Polyhydroxyalkanoate production using two‐stage continuous stirred tank activated sludge systems with glycerol as a carbon source

Author(s):  
Pimsiri Heepkaew ◽  
Benjaporn Boonchayaanant Suwannasilp
1999 ◽  
Vol 39 (6) ◽  
pp. 61-68 ◽  
Author(s):  
Klangduen Pochana ◽  
Jürg Keller

Experiments have been performed to gain an understanding of the conditions and processes governing the occurrence of SND in activated sludge systems. Sequencing batch reactors (SBRs) have been operated under controlled conditions using the wastewater from the first anaerobic pond in an abattoir wastewater treatment plant. Under specific circumstances, up to 95% of total nitrogen removal through SND has been found in the system. Carbon source and oxygen concentrations were found to be important process parameters. The addition of acetate as an external carbon source resulted in a significant increase of SND activity in the system. Stepwise change of DO concentration has also been observed in this study. Experiments to determine the effect of the floc size on SND have been performed in order to test the hypothesis that SND is a physical phenomenon, governed by the diffusion of oxygen into the activated sludge flocs. Initial results support this hypothesis but further experimental confirmation is still required.


2013 ◽  
Vol 8 (1) ◽  
pp. 18-26
Author(s):  
T. Weinpel ◽  
V. Bakos ◽  
A. Jobbágy

Part-time aeration is frequently applied in activated sludge systems in order to decrease treatment costs by achieving nitrification and denitrification in the same basin. However, measurements and mathematical simulations carried out at the North-Budapest Wastewater Treatment Plant (Budapest, Hungary), clearly show that especially in the increasingly characteristic shortage of readily biodegradable carbon-source, this technique may lead to high effluent nitrate and/or ammonia concentrations at decreased temperatures. This situation may be worsened when co-digestion of external wastes with high N-content increase the ammonia concentration of sludge processing return flows. In these cases, denitrification should rather be enhanced in pre-anoxic zones. Pronounced pre-denitrification leads to better usage of the influent carbon-source and to considerably less methanol demand when dosing external carbon-source proves to be necessary.


2010 ◽  
Vol 152-153 ◽  
pp. 702-707
Author(s):  
An Ying Jiao ◽  
Yong Feng Li ◽  
Bing Liu ◽  
Kun Liu ◽  
Jing Li Xu

Ethanoligenens sp. R3 isolated from anaerobic sludge in a continuous stirred tank reactor was investigated for its characteristics of fermentative hydrogen production in this study. Effects of initial pH value, fermentation temperature and proportion of carbon/nitrogen source on hydrogen production were investigated in batch experiments. The typical substrate for hydrogen production of glucose and peptone were used as the carbon source and nitrogen source, respectively. The results show that the maximum hydrogen production yield of 834 mlH2/L culture was obtained with initial pH value of 5.5 and fermentation temperature at 35°C. In addition, the maximum average hydrogen production rate of 10.87mmolH2/g cell dry weighth was achieved at the carbon/nitrogen source ratio of 3.3. The degradation efficiency of the glucose used as the carbon source ranged from 91.5% to 95.43% during the conversion of glucose to hydrogen by bacteria Ethanoligenens sp. R3.


2001 ◽  
Vol 43 (1) ◽  
pp. 83-90 ◽  
Author(s):  
J. van Heerden ◽  
M. M. Ehlers ◽  
T. E. Cloete

In this study, different carbon source profiles were generated by inoculating Biolog GN microwell plates, with different dilutions of microbial communities from a number of activated sludge systems. This led to the successful generation of patterns reflecting diversity and evenness in the different systems. The high number of substrates utilized at the lower dilutions (10–1 and 10–2) indicated a high microbial diversity in the community, but not necessarily evenness of each species. Evenness of each species was reflected upon further dilution. Our results indicated differences in the microbial community composition amongst some of the activated sludge systems studied. These differences were not specifically related to phosphate removing and non phosphate removing systems.


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