Browsing by Author "You, HS"

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Behavior of membrane scaling during crossflow filtration in the anaerobic MBR system
(2006)
You, HS
;
Huang, CP
;
Pan, JR
;
Chang, SC
;
環境工程研究所
Fouling of membrane bioreactor (MBR) has been studied intensively. Because of the high concentration of carbonates, scaling can be a serious problem in anaerobic bioreactor, which attracts little attention. In this study, the wastewater was treated with an anaerobic process followed by either a submerged or a side-stream aerobic membrane reactor. The wastewater was spiked with calcium to investigate the effect of scaling on membrane filtration. Very little scaling was detected in the external membrane system (the side-stream MBR). Results from chemical cleaning of internal membrane system indicated that the flux decline caused by membrane scaling was far more severe than that by membrane fouling. However, the flux decline from membrane scaling can be effectively recovered by the chemical cleaning of EDTA and NaOCl. Fouling of membrane bioreactor (MBR) has been studied intensively. Because of the high concentration of carbonates, scaling can be a serious problem in anaerobic bioreactor, which attracts little attention. In this study, the wastewater was treated with an anaerobic process followed by either a submerged or a side-stream aerobic membrane reactor. The wastewater was spiked with calcium to investigate the effect of scaling on membrane filtration. Very little scaling was detected in the external membrane system (the side-stream MBR). Results from chemical cleaning of internal membrane system indicated that the flux decline caused by membrane scaling was far more severe than that by membrane fouling. However, the flux decline from membrane scaling can be effectively recovered by the chemical cleaning of EDTA and NaOCl.
Effect of biofiltration on particle characteristics and flocculation behavior
(2005-06-01)
You, HS
;
Huang, CP
;
Cheng, HS
;
Pan, JR
;
環境工程研究所
Biodegradable dissolved organic material and ammonia present problems for conventional water treatment processes and may contribute to biological instability in the treated water. One solution may be to use a biological process upstream of the regular water treatment process. Biofiltration may be cost-effective in removing ammonia and the precursors of trihalomethanes but the characteristics of the biotreated effluent may affect to the subsequent coagulation process. A continuous flow biological filter packed with reticulated polyurethane foam markedly altered the particle size distribution and the charge density of the mixed liquor, shifting the granulometric distribution toward larger sizes. The mean and median diameter of the particles increased from 9.7 and 5.9 mu m to 97.6 and 37.1 mu m, respectively. The average charge density of the biofilter effluent (7.6 meq dm(-3)) was much lower than that of the raw water (12.7 meq dm(-3)). The optimum coagulant dosage for the subsequent coagulation was reduced substantially from 10 mg dm(-3) to 1 mg dm(-3) as Al due to the lowered charge density of the mixed liquor and the enhanced cation bridging of the extracellular polymers on the bioparticle surface. (c) 2005 Society of Chemical Industry.