Estimation of biokinetic parameters in the acid fermentation of primary sludge using an anaerobic baffled reactor

2018 ◽  
Vol 4 (12) ◽  
pp. 1997-2011
Author(s):  
Allen Kurniawan ◽  
Yanuar Chandra Wirasembada ◽  
Ki Young Park ◽  
Young Mo Kim ◽  
Jin Hur ◽  
...  

Biokinetic models of anaerobic baffled reactor (ABR) type-acid fermentation with a short hydraulic retention time (HRT) of four days were proposed for obtaining high concentrations of volatile fatty acids (VFAs) based on the dynamic microbial growth rate.

2021 ◽  
Author(s):  
Umme Sharmeen Hyder

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.


2021 ◽  
Author(s):  
Umme Sharmeen Hyder

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.


2014 ◽  
Vol 28 (1) ◽  
pp. 13-23
Author(s):  
Se Young Kwon ◽  
Min Sun Kang ◽  
Se Woon Kim ◽  
Jung-Hun Shin ◽  
Han-Na Choi ◽  
...  

2021 ◽  
Author(s):  
Muhammed Ali Abdullah Khan

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.


2021 ◽  
Author(s):  
Muhammed Ali Abdullah Khan

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.


2019 ◽  
Vol 2019 ◽  
pp. 1-8 ◽  
Author(s):  
Qian Fang ◽  
Sinmin Ji ◽  
Dingwu Huang ◽  
Zhouyue Huang ◽  
Zilong Huang ◽  
...  

This study explores the use of alkaline pretreatments to improve the hydrolyzation of rice husks to produce volatile fatty acids (VFAs). The study investigated the effects of reagent concentration and pretreatment time on protein, carbohydrates, and dissolved chemical oxygen demand (SCOD) dissolution after the pretreatment. The optimum alkaline pretreatment conditions were 0.30 g NaOH (g VS)−1, with a reaction time of 48 h. The experimental results show that when comparing the total VFA (TVFA) yields from the alkaline-pretreated risk husk with those from the untreated rice husk, over 14 d and 2 d, the maximum value reached 1237.7 and 716.0 mg·L−1 with acetic acid and propionic acid and with acetic acid and butyric acid, respectively. After the alkaline pretreatment, TVFAs increased by 72.9%; VFA accumulation grew over time. The study found that alkaline pretreatment can improve VFA yields from rice husks and transform butyric acid fermentation into propionic acid fermentation. The study results can provide guidelines to support the comprehensive utilization of rice husk and waste treatment.


Energies ◽  
2019 ◽  
Vol 12 (4) ◽  
pp. 577 ◽  
Author(s):  
Gabriele Mancini ◽  
Stefano Papirio ◽  
Piet Lens ◽  
Giovanni Esposito

Rice straw is an abundant and sustainable substrate for anaerobic digestion (AD), but it is often deficient in essential trace elements (TEs) for proper microbial growth and metabolism. A lack of TEs leads to AD imbalances and suboptimal biogas yields. However, the total TE concentration is not a sufficient indicator of the amount of TEs available to the microorganisms. Therefore, this study investigated the degree of bioavailability of iron (Fe) and cobalt (Co) during the AD of rice straw, and correlated it to the biomethane yields and volatile fatty acids (VFAs) produced. When the two TEs were dosed at 205 µg Fe/g TS and 18 µg Co/g TS of rice straw, the biomethane production was approximately 260 mL CH4/g VS, i.e., similar to that obtained when Fe and Co were not added. Despite an increased bioavailable fraction of 23 and 48% for Fe and Co, respectively, after TEs addition, the AD performance was not enhanced. Moreover, VFAs did not exceed 250 mg HAc/L both in the presence and absence of added TEs, confirming no enhancement of the methanogenesis step. Therefore, the bioavailability of Fe and Co was not a limiting factor for the biomethane production at low total VFAs concentration.


1972 ◽  
Vol 27 (1) ◽  
pp. 57-64 ◽  
Author(s):  
Susan J. Henning ◽  
F. J. R. Hird

1. Wild rabbits were caught during both phases of the excretory cycle and their gut contents were analysed for volatile fatty acids (VFA).2. All rabbits were found to have high concentrations of VFA in the caecum and in the proximal colon. Acetic was the most abundant acid followed by n-butyric, then propionic.3. VFA concentrations in the caecum and in the proximal colon of rabbits caught during the day and during the night were similar. Hard pellets from the distal colon and rectum of rabbits caught during the night had considerably less VFA than did the soft pellets from rabbits caught during the day.4. Owing to the ingestion of soft faeces, the VFA content of stomach material was greater in rabbits caught during the day than in those caught at night.5. The results are discussed in terms of the mechanism of the diurnal excretion pattern and the role of coprophagy in the rabbit.


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