Integration of sulphate reduction, autotrophic denitrification and nitrification to achieve low-cost excess sludge minimisation for Hong Kong sewage

An integrated anaerobic-aerobic treatment system of sulphate-laden wastewater was proposed here to achieve low sludge production, low energy consumption and effective sulphide control. Before integrating the whole system, the feasibility of autotrophic denitrification utilising dissolved sulphide produced during anaerobic treatment of sulphate rich wastewater was studied here. An upflow anaerobic sludge blanket reactor was operated to treat sulphate-rich synthetic wastewater (TOC = 100 mg/L and sulphate = 500 mg/L) and its effluent with dissolved sulphide and external nitrate solution were fed into an anoxic biofilter. The anaerobic reactor was able to remove 77-85% of TOC at HRT of 3 h and produce 70-90 mg S/L sulphide in dissolved form for the subsequent denitrification. The performance of anoxic reactor was stable, and the anoxic reactor could remove 30 mg N/L nitrate at HRT of 2 h through autotrophic denitrification. Furthermore, sulphur balance for the anoxic filter showed that more than 90% of the removed sulphide was actually oxidised into sulphate, thereby there was no accumulation of sulphur particles in the filter bed. The net sludge productions were approximately 0.15 to 0.18 g VSS/g COD in the anaerobic reactor and 0.22 to 0.31 g VSS/g NO3--N in the anoxic reactor. The findings in this study will be helpful in developing the integrated treatment system to achieve low-cost excess sludge minimisation.

Feasibility of controlling nitrification in predenitrification plants using DO, pH and ORP sensors

Experimental studies were carried out on a bench-scale nitrogen removal system with a predenitrification configuration to gain insights into the spatial and temporal variations of DO, pH and ORP in such systems. It is demonstrated that these signals correlate strongly with the operational states of the system, and could therefore be used as system performance indicators. The DO concentration in the first aerobic zone, when receiving constant aeration, and the net pH change between the last and first aerobic zones display strong correlations with the influent ammonia concentration for the domestic wastewater used in this study. The pH profile along the aerobic zones gives good indication on the extent of nitrification. The experimental results also showed a good correlation between ORP values in the last aerobic zone and effluent ammonia and nitrate concentrations, provided that DO in this zone is controlled at a constant level. These results suggest that the DO, pH and ORP sensors could potentially be used as alternatives to the on-line nutrient sensors for the control of continuous systems. An idea of using a fuzzy inference system to make an integrated use of these signals for on-line aeration control is presented and demonstrated on the bench-scale system with promising results. The use of these sensors has to date only been demonstrated in intermittent systems, such as sequencing batch reactor systems.

International symposium on career development and public policy: Synthesis of country papers

During the conference, country teams were asked to select and address selection of six themes: human capital, labour supply, employability skills, carer development services for workforce development, older workers or evidence based research. This synthesis of country papers covers the conceptual links between these themes. It then goes on to cover three reframed themes focusing on career development policies and services, but distinguishing three levels of such policies and services: workforce preparation, workforce adaptability and workforce re-integration.

Going up? Women in the public sector

Abstract: Purpose – This paper aims to document women's reflections on their careers over a ten-year period to provide quantitative baseline data on which to frame follow-up in-depth interviews. The participants work in the public service in Queensland (Australia) and had been recommended for, and participated in, women in management (WIM) courses conducted in the early 1990s. Design/methodology/approach – Data were collected by means of a survey (containing closed and open items) which gathered demographic data and data related to employment history, perceptions of success and satisfaction, and the women's future career expectations. Findings – Findings revealed that the percentage of women in middle and senior management had increased over the ten-year period, although not to the extent one might have anticipated, given that the women had been targeted as high flyers by their supervisors. While not content with their classification levels (i.e. seniority), the majority of the cohort viewed their careers as being successful. Practical implications – Questions arise from this study as to why women are still “not getting to the top”. There are also policy implications for the public service concerning women's possible “reinventive contribution” and training implications associated with women only courses. Originality/value – The study is part of an Australian longitudinal study on the careers of women who attended a prestigious women-only management course in the early 1990s in Queensland. This is now becoming a study of older women.

Bioerosion Research Before and After 1996 - A Discussion of What Has Changed Since the First International Bioerosion Workshop

The First International Bioerosion Workshop held in 1996 provided a forum for an increasing interest in bioerosion research and helped foster convivial relations among researchers in this specialization. The current trend in bioerosion publishing is positive and will be aided with consolidated efforts to attract both new recruits and grant awards. Contributors of the Fourth IBW in Prague decided to hold the next meeting in Erlangen, Germany.

Managing change and time in dynamic workflow processes

Business environments have become exceedingly dynamic and competitive in recent times. This dynamism is manifested in the form of changing process requirements and time constraints. Workflow technology is currently one of the most promising fields of research in business process automation. However, workflow systems to date do not provide the flexibility necessary to support the dynamic nature of business processes. In this paper we primarily discuss the issues and challenges related to managing change and time in workflows representing dynamic business processes. We also present an analysis of workflow modifications and provide feasibility considerations for the automation of this process.