Submersible probe type microbial electrochemical sensor for volatile fatty acids monitoring in the anaerobic digestion process

2019 ◽  
Vol 232 ◽  
pp. 1371-1378 ◽  
Author(s):  
Yong Jiang ◽  
Na Chu ◽  
Raymond Jianxiong Zeng
Keyword(s):  
Fatty Acids ◽  
Anaerobic Digestion ◽  
Electrochemical Sensor ◽  
Volatile Fatty Acids ◽  
Probe Type ◽  
Anaerobic Digestion Process ◽  
Digestion Process

scholarly journals Bio-electrolytic sensor for rapid monitoring of volatile fatty acids in anaerobic digestion process

2017 ◽  
Vol 111 ◽  
pp. 74-80 ◽  
Author(s):  
Xiangdan Jin ◽  
Xiaohu Li ◽  
Nannan Zhao ◽  
Irini Angelidaki ◽  
Yifeng Zhang
Keyword(s):  
Fatty Acids ◽  
Anaerobic Digestion ◽  
Volatile Fatty Acids ◽  
Anaerobic Digestion Process ◽  
Digestion Process ◽  
Rapid Monitoring

Highly Efficient Anaerobic Digestion with Thermal Pretreatment

1985 ◽  
Vol 17 (4-5) ◽  
pp. 529-539 ◽  
Author(s):  
M. Hiraoka ◽  
N. Takeda ◽  
S. Sakai ◽  
A. Yasuda
Keyword(s):  
Fatty Acids ◽  
Anaerobic Digestion ◽  
Pilot Plant ◽  
Molecular Size ◽  
Gas Production ◽  
Thermal Pretreatment ◽  
Anaerobic Digestion Process ◽  
Digestion Process ◽  
Before And After ◽  
Pilot Plant Study

The effectiveness of an anaerobic digestion process with thermal pretreatment at a comparatively low temperature was examined. The waste activated sludge was thermally pretreated in the process. A laboratory scale experiment and a pilot plant study were conducted. Changes in volatile acids concentration, in major constituents of sludge and in molecular size distribution were examined before and after thermal pretreatment and anaerobic digestion. Thermal pretreatment resulted in an increase of more than 30 percent in digestion gas production. The major substrates decomposed were fats in the pilot plant study. Glyceride fatty acids are decomposed with thermal pretreatment and produce volatile acids such as acetic and propionic acids. The volatile acids are directly utilized by anaerobes to produce methane. Organic matter such as fats and carbohydrates are depolymerized with thermal pretreatment and produce soluble intermediate compounds such as higher fatty acids. The intermediates are utilized in the anaerobic digestion process. These two major effects facilitate the methane production process.

Evaluation of a four year experience with a fully instrumented anaerobic digestion process

2002 ◽  
Vol 45 (4-5) ◽  
pp. 495-502 ◽  
Author(s):  
J.P. Steyer ◽  
J.C. Bouvier ◽  
T. Conte ◽  
P. Gras ◽  
P. Sousbie
Keyword(s):  
Wastewater Treatment ◽  
Anaerobic Digestion ◽  
Gas Flow ◽  
Volatile Fatty Acids ◽  
Fixed Bed ◽  
Total Alkalinity ◽  
Wastewater Treatment Process ◽  
Loop Control ◽  
Anaerobic Digestion Process ◽  
Digestion Process

For several years, a 1 m3 fixed bed anaerobic digestion process has been operated for the treatment of distillery vinasses. This reactor has been fully instrumented with the following variables available on-line: pH, temperature, liquid and gas flow rates, gas composition (i.e., CH4, CO2 and H2), concentration of bicarbonate, chemical oxygen demand, total organic carbon, volatile fatty acids and partial and total alkalinity, these last four variables being measured twice by different techniques (i.e., using a TOC analyzer, a titrimetric sensor and an infrared spectrometer). The purpose of this paper is to compare the respective benefits of advanced instrumentation for the monitoring of wastewater treatment processes in general, and for anaerobic digestion in particular. It will also provide some statistical analysis of the time required to operate a fully instrumented wastewater treatment process. It is indeed well admitted in the literature that instrumentation is usually the main limitation step for using closed-loop control. However, it is our opinion that, in the near future, this situation will change. This point is discussed based on our four years practical experience.

Volatile Fatty Acids Production through Degradation of Biomass by Anaerobic Digestion (Mesophilic and Thermophilic)

2014 ◽  
Vol 567 ◽  
pp. 172-176
Author(s):  
Ahmad Fitri Abd Rahim ◽  
Shamsul Rahman Mohamed Kutty ◽  
Ezerie Henry Ezechi
Keyword(s):  
Fatty Acids ◽  
Anaerobic Digestion ◽  
Standard Method ◽  
Volatile Fatty Acids ◽  
Suspended Solid ◽  
Anaerobic Sludge ◽  
Cycle Period ◽  
Mixed Liquor ◽  
Digestion Process ◽  
Wide Range

Volatile fatty acids (VFAs) are fatty acids with a carbon chain of six carbons or fewer and usually referred to as short-chain fatty acids (SCFA). Degradation of biomass through anaerobic digestion will produce volatile fatty acid (VFAs) through anaerobic digestion process. The volatile fatty acids obtained can be recovered and used to produce methyl or ethyl esters which, could be advantageously used as additive for biodiesel [1]. Anaerobic digestion is a biological process that can degrade waste organic material by concerted action of a wide range of microorganisms in the absence of oxygen. The objective of this study is to degrade the biomass through anaerobic digestion for the production of volatile fatty acids by two different temperatures condition which are mesophilic and thermophilic; 35°C and 55°C respectively. The production of volatile fatty acids was optimized by varying the cycle period of the digestion process with the concentration of Mixed Liquor Suspended Solid (MLSS) maintained at 8000 mg/L for each cycle. The degradation of biomass was carried out using anaerobic sludge digester which 2L of biomass was digested from day 1 until day 24 (cycle period). The tests of MLSS and Mixed Liquor Volatile Suspended Solid (MLVSS) was conducted by Standard Method 2540-D while test for VFAs was conducted through Standard Method 8196. The highest production of volatile fatty acids was obtained in day 5 of cycle period where the concentration is 441 mg/L as acetic acid (HOAC).

A Mathematical Model for the Anaerobic Digestion Process Applied to a Mixture of Night Soil and Septic Tank Sludge

1986 ◽  
Vol 18 (7-8) ◽  
pp. 239-248 ◽  
Author(s):  
Sung Ryong Ha ◽  
Dwang Ho Lee ◽  
Sang Eun Lee
Keyword(s):  
Mathematical Model ◽  
Anaerobic Digestion ◽  
Biomass Concentration ◽  
Gas Production ◽  
Septic Tank ◽  
Volatile Acid ◽  
Hydraulic Residence Time ◽  
Anaerobic Digestion Process ◽  
Digestion Process ◽  
Proposed Model

Laboratory scale experiments were conducted to develop a mathematical model for the anaerobic digestion of a mixture of night soil and septic tank sludge. The optimum mixing ratio by volume between night soil and septic tank sludge was found to be 7:3. Due to the high solids content in the influent waste, mixed-liquor volatile suspended solids (MLVSS) was not considered to be a proper parameter for biomass concentration, therefore, the active biomass concentration was estimated based on deoxyribonucleic acid (DNA) concentration in the reactor. The weight ratio between acidogenic bacteria and methanogenic bacteria in the mixed culture of a well-operated anaerobic digester was approximately 3:2. The proposed model indicates that the amount of volatile acid produced and the gas production rate can be expressed as a function of hydraulic residence time (HRT). The kinetic constants of the two phases of the anaerobic digestion process were determined, and a computer was used to simulate results using the proposed model for the various operating parameters, such as BOD5 and volatile acid concentrations in effluent, biomass concentrations and gas production rates. These were consistent with the experimental data.

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