High-rate anaerobic hydrolysis and acidogenesis of sewage sludge in a modified upflow reactor

2003 ◽  
Vol 48 (4) ◽  
pp. 69-75 ◽  
Author(s):  
H.-Q. Yu ◽  
X.-J. Zheng ◽  
Z.-H. Hu ◽  
G.-W. Gu
Keyword(s):  
Fatty Acids ◽  
Sewage Sludge ◽  
Hydrogen Production ◽  
Production Rate ◽  
Retention Time ◽  
Methane Production ◽  
Volatile Fatty Acids ◽  
Suspended Solids ◽  
Hydraulic Retention Time ◽  
High Rate

Continuous experiments were conducted to study the hydrolysis and acidogenesis of sewage sludge in an upflow reactor with an agitator and a gas-liquid-solid separator. Results of this study showed that 34-78% of volatile suspended solids (VSS) in sewage sludge was hydrolyzed at pH in the range 4.0-6.5, 35°C and 4-24 hours of hydraulic retention time (HRT). About 31-65% of carbohydrate in sewage sludge, 20-45% of protein and 14-24% of lipid were acidified in this reactor. Hydrogen production was favored in lower pH and HRT, whereas methane production was encouraged at higher pH and HRT. Acetate, propionate, butyrate, and i-butyrate were the main aqueous acidogenic products. The distribution of these compounds in the effluent was more sensitive to pH, but was less sensitive to HRT. The maximum specific COD solubilization rate and specific volatile fatty acids production rate were 126 mg-COD/g-VSS·d and 102 mg-VFA/g-VSS·d, respectively. Compared with a CSTR, this modified upflow reactor was shown to be a more promising biosystem for the hydrolysis and acidogenesis of sewage sludge.

scholarly journals The Effect of pH And Hydraulic Retention Time On Production Of Volatile Fatty Acids From Primary Sludge Anaerobic Fermentation

2021 ◽  
Author(s):  
Umme Sharmeen Hyder
Keyword(s):  
Fatty Acids ◽  
Retention Time ◽  
Volatile Fatty Acids ◽  
Hydraulic Retention Time ◽  
Wastewater Treatment Plants ◽  
Anaerobic Fermentation ◽  
Nitrogen And Phosphorus ◽  
Primary Sludge ◽  
Effect Of Ph ◽  
Ph Range

Primary Sludge (PS) from wastewater treatment plants contains high biodegradable organic matter and therefore can be used to produce Volatile Fatty Acids (VFAs). The produced VFAs can be utilized in biological nitrogen and phosphorus removal processes as an external carbon source. The objective of this research was to investigate the effect of pH and hydraulic retention time (HRT) on the production of VFAs from PS through the anaerobic fermentation process. The experiments were conducted in both batch and semi-continuous flow regimes using bench scale fermenters under the mesophilic temperature. The Design of experiments included the HRT of 1 – 3 days and pH range of 4.5 - 11.0 for batch and 4.5 - 6.5 for semi-continuous modes. According to the obtained results, the VFAs production increased with an increase in HRT from 1 to 3 days. For the batch study, the pH range for maximum VFAs yield was pH 6.5 –10.0 achieved at HRT of 3 days. For the semi-continuous study, the maximum amount of VFAs production was observed at a pH of 6.5 and HRT of 3 days.

scholarly journals The Effect of pH And Hydraulic Retention Time On Production Of Volatile Fatty Acids From Primary Sludge Anaerobic Fermentation

2021 ◽  
Author(s):  
Umme Sharmeen Hyder
Keyword(s):  
Fatty Acids ◽  
Retention Time ◽  
Volatile Fatty Acids ◽  
Hydraulic Retention Time ◽  
Wastewater Treatment Plants ◽  
Anaerobic Fermentation ◽  
Nitrogen And Phosphorus ◽  
Primary Sludge ◽  
Effect Of Ph ◽  
Ph Range

Primary Sludge (PS) from wastewater treatment plants contains high biodegradable organic matter and therefore can be used to produce Volatile Fatty Acids (VFAs). The produced VFAs can be utilized in biological nitrogen and phosphorus removal processes as an external carbon source. The objective of this research was to investigate the effect of pH and hydraulic retention time (HRT) on the production of VFAs from PS through the anaerobic fermentation process. The experiments were conducted in both batch and semi-continuous flow regimes using bench scale fermenters under the mesophilic temperature. The Design of experiments included the HRT of 1 – 3 days and pH range of 4.5 - 11.0 for batch and 4.5 - 6.5 for semi-continuous modes. According to the obtained results, the VFAs production increased with an increase in HRT from 1 to 3 days. For the batch study, the pH range for maximum VFAs yield was pH 6.5 –10.0 achieved at HRT of 3 days. For the semi-continuous study, the maximum amount of VFAs production was observed at a pH of 6.5 and HRT of 3 days.

scholarly journals Effect of pH and hydraulic retention time on volatile fatty acids production from real waste in dark fermentation process

2021 ◽  
Author(s):  
Muhammed Ali Abdullah Khan
Keyword(s):  
Fatty Acids ◽  
Activated Sludge ◽  
Retention Time ◽  
Volatile Fatty Acids ◽  
Hydraulic Retention Time ◽  
Oxygen Demand ◽  
Biological Nutrient Removal ◽  
Waste Activated Sludge ◽  
Carbon Substrate ◽  
Primary Sludge

Waste-derived volatile fatty acids (VFAs) is an important carbon substrate for microorganisms engaged in the production of bioenergy, biodegradable plastics, and biological nutrient removal process. In this project, the generation and applications of waste-derived VFA were examined. Three solid wastes were used Primary sludge (PS), thickened waste activated sludge (TWAS) which were collected from Ashbridges Bay and source separated organics (SSO) that was collected from Disco Road facility. All the water quality analyses such as pH, TCOD, SCOD, TVFA, TSS, VSS, NH3 and, alkalinity were monitored. The results of this study showed that with increasing the Hydraulic retention time (HRT), the percentage of acidification increased. Furthermore, the results showed that alkaline pH was better than the acid pHs. Keywords: Total Volatile Fatty Acids, Soluble Chemical Oxygen Demand, Primary Sludge, Thickened Waste Activated Sludge, Source Separated Organics.

scholarly journals Effect of pH and hydraulic retention time on volatile fatty acids production from real waste in dark fermentation process

2021 ◽  
Author(s):  
Muhammed Ali Abdullah Khan
Keyword(s):  
Fatty Acids ◽  
Activated Sludge ◽  
Retention Time ◽  
Volatile Fatty Acids ◽  
Hydraulic Retention Time ◽  
Oxygen Demand ◽  
Biological Nutrient Removal ◽  
Waste Activated Sludge ◽  
Carbon Substrate ◽  
Primary Sludge

Waste-derived volatile fatty acids (VFAs) is an important carbon substrate for microorganisms engaged in the production of bioenergy, biodegradable plastics, and biological nutrient removal process. In this project, the generation and applications of waste-derived VFA were examined. Three solid wastes were used Primary sludge (PS), thickened waste activated sludge (TWAS) which were collected from Ashbridges Bay and source separated organics (SSO) that was collected from Disco Road facility. All the water quality analyses such as pH, TCOD, SCOD, TVFA, TSS, VSS, NH3 and, alkalinity were monitored. The results of this study showed that with increasing the Hydraulic retention time (HRT), the percentage of acidification increased. Furthermore, the results showed that alkaline pH was better than the acid pHs. Keywords: Total Volatile Fatty Acids, Soluble Chemical Oxygen Demand, Primary Sludge, Thickened Waste Activated Sludge, Source Separated Organics.

scholarly journals Application of membrane-coupled anaerobic volatile fatty acids fermentor for dissolved organics recovery from coagulated raw sludge

2002 ◽  
Vol 45 (12) ◽  
pp. 167-174 ◽  
Author(s):  
J.-O. Kim ◽  
I. Somiya ◽  
E.-B. Shin ◽  
W. Bae ◽  
S.-K. Kim ◽  
...  
Keyword(s):  
Fatty Acids ◽  
Retention Time ◽  
Membrane Filtration ◽  
Volatile Fatty Acids ◽  
Hydraulic Retention Time ◽  
Hydrolysis Rate ◽  
Organic Loading Rate ◽  
Recovery Ratio ◽  
Operational Parameters ◽  
Dissolved Organics

To investigate the treatment performance of membrane-coupled anaerobic volatile fatty acids fermentor system, the effects of operational parameters for volatile fatty acids production were evaluated through experiments and a mathematical model. The volatile fatty acids recovery ratio was largely affected by the change of hydraulic retention time, reaching its maximum value at 12 hrs. Over the range of hydraulic retention time 8 to 96 hrs, the volatile fatty acids recovery ratio decreased with the increase of hydraulic retention time above 12 hrs, while the ratio of mineralization and gasification increased. Hydraulic retention time and membrane filtration ratio should be maintained less than 1 day and above 0.9, respectively, to attain over 40% of organic materials recovery ratio at 10 days of solids retention time. When the hydrolysis rate constant was 0.01 hr−1, the organic loading rate should be maintained at above 1.0 (kgC/m3/day) to attain over 45% of volatile fatty acids recovery ratio. Based on experimental and simulated results, membrane-coupled anaerobic volatile fatty acids fermentor system was thought to be effective for dissolved organics recovery from coagulated sewage sludge.

Effects of Heat Treatment on the High-Rate Anaerobic Digestion of Human Wastes Concentrates

1991 ◽  
Vol 23 (7-9) ◽  
pp. 1137-1145 ◽  
Author(s):  
M. Takashima ◽  
Y. Sugawara ◽  
T. Ohkawa ◽  
Y. Ohkubo
Keyword(s):  
Heat Treatment ◽  
Fatty Acids ◽  
Anaerobic Digestion ◽  
Methane Production ◽  
Volatile Fatty Acids ◽  
High Rate ◽  
Heat Treated ◽  
Solids Separation ◽  
Human Wastes ◽  
Severe Degree

Effects of heat treatment (100-250 °C, 1 hour) on the solubilization of particulate organic matter and methane production were examined using human wastes concentrates with a view to applying an anaerobic digestion technology to human wastes. In batch studies, the heat treatments above 150 ° C were found to inhibit methane production to a severe degree as the temperature was raised. The addition of powdered activated carbon (PAC) or calcium to the heat-treated concentrates showed a complete reduction of the inhibition. This remedial effect of calcium and measurements on volatile fatty acids make long-chain fatty acids suspected as the inhibitory substances produced. The effectiveness of the heat treatment at 150 and 175 ° C was demonstrated in a continuous study which simulated a high-rate digestion process having a solids separation device, and was conducted at a HRT of 2.5 days and SRT of about 15 days and at a mesophilic operating temperature of 35 ° C : the fraction of particulate substrates solubilized increased about two-fold, and methane production increased 40% when combined with the PAC addition.

Granulation and sludge retainment during start-up of a thermophilic UASB reactor

1998 ◽  
Vol 38 (8-9) ◽  
pp. 349-357 ◽  
Author(s):  
Kazuaki Syutsubo ◽  
Hideki Harada ◽  
Akiyoshi Ohashi
Keyword(s):  
Fatty Acids ◽  
Sewage Sludge ◽  
Retention Time ◽  
Volatile Fatty Acids ◽  
Synthetic Wastewater ◽  
Uasb Reactor ◽  
Start Up ◽  
Thermophilic Conditions ◽  
Digested Sewage Sludge ◽  
Granulation Mechanism

A laboratory-scale UASB reactor was operated at 55°C over 600 days in order to investigate the granulation mechanism under thermophilic conditions. The reactor was seeded with a thermophilic digested sewage sludge, and fed with a synthetic wastewater composed of sucrose and volatile fatty acids. As a result of establishment of the whole granulated sludge bed, the reactor allowed ultimately a volumetric COD loading of 45 kgCOD m−3 d−1 with 90% COD removal. The maximum sludge loading achieved was 3.7 gCOD·gVSS−1 d−1, that is two to three times as large as that of mesophilically grown sludge. The behavior of SRT (sludge retention time) was closely correlated with the biogas evolution flux: excessive biogas evolution at the highest COD loading (45 kgCOD m−3 d−1) enhanced the sludge washout, and thus led to shortening of SRT into less than 7 days. Methanogenic activities of the retained sludge increased finally up to 110 times for acetate, 25 times for propionate, and 3.6 times for hydrogen as large as those of the seeded sludge.

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