Toray RO Handling Manual

INTRODUCTION Purpose of Good Practice Guide The catchment-to-consumer risk-based approach to the production of microbially-safe drinking water, which is detailed in the Framework for Management of Drinking Water Quality (the Framework) that underpins the Australian Drinking Water Guidelines (ADWG), is based on the identification and control of risks to the quality of drinking water supplied to consumers. This reduction in risk is achieved by implementing a multiple barrier approach, where a number of different barriers to contamination are put in place, from the catchment to the consumer. Whilst the risk management process stretches all the way from catchment to consumer, in practice the majority of risks are managed through the use of various water treatment processes. Most Australian source waters require some level of treatment prior to being supplied to consumersas drinking water. The level of treatment required to produce microbially-safe drinking water will be a function of the quality of the source water and should be informed by a system-specific risk assessment process that is consistent with the approach described under Element 2 (Assessment of the drinking water supply system) of the Framework. The production of microbially-safe drinking water is difficult to consistently achieve, and requires constant vigilance, as well as well-maintained and operated water treatment processes (Element 3 (Preventive measures for drinking water quality management) and Element 4 (Operational procedures and process control) of the Framework). Within this risk-based approach, the purpose of this Guide is to provide concise advice on good practice preventive measures for the management of drinking water treatment processes and the distribution of this treated water to consumers. This is achieved by providing targets, both numerical and observational, for the various activities that should be undertaken in order to produce microbiallysafe drinking water. The Guide is not intended to be a risk assessment tool; it assumes that a system-specific risk assessment has been done, and that the treatment and distribution processes that are present are suitable for the assessed level of microbial risk. The Guide is therefore focused on the optimisation, management and control of existing water supply systems. The advice in this Guide is applicable to existing water supply systems and is intended to help water utilities produce microbially-safe drinking water under existing arrangements; it will also assist utilities meet any future microbial health-based targets that may be includes in the ADWG. The Guide is presented in a tabular format for simplicity. The table is broken into sections that relate to the key control points in typical water treatment and distribution systems.

Introduction Since several years, conventional wastewater treatment has been dealing with low volumetric loading rates and a high energy consumption (Van Haandel & Van der Lubbe, 2007; Pronk et al., 2017). Especially with the increasing standard of living and an increasing amount of households connected to a sewage system constant improvements are needed (Vlaamse milieumaatschappij, 2019a). The question arises how these challenges can be met in an efficient way. Over the past 20 years, aerobic granular sludge is presented as a promising technology to meet these challenges. Conventional activated sludge flocs, i.e. suspended microorganisms forming bulky aggregates, are converted into compact aerobic granules. This results in 25-75% less land area, 20-50% less energy and up to 7-17% less costs compared to conventional activated sludge plants (Pronk et al, 2017). The conventional use of aerobic granular sludge is in batch systems, but continuous systems are under research as well (Jahn et al., 2019). The aim of this thesis is to gain further insight in continuous processes with aerobic granular sludge. Given that the current continuous systems are not depreciated, yet cannot meet the demand for higher treatment capacity, continuous aerobic granular sludge systems seem promising. Better settleability of granules could lead to higher biomass concentrations in the existing continuous systems, possibly resulting in a higher treatment capacity. Before researching how to get stable granules in a continuous flow reactor, it is needed to investigate the overall effect of granules on the performance of continuous reactors. In this thesis it is questioned if refurbishment of the current continuous activated sludge plants into continuous aerobic granular sludge plants would be advantageous in terms of treatment capacity and energy consumption, in order to meet the effluent criteria. This was investigated by developing the comparison between continuous systems with activated sludge and with aerobic granular sludge. The comparative study is obtained in different steps. In the literature review, a state-of-the-art on current wastewater treatment with activated sludge and aerobic granular sludge is given. Both the typical aerobic granular sludge implementation in batch systems and perspectives on aerobic granular sludge in continuous systems are discussed and compared based on literature findings. The chapter ‘Materials and methods’ describes the mathematical model based on the Benchmark Simulations Model No. 1 (BSM1) in Matlab-Simulink. A continuous activated sludge system serves as the reference model. Furthermore, this model is adapted to make it representable as a continuous design with aerobic granular sludge based on two characteristics: better settleability and diffusion limitation. In the chapter ‘Results and discussion’, the differences between both continuous systems are elucidated to answer the research question. Both the maximal treatment capacity and energy consumption in order to meet the effluent criteria were calculated and compared for both systems. Conclusions are summarized in the chapter ‘General conclusions’ and ‘Recommendations for further research’ are given.