A review of strategies for RO brine minimization in inland desalination plants

Water scarcity in many inland areas is increasing the demand for new groundwater desalination plants. Co-produced coal seam gas (CSG) water (or coal bed methane as known in the USA), which is mostly brackish, is extracted in huge quantities during CSG production and requires advanced treatment. Reverse osmosis (RO) is the leading technology applied in municipal desalination and for treating CSG water in Australia and in some locations in the USA. Antiscalants are often dosed during RO pretreatment to prevent membrane scaling. Recovery rates are limited by antiscalant efficacy and large volumes of brine are frequently disposed of in evaporation ponds. The search for environmentally friendly methods for RO brine minimization is considered as a key global issue. In this paper, differences between inland and seawater desalination are highlighted. The existing technologies for RO brine minimization and zero liquid discharge (ZLD) for inland desalination are reviewed. The efficacy and application of two scaling reduction technologies for RO brine minimization: (i) acid/antiscalant addition and (ii) ‘high pH precipitation treatment’ are compared. Finally, more complex ZLD and volume reduction systems, such as the high efficiency RO (HERO™) and the SAL-PROC™, are analyzed as well

Editorial: Special issue on the challenges in environmental science and engineering: CESE-2012 9-13 September 2012, RACV City Club, Melbourne, Australia

This special issue carries selected peer-reviewed manuscripts based on the presentations made at CESE-2012, the Fifth Annual International Conference on Challenges in Environmental Science & Engineering , CESE Conference Series that was held from the 9th to the 13th of September 2012 at the RACV City Club in Melbourne, Australia

Evaporation, seepage and water quality management in storage dams: a review of research methods

One of the most significant sources of water wastage in Australia is loss from small storage dams, either by seepage or evaporation. Over much of Australia, evaporative demand routinely exceeds precipitation. This paper outlines first, methodologies and measurement techniques to quantify the rate of evaporative loss from fresh water storages. These encompass high-accuracy water balance monitoring; determination of the validity of alternative estimation equations, in particular the FAO56 Penman- Monteith ETo methodology; and the commencement of CFD modeling to determine a 'dam factor' in relation to practical atmospheric measurement techniques. Second, because the application of chemical monolayers is the only feasible alternative to the high cost of physically covering the storages to retard evaporation, the use of cetyl alcohol-based monolayers is reviewed, and preliminary research on their degradation by photolytic action, by wind break-up and by microbial degradation reported. Similarly, preliminary research on monolayer visualisation techniques for field application is reported; and potential enhancement of monolayers by other chemicals and attendant water quality issues are considered

Effectiveness of self-assessment quizzes as a learning tool

To enhance the students' learning experience, self-assessment formative quizzes are being incorporated into the curriculum by several lecturers. With the technological developments in webbased delivery, online quizzes may be an effective learning tool, especially when courses are offered via external mode of study. Among the several advantages of providing online quizzes, the most attractive feature is providing the correct answer and appropriate feedback immediately after students attempt a quiz. This paper evaluates the overall performance of students in two engineering courses where self-assessment quizzes were made available through the e-learning system. As formative assessment, it was noted that the frequent attempts by students tend to cluster near the final examination period, however, a few students attempted them as soon as they were released. The results showed there is a strong correlation between students who attempt the quizzes and their overall student performance assessed by final grades. This paper will further discuss the important aspects that need to be considered when developing well formulated quizzes for technical courses and thereby maximising their potential as an effective learning tool

Designing an ideal assessment scheme for dual mode delivery

Designing assessment schemes for higher level technical undergraduate courses in engineering is a challenge nowadays, especially in a changing educational environment. With more emphasis being placed on flexible learning modes and flexible assessment schemes, examiners are confronted with the review of the existing assessment schemes for the courses they teach. Traditionally, having a combination of assignments and examination has been the most popular method of assessments designed by course examiners. While different assessments give students a variety of opportunities to demonstrate their understanding of a subject, it is important to have a well-formulated assessment scheme to evaluate the students’ knowledge. When such courses are delivered for both on-campus and external students, achieving the correct balance between various assessment schemes is important while maintaining the quality of assessments. The University of Southern Queensland in Australia is reputed for its external delivery of courses where 80% of the students study through this mode. Considering two courses offered at USQ in dual mode as case-studies, this paper will highlight the main issues in reaching the right balance when designing assessment schemes, and discussing potential changes to assessment schemes to enhance student learning, as well as effective course delivery

Potable reuse of reclaimed wastewater: challenges for sustainable water management

Australia, being the driest continent in the world, experiences its worst drought currently. The cities located around the coastal areas look for desalination of seawater for potable supplies whereas inland cities explore the possibilities of wastewater reclamation as a last resort for indirect potable supply. The concept of reclaimed wastewater to be considered as a resource for indirectly augmenting the potable supplies has been a subject of debate. Wastewaters can introduce microbial and chemical contaminants into the environment. Even though the existing wastewater treatment plants can successfully remove the conventional contaminants such as organics and nutrients, they are less effective in removing the emerging contaminants such as pharmaceutical and personal care products, endocrine disrupting chemicals and new emerging microbial contaminants. Surface water partly fed with the effluents is widely used as water resource for drinking water and therefore the occurrence of trace organics in surface water is of concern. They are not causing any immediate threat to the humans when exposed since they are present in very low concentrations; however, we need to take precautionary measures to remove the presence of them from potable supplies to minimize the risk of unpredictable long-term effects. Planned indirect potable reuse aims to remove these contaminants in the tertiary treated effluent using advanced treatment technologies with multiple barriers before discharging them into the water bodies to augment the drinking water supply downstream or of their own. Advanced drinking water treatments could also be used to enhance the treatment. This paper discusses how waste treatment and source control will have to be equally managed for successful sustainable water resources management system of potable reuse of reclaimed wastewater

Reclaimed wastewater as a resource for sustainable water management

Population growth accompanied by higher standard of living and ongoing drought conditions caused by changing climatic patterns tend to make water availability as a key national issue not only at present but for the decades to come. The urban cities located around the coastal areas look for the possibility of desalination of sea water whereas the inland cities explore wastewater reuse as a last resort for indirect potable use to meet the envisaged water shortage. Toowoomba City Council acknowledged that Toowoomba would run out of water in two years if the current drought persisted and, therefore, is planning to augment the present water supply with highly treated wastewater using the best technologies available. The concept of reclaimed wastewater to be considered as a resource rather than a waste has been a subject of debate. There are many instances of communities practicing the unplanned indirect potable reuse unknowingly. Tertiary treated wastewater and sometimes untreated industrial and agricultural wastes are returned to the water body from where downstream utilities withdraw water for potable uses. The receiving water bodies have the natural assimilative capacity to clean up the waste discharged into them; however, their limits have been exhausted during the last decade or so due to increased loading discharged containing synthetic chemicals. Planned indirect potable reuse aims to remove these contaminants present in the tertiary treated effluent using advanced treatment technologies with multiple barriers before discharging them into the water bodies to augment the drinking water supply downstream or of their own. Considering the facts that many conventional sources of fresh water become scarcer and more contaminated but emerging innovative state-of-the-art technologies are available to remove the contaminants, planned indirect potable reuse could be a promising solution for sustainable water resources management. This has been reflected in that many utilities around the world have either been planning or already implementing the advanced reuse systems. This paper reviews some indirect potable reuses practiced in the world, the treatment methodologies adopted and discusses how stakeholders can contribute for continued sustainable supply of these water resources

Work in progress - challenges in designing an assessment scheme for a diverse cohort of students

Designing an assessment scheme for a diverse cohort of students having different backgrounds and competencies is a challenge in itself. A case study on a course titled 'Environmental technology' delivered in the Faculty of Engineering and Surveying at University of Southern Queensland in Australia is an example that depicts this challenge. This paper reports a critical analysis undertaken using the available data to understand the diverse characteristics of the students in terms of their majors and programs, their corresponding performance in the assessment and finally the interpretation of how their performance is related to their majors and programs. Having critically reviewed the existing assessment practices along with the students' feedback, a new assessment strategy is proposed that can influence the students' approaches to learning from surface to deep learning and that takes into account the diverse nature of the students

Animations as a tool for enhancing teaching and learning outcomes in civil engineering courses

Many students today are visual learners and little inclined to study printed materials or text-based on-line courses. Animations can serve as effective multimedia tools to engage these students while facilitating and enhancing the student learning experience by explaining difficult concepts through visual means instead of the traditional way of heavy textual based presentation. The importance of animations would further be realized especially when the courses are offered at distance mode where students have to rely solely on the course materials to gain in-depth understanding. The University of Southern Queensland (USQ) in Australia is internationally recognized for its external delivery of courses. In this paper, we discuss the design and delivery of animations for two courses namely Public health Engineering and Geology and Geomechanics that are normally perceived to be challenging by civil and environmental engineering undergraduates. A new and innovative teaching approach was required to facilitate the students' learning of these unfamiliar materials in these courses. Animations including multimedia facilities were conceived as a better way of presenting the concepts to the students. In this paper, we discuss and further evaluate the overall performance of students as a result of introducing animations into the curriculum

Design of public health engineering course using multimedia resources for dual mode delivery

Educating students who aspire to be engineers and technologists in the field of Public Health Engineering is a challenge as it encompasses a diverse technical content demanding an interdisciplinary knowledge encompassing chemistry and microbiology. Students find it hard to visualize the processes that occur within the treatment systems for successfully designing the components. This difficulty is even more complicated especially when the courses are offered at distance mode where students have to rely solely on the course materials to gain in-depth understanding. This paper presents successful design and development of multimedia resources such as animations for Public Health Engineering course which is perceived to be challenging by civil and environmental engineering undergraduates. The preliminary evaluation of the revitalized course indicates that the overall performance of the students increased by 12.1% in 2009 compared to 2008 as a result of enhancement