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Performance of an inner tube-type gas-solid separator device in a UASB reactor
No full textIn this study a 3.3 m pilot-scale UASB reactor was operated to investigate the performance of an inner tube (IT)-type gas-solid separator (GSS) device, as well as the effects of the superficial gas velocity on the hydrodynamic characteristics of an upflow bioreactor The sludge hold-up efficiency of the IT-type GSS device increased gradually as the superficial gas production rate increased. When the superficial gas velocity was 0.26 m/h, the UASB reactor excluding the settling compartment was described as a non-ideal plug flow with a dead space of about 20%. However; when the superficial gas velocity increased to 0.67 m/h, the overall flow pattern was close to a completely stirred tank reactor (CSTR), without significant difference inflow pattern in the settler. (C) 1998 Elsevier Science Ltd.This study was fully supported by the Ministry of Commerce and Industry and the Daewoo Co., for which great acknowledgement is given
PRESERVATION CHARACTERISTICS OF ANAEROBIC GRANULAR SLUDGE
No full textThe preservation characteristics of granular sludges were investigated in terms of storing age and environmental condition. As a preservative index, physicochemical, microbiological, and morphological parameters were measured in order to quantify the change in granular sludge. Results from this research indicated that, as the anaerobic granular sludge had an outstanding preservation characteristic, UASB system could be effectively applied to the industries operating seasonally or intermittently
Treatment of landfill leachate using activated sludge process and electron-beam radiation
No full textElectron-beam (EB) radiation technology was applied to the Kimpo coastal landfill leachate to treat the biologically refractory substances remaining after an activated sludge process. Kimpo landfill leachates were analyzed in terms of molecular weight distribution (MWD) and aquatic humic substances (AHS) before and after the activated sludge process and EB radiation. When the raw leachate with an initial BOD of 1370 mg/l was treated by the activated sludge process, about 98% of BOD was successfully removed during the 72-h batch test. However, the biodegradability of leachate, defined as BOD/DOC, decreased from 1.3 to 0.1 due to the presence of biologically refractory organic matter. Fractionation of organic matter using an ultrafiltration apparatus revealed that large organics. above MW 30,000, were the most refractory component. However, this high organic component was sharply reduced after EB radiation. The AHS of the raw leachate and the effluent from activated sludge process (AS(eff)) were estimated to be 57.7 and 64.1% of DOG, respectively. When the AS(eff) was subjected to EB radiation at a dose of 30 kGy and pH 3, DOC concentration decreased from 324 to 215 mg/l and AHS content also fell from 68.6 to 52.9%. The efficiency of EB radiation was affected by pH condition and dose. In the case of AS,(eff), pH condition was the most important parameter affecting the efficiency of EB radiation. (C) 1999 Elsevier Science Ltd. All rights reserved
Anaerobic co-digestion of sewage sludge and food waste using two-stage anaerobic sequencing batch reactor processes
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Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
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