Australian examples of residential integrated water cycle planning: accepted current practice and a suggested alternative

Australian examples of Integrated Water Cycle Planning (IWCP) for residential development demonstrate that providing multiple household-water connections is a generally accepted practice. These connections typically include a potable mains supply, a separate non-potable supply utilising reclaimed water and/or a household roofwater tank for non-potable uses. Stormwater is not fully exploited as a potential urban water source. The advent of national guidelines for using recycled water for drinking purposes is expected to simplify IWCP towards a single-line household-water supply reclaimed from a range of different sources. An IWCP approach is suggested in this paper based on a single household supply complemented by: 1) potential separation of blackwater to reduce human health risk and to enhance community acceptance of recycled water, 2) the use of water sensitive urban design requirements of storing and slowly releasing urban stormwater, and 3) taking advantage of economies of scale by integrating communal roofwater tanks into the urban stormwater system

Presumptions of linearity and faith in the power of centralised decision-making: two challenges to the efficient management of environmental water in Australia

Water policy in the Murray-Darling Basin continues to be dominated by the trade-offs between agricultural and environmental interests. This has recently been played out with the acrimonious debate that circumscribed the release of the Guide to the Murray-Darling Basin Plan. In this paper, we argue that too much emphasis has been placed on the volume of held water as an indicator of environmental benefit. We also contend that there is an attendant presumption of linearity in the relationship between volumes of held water and environmental benefit which could lead to perverse outcomes. A second problem is that there is too much enthusiasm for contemplating the solutions to water management problems as residing primarily at the federal level of government. These factors stand to ultimately limit the efficient delivery of environmental objectives

Developing a water accounting framework for the Australian minerals industry

The development of a water accounting framework that enables consistent and contextual reporting of minerals operations' water use, represents a key sustainable development objective that many Australian minerals companies have committed to. A future water accounting framework will require: • key terms and definitions for water metrics for use in the Australian minerals industry that are consistent with the wider water sector, • a suite of metrics representing key components of an operation's water balance, • a calculation method for some of the metrics, and • a reporting protocol. This paper presents the methodology that was used to derive these four components. Existing accounting frameworks were reviewed and key terms and definitions that were consistent with current regulatory requirements and voluntary approaches were proposed. A calculation methodology was developed to obtain some of the key indicators and variables that cannot be easily measured directly (eg water loss through evaporation). The adopted terms and definitions typically require a combination of empirical and estimated data. To test the proposed definitions and calculation methodology, values for water metrics were derived for eight sites, selected to test a variety of commodity and biophysical situations. The proposed framework and definitions could deal with the specific situations selected as case studies. The associated calculation methodology produced complete accounts at various levels. Some elements of the accounts could be directly checked against available data and simulations. The framework captured well variations in the reuse efficiencies; reuse efficiency could even vary for similar processes. It is concluded that this preliminary accounting framework provides a consistent language and metrics for quantifying and communicating water management, both at the intersection of the site with the surrounding landscape (through detailed reporting of site inputs and outputs) and within operational activities. Using this consistent framework for quantifying and documenting water use within an operation will provide a platform for compiling and comparing minerals industry water use with other sectors. This may support benchmarking activities within regions or companies and help demonstrate leadership amongst water users in water resource stewardship. The approach presented here is applicable to a wide variety of mining and processing activities, and biophysical environments, and following a period of stakeholder engagement and third party review, is being refined as a first step towards developing nationally consistent water use reporting for the Australian minerals industry. © 2010 Australasian Institute of Mining and Metallurgy

Two-phase numerical study of the flow field formed in water pump sump: influence of air entrainment

In a pump sump it is imperative that the amount of non-homogenous flow and entrained air be kept to a minimum. Free air-core vortex occurring at a water-intake pipe is an important problem encountered in hydraulic engineering. These vortices reduce pump performances, may have large effects on the operating conditions and lead to increase plant operating costs.This work is an extended study starting from 2006 in LML and published by ISSA and al. in 2008, 2009 and 2010. Several cases of sump configuration have been numerically investigated using two specific commercial codes and based on the initial geometry proposed by Constantinescu and Patel. Fluent and Star CCM+ codes are used in the previous studies. The results, obtained with a structured mesh, were strongly dependant on main geometrical sump configuration such as the suction pipe position, the submergence of the suction pipe on one hand and the turbulence model on the other hand. Part of the results showed a good agreement with experimental investigations already published. Experiments, conducted in order to select best positions of the suction pipe of a water-intake sump, gave qualitative results concerning flow disturbances in the pump-intake related to sump geometries and position of the pump intake. The purpose of this paper is to reproduce the flow pattern of experiments and to confirm the geometrical parameter that influences the flow structure in such a pump. The numerical model solves the Reynolds averaged Navier-Stokes (RANS) equations and VOF multiphase model. STAR CCM+ with an adapted mesh configuration using hexahedral mesh with prism layer near walls was used. Attempts have been made to calculate two phase unsteady flow for stronger mass flow rates and stronger submergence with low water level in order to be able to capture air entrainment. The results allow the knowledge of some limits of numerical models, of mass flow rates and of submergences for air entrainment. In the validation of this numerical model, emphasis was placed on the prediction of the number, location, size and strength of the various types of vortices coming from the free surface. Contours of vorticity at free surface, air cores, isoline of pressure surface were particularly examined for some cases. Streamlines issued from the free surface and the volume of fraction of air allows visualizing the air entrainment