http://nova.newcastle.edu.au/vital/access/services/Feed ${session.getAttribute("locale")} 5 http://nova.newcastle.edu.au/vital/access/manager/Repository/uon:11999 Our recent pilot-scale investigations have shown that Ozone/BAC can provide significant removal of THM precursors and hence reductions in THM formation potential. However, the removal efficiency was found to be highly dependent on the empty bed contact time of the filter, with longer times yielding significantly better removal. The characteristics of the organic matter in the water may also influence the removal efficiency. While Ozone/BAC treatment may be capable of meeting the current ADWG limit in THMs even for a water that is highly laden with natural organic matter, it may struggle if tighter THM limits are introduced. Our work highlights the importance of undertaking pre-design testing to ascertain the effectiveness of Ozone/BAC in reducing THM precursors for a specific water. 2012-11-09T07:25:27.131Z ]]> http://nova.newcastle.edu.au/vital/access/manager/Repository/uon:6226 Geosmin and 2-methylisoborneol (MIB) are two common taste and odour compounds found in drinking water supply sources and are often source of customer complaints of water quality. This paper presents an investigation into the removal of these compounds using photocatalysis with UV/Ti0₂. Our focus was on the performance of immobilised Ti0₂, due to its simplicity in terms of recovery and reuse compared to the Ti0₂ particles in the suspension form. The influence of adding another oxidant (i.e., hydrogen peroxide) and presence of natural organic matter (i.e., humic acid) was also investigated. It was found that for the same UV exposure area, immobilisation of the Ti0₂ particles led to a slower rate of degradation when compared with the suspended Ti0₂ system; total degradation of geosmin and MIB at concentrations of 2010-05-13T02:10:01.174Z ]]> http://nova.newcastle.edu.au/vital/access/manager/Repository/uon:6235 The ozone and biological activated carbon (Ozone/BAC) process is known for being able to provide a wide range of drinking water treatment benefits including destruction of organic contaminants such as taste and odour compounds, algal toxins, pesticides and herbicides. However, its ability to remove disinfection by-product (DBP) precursors is often found to be dependent on water characteristics. This paper presents results from our recent Ozone/BAC pilot plant investigation. The main objective of this work was to assess the efficacy of this process in reducing DBP precursors for one of the most challenging raw water sources in Australia. The pilot plant was operated in the intermediate ozonation mode, with its feed water drawn from the settled water of a full-scale treatment plant operating in the enhanced coagulation mode. The Ozone/BAC process was found to be capable of providing significant removal of DBP precursors and hence reductions in trihalomethane (THM) formation. The removal efficiency was however found to be highly dependent on the empty bed contact time (EBCT) used, with longer EBCTs yielding significantly better removal. Our results highlight the importance of conducting pre-design testing to prove the suitability of this process for DBP precursor removal for a specific water to be treated. 2010-05-11T04:30:05.533Z ]]> http://nova.newcastle.edu.au/vital/access/manager/Repository/uon:5396 Humic substances influence adsorption and aggregation of colloids and ions in natural aquatic environment and thereby affect drinking water treatment by ozonation. In this paper the effect of ozonation on the ability of humic substances to form supramolecular structures was investigated by atomic force microscopy(AFM) surface topography. Ozonated and unozonated solutions of Suwannee River humic acid and fulvic acid were deposited onto molecularly smooth mica surfaces, left to dry and then imaged by AFM in non-contact mode. Two solutions with pH 4 and pH 7 were investigated. At each pH, significant differences in the aggregation behavior between these humic substances before and after ozonation were observed. In particular, ozonation increased the aggregate size of fulvic acid at the neutral pH. Size exclusion chromatography also revealed similar molecular weight distributions for the humic substances after ozonation. It was argued that difference in the molecular hydrophobicity or factors other than molecular weight could be responsible for the observed aggregation behavior. The outcome of this study is important for a better understanding of supramolecular structures of humic substances in ozonation, particularly those in drinking water treatment. 2010-04-27T04:37:38.351Z ]]>