Effect of pyrolysis conditions on bone char characterization and its ability for arsenic and fluoride removal
- Authors: Alkurdi, Susan , Al-Juboori, Raed , Bundschuh, Jochen , Bowtell, Les , McKnight, Stafford
- Date: 2020
- Type: Text , Journal article
- Relation: Environmental Pollution Vol. 262, no. (2020), p.
- Full Text: false
- Reviewed:
- Description: This study examined arsenite [As(III)], arsenate [As(V)] and fluoride (F−) removal potential of bone char produced from sheep (Ovis aries) bone waste. Pyrolysis conditions tested were in the 500 °C–900 °C range, for a holding time of 1 or 2 h, with or without N2 gas purging. Previous bone char studies mainly focused on either low or high temperature range with limited information provided on As(III) removal. This study aims to address these gaps and provide insights into the effect of pyrolysis conditions on bone char sorption capacity. A range of advanced chemical analyses were employed to track the change in bone char properties. As pyrolysis temperature and holding time increased, the resulting pH, surface charge, surface roughness, crystallinity, pore size and CEC all increased, accompanied by a decrease in the acidic functional groups and surface area. Pyrolysis temperature was a key parameter, showing improvement in the removal of both As(III) and As(V) as pyrolysis temperature was increased, while As(V) removal was higher than As(III) removal overall. F− removal displayed an inverse relationship with increasing pyrolysis temperature. Bone char prepared at 500 °C released significantly more dissolved organic carbon (DOC) then those prepared at a higher temperature. The bone protein is believed to be a major factor. The predominant removal mechanisms for As were surface complexation, precipitation and interaction with nitrogenous functional groups. Whereas F− removal was mainly influenced by interaction with oxygen functional groups and electrostatic interaction. This study recommends that the bone char pyrolysis temperature used for As and F− removal are 900 °C and 650 °C, respectively. © 2020 Elsevier Ltd
- Description: This research was performed as a part of PhD research which was supported in part by the Iraqi Government and the Australian Research Training Program.
Rotational traction testing : How can we improve the current test device?
- Authors: Twomey, Dara , Connell, Monique , Petrass, Lauren
- Date: 2014
- Type: Text , Conference paper
- Relation: 2014 10th Conference of the International Sports Engineering Association, ISEA 2014; Sheffield, United Kingdom; 14th-17th July 2014; published in Procedia Engineering, Vol. 72, p. 919-924
- Full Text:
- Reviewed:
- Description: Rotational resistance is an important sports surface property in optimising both performance and safety for participants. Despite various attempts to create valid devices to measure the rotational traction, the Studded Boot Apparatus (SBA) originally developed in 1975 is still used in the synthetic turf standards of many governing bodies of sport. In addition to validity limitations, poor operator reliability of the SBA has been reported and it was postulated that the manual nature of the device contributed significantly to this result. Therefore, the aim of this paper is to present data on the automation of the SBA and to discuss the reliability and validity issues of the device. An automated version of the SBA was developed called the UB Turf Tester (UBTT) and data was collected by ten inexperienced operators using the original SBA and the UBTT. Testing was undertaken on a synthetic turf and each operator completed ten trials with each device. Despite a slightly greater peak traction value for the UBTT, there was no significant difference between the peak traction for the two devices, F 1,2 = 0.341, p = 0.57. Greater reliability was found between operators for the UB Turf Tester. Given that the SBA is still commonly used to comply with standards, achieving the highest level of intra- and inter-operator reliability is both desirable and invaluable. However, the research on the validity of the device also needs to continue. Interestingly, limitations of the device were identified when it was first developed but very few adaptations have been implemented since then. Undoubtedly, the interaction between the human and the surface is a complex phenomenon but the weight force, the level of penetration, the pattern, shape and position of the cleats and the possibility of measuring rotational stiffness rather than peak traction all require further discussion and investigation.
Drying and denaturation characteristics of whey protein isolate in the presence of lactose and trehalose
- Authors: Haque, M. Amdadul , Chen, Jie , Aldred, Peter , Adhikari, Benu
- Date: 2015
- Type: Text , Journal article
- Relation: Food Chemistry Vol. 177, no. (2015), p. 8-16
- Full Text: false
- Reviewed:
- Description: The denaturation kinetics of whey protein isolate (WPI), in the presence and absence of lactose and trehalose, was quantified in a convective air-drying environment. Single droplets of WPI, WPI-lactose and WPI-trehalose were dried in conditioned air (2.5% RH, 0.5 m/s air velocity) at two temperatures (65°C and 80°C) for 500 s. The initial solid concentration of these solutions was 10% (w/v) in all the samples. Approximately 68% of WPI was denatured when it was dried in the absence of sugars. Addition of 20% trehalose prevented the irreversible denaturation of WPI at both temperatures. Thirty percent lactose was required to prevent denaturation of WPI at 65°C and the same amount of lactose protected only 70% of WPI from denaturation at 80°C. The secondary structures of WPI were found to be altered by the drying-induced stresses, even in the presence of 20% trehalose and 30% lactose.
Thiamin analysis in red wine by fluorescence reverse phase-HPLC
- Authors: Liddicoat, Callum , Hucker, Barry , Liang, Hao , Vriesekoop, Frank
- Date: 2015
- Type: Text , Journal article
- Relation: Food Chemistry Vol. 177, no. (2015), p. 325-329
- Full Text: false
- Reviewed:
- Description: The derivatization of thiamin vitamers to their respective thiochrome by ferricyanide to facilitate fluorescence detection following separation by HPLC provides a powerful analytical tool. However the polyphenolic compounds in red wine readily interact with ferricyanide, reducing the effectiveness of ferricyanide oxidation in the derivatization of thiamin. We describe a method to facilitate the removal of polyphenolic compounds that interfere with the ferricyanide derivatization of thiamin. Polyvinylpolypyrrolidone afforded the total removal of phenolic compounds from red wines and allowed a spike recovery of thiamin vitamers (101% for thiamin; 104% for TMP; and 100% for TDP) in a wide range of red wines. This research found that Merlot styles of red wine contained the highest concentration of total thiamin (29.01 ng/mL) while Pinot Noir wines contained the lowest total concentration (8.27 ng/mL).
Finite fracture mechanics analysis using the scaled boundary finite element method
- Authors: Sun, Zhicheng , Ooi, Ean Tat , Song, Chongmin
- Date: 2015
- Type: Text , Journal article
- Relation: Engineering Fracture Mechanics Vol. 134, no. (2015), p. 330-353
- Full Text: false
- Reviewed:
- Description: The polygon-based scaled boundary finite element method is applied to two finite fracture mechanics based failure criteria to predict the crack initiation from stress concentrations, i.e. notches and holes. The stress and displacement fields are modelled by the scaled boundary finite element method through semi-analytical expressions that resemble asymptotic expansions around cracks and notches. Important fracture parameters, i.e. energy release rate and stress, are accurately and conveniently computed from the solutions of stresses and displacements via analytical integration. One distinguished advantage of applying the scaled boundary finite element method to finite fracture mechanics is that the required changes in the mesh are easily accommodated by shifting the crack tip within the cracked polygon without changing the global mesh structure. The developed framework is validated using four numerical examples. The crack initiation predictions obtained from the scaled boundary finite element method agree well with the reference finite element results.
A convolutional recursive modified Self Organizing Map for handwritten digits recognition
- Authors: Mohebi, Ehsan , Bagirov, Adil
- Date: 2014
- Type: Text , Journal article
- Relation: Neural Networks Vol. 60, no. (2014), p. 104-118
- Relation: http://purl.org/au-research/grants/arc/DP140103213
- Full Text: false
- Reviewed:
- Description: It is well known that the handwritten digits recognition is a challenging problem. Different classification algorithms have been applied to solve it. Among them, the Self Organizing Maps (SOM) produced promising results. In this paper, first we introduce a Modified SOM for the vector quantization problem with improved initialization process and topology preservation. Then we develop a Convolutional Recursive Modified SOM and apply it to the problem of handwritten digits recognition. The computational results obtained using the well known MNIST dataset demonstrate the superiority of the proposed algorithm over the existing SOM-based algorithms.
In-vitro digestion of probiotic bacteria and omega-3 oil co-microencapsulated in whey protein isolate-gum Arabic complex coacervates
- Authors: Eratte, Divya , Dowling, Kim , Barrow, Colin , Adhikari, Benu
- Date: 2017
- Type: Text , Journal article
- Relation: Food Chemistry Vol. 227, no. (2017), p. 129-136
- Full Text: false
- Reviewed:
- Description: Solid co-microcapsules of omega-3 rich tuna oil and probiotic bacteria L. casei were produced using whey protein isolate-gum Arabic complex coacervate as wall material. The in-vitro digestibility of the co-microcapsules and microcapsules was studied in terms of survival of L. casei and release of oil in sequential exposure to simulated salivary, gastric and intestinal fluids. Co-microencapsulation significantly increased the survival and surface hydrophobicity and the ability of L. casei to adhere to the intestinal wall. No significant difference in the assimilative reduction of cholesterol was observed between the microencapsulated and co-microencapsulated L. casei. The pattern of release of oil from the microcapsules and co-microcapsules was similar. However, the content of total chemically intact omega-3 fatty acids was higher in the oil released from co-microcapsules than the oil released from microcapsules. The co-microencapsulation can deliver bacterial cells and omega-3 oil to human intestinal system with less impact on functional properties. © 2017 Elsevier Ltd
Effect of schwertmannite and jarosite on the formation of hypoxic blackwater during inundation of grass material
- Authors: Vithana, Chamindra , Sullivan, Leigh , Shepherd, Troy
- Date: 2017
- Type: Text , Journal article
- Relation: Water Research Vol. 124, no. (2017), p. 1-10
- Full Text: false
- Reviewed:
- Description: This study focused on understanding the effect of schwertmannite and jarosite, commonly found in floodplains containing acid sulfate soil materials, on the characteristics of the hypoxic blackwaters that can form when floodplain vegetation experiences prolonged inundation. The formation of these ‘blackwaters’ was simulated in the laboratory by inundating flood-intolerant pasture grass leaf material in both the presence of schwertmannite/jarosite (schwertmannite and jarosite treatments) minerals and their absence (control treatment) at 27.5 °C for 32 days. The presence of either schwertmannite or jarosite was able to decrease the concentrations of DOC, nutrients (e.g. NH3 and PO4 3−) and the biological oxygen demand (BOD) in the incubating water compared to the control treatment. Being fresh and labile, the pasture grass material liberated DOC immediately following inundation with a concomitant decrease in dissolved O2 thereby resulting in anoxic and reducing conditions in the incubating water. With the onset of anoxic and reducing conditions, the biogeochemical cycling of DOC in schwertmannite and jarosite treatments might have proceeded via microbially mediated iron(III) and sulfate reduction and electron shuttling processes. Under anoxic, slightly acidic conditions, microbially mediated iron(III) reduction and subsequent dissolution of schwertmannite and jarosite were triggered by liberating Fe2+, SO4 2− and alkalinity to the incubating water. The resultant increase in pH led to SO4 2− reduction in schwertmannite, and the Fe2+ catalysed transformation of both schwertmannite and jarosite to goethite. Schwertmannite almost completely transformed to goethite within two weeks of incubation. Iron(III) in goethite (formed from schwertmannie transformation) was also reduced and likely proceeded via direct microbial reduction or via electron shuttling using the humic acids in the incubating water derived from pasture grass. These findings are highly useful in managing the coastal low lying acid sulfate soils landscapes which are subject to frequent flooding during wet seasons. © 2017 Elsevier Ltd
Tidally driven water column hydro-geochemistry in a remediating acidic wetland
- Authors: Johnston, Scott , Keene, Annabelle , Bush, Richard , Sullivan, Leigh , Wong, Vanessa
- Date: 2011
- Type: Text , Journal article
- Relation: Journal of Hydrology Vol. 409, no. 1-2 (2011), p. 128-139
- Full Text: false
- Reviewed:
- Description: Managed tidal inundation is a newly evolved technique for remediating coastal acid sulphate soil (CASS) wetlands. However, there remains considerable uncertainty regarding the hydro-geochemical pathways and spatiotemporal dynamics of residual H+ and metal(loid) mobilisation into the tidal fringe surface waters of these uniquely iron-rich landscapes. Here, we examine the hydrology and water column chemistry across the intertidal slope of a remediating CASS wetland during several tide cycles. There was extreme spatial and temporal dynamism in water column chemistry, with pH fluctuating by ∼3 units (∼3.5-6.5) during a single tide cycle. Acute acidity was spatially confined to the upper intertidal slope, reflecting surface sediment properties, and tidal overtopping is an important pathway for mobilisation of residual H+ and Al3+ to the water column. Marine derived HCO3- was depleted from surface waters migrating across the intertidal slope and a strong gradient in HCO3- was observed from the tidal fringe to the adjacent tributary channel and nearby estuary. Tidal forcing generated oscillating hydraulic gradients in the shallow fringing aquifer, favouring ebb-tide seepage and driving rapid, heterogeneous advection of groundwater on the lower intertidal slope via surface connected macropores. A combination of diffusive and advective flux across the sediment-water interface led to persistent, elevated surface water Fe2+ (∼10-1000μM). The geochemical processes associated with Fe2+ mobilisation displayed distinct spatial zonation, with low pH, proton-promoted desorption occurring on the upper intertidal slope, whilst circum-neutral pH, Fe(III)-reducing processes dominated the lower intertidal slope. Arsenic was also mobilised into surface waters on the lower intertidal slope under moderate pH (∼6.0) conditions and was strongly positively correlated with Fe2+. Saturation index values for aragonite were substantially depressed (-1 to -5) and significantly negatively correlated with elevation, thereby presenting a barrier to re-colonisation of the upper intertidal slope by calcifying benthic organisms. These findings highlight the spatially complex hydrological and geochemical controls on surface water quality that can occur in tidally inundated acid sulphate soil environments. © 2011 Elsevier B.V.
Adaptation of quadtree meshes in the scaled boundary finite element method for crack propagation modelling
- Authors: Ooi, Ean Tat , Man, Hou , Natarajan, Sundararajan , Song, Chongmin
- Date: 2015
- Type: Text , Journal article
- Relation: Engineering Fracture Mechanics Vol. 144, no. (2015), p. 101-117
- Full Text:
- Reviewed:
- Description: A crack propagation modelling technique combining the scaled boundary finite element method and quadtree meshes is developed. This technique automatically satisfies the compatibility requirement between adjacent quadtree cells irrespective of the presence of hanging nodes. The quadtree structure facilitates efficient data storage and rapid computations. Only a single cell is required to accurately model the stress field near crack tips. Crack growth is modelled by splitting the cells in the mesh into two. The resulting polygons are directly modelled by the scaled boundary formulation with minimal changes to the mesh. Four numerical examples demonstrate the salient features of the technique. © 2015.
Reactive trace element enrichment in a highly modified, tidally inundated acid sulfate soil wetland : East Trinity, Australia
- Authors: Keene, Annabelle , Johnston, Scott , Bush, Richard , Burton, Edward , Sullivan, Leigh
- Date: 2010
- Type: Text , Journal article
- Relation: Marine Pollution Bulletin Vol. 60, no. 4 (2010), p. 620-626
- Full Text: false
- Reviewed:
- Description: This study examines the abundance of trace elements in surface sediments of a former acid sulfate soil (ASS) wetland subjected to marine tidal inundation. Sediment properties of this highly modified study site are compared with those of an adjacent unmodified, intertidal mangrove forest. Whilst some trace elements (Al, Cd, Mn, Ni and Zn) were clearly depleted due to mobilisation and leaching in the previous oxic-acidic phase, other trace elements (As and Cr) displayed significant enrichment in the tidally inundated ASS. Many trace elements were strongly associated with the reactive Fe and acid volatile sulfide (AVS) fractions, suggesting that trace elements may be adsorbed to abundant reactive Fe phases or sequestered as sulfide minerals. These findings provide an important understanding of the fate and mobility of reactive iron, AVS and trace elements during tidal remediation of a formerly acidified Great Barrier Reef (GBR) catchment. © 2010 Elsevier Ltd.
Monosulfidic black ooze accumulations in sediments of the Geographe Bay area, Western Australia
- Authors: Ward, Nicholas , Bush, Richard , Burton, Edward , Appleyard, Steve , Wong, Stephen , Sullivan, Leigh , Cheeseman, Paul
- Date: 2010
- Type: Text , Journal article
- Relation: Marine Pollution Bulletin Vol. 60, no. 11 (2010), p. 2130-2136
- Full Text: false
- Reviewed:
- Description: Mobilisation of sedimentary monosulfidic black ooze (MBO) may result in rapid deoxygenation and acidification of surface waters, and release of potentially toxic metals. This study examines the extent and nature of MBO accumulation in the Geographe Bay area, Western Australia. MBO accumulations were found to be widespread in benthic sediments of the Geographe Bay area with acid-volatile sulfide (AVS) contents as high as 320μmolg-1. The MBO materials often had unusually high dissolved sulfide (S-II) concentrations in their pore-waters (up to 610mgL-1) and elevated elemental sulfur (S0) contents (up to 51μmolg-1). Dissolved S-II is able to accumulate due to limited iron availability and S0 is largely its partial oxidation product. The availability of organic carbon and Fe limited MBO accumulation at many sites. A comparison of AVS and simultaneously extracted metal (SEM) concentrations has shown that metals are likely to be bound in sulfide complexes. © 2010 Elsevier Ltd.
Effects of prescribed fire and post-fire rainfall on mercury mobilization and subsequent contamination assessment in a legacy mine site in Victoria, Australia
- Authors: Abraham, Joji , Dowling, Kim , Florentine, Singarayer
- Date: 2018
- Type: Text , Journal article
- Relation: Chemosphere Vol. 190, no. (2018), p. 144-153
- Full Text: false
- Reviewed:
- Description: Prescribed fire conducted in fire-prone areas is a cost-effective choice for forest management, but it also affects many of the physicochemical and bio-geological properties of the forest soil, in a similar manner to wild fires. The aim of this study is to investigate the nature of the mercury mobilization after a prescribed fire and the subsequent temporal changes in concentration. A prescribed fire was conducted in a legacy mine site in Central Victoria, Australia, in late August 2015 and soil sample collection and analyses were carried out two days before and two days after the fire, followed by collection at the end of each season and after an intense rainfall event in September 2016. Results revealed the occurrence of mercury volatilization (8.3–97%) during the fire, and the mercury concentration displayed a significant difference (p < 0.05) before and immediately after the fire. Integrated assessment with number of pollution indices has shown that the study site is extremely contaminated with mercury during all the sampling events, and this poses a serious ecological risk due to the health impacts of mercury on human and ecosystems. In times of climate fluctuation with concomitant increase in forest fire (including prescribed fire), and subsequent precipitation and runoff, the potential for an increased amount of mercury being mobilized is of heighted significance. Therefore, it is recommended that prescribed fire should be cautiously considered as a forest management strategy in any mercury affected landscapes. © 2017 Elsevier Ltd
Annual ryegrass (Lolium rigidum Gaud) competition altered wheat grain quality : A study under elevated atmospheric CO2 levels and drought conditions
- Authors: Fernando, Nimesha , Florentine, Singarayer , Naiker, Mani , Panozzo, Joe , Chauhan, Bhagirath
- Date: 2019
- Type: Text , Journal article
- Relation: Food Chemistry Vol. 276, no. (2019), p. 285-290
- Full Text:
- Reviewed:
- Description: Annual ryegrass is one of the most serious, costly weeds of winter cropping systems in Australia. To determine whether its competition-mediated plant defence mechanisms effect on wheat grain quality, wheat (cv. Yitpi) and annual ryegrass were grown under two levels of CO2 (400 ppm; (a[CO2]) vs 700 ppm; (e[CO2]), two levels of water (well-watered vs drought) and two types of competition (wheat only; (W), and wheatxannual ryegrass; (W x R) with four replicates. The competitionx[CO2] interaction had a significant effect on wheat grain protein content, where it was increased in W x R under both e[CO2] (+ 17%) and a[CO2] (+ 21%). Grain yield, total grain reducing power and phenolic content were significantly affected by [CO2] x drought x competition. In a summary, annual ryegrass competition significantly altered the wheat grain quality under both [CO2] levels (depending on the soil water level), while also decreasing the grain yield.
Lost in optimisation of water distribution systems? A literature review of system operation
- Authors: Mala-Jetmarova, Helena , Sultanova, Nargiz , Savic, Dragan
- Date: 2017
- Type: Text , Journal article , Review
- Relation: Environmental Modelling and Software Vol. 93, no. (2017), p. 209-254
- Full Text:
- Reviewed:
- Description: Optimisation of the operation of water distribution systems has been an active research field for almost half a century. It has focused mainly on optimal pump operation to minimise pumping costs and optimal water quality management to ensure that standards at customer nodes are met. This paper provides a systematic review by bringing together over two hundred publications from the past three decades, which are relevant to operational optimisation of water distribution systems, particularly optimal pump operation, valve control and system operation for water quality purposes of both urban drinking and regional multiquality water distribution systems. Uniquely, it also contains substantial and thorough information for over one hundred publications in a tabular form, which lists optimisation models inclusive of objectives, constraints, decision variables, solution methodologies used and other details. Research challenges in terms of simulation models, optimisation model formulation, selection of optimisation method and postprocessing needs have also been identified. © 2017
Iron-sulfide and trace element behaviour in sediments of Coombabah Lake, southern Moreton Bay (Australia)
- Authors: Burton, Edward , Sullivan, Leigh , Bush, Richard , Powell, Bernard
- Date: 2008
- Type: Text , Journal article
- Relation: Marine Pollution Bulletin Vol. 56, no. 7 (2008), p. 1353-1358
- Full Text: false
- Reviewed:
- Description: Iron-sulfide minerals in benthic sediments may sequester potentially toxic trace elements that are introduced to estuaries from natural and anthropogenic sources (Chapman et al., 1998, Morse and Luther, 1999, Simpson et al., 2002 and Teasdale et al., 2003). Understanding iron-sulfide formation in benthic sediments is therefore central to assessing the risk posed by sedimentary trace elements (Machado et al., 2004, Burton et al., 2005a and Burton et al., 2006a). This report provides a baseline description of sedimentary iron-sulfide and trace element behaviour in Coombabah Lake – a sub-tropical estuarine lake in southern Moreton Bay, Australia (Fig. 1).
Comparison of multiple surrogates for 3D CFD model in tidal farm optimisation
- Authors: Moore, William , Mala-Jetmarova, Helena , Gebreslassie, Mulualem , Tabor, Gavin , Belmont, Michael , Savic, Dragan
- Date: 2016
- Type: Text , Conference proceedings
- Relation: 12th International Conference on Hydroinformatics - Smart Water for the Future, HIC 2016; Songdo Convensialncheon, South Korea; 21st-26th August 2016; published in Procedia Engineering Vol. 154, p. 1132-1139
- Full Text:
- Reviewed:
- Description: Marine currents have been identified as a considerable renewable energy source. Therefore, in recent years, research on optimising tidal stream farm layouts in order to maximise power output has emerged. Traditionally, computational fluid dynamics (CFD) models are used to model power output, but their computational cost is prohibitive within an optimisation algorithm. This paper uses surrogate models in place of CFD simulations to optimise the layout of tidal stream farm layouts. Surrogates are functions which are designed to emulate the behaviour of other models with radically reduced computational expense. Two surrogate models are applied and compared: artificial neural network (ANN) and k-nearest neighbours regression (k-NN). We measure their suitability by four criteria: accuracy, efficiency, robustness and performance within an optimisation algorithm. The results reveal that the ANN surrogate is superior in every criteria to the k-NN surrogate. However, the k-NN surrogate is also able to perform adequate optimisation. Finally, we demonstrate that optimisation relying solely on surrogate models is a viable approach, with dramatically reduced computational expense of optimisation. © 2016 The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY-NC-ND license.
- Description: Procedia Engineering
Assessment of potentially toxic metal contamination in the soils of a legacy mine site in Central Victoria, Australia
- Authors: Abraham, Joji , Dowling, Kim , Florentine, Singarayer
- Date: 2018
- Type: Text , Journal article
- Relation: Chemosphere Vol. 192, no. (2018), p. 122-132
- Full Text: false
- Reviewed:
- Description: The environmental impact of toxic metal contamination from legacy mining activities, many of which had operated and were closed prior to the enforcement of robust environmental legislation, is of growing concern to modern society. We have carried out analysis of As and potentially toxic metals (Cd, Co, Cr, Cu, Hg, Mn, Ni, Pb, and Zn) in the surface soil of a legacy gold mining site in Maldon, Victoria, Australia, to reveal the status of the current metal concentration. The results revealed the median concentrations of metals from highest to lowest, in the order: Mn > Zn > As > Cr > Cu > Pb > Ni > Co > Hg > Cd. The status of site was assessed directly by comparing the metal concentrations in the study area with known Australian and Victorian average top soil levels and the health investigation levels set by the National Environmental Protection Measures (NEPM) and the Department of Environment and Conservation (DEC) of the State of Western Australia. Although, median concentrations of As, Hg, Pb, Cu and Zn exceeded the average Australian and Victorian top soil concentrations, only As and Hg exceeded the ecological investigation levels (EIL) set by DEC and thus these metals are considered as risk to the human and aquatic ecosystems health due to their increase in concentration and toxicity. In an environment of climate fluctuation with increased storm events and forest fires may mobilize these toxic metals contaminants, pose a real threat to the environment and the community. © 2017 Elsevier Ltd
A review of practical tools for rapid monitoring of membrane bioreactors
- Authors: Scholes, Emily , Verheyen, Vincent , Brook-Carter, Phillip
- Date: 2016
- Type: Text , Journal article , Review
- Relation: Water Research Vol. 102, no. (2016), p. 252-262
- Full Text:
- Reviewed:
- Description: The production of high quality effluent from membrane bioreactors (MBRs) arguably requires less supervision than conventional activated sludge (CAS) processes. Nevertheless, the use of membranes brings additional issues of activated sludge filterability, cake layer formation and membrane fouling. From a practical standpoint, process engineers and operators require simple tools which offer timely information about the biological health and filterability of the mixed liquor as well as risks of membrane fouling. To this end, a range of analytical tools and biological assays are critically reviewed from this perspective. This review recommends that Capillary Suction Time (CST) analysis along with Total Suspended and Volatile Solids (TSS/VSS) analysis is used daily. For broad characterisation, total carbon and nitrogen analysis offer significant advantages over the commonly used chemical and biological oxygen demand (COD/BOD) analyses. Of the technologies for determining the vitality of the microbial biomass the most robust and reproducible, are the second generation adenosine-5'-triphosphate (ATP) test kits. Extracellular polymer concentrations are best monitored by measurement of turbidity after centrifugation. Taken collectively these tools can be used routinely to ensure timely intervention and smoother operation of MBR systems. © 2016 Elsevier Ltd.
A review of the scaled boundary finite element method for two-dimensional linear elastic fracture mechanics
- Authors: Song, Chongmin , Ooi, Ean Tat , Natarajan, Sundararajan
- Date: 2018
- Type: Text , Journal article , Review
- Relation: Engineering Fracture Mechanics Vol. 187, no. (2018), p. 45-73
- Full Text:
- Reviewed:
- Description: The development and the application of the scaled boundary finite element method for fracture analysis is reviewed. In this method, polygonal elements (referred to as subdomains) of arbitrary number of edges are constructed, with the only limitation that the whole boundary is directly visible from the scaling centre. The element solution is semi-analytical. When applied to two-dimensional linear fracture mechanics, any kinds of stress singularities are represented analytically without local refinement, special elements and enrichment functions. The flexibility of polygons to represent arbitrary geometric shapes leads to simple yet efficient remeshing algorithms to model crack propagation. Coupling procedures with the extended finite element method, meshless method and boundary element method to handle changes in the crack morphology have been established. These developments result in an efficient framework for fracture modelling. Examples of applications are provided to demonstrate their feasibility. © 2017 Elsevier Ltd