Publications by authors named "Gordon Ooi"

A hybrid wastewater treatment process with combined attached biofilm (moving bed biofilm reactor) and activated sludge, named as Hybas™, was implemented for the treatment of municipal wastewater. The system consisted of six staged reactors in series including pre-denitrification and nitrification in the Hybas™ line and post-denitrification in a pure MBBR. In addition to the significant removal of nutrients and organic matter from municipal wastewater, Hybas™ also showed removal capacity for pharmaceuticals.

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Hospital wastewater contains high concentrations of pharmaceuticals, which pose risks to receiving waters. In this study, a pilot plant consisting of six moving bed biofilm reactors (MBBRs) in series (with the intention to integrate Biological Oxygen Demand (BOD) removal, nitrification and denitrification as well as prepolishing Chemical Oxygen Demand (COD) for ozonation) was built to integrate pharmaceutical removal and intermittent feeding of the latter reactors aimed for micropollutant removal. Based on the experimental resultss, nitrifying MBBRs achieved higher removal as compared to denitrifying MBBRs except for azithromycin, clarithromycin, diatrizoic acid, propranolol and trimethoprim.

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Previous studies have demonstrated that aerobic moving bed biofilm reactors (MBBRs) remove pharmaceuticals better than activated sludge. Thus we used a MBBR system to polish the effluent of an activated sludge wastewater treatment plant. To overcome that effluent contains insufficient organic matter to sustain enough biomass, the biofilm was intermittently fed with raw wastewater.

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Clindamycin is widely prescribed for its ability to treat a number of common bacterial infections. Thus, clindamycin enters wastewater via human excretion or disposal of unused medication and widespread detection of pharmaceuticals in rivers proves the insufficiency of conventional wastewater treatment plants in removing clindamycin. Recently, it has been discovered that attached biofilm reactors, e.

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The degradation of organic micropollutants in wastewater treatment is suspected to depend on co-degradation i.e. be dependent on concentrations of substrate.

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Hospital wastewater represents a significant input of pharmaceuticals into municipal wastewater. As Moving Bed Biofilm Reactors (MBBRs) appear to remove organic micro-pollutants, hospital wastewater was treated with a pilot plant consisting of three MBBRs in series. The removal of pharmaceuticals was studied in two experiments: 1) A batch experiment where pharmaceuticals were spiked to each reactor and 2) a continuous flow experiment at native concentrations.

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Hospital wastewater contributes a significant input of pharmaceuticals into municipal wastewater. The combination of suspended activated sludge and biofilm processes, as stand-alone or as hybrid process (hybrid biofilm and activated sludge system (Hybas™)) has been suggested as a possible solution for hospital wastewater treatment. To investigate the potential of such a hybrid system for the removal of pharmaceuticals in hospital wastewater a pilot plant consisting of a series of one activated sludge reactor, two Hybas™ reactors and one moving bed biofilm reactor (MBBR) has been established and adapted during 10 months of continuous operation.

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