A streamlined sustainability assessment tool for improved decision making in the urban water industry

Abstract

Water supply is a key consideration in sustainable urban planning. Ideally, detailed quantitative sustainability assessments are undertaken during the planning stage to inform the decision-making process. In reality, however, the significant time and cost associated with undertaking such detailed environmental and economic assessments is often cited as a barrier to wider implementation of these key decision support tools, particularly for decisions made at the local or regional government level. In an attempt to overcome this barrier of complexity, 4 water service providers in Melbourne, Australia, funded the development of a publicly available streamlined Environmental Sustainability Assessment Tool, which is aimed at a wide range of decision makers to assist them in broadening the type and number of water servicing options that can be considered for greenfield or backlog developments. The Environmental Sustainability Assessment Tool consists of a simple user interface and draws on life cycle inventory data to allow for rapid estimation of the environmental and economic performance of different water servicing scenarios. Scenario options can then be further prioritized by means of an interactive multicriteria analysis. The intent of this article is to identify the key issues to be considered in a streamlined sustainability assessment tool for the urban water industry, and to demonstrate the feasibility of generating accurate life cycle assessments and life cycle costings, using such a tool. We use a real-life case study example consisting of 3 separate scenarios for a planned urban development to show that this kind of tool can emulate life cycle assessments and life cycle costings outcomes obtained through more detailed studies. This simplified approach is aimed at supporting "sustainability thinking" early in the decision-making process, thereby encouraging more sustainable water and sewerage infrastructure solutions.

Comparing the Life Cycle Energy Consumption, Global Warming and Eutrophication Potentials of Several Water and Waste Service Options

“…Compared with municipal centralized water treatment/distribution, or onsite greywater treatment/distribution, on-site rainwater collection/treatment was the most carbon-intensive option for supplying shower water for households due to the energy-intensive characteristics of both pump operation and UV disinfection for rainwater (Figure 3). Previous studies in Australia and the United Kingdom reported that the carbon intensity of rainwater treatment ranges from 0.03 to 0.07 kg CO 2¨L´1 treated rainwater, consistent with our results [50][51][52]. In addition, the relative GWP contributions of infrastructure components to each stage in the water cycle are presented in Figure S2, showing that the infrastructure components account for less than 5% of the total GWP.…”

“…Small-scale medium-pressure UV lamps were assumed for greywater disinfection, operating at 0.02-0.08 mJ¨m´2 at 35% of UV light efficiency to reach the water quality requirement for toilet flushing [48,49]. The additional energy required for pumping treated greywater to its destination was estimated based on the flow rate, water pressure, pump and motor efficiencies [50] described in Table S6.…”

“…The on-site rain water treatment processes include in-line filtration (nominal 20 µm household water filter), household UV disinfection, and pressure distribution of treated rainwater to the hot water heater system. The energy consumption for infiltration and disinfection processes was calculated based on manufacturing and pilot testing datasets [50,51]. In addition, the energy consumption for redistributing the treated rainwater was estimated according to the pump performance curve of a Grundfos CH2 pump, as adopted for multiple Australian on-site rainwater treatment systems [50,51] (Table S7).…”

Assessment of Sustainability of Urban Water Supply and Demand Management Options: A Comprehensive Approach

“…The trend is accompanied by the increased complexity of urban water systems and the dynamic interactions which increase the uncertainty of water management decisions. Often these evaluations are supported by methods such as multi-criteria analysis [13,[15][16][17][18], cost-benefit analysis [18,19], life cycle assessment [20][21][22][23][24], and optimisation techniques [17,[24][25][26]. While few studies compare water supply options using available data [27], the majority of studies model the entirety of the urban water cycle to estimate impacts of different water supply options on other components of the system [14,25,28,29].…”

“…River and waterbody health Quality of waste water produced and their impacts (contribution to acidification and eutrophication, effects on flora and fauna) [13][14][15][17][18][19][20][21][22][23]28,29,39] Quantity of wastewater produced [15,22,25,29,40] Stormwater runoff [15,25,29] Maintain river, local creaks, and wetlands Effect on environmental flow and surface water [14,18,25,40] Freshwater/portable water saved [13,15,17,24] Effects on groundwater level and pattern (ground water infiltration, recharge, and depletion) [14,19,24,39,41] Protect land ecosystem…”