Craig A. Styan

Sperm Accumulated Against Surface: A novel alternative bioassay for environmental monitoring.

Forecasting the impacts of changes in water quality on broadcast spawning aquatic organisms is a key aspect of environmental monitoring. Rapid assays of reproductive potential are central to this monitoring, and there is a need to develop a variety of methods to identify responses. Here, we report a proof-of-concept study that assesses whether quantification of Sperm Accumulated Against Surface (SAAS) of tissue culture well-plates could be a rapid and simple proxy measure of fertilisation success. Our results confirm that motile sperm (but not immotile sperm) actively accumulate at surfaces and that the pattern of accumulation reflects fertilisation success in the model oyster species Crassostrea gigas. Furthermore, we confirm these patterns of SAAS for another marine species, the polychaete Galeolaria caespitosa, as well as for a freshwater species, the fish Gasterosteus aculeatus. For all species considered, SAAS reflected changes in sperm performance caused by experimentally manipulated differences in water quality (here, salinity). These findings indicate that SAAS could be applied easily to a range of species when examining the effects of water quality. Measurement of SAAS could, therefore, form the basis of a rapid and reliable assay for bioassessments of broadcast spawning aquatic organisms.

Optimal design of water treatment processes

Predicted water shortages assign water treatment a leading role in improving water resources management. One of the main challenges associated with the processes remains early stage design of techno-economically optimised purification. This work addresses the current gap by undertaking a whole-system approach of flowsheet synthesis for the production of water at desired purity at minimum overall cost. The optimisation problem was formulated as a mixed-integer non-linear programming model. Two case studies were presented which incorporated the most common commercial technologies and the major pollution indicators, such as chemical oxygen demand, dissolved organic carbon, total suspended solids and total dissolved solids. The results were analysed and compared to existing guidelines in order to examine the applicability of the proposed approach.

Low sensitivity of reproductive life-stages in the Pacific oyster (Crassostrea gigas) to abamectin

Hard surfaces submerged in the marine environment often become colonised by macro-organisms unless the surfaces have some form of biofouling protection. While protective paints that contain tributyltin or copper work well to prevent biofouling, release of these materials into the environment has been shown to have wider negative impacts. Consequently, new low-release antifouling paints are being developed with alternative active ingredients, such as avermectins, yet little is known about their potential effects on non-target organisms in marine environments. Here we investigated the toxicity of a key avermectin, specifically abamectin, on several aspects of reproduction (sperm motility, fertilisation success, early larval development) in the Pacific oyster, Crassostrea gigas. Oyster reproduction was generally insensitive to the low concentrations of abamectin, although greater concentrations of abamectin did negatively affect all three endpoints - LOECs were 1000xa0μgxa0l-1, 500xa0μgxa0l-1, and 100xa0μgxa0l-1 abamectin for sperm motility, fertilisation success, and larval development, respectively. A similar pattern was found in the EC50s of the three endpoints (meanxa0±xa0SE) 934xa0±xa059xa0μgxa0l-1, 1076.26xa0±xa0725.61xa0μgxa0l-1, and 140xa0±xa078xa0μgxa0l-1 abamectin (sperm motility, fertilisation success, and larval development, respectively). Together, these results clearly indicate that of the three endpoints considered, larval development was more sensitive to abamectin (lower LOEC, EC50) than fertilisation success and sperm motility. Although more data are needed from a wider range of marine species and environments to fully assess potential toxicity effects on non-target organisms, our results highlight the potential utility of abamectin in low-release antifouling paints.

Synthesis of Water Treatment Processes using Mixed Integer Programming

Abstract With exerting pressures on water systems, efforts have recently been focused on optimisation of existing, and design of new treatment facilities. Modelling, specifically, offers the advantage of early stage processes synthesis at minimum design change expenses. Current research and industry gaps lie in overall construction of water treatment flowsheets by crossing various disciplines. In the current work a systematic approach for the synthesis of water treatment processes is proposed. The design combines technological robustness, improved economic performance and environmental reliability. The problem is formulated as a mixed integer non-linear programming (MINLP) model. A case study of seawater desalination is presented where conventional and non-conventional treatment technologies are considered. The flowsheet structure is selected based on units separation and recovery efficiencies, operating and capital costs, and carbon footprint. The model is solved for desired water purity to meet drinking water standards with the objective to minimise water production costs. The results are analysed to investigate the applicability of the presented approach. The developed methodology can have a significant impact on reducing the design time and simultaneously, increasing the cost effectiveness of water treatment processes.

Social media use in the Australian energy and resources sectors

Social media is becoming ubiquitous, but may not always be an effective way for companies to interact with their stakeholders. This paper reports the results of ongoing assessments of social media use in the Australian energy and resource sectors, starting from 2013. Nearly all energy and mining companies had publicly accessible websites but, although increasing, social media use is (still) relatively limited compared with other industries. LinkedIn (with a recruitment focus) was the social media channel most commonly adopted across the extractive sectors, although Twitter and YouTube are increasingly being adopted. Larger companies use more channels, post more and have more followers. In contrast, even small environmental and community groups frequently used a range of social media. Although this may suggest social media should be a place to engage such groups in dialogue, other recent studies suggest that, in practice, social media platforms are often difficult venues to do this, not least because companies cannot control the directions of conversations. For example, customers of utility companies frequently use social media to bypass official grievance mechanisms, which, over time, has apparently led to demand-driven increases in resourcing needed to deal with this. In addition to providing an industry-wide benchmark of social media use, these surveys provide a basis for comparison with other industries to understand what role social media could have in better engaging stakeholders associated with the extractive sectors.

Integration of environmental aspects in modelling and optimisation of water supply chains

Climate change becomes increasingly more relevant in the context of water systems planning. Tools are necessary to provide the most economic investment option considering the reliability of the infrastructure from technical and environmental perspectives. Accordingly, in this work, an optimisation approach, formulated as a spatially-explicit multi-period Mixed Integer Linear Programming (MILP) model, is proposed for the design of water supply chains at regional and national scales. The optimisation framework encompasses decisions such as installation of new purification plants, capacity expansion, and raw water trading schemes. The objective is to minimise the total cost incurring from capital and operating expenditures. Assessment of available resources for withdrawal is performed based on hydrological balances, governmental rules and sustainable limits. In the light of the increasing importance of reliability of water supply, a second objective, seeking to maximise the reliability of the supply chains, is introduced. The epsilon-constraint method is used as a solution procedure for the multi-objective formulation. Nash bargaining approach is applied to investigate the fair trade-offs between the two objectives and find the Pareto optimality. The models capability is addressed through a case study based on Australia. The impact of variability in key input parameters is tackled through the implementation of a rigorous global sensitivity analysis (GSA). The findings suggest that variations in water demand can be more disruptive for the water supply chain than scenarios in which rainfalls are reduced. The frameworks can facilitate governmental multi-aspect decision making processes for the adequate and strategic investments of regional water supply infrastructure.

Multi-objective Optimisation Approach for the Synthesis of Water Treatment Plants

More efficient water treatment plants are needed if future global water requirements are going to be met. Plant design, however, is complicated by the need to optimise separate but linked treatment processes, with individual process optima not necessarily leading to the most efficient overall systems. In this work, a superstructure optimisation-based methodology for flowsheet synthesis is proposed. The problem is formulated as a mixed integer non-linear programming (MINLP) model. The superstructure encompasses the most commonly used technologies (coagulation-flocculation, sedimentation, dissolved air flotation, media filtration, microfiltration, ultrafiltration, nanofiltration, reverse osmosis) in water treatment, advanced wastewater treatment and desalination, which enables the design of fit-for-purpose treatment. Physico-chemical characteristics (e.g. pressure, temperature, hydrophobicity, mixing gradient, etc.) of the candidates allow the prediction of their technical and economic performance. The model identifies the optimum configuration of passes and stages in the flow diagram and capital costs estimation. A multi-objective optimisation is performed for the minimisation of water net cost and minimisation of contaminants concentrations using e − constraint method. The applicability of the model is verified through a theoretical case study. The computational results fall into the lower margin of water purification facilities worldwide and indicate the effectiveness and efficiency of the developed approach.