bacteria and rendering the supply safe for potable use. The “greywater” treatment/re-use system passes effluent from the bath and shower to treatment in a gravel-based reed bed located in the backyard : treated water emerging from the bed is pumped to storage in the house where it is used for toilet flushing. The combination of the rainwater use and “greywater” treatment/re-use schemes are expected to decrease mains water use in the home by at least 30%.
Treatment and re-use of septic tank effluents
Urban Water Resources Group was approached at the end of 1994 by Mr. Leon Broster, CEO of the Murray-Darling Association, with funds to support a project involving on-site treatment and re-use of septic tank effluents generated in holiday home settlements along the River Murray. Simultaneously, a parallel interest was disclosed by Salisbury Council relating to its settlement at St. Kilda. These two initiatives have been joined and Mr. Martin Allen, M.Eng., appointed to explore ways and means to achieve on-site treatment/re-use of septic tank effluents in remote settlements in a Ph.D. study. The potential applications of a successful outcome of this study go far beyond the boundaries of South Australia. Use of septic tanks is the norm in communities in the greater part of South-East Asia and in the Middle East where present practices of effluent disposal are leading to serious problems of groundwater pollution. In many places the groundwater is the only “potable” water available.