Browsing by Author "Lin, GT"

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Application of a membrane bioreactor system for opto-electronic industrial wastewater treatment - a pilot study
(2003)
Chen, TK
;
Chen, JN
;
Ni, CH
;
Lin, GT
;
Chang, CY
The membrane bioreactor (MBR) system has become more and more attractive in the field of wastewater treatment. It is particularly attractive in situations where long solids retention times are required, such as nitrifying bacteria, and physical retention is critical to achieving more efficiency for biological degradation of pollutants. Although it is a new technology, the MBR process has been applied to industrial wastewater treatment for only the past decade. The opto-electronic industry, developed very fast over the past decade in the world, is a high technological manufacturing industry. The treatment of the opto-electronic industrial wastewater containing a significant quantity of organic nitrogen compounds, with a ratio over 95% in organic nitrogen (Org-N) to total nitrogen (T-N), is very difficult to meet the discharge limits. The purpose of this research is mainly to discuss the treatment capacity of high-strength organic nitrogen wastewater, and to investigate the capabilities of the MBR process. A 2 m(3)/day capacity MBR pilot plant consisting of anoxic and aerobic tanks and a membrane bioreactor was installed for evaluation. The operation was continued for 130 days. Over the whole experimental period, a satisfactory organic removal performance was achieved. The COD could be removed with an average of over 94.5%. For TOC and BOD5, the average removal efficiencies were 96.3 and 97.6%, respectively. The nitrification and denitrification were also successfully achieved. The effluent did not contain any suspended solids. Only a small concentration of ammonia nitrogen was found in the effluent. The stable effluent quality and satisfactory removal performance mentioned above were ensured by the efficient interception performance of the membrane device incorporated within the biological reactor. The MBR system shows promise as a means of treating very high organic nitrogen wastewater without dilution. The effluent of TKN, NOx-N and COD can fall below 20 mg/L, 30 mg/L and 50 mg/L.
Identification and characterization of KvgAS, a two-component system in Klebsiella pneumoniae CG43
(2003-01-21)
Lai, YC
;
Lin, GT
;
Yang, SL
;
Chang, HY
;
Peng, HL
A two-component system encoding gene cluster kvgAS that is present only in virulent Klebsiella pneumoniae CG43 was isolated and its sequence determined. RT-PCR and Southern analysis demonstrated that kvgAS is organized as an operon. No apparent effect of a kvgS deletion on bacterial virulence was observed in a mouse peritonitis model. In the presence of paraquat or 2,2-dipyridyl, the activity of kvgAS promoter in the kvgS mutant was found to be reduced to half of the level in the wild-type strain. The data suggest that the KvgAS system is autoregulated and plays a role in countering free radical stresses and sensing iron-limiting conditions. (C) 2002 Federation of European Microbiological Societies. Published by Elsevier Science B.V. All rights reserved.