Oxidation of isobutene to methacrolein using bismuth molybdate catalysts: Comparison of operation in periodic and continuous feed mode

2005 ◽  
Vol 236 (2) ◽  
pp. 282-291 ◽  
Author(s):  
N SONG ◽  
C RHODES ◽  
J BARTLEY ◽  
S TAYLOR ◽  
D CHADWICK ◽  
...  
2006 ◽  
Vol 53 (9) ◽  
pp. 185-191 ◽  
Author(s):  
Xiaoling Zhang ◽  
Zhiying Wang ◽  
Qing Zhao

Biological phosphorus removal was studied in a sequencing batch reactor (SBR). The results showed that nitrite could be used as electron acceptor in denitrifying phosphorus removal. Feed mode of nitrite had significant influence on denitrifying phosphorus removal. Anoxic phosphorus assimilation rate could reach 10.44 mgP/gSS.h and the percentage of anoxic phosphorus assimilation amount was more than 97% with continuous feed mode. Granular sludge with denitrifying phosphorus removal activity was found in the SBR. The effects of different operational conditions, such as COD loading, settling time, HRT etc., on the formation of granules were also studied.


1997 ◽  
Vol 35 (8) ◽  
pp. 145-152 ◽  
Author(s):  
T. Panswad ◽  
L. Komolmethee

This research was to determine the effects of hydraulic shock loads by intermittent feeding on the removal efficiency of a small prefabricated real-sized septic tank/anaerobic filter unit. Besides the ‘control’ 24-hour continuous runs the other twice a day feeding periods covered 16, 12 and 8 hours per day, with the tank's retention time varying from 22.5 to 90 hours. It was demonstrated that the variation of the hydraulic feeding patterns ranging from 24-hour continuous feed to 8 h per day intermittent feed did not affect the performance of the system much. The percentage of BOD reduction was decreased from 85 to 82 and 81 percent for the feed times of 24, 16 and 8 hours per day, respectively. The tank capacity played a relatively major role in determining the removal efficiency of the process. The efficiency of BOD and SS reduction dwindled from 82.2 to 68.9 and 56.0% with the corresponding reduction in tank sizes from 90 to 45 and 22.5 hours retention, respectively. In any event, the unit could not satisfactorily remove nutrients. A retention period of not less than 48 hours is recommended if the Thai effluent standards are to be met. Equations for predicting the BOD removal capability were also developed.


2000 ◽  
Vol 41 (4-5) ◽  
pp. 503-508 ◽  
Author(s):  
R.F. Gonçalves ◽  
F. Rogalla

This work describes laboratory scale research about Enhanced Biological Phosphorus Removal (EBPR) in a submerged biofilter under Anaerobic/Oxic (A/O) alternation and continuous feed. Its main purpose is to detail the behaviour of the reactor throughout the anaerobic and the aerobic phases of the A/O cycle, to study the importance of the anaerobic phase in the selection of the EBPR bacteria in the biofilm and to evaluate the consumption and the importance of the organic substrate during the anaerobic phase. The mass balance over the Phosphorus (P) element indicates that long anaerobic phases (6 h) are more efficient than short ones (3 h) as a selector of EBPR bacteria in biofilms. In both comparisons, thespecific mass of P released in a 6 h period represents almost 50% more than the amount of P release in the shorter period (3 h). However, the presence of rapidly biodegradable COD in the influent of the anaerobic phase is a more effective selector, more important than the duration of the anaerobic phase: by doubling the amount of acetic acid in the influent, a similar 50% increase of P-release can be achieved at short anaerobic periods of 3 h. The effect of the strategy adopted in this study, focusing on selecting EBPR bacteria in biofilm, is shown by the P levels of 4% (total P/SST) in the sludge removed from the BF by backwashing in all periods.


2021 ◽  
Vol 209 ◽  
pp. 111828
Author(s):  
Alagumalai Krishnapandi ◽  
Balamurugan Muthukutty ◽  
Shen-Ming Chen ◽  
Kumaravelu Thanigai Arul ◽  
Huang Ji Shiuan ◽  
...  

2015 ◽  
Vol 59 (2) ◽  
pp. 205011-205017 ◽  
Author(s):  
Akira Sakamoto ◽  
Manabu Numata ◽  
Yasuhiro Ogasawara ◽  
Mami Hatanaka ◽  
Yukari Motosugi ◽  
...  

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