Performance evaluation of onsite wastewater treatment : field sampling and preliminary evaluation of results

Background The onsite treatment of sewage and effluent disposal within the premises is widely prevalent in rural and urban fringe areas due to the general unavailability of reticulated wastewater collection systems. Despite the seemingly low technology of the systems, failure is common and in many cases leading to adverse public health and environmental consequences. Therefore it is important that careful consideration is given to the design and location of onsite sewage treatment systems. It requires an understanding of the factors that influence treatment performance. The use of subsurface effluent absorption systems is the most common form of effluent disposal for onsite sewage treatment and particularly for septic tanks. Additionally in the case of septic tanks, a subsurface disposal system is generally an integral component of the sewage treatment process. Therefore location specific factors will play a key role in this context. The project The primary aims of the research project are: • to relate treatment performance of onsite sewage treatment systems to soil conditions at site; • to identify important areas where there is currently a lack of relevant research knowledge and is in need of further investigation. These tasks were undertaken with the objective of facilitating the development of performance based planning and management strategies for onsite sewage treatment. The primary focus of the research project has been on septic tanks. Therefore by implication the investigation has been confined to subsurface soil absorption systems. The design and treatment processes taking place within the septic tank chamber itself did not form a part of the investigation. In the evaluation to be undertaken, the treatment performance of soil absorption systems will be related to the physico-chemical characteristics of the soil. Five broad categories of soil types have been considered for this purpose. The number of systems investigated was based on the proportionate area of urban development within the Brisbane region located on each soil types. In the initial phase of the investigation, though the majority of the systems evaluated were septic tanks, a small number of aerobic wastewater treatment systems (AWTS) were also included. This was primarily to compare the effluent quality of systems employing different generic treatment processes. It is important to note that the number of different types of systems investigated was relatively small. As such this does not permit a statistical analysis to be undertaken of the results obtained. This is an important issue considering the large number of parameters that can influence treatment performance and their wide variability. The report This report is the second in a series of three reports focussing on the performance evaluation of onsite treatment of sewage. The research project was initiated at the request of the Brisbane City Council. The work undertaken included site investigation and testing of sewage effluent and soil samples taken at distances of 1 and 3 m from the effluent disposal area. The project component discussed in the current report formed the basis for the more detailed investigation undertaken subsequently. The outcomes from the initial studies have been discussed, which enabled the identification of factors to be investigated further. Primarily, this report contains the results of the field monitoring program, the initial analysis undertaken and preliminary conclusions. Field study and outcomes Initially commencing with a list of 252 locations in 17 different suburbs, a total of 22 sites in 21 different locations were monitored. These sites were selected based on predetermined criteria. To obtain house owner agreement to participate in the monitoring study was not an easy task. Six of these sites had to be abandoned subsequently due to various reasons. The remaining sites included eight septic systems with subsurface effluent disposal and treating blackwater or combined black and greywater, two sites treating greywater only and six sites with AWTS. In addition to collecting effluent and soil samples from each site, a detailed field investigation including a series of house owner interviews were also undertaken. Significant observations were made during the field investigations. In addition to site specific observations, the general observations include the following: • Most house owners are unaware of the need for regular maintenance. Sludge removal has not been undertaken in any of the septic tanks monitored. Even in the case of aerated wastewater treatment systems, the regular inspections by the supplier is confined only to the treatment system and does not include the effluent disposal system. This is not a satisfactory situation as the investigations revealed. • In the case of separate greywater systems, only one site had a suitably functioning disposal arrangement. The general practice is to employ a garden hose to siphon the greywater for use in surface irrigation of the garden. • In most sites, the soil profile showed significant lateral percolation of effluent. As such, the flow of effluent to surface water bodies is a distinct possibility. • The need to investigate the subsurface condition to a depth greater than what is required for the standard percolation test was clearly evident. On occasion, seemingly permeable soil was found to have an underlying impermeable soil layer or vice versa. The important outcomes from the testing program include the following: • Though effluent treatment is influenced by the physico-chemical characteristics of the soil, it was not possible to distinguish between the treatment performance of different soil types. This leads to the hypothesis that effluent renovation is significantly influenced by the combination of various physico-chemical parameters rather than single parameters. This would make the processes involved strongly site specific. • Generally the improvement in effluent quality appears to take place only within the initial 1 m of travel and without any appreciable improvement thereafter. This relates only to the degree of improvement obtained and does not imply that this quality is satisfactory. This calls into question the value of adopting setback distances from sensitive water bodies. • Use of AWTS for sewage treatment may provide effluent of higher quality suitable for surface disposal. However on the whole, after a 1-3 m of travel through the subsurface, it was not possible to distinguish any significant differences in quality between those originating from septic tanks and AWTS. • In comparison with effluent quality from a conventional wastewater treatment plant, most systems were found to perform satisfactorily with regards to Total Nitrogen. The success rate was much lower in the case of faecal coliforms. However it is important to note that five of the systems exhibited problems with regards to effluent disposal, resulting in surface flow. This could lead to possible contamination of surface water courses. • The ratio of TDS to EC is about 0.42 whilst the optimum recommended value for use of treated effluent for irrigation should be about 0.64. This would mean a higher salt content in the effluent than what is advisable for use in irrigation. A consequence of this would be the accumulation of salts to a concentration harmful to crops or the landscape unless adequate leaching is present. These relatively high EC values are present even in the case of AWTS where surface irrigation of effluent is being undertaken. However it is important to note that this is not an artefact of the treatment process but rather an indication of the quality of the wastewater generated in the household. This clearly indicates the need for further research to evaluate the suitability of various soil types for the surface irrigation of effluent where the TDS/EC ratio is less than 0.64. • Effluent percolating through the subsurface absorption field may travel in the form of dilute pulses. As such the effluent will move through the soil profile forming fronts of elevated parameter levels. • The downward flow of effluent and leaching of the soil profile is evident in the case of podsolic, lithosol and kransozem soils. Lateral flow of effluent is evident in the case of prairie soils. Gleyed podsolic soils indicate poor drainage and ponding of effluent. In the current phase of the research project, a number of chemical indicators such as EC, pH and chloride concentration were employed as indicators to investigate the extent of effluent flow and to understand how soil renovates effluent. The soil profile, especially texture, structure and moisture regime was examined more in an engineering sense to determine the effect of movement of water into and through the soil. However it is not only the physical characteristics, but the chemical characteristics of the soil also play a key role in the effluent renovation process. Therefore in order to understand the complex processes taking place in a subsurface effluent disposal area, it is important that the identified influential parameters are evaluated using soil chemical concepts. Consequently the primary focus of the next phase of the research project will be to identify linkages between various important parameters. The research thus envisaged will help to develop robust criteria for evaluating the performance of subsurface disposal systems.

Performance evaluation of onsite sewage treatment : results of soil investigations

Background The onsite treatment of sewage and effluent disposal is widely prevalent in rural and urban fringe areas due to the general unavailability of reticulated wastewater collection systems. Despite the low technology of the systems, failure is common and in many cases leading to adverse public health and environmental consequences. It is important therefore that careful consideration is given to the design and location of onsite sewage treatment systems. This requires an understanding of the factors that influence treatment performance. The use of subsurface absorption systems is the most common form of effluent disposal for onsite sewage treatment, particularly for septic tanks. Also, in the case of septic tanks, a subsurface disposal system is generally an integral component of the sewage treatment process. Site specific factors play a key role in the onsite treatment of sewage. The project The primary aims of the research project were: • to relate treatment performance of onsite sewage treatment systems to soil conditions at site; • to evaluate current research relating to onsite sewage treatment; and, • to identify key issues where currently there is a lack of relevant research. These tasks were undertaken with the objective of facilitating the development of performance based planning and management strategies for onsite sewage treatment. The primary focus of this research project has been on septic tanks. By implication, the investigation has been confined to subsurface soil absorption systems. The design and treatment processes taking place within the septic tank chamber itself did not form a part of the investigation. Five broad categories of soil types prevalent in the Brisbane region have been considered in this project. The number of systems investigated was based on the proportionate area of urban development within the Brisbane region located on each of the different soil types. In the initial phase of the investigation, the majority of the systems evaluated were septic tanks. However, a small number of aerobic wastewater treatment systems (AWTS) were also included. The primary aim was to compare the effluent quality of systems employing different generic treatment processes. It is important to note that the number of each different type of system investigated was relatively small. Consequently, this does not permit a statistical analysis to be undertaken of the results obtained for comparing different systems. This is an important issue considering the large number of soil physico-chemical parameters and landscape factors that can influence treatment performance and their wide variability. The report This report is the last in a series of three reports focussing on the performance evaluation of onsite treatment of sewage. The research project was initiated at the request of the Brisbane City Council. The project component discussed in the current report outlines the detailed soil investigations undertaken at a selected number of sites. In the initial field sampling, a number of soil chemical properties were assessed as indicators to investigate the extent of effluent flow and to help understand what soil factors renovate the applied effluent. The soil profile attributes, especially texture, structure and moisture regime were examined more in an engineering sense to determine the effect of movement of water into and through the soil. It is important to note that it is not only the physical characteristics, but also the chemical characteristics of the soil as well as landscape factors play a key role in the effluent renovation process. In order to understand the complex processes taking place in a subsurface effluent disposal area, influential parameters were identified using soil chemical concepts. Accordingly, the primary focus of this final phase of the research project was to identify linkages between various soil chemical parameters and landscape patterns and their contribution to the effluent renovation process. The research outcomes will contribute to the development of robust criteria for evaluating the performance of subsurface effluent disposal systems. The outcomes The key findings from the soil investigations undertaken are: • Effluent renovation is primarily undertaken by a combination of various soil physico-chemical parameters and landscape factors, thereby making the effluent renovation processes strongly site dependent. • Decisions regarding site suitability for effluent disposal should not be based purely in terms of the soil type. A number of other factors such as the site location in the catena, the drainage characteristics and other physical and chemical characteristics, also exert a strong influence on site suitability. • Sites, which are difficult to characterise in terms of suitability for effluent disposal, will require a detailed soil physical and chemical analysis to be undertaken to a minimum depth of at least 1.2 m. • The Ca:Mg ratio and Exchangeable Sodium Percentage are important parameters in soil suitability assessment. A Ca:Mg ratio of less than 0.5 would generally indicate a high ESP. This in turn would mean that Na and possibly Mg are the dominant exchangeable cations, leading to probable clay dispersion. • A Ca:Mg ratio greater than 0.5 would generally indicate a low ESP in the profile, which in turn indicates increased soil stability. • In higher clay percentage soils, low ESP can have a significant effect. • The presence of high exchangeable Na can be counteracted by the presence of swelling clays, and an exchange complex co-dominated by exchangeable Ca and exchangeable Mg. This aids absorption of cations at depth, thereby reducing the likelihood of dispersion. • Salt is continually added to the soil by the effluent and problems may arise if the added salts accumulate to a concentration that is harmful to the soil structure. Under such conditions, good drainage is essential in order to allow continuous movement of water and salt through the profile. Therefore, for a site to be sustainable, it would have a maximum application rate of effluent. This would be dependent on subsurface characteristics and the surface area available for effluent disposal. • The dosing regime for effluent disposal can play a significant role in the prevention of salt accumulation in the case of poorly draining sites. Though intermittent dosing was not considered satisfactory for the removal of the clogging mat layer, it has positive attributes in the context of removal of accumulated salts in the soil.

Understanding treatment characteristics of constructed stormwater wetlands

Constructed wetlands are a common structural treatment measure employed to remove stormwater pollutants and forms an important part of the Water Sensitive Urban Design (WSUD) treatment suite. In a constructed wetland, a range of processes such as settling, filtration, adsorption, and biological uptake play a role in stormwater treatment. Occurrence and effectiveness of these processes are variable and influenced by hydraulic, chemical and biological factors. The influence of hydraulic factors on treatment processes are of particular concern. This paper presents outcomes of a comprehensive study undertaken to define the treatment performance of a constructed wetland highlighting the influence of hydraulic factors. The study included field monitoring of a well established constructed wetland for quantity and quality factors, development of a conceptual hydraulic model to simulate water movement within the wetland and multivariate analysis of quantity and quality data to investigate correlations and to define linkages between treatment performance and influential hydraulic factors. Total Suspended Solids (TSS), Total Nitrogen (TN) and Total Phosphorus (TP) concentrations formed the primary pollutant parameters investigated in the data analysis. The outcomes of the analysis revealed significant reduction in event mean concentrations of all three pollutants species. Treatment performance of the wetland was significantly different for storm events above and below the prescribed design event. For events below design event, TSS and TN load reduction was comparatively high and strongly influenced by high retention time. For events above design event, TP load reduction was comparatively high and was found to be influenced by the characteristics of TP wash-off from catchment surfaces.

Engineering across cultures : new learning resources for intercultural competency in engineering

BACKGROUND The work described in this paper has emerged from an ALTC/OLT funded project, Exploring Intercultural Competency in Engineering. The project indentified many facets of culture and intercultural competence that go beyond a culture-as-nationality paradigm. It was clear from this work that resources were needed to help engineering educators introduce students to the complex issues of culture as they relate to engineering practice. A set of learning modules focussing on intercultural competence in engineering practice were developed early on in the project. Through the OLT project, these modules have been expanded into a range of resources covering various aspects of culture in engineering. Supporting the resources, an eBook detailing the ins and outs of intercultural competency has also been developed to assist engineering educators to embed opportunities for students to develop skills in unpacking and managing cross-cultural challenges in engineering practice. PURPOSE This paper describes the key principles behind the development of the learning modules, the areas they cover and the eBook developed to support the modules. The paper is intended as an introduction to the approaches and resources and extends an invitation to the community to draw from, and contribute to this initial work. DESIGN/METHOD A key aim of this project was to go beyond the culture-as-nationality approach adopted in much of the work around intercultural competency (Deardorff, 2011). The eBook explores different dimensions of culture such as workplace culture, culture’s influence on engineering design, and culture in the classroom. The authors describe how these connect to industry practice and explore what they mean for engineering education. The packaged learning modules described here have been developed as a matrix of approaches moving from familiar known methods through complicated activities relying to some extent on expert knowledge. Some modules draw on the concept of ‘complex un-order’ as described in the ‘Cynefin domains’ proposed by Kurtz and Snowden (2003). RESULTS Several of the modules included in the eBook have already been trialled at a variety of institutions. Feedback from staff has been reassuringly positive so far. Further trials are planned for second semester 2012, and version 1 of the eBook and learning modules, Engineering Across Cultures, is due to be released in late October 2012. CONCLUSIONS The Engineering Across Cultures eBook and learning modules provide a useful and ready to employ resource to help educators tackle the complex issue of intercultural competency in engineering education. The book is by no means exhaustive, and nor are the modules, they instead provide an accessible, engineering specific guide to bringing cultural issues into the engineering classroom.

An update on the Mackay Renewable Biocommodities Pilot Plant : preliminary trial results

THE Mackay Renewable Biocommodities Pilot Plant is a pilot scale facility owned and operated by QUT for research and demonstration of the conversion of lignocellulosic biomass such as sugarcane bagasse into biofuels. The pilot plant accommodates unique state-of-the-art equipment to process a wide range of feedstocks and is strategically located on the site of the Mackay Sugar Ltd Racecourse Mill. Major facilities include a biomass handling system, pre-treatment reactor, saccharification reactor, fermentors, distillation column and bioseparations equipment. This paper provides an update on the design, construction, commissioning and start-up of the facility. In addition, the paper provides results from preliminary facility trials on the pre-treatment of sugarcane bagasse for cellulosic ethanol production.

Getting the point : the role of gesture in managing intersubjectivity in a design activity

This paper illustrates the complexity of pointing as it is employed in a design workshop. Using the method of interaction analysis, we argue that pointing is not merely employed to index, locate, or fix reference to an object. It also constitutes a practice for reestablishing intersubjectivity and solving interactional trouble such as misunderstandings or disagreements by virtue of enlisting something as part of the participants’ shared experience. We use this analysis to discuss implications for how such practices might be supported with computer mediation, arguing for a “bricolage” approach to systems development that emphasizes the provision of resources for users to collaboratively negotiate the accomplishment of intersubjectivity ra- ther than systems that try to support pointing as a specific gestural action.

Towards a capabilities database to inform inclusive design : Experimental investigation of effective survey-based predictors of human-product interaction

A key issue in the field of inclusive design is the ability to provide designers with an understanding of people's range of capabilities. Since it is not feasible to assess product interactions with a large sample, this paper assesses a range of proxy measures of design-relevant capabilities. It describes a study that was conducted to identify which measures provide the best prediction of people's abilities to use a range of products. A detailed investigation with 100 respondents aged 50-80 years was undertaken to examine how they manage typical household products. Predictor variables included self-report and performance measures across a variety of capabilities (vision, hearing, dexterity and cognitive function), component activities used in product interactions (e.g. using a remote control, touch screen) and psychological characteristics (e.g. self-efficacy, confidence with using electronic devices). Results showed, as expected, a higher prevalence of visual, hearing, dexterity, cognitive and product interaction difficulties in the 65-80 age group. Regression analyses showed that, in addition to age, performance measures of vision (acuity, contrast sensitivity) and hearing (hearing threshold) and self-report and performance measures of component activities are strong predictors of successful product interactions. These findings will guide the choice of measures to be used in a subsequent national survey of design-relevant capabilities, which will lead to the creation of a capability database. This will be converted into a tool for designers to understand the implications of their design decisions, so that they can design products in a more inclusive way.

A framework for collecting inclusive design data for the UK population

Successful inclusive product design requires knowledge about the capabilities, needs and aspirations of potential users and should cater for the different scenarios in which people will use products, systems and services. This should include: the individual at home; in the workplace; for businesses, and for products in these contexts. It needs to reflect the development of theory, tools and techniques as research moves on.

Water Sensitive Urban Design (WSUD) application auditing

Background WSUD implementation in the Gold Coast City Council area commenced more than a decade ago. As a result, Council is expected to be in possession of WSUD assets valued at over tens of million dollars. The Gold Coast City Council is responsible for the maintenance and long-term management of these WSUD assets. Any shortcoming in implementation of best WSUD practices can potentially result in substantial liabilities and ineffective expenditure for the Council in addition to reduced efficiencies and outcomes. This highlights the importance of periodic auditing of WSUD implementation. Project scope The overall study entailed the following tasks: * A state-of-the-art literature review of the conceptual hydraulic and water quality treatment principles, current state of knowledge in relation to industry standards, best practice and identification of knowledge gaps in relation to maintenance and management practices and potential barriers to the implementation of WSUD. * Council stakeholder interviews to understand current practical issues in relation to the implementation of WSUD and the process of WSUD application from development application approval to asset management. * Field auditing of selected WSUD systems for condition assessment and identification of possible strengths and weaknesses in implementation. * Review of the Land Development Guidelines in order to identify any gaps and to propose recommendations for improvement. Conclusions Given below is a consolidated summary of the findings of the study undertaken. State-of-the-art literature review Though the conceptual framework for WSUD implementation is well established, the underlying theoretical knowledge underpinning the treatment processes and maintenance regimes and life cycle costing are still not well understood. Essentially, these are the recurring themes in the literature, namely, the inadequate understanding of treatment processes and lack of guidance to ensure specificity of maintenance regimes and life cycle costing of WSUDs. The fundamental barriers to successful WSUD implementation are: * Lack of knowledge transfer – This essentially relates to the lack of appropriate dissemination of research outcomes and the common absence of protocols for knowledge transfer within the same organisation. * Cultural barriers – These relate to social and institutional factors, including institutional inertia and the lack of clear understanding of the benefits. * Fragmented responsibilities – This results from poor administrative integration within local councils in relation to WSUDs. * Technical barriers – These relate to lack of knowledge on operational and maintenance practices which is compounded by model limitations and the lack of long-term quantitative performance evaluation data. * Lack of engineering standards – Despite the availability of numerous guidelines which are non-enforceable and can sometimes be confusing, there is a need for stringent engineering standards. The knowledge gaps in relation to WSUDs are only closing very slowly. Some of the common knowledge gaps identified in recent publications have been recognised almost a decade ago. The key knowledge gaps identified in the published literature are: * lack of knowledge on operational and maintenance practices; * lack of reliable methodology for identifying life cycle issues including costs; * lack of technical knowledge on system performance; * lack of guidance on retrofitting in existing developments. Based on the review of barriers to WSUD implementation and current knowledge gaps, the following were identified as core areas for further investigation: * performance evaluation of WSUD devices to enhance model development and to assess their viability in the context of environmental, economic and social drivers; establishing realistic life cycle costs to strengthen maintenance and asset management practices; * development of guidelines specific to retrofitting in view of the unique challenges posed by existing urban precincts together with guidance to ensure site specificity; establishment of a process for knowledge translation for enhancing currently available best practice guidelines; * identification of drivers and overcoming of barriers in the areas of institutional fragmentation, knowledge gaps and awareness of WSUD practices. GCCC stakeholder interviews Fourteen staff members involved in WSUD systems management in the Gold Coast City Council, representing four Directorates were interviewed using a standard questionnaire. The primary issues identified by the stakeholders were: * standardisation of WSUD terminology; * clear protocols for safeguarding devices during the construction phase; * engagement of all council stakeholders in the WSUD process from the initial phase; * limitations in the Land Development Guidelines; * ensuring public safety through design; * system siting to avoid conflicts with environmental and public use of open space; * provision of adequate access for maintenance; * integration of social and ecosystem issues to ensure long-term viability of systems in relation to both, vandalism and visual recreation; * lack of performance monitoring and inadequacy of the maintenance budget; * lack of technical training for staff involved in WSUD design approvals and maintenance; incentives for developers for acting responsibly in stormwater management. Field auditing of WSUD systems A representative cross section of WSUD systems in the Gold Coast were audited in the field. The following strengths and weaknesses in WSUD implementation were noted: * The implementation of WSUD systems in the field is not consistent. * The concerns raised by the stakeholders during the interviews in relation to WSUD implementation was validated from the observations from the field auditing, particularly in relation to the following: * safeguarding of devices during the construction phase * public safety * accessibility for maintenance * lack of performance monitoring by Council to assess system performance * inadequate maintenance of existing systems to suit site specific requirements. * A treatment train approach is not being consistently adopted. * Most of the systems audited have satisfactorily catered for public safety. Accessibility for maintenance has been satisfactorily catered for in most of the systems that were audited. * Systems are being commissioned prior to construction activities being substantially completed. * The hydraulic design of most systems appears to be satisfactory. * The design intent of the systems is not always clear. Review of Land Development Guidelines The Land Development Guidelines (TDG) was extensively reviewed and the following primary issues were noted in relation to WSUD implementation: * the LDG appears to have been prepared primarily to provide guidance to developers. It is not clear to what extent the guidelines are applicable to Council staff involved in WSUD maintenance and management; * Section 13 is very voluminous and appears to be a compilation of a series of individual documents resulting in difficulties in locating specific information, a lack of integration and duplication of information; * the LDG has been developed with a primary focus on new urban precinct development and the retrofitting of systems in existing developments has not been specifically discussed; * WSUDs are discussed in two different sections in the LDG and it is not clear which section takes precedence as there are inconsistencies between the two sections; there is inconsistent terminology being used; * there is a need for consolidation of information provided in different sections in the LDG; * there are inconsistencies in the design criteria provided; * there is a need for regular updating of the LDG to ensure that the information provided encompasses the state-of-the-art; * there is limited guidance provided for the preparation of maintenance plans and life cycle costing to assist developers in asset handover and to assist Council staff in assessment. * Based on these observations, eleven recommendations have been provided which are discussed below. Additionally, the stakeholder provided the following specific comments during the interviews in relation to the LDG: * lack of flexibility to cover the different stages of the life cycle of the systems; * no differentiation in projects undertaken by developers and Council; * inadequate information with regards to safety issues such as maximum standing water depth, fencing and safety barriers and public access; * lack of detailed design criteria in relation to Crime Prevention through Environmental Design, safety, amenity, environment, surrounding uses and impacts on surroundings; * inadequate information regarding maintenance requirements specific to the assessment and compliance phases; * recommendations for plantings are based primarily on landscape requirements rather than pollutant uptake capability. Recommendations With regards to the Land Development Guidelines, the following specific recommendations are provided: 1. the relevant sections and their extent of applicability to Council should be clearly identified; 2. integration of the different subsections within Section 13 and re-formatting the document for easy reference; 3. the maintenance guidelines provided in Section 13 should be translated to a maintenance manual for guidance of Council staff; 4. should consider extending the Guidelines to specifically encompass retrofitting of WSUD systems to existing urban precincts; 5. Section 3 needs to be revised to be made consistent with Section 13, to ensure priority for WSUD practices in urban precincts and to move away from conventional stormwater drainage design such as kerb and channelling; 6. it would also be good to specify as to which Section takes predominance in relation to stormwater drainage. It is expected that Section 13 would take predominance over the other sections in the LDG; 7. terminology needs to be made consistent to avoid confusion among developers and Council staff. Water Sensitive Urban Design is the term commonly used in Australia for stormwater quality treatment, rather than Stormwater Quality Improvement Devices. This once again underlines the need for ensuring consistency between Section 3 and Section 13; 8. it would also be good if there is a glossary of commonly used terms in relation to WSUD for use by all stakeholders and which should also be reflected in the LDG; 9. consolidation of all WSUD information into one section should be considered together with appropriate indicators in other LDG Sections regarding the availability of WSUD information. Ensuring consistency in the information provided is implied; 10. Section 13 should be updated at regular intervals to ensure the incorporation of the latest in research outcomes and incorporating criteria and guidance based on the state-of-the-art knowledge. The updating could be undertaken, say, in five year cycles. This would help to overcome the current lack of knowledge transfer; 11. the Council should consider commissioning specialised studies to extend the current knowledge base in relation to WSUD maintenance and life cycle costing. Additionally, Recommendation 10 is also applicable in this instance. The following additional recommendations are made based on the state-of-the-art literature review, stakeholder interviews and field auditing of WSUD systems: 1. Performance monitoring of existing systems to assess improvements to water quality, identify modifications and enhancements to improve performance; 2. Appropriate and monitored maintenance during different phases of development of built assets over time is needed to investigate the most appropriate time/phase of development to commission the final WSUD asset. 3. Undertake focussed investigations in the areas of WSUD maintenance and asset management in order to establish more realistic life cycle costs of systems and maintenance schedules; 4. the engagement of all relevant Council stakeholders from the initial stage of concept planning through to asset handover, and ongoing monitoring. This close engagement of internal stakeholders will assist in building a greater understanding of responsibilities and contribute to overcoming constraints imposed by fragmented responsibilities; 5. the undertaking of a public education program to inform the community of the benefits and ecosystem functions of WSUD systems; 6. technical training to impart state-of-the-art knowledge to staff involved in the approval of designs and maintenance and management of WSUD projects; 7. during the construction phase, it is important to ensure that appropriate measures to safeguard WSUD devices are implemented; 8. risks associated with potential public access to open water zones should be minimised with the application of appropriate safety measures; 9. system siting should ensure that potential conflicts are avoided with respect to public and ecosystem needs; 10. integration of social and ecosystem issues to ensure long-term viability of systems; provide incentives to developers who are proactive and responsible in the area of stormwater management.

Improved design rules for cold-formed steel columns

Current design rules for determining the member strength of cold-formed steel columns are based on the effective length of the member and a single column capacity curve for both pin-ended and fixed-ended columns. This research has reviewed the use of AS/NZS 4600 design rules for their accuracy in determining the member compression capacities of slender cold-formed steel columns using detailed numerical studies. It has shown that AS/NZS 4600 design rules accurately predicted the capacities of pinned and fixed ended columns undergoing flexural buckling. However, for fixed ended columns undergoing flexural-torsional buckling, it was found that current AS/NZS 4600 design rules did not include the beneficial effect of warping fixity. Therefore AS/NZS 4600 design rules were found to be excessively conservative and hence uneconomical in predicting the failure loads obtained from tests and finite element analyses of fixed-ended lipped channel columns. Based on this finding, suitable recommendations have been made to modify the current AS/NZS 4600 design rules to more accurately reflect the results obtained from the numerical and experimental studies conducted in this research. This paper presents the details of this research on cold-formed steel columns and the results.

Direct second-order elastic analysis for steel frame design

The traditional structural design procedure, especially for the large-scale and complex structures, is time consuming and inefficient. This is due primarily to the fact that the traditional design takes the second-order effects indirectly by virtue of design specifications for every member instead of system analysis for a whole structure. Consequently, the complicated and tedious design procedures are inevitably necessary to consider the second-order effects for the member level in design specification. They are twofold in general: 1) Flexural buckling due to P-d effect, i.e. effective length. 2) Sway effect due to P-D effect, i.e. magnification factor. In this study, a new system design concept based on the second-order elastic analysis is presented, in which the second-order effects are taken into account directly in the system analysis, and also to avoid the tedious member-by-member stability check. The plastic design on the basis of this integrated method of direct approach is ignored in this paper for simplicity and clarity, as the only emphasis is placed on the difference between the second-order elastic limit-state design and present system design approach. A practical design example, a 57m-span dome steel skylight structure, is used to demonstrate the efficiency and effectiveness of the proposed approach. This skylight structure is also designed by the traditional design approach BS5950-2000 for comparison on which the emphasis of aforementioned P-d and P-D effects is placed.

Performance-based structural fire design of steel frames using conventional computer software

Fire incident in buildings is common, so the fire safety design of the framed structure is imperative, especially for the unprotected or partly protected bare steel frames. However, software for structural fire analysis is not widely available. As a result, the performance-based structural fire design is urged on the basis of using user-friendly and conventional nonlinear computer analysis programs so that engineers do not need to acquire new structural analysis software for structural fire analysis and design. The tool is desired to have the capacity of simulating the different fire scenarios and associated detrimental effects efficiently, which includes second-order P-D and P-d effects and material yielding. Also the nonlinear behaviour of large-scale structure becomes complicated when under fire, and thus its simulation relies on an efficient and effective numerical analysis to cope with intricate nonlinear effects due to fire. To this end, the present fire study utilizes a second order elastic/plastic analysis software NIDA to predict structural behaviour of bare steel framed structures at elevated temperatures. This fire study considers thermal expansion and material degradation due to heating. Degradation of material strength with increasing temperature is included by a set of temperature-stress-strain curves according to BS5950 Part 8 mainly, which implicitly allows for creep deformation. This finite element stiffness formulation of beam-column elements is derived from the fifth-order PEP element which facilitates the computer modeling by one member per element. The Newton-Raphson method is used in the nonlinear solution procedure in order to trace the nonlinear equilibrium path at specified elevated temperatures. Several numerical and experimental verifications of framed structures are presented and compared against solutions in literature. The proposed method permits engineers to adopt the performance-based structural fire analysis and design using typical second-order nonlinear structural analysis software.

Forming a joint venture project team for multi-discipline engineering services in Australia

Joint venture design teams are formed to combine resources and expertise in order to secure multi-discipline engineering design services on major projects. Bringing together resources from two ordinarily competing companies to form one joint team is however challenging as each parent company brings to the project its own organisational culture, processes and team attitudes. This study examined the factors that impact on forming a successful joint venture project team. Three critical areas were identified from an extensive literature review; Joint Venture Arrangements, Parent Companies and Forming the Team; and a survey was conducted with professionals who have worked in joint venture project teams in the Australian building industry in order to identify factors that affected successful joint venture team formation, and the common lessons learnt. This study reinforced the importance of three key criteria - trust, commitment and compatibility - for partner alignment. The results also identified four key lessons learnt which included; selecting the right resources, enabling a collaborative working environment by way of project office, implementing an independent Joint Venture Manager, and allocating work which is best for project with fees reflecting risk where risk is disproportionate.

Using biomimicry to inform urban infrastructure design that addresses 21st century needs

The design of society’s major infrastructure systems are generally based on anthropogenic learnings and seldom encapsulate learning from nature. This results from a pervading attitude of superiority of human-designed systems, particularly since the Industrial Revolution. Problems created by such behaviours have previously not been thought to present a serious threat to humanity. However, many built environment professionals are now reconsidering the impact of such systems on the environment and their vulnerability to issues such as climate change. This paper presents an approach to delivering sustainable urban infrastructure that addresses 21st Century needs by emulating natural form, function and process - biomimicry – in infrastructure design. The analysis reveals the context for infrastructure change and the need for sustainable solutions, detailing the current inquiry into biomimicry informed design and highlighting potential applications from literature that demonstrate precedence for nature to inspire the design of urban infrastructure, in particular water and energy systems.

Energy Transformed : Building Capacity in the Engineering Profession in Australia

Global pressures of burgeoning population growth and consumption are threatening efforts to reduce negative environmental pressures associated with development such as atmospheric, land and water pollution. For example, the world’s population is now growing at over 70 million per year or 1 billion per decade (Brown, 2007), increasing from 3.5 billion in 1970, to 5 billion in 1990, to 7 billion by 2010 (United Nations, 2002). In 1990 only 13 percent of the global population lived in cities, while in 2007 more than half did. More than 60 percent of the global population lives within 100 kilometers of the coastline (World Resources Institute, 2005) and nearly all of the population growth hereon is forecast to happen in developing countries (Postel, 1999). Future levels of stress on the global environment are therefore likely to increase if current trends are used for forecasting, which is particularly challenging as scientists are already observing significant signs of degradation and failure in environmental systems. For example, the Intergovernmental Panel on Climate Change Fourth Assessment Report (IPCC, 2007) provided an nequivocal link between climate change and current human activities, in particular: the burning of fossil fuels; deforestation and land clearing; the use of synthetic greenhouse gases; and decomposition of wastes from landfill. The UK Stern Review concluded that within our lifetime there is between a 77 to 99 percent chance (depending on the climate model used) of the global average temperature rising by more than 2 degrees Celsius (Stern, 2006), with a likely greenhouse gas concentration in the atmosphere of 550 parts per million (ppm) or more by around 2100.