Development of decentralized systems in Australia

In recent years, several buildings have been constructed in Switzerland based on decentralized concepts of fully or partly self-sufficient energy and water managment. These forst attempts covered rainwater and snowmelt harvesting, reuse of greywater, brownwater and blackwater, urine separation and recovery of nutrients from urine. They demostrate that in-house technology is now ready to accommodate dramatic changes in urban water cycles to acheive higher levels of environmental sustainabilty. As a rule, the technologies tested in six key buildings usually performed successfully and could be operated satisfactorily over long periods. Some conditions neccessary for constructing such systems and possible reasons for project failures are discussed

A desktop analysis of potable water savings from internally plumbed rainwater tanks in South-East Queensland, Australia

A methodology for the estimation of household potable water saving due to internally plumbed rainwater tanks (IPT) is presented in this paper. The methodology is based on a pairwise comparison of household water billing data between homes with IPT and without rainwater tanks (No Tank). These savings were compared with estimations using measured end use data and rainwater demand predictions using the Rainwater TANK model. The paper describes the application of this methodology to a case study in the south-east Queensland (SEQ) region of Australia. There was a significant reduction in mains water consumption for IPT properties in all regions studied in SEQ. Water reductions from mains supplies varied markedly across regions with mean values ranging from 20 to 95 kL/hh/y with an average mean of 50 kL/hh/y. Median water consumption values, ranged in mains water reductions from 28 to 52 kL/hh/y, with an average median of 40 kL/hh/y. Considering both measures an average water saving between 40 and 50 kL/hh/y can be expected from internally plumbed rainwater tanks. Water restrictions appear to have a strong influence on estimated reductions in mains water use. In regions where water restrictions were severe, water consumption was less varied between No Tank and IPT homes with a consequent reduction in estimated savings observed. Recommendations for further work include a survey to capture confounding factors that could not be fully controlled in the desktop study and a controlled pairwise experiment to monitor water consumption from raintanks

How supply system design can reduce the energy footprint of rainwater supply in urban areas in Australia

In Australia rainwater tanks are used in cities to reduce demand of mains water and increase the resilience of cities to drought. Rainwater is collected in a tank and supplied to a dwelling through a small pump. Typically the energy footprint for rainwater supply (in kWh/kL) is higher than for centralised water supply, but it can also vary markedly from dwelling to dwelling. This study aimed to understand how the design of the rainwater supply system from the collection tank to the household can reduce the energy consumption of pumping. Therefore we examined the operation of a range of system components for rainwater supply, such as pumps, switches and pressure vessels, in a controlled residential environment (a model house) to understand their impact on the energy footprint for rainwater supply in urban dwellings. Results show the impact of end uses, pump size and switches on the effectiveness of pressure vessels in reducing the energy footprint for rainwater supply

Phosphorus as a limiting factor on sustainable greywater irrigation

Water reuse through greywater irrigation has been adopted worldwide and has been proposed as a potentialsustainable solution to increasedwater demands. Despite widespread adoption, there is limited domestic knowledgeof greywater reuse. There is no pressure to produce low-level phosphorus products and current guidelinesand legislation, such as those in Australia,may be inadequate due to the lack of long-termdata to provide a soundscientific basis. Research has clearly identified phosphorus as a potential environmental risk to waterways frommany forms of irrigation. To assess the sustainability of greywater irrigation, this study compared four residentiallots that had been irrigated with greywater for four years and adjacent non-irrigated lots that acted as controls.Each lot was monitored for the volume of greywater applied and selected physic-chemicalwater quality parametersand soil chemistry profiles were analysed. The non-irrigated soil profiles showed low levels of phosphorusand were used as controls. The Mechlich3 Phosphorus ratio (M3PSR) and Phosphate Environmental Risk Index(PERI) were used to determine the environmental risk of phosphorus leaching from the irrigated soils. Soilphosphorus concentrations were compared to theoretical greywater irrigation loadings. The measured phosphorussoil concentrations and the estimated greywater loadings were of similar magnitude. Sustainable greywaterreuse is possible; however incorrect use and/or lack of understanding of howhousehold products affect greywatercan result in phosphorus posing a significant risk to the environment

Corrigendum to “Export of acidity in drainage water from acid sulphate soils” [Mar. Pollut. Bull. 41 (7–12) (2000) 319–326]

The authors regret .The authors would like to apologise for any inconvenience caused

Novel pre-treatment of zeolite materials for the removal of sodium ions: Potential materials for coal seam gas co-produced wastewater

Coal seam gas (CSG) is the extraction of methane gas that is desorbed from the coal seam and brought to the surface using a dewatering and depressurisation process within the saturated coalbed. The extracted water is often referred to as co-produced CSG water. In this study, co-produced water from the coal seam of the Bowen Basin (QLD, Australia) was characterised by high concentration levels of Na+ (1156 mg/L), low concentrations of Ca2+ (28.3 mg/L) and Mg2+ (5.6 mg/L), high levels of salinity, which are expected to cause various environmental problems if released to land or waters. The potential treatment of co-produced water using locally sourced natural ion exchange (zeolite) material was assessed. The zeolite material was characterized for elemental composition and crystal structure. Natural, untreated zeolite demonstrated a capacity to adsorb Na+ ions of 16.16 mEq/100 g, while a treated zeolite using NH4 + using a 1.0 M ammonium acetate (NH4C2H3O2) solution demonstrated an improved 136 % Na+ capacity value of 38.28 mEq/100 g after 720 min of adsorption time. The theoretical exchange capacity of the natural zeolite was found to be 154 mEq/100 g. Reaction kinetics and diffusion models were used to determine the kinetic and diffusion parameters. Treated zeolite using a NH4 + pre-treatment represents an effective treatment to reduce Na+ concentration in coal seam gas co-produced waters, supported by the measured and modelled kinetic rates and capacity

Can stormwater harvesting restore pre-development flows in urban catchments in South East Queensland?

Increases in the impervious area due to urbanisation have been shown to have negative impacts on the physical and ecological condition of streams, primarily through increased volume and frequency of runoff. The harvesting and detention of runoff has a potential to decrease this impact. This paper describes the effects of urbanisation on catchment flow and of stormwater harvesting on reducing those adverse impacts on a stream in South East Queensland (SEQ), Australia. A largely undeveloped catchment located southeast of Brisbane city was calibrated and validated using the Stormwater Management Model (SWMM). This model was used to investigate the effect of a range of future increases in urbanisation (represented by impervious area) on stream hydrology as well as the potential of stormwater harvesting to return the catchments to predevelopment flow conditions. Stormwater harvesting was modelled according to flow frequency measures specified in current SEQ development guidelines. These guidelines stipulate the capture of the first 10 mm of runoff from impervious areas of 0–40% and the first 15 mm from impervious areas of 40% or greater for urban developments. We found that increases in the impervious area resulted in increases in the mean, frequency and duration of high flows, and an increase in the mean rate of rise and fall for storm events in the catchment. However, the predevelopment (non-urbanised) flow distribution was very flashy in comparison with all urbanised scenarios; i.e. it had the quickest response to rainfall indicated by a high rate of rise to and fall from peak flow volume, followed by a return to zero flow conditions. Capturing the runoff according to the development guidelines resulted in a reduction in flow towards the flow distribution of a lower impervious area, however this was insufficient to meet predevelopment conditions. This suggests a stronger influence of impervious areas in this catchment on the volume of runoff than flow frequency measures are able to ameliorate