Analysis of ASR Clogging Investigations at Three Australian ASR Sites in a Bayesian Context

When evaluating uncertainties in developing an aquifer storage and recovery (ASR) system, under normal budgetary constraints, a systematic approach is needed to prioritise investigations. Three case studies where field trials have been undertaken, and clogging evaluated, reveal the changing perceptions of viability of ASR from a clogging perspective as a result of the progress of investigations. Two stormwater and one recycled water ASR investigations in siliceous aquifers are described that involved different strategies to evaluate the potential for clogging. This paper reviews these sites, as well as earlier case studies and information relating water quality, to clogging in column studies. Two novel theoretical concepts are introduced in the paper. Bayesian analysis is applied to demonstrate the increase in expected net benefit in developing a new ASR operation by undertaking clogging experiments (that have an assumed known reliability for predicting viability) for the injectant treatment options and aquifer material from the site. Results for an example situation demonstrate benefit cost ratios of experiments ranging from 1.5 to 6 and apply if decisions are based on experimental results whether success or failure are predicted. Additionally, a theoretical assessment of clogging rates characterised as acute and chronic is given, to explore their combined impact, for two operating parameters that define the onset of purging for recovery of reversible clogging and the onset of occasional advanced bore rehabilitation to address recovery of chronic clogging. These allow the assessment of net recharge and the proportion of water purged or redeveloped. Both analyses could inform economic decisions and help motivate an improved investigation methodology. It is expected that aquifer heterogeneity will result in differing injection rates among wells, so operational experience will ultimately be valuable in differentiating clogging behaviour under different aquifer conditions for the same water type. This paper was originally presented at ISMAR9, Mexico City 20–24 June 2016

Chemical synthesis and characterization of nano alumina, nano composite of carbon-alumina and their comparative studies

Aluminium oxide (Al2O3) nano particles were synthesized by using both the sol gel technique and solid state reaction (SSR) method. Different proportion of nano carbon cones from 0.5% to 3.5% is doped with aluminium nitrate nano hydrate and annealed subsequently at 1000°C for 3 h to synthesize the nano composite of carbon-alumina. The synthesized samples were characterized by X-ray diffraction to identify the presence of different phases and transitions during this process. The average crystallite size of the nano alumina is found to be 45 nm by sol gel and 43 nm by SSR method respectively by Debye-Scherrer method. Average crystallite size and lattice strain of nano alumina are also estimated from Williamson Hall (WH) plot analysis. It is found to be 69 nm with the strain of 3.3×10-3 in sol gel, and in SSR method, it is 72 nm with the strain is 3.9×10-3. The interplanar distance of various planes of alumina are estimated and compared with JCPDS values. Similar analysis has also been extended for the nano composite of carbon-alumina. The surface morphology of the samples are analyzed using scanning electron microscopy and rough estimate of the crystallites is also given. From the Raman analysis, the presence of alpha phase of alumina has been confirmed. The presence of carbon in the composite has been established through diffuse reflectance spectroscopy. The FTIR spectra of the composite samples ensured the presence of Al-O-Al, O-H and C=O bonds

Vision and perception of community on the use of recycled water for household laundry: A case study in Australia

ABSTRACT This study investigates the community perception of household laundry as a new end use of recycled water in three different locations of Australia through a face to face questionnaire survey (n = 478). The study areas were selected based on three categories of (1) non-user, (2) perspective user and (3) current user of recycled water. The survey results indicate that significantly higher number (70%) of the respondents supported the use of recycled water for washing machines (χ 2 = 527.40, df = 3; p = 0.000). Significant positive correlation between the overall support for the new end use and the willingness of the respondents to use recycled water for washing machine was observed among all users groups (r = 0.43, p = 0.000). However, they had major concerns regarding the effects of recycled water on the aesthetic appearance of cloth, cloth durability, machine durability, odour of the recycled water and cost along with the health issues. The perspective user group had comparatively more reservations and concerns about the effects of recycled water on washing machines than the non-users and the current users (χ 2 = 52.73, df = 6; p = 0.000). Overall, community from all three study areas are willing to welcome this new end use as long as all their major concerns are addressed and safety is assured