On-line measurements of COD, TOC, VFA, total and partial alkalinity in anaerobic digestion processes using infra-red spectrometry

2002 ◽  
Vol 45 (10) ◽  
pp. 133-138 ◽  
Author(s):  
J.P. Steyer ◽  
J.C. Bouvier ◽  
T. Conte ◽  
P. Gras ◽  
J. Harmand ◽  
...  
Keyword(s):  
Anaerobic Digestion ◽  
Volatile Fatty Acids ◽  
Ph Regulation ◽  
Oxygen Demand ◽  
Total Alkalinity ◽  
Treatment Processes ◽  
Infra Red ◽  
Biomass Activity ◽  
On Line ◽  
Ft Ir

This paper describes the use of a Fourier Transform Infra-Red (FT-IR) spectrometer as an on-line sensor to measure Chemical Oxygen Demand (COD), Total Organic Carbon (TOC), Volatile Fatty Acids (VFA), and Partial and Total Alkalinity (PA and TA) in anaerobic digestion processes for the treatment of industrial wastewaters. Comparison with manual off-line analysis and with an on-line industrial TOC analyser and an on-line titrimetric sensor (for the measurements of VFA, TA and PA) are provided to demonstrate the interest of spectral analysis in the mid infra-red domain for the monitoring of anaerobic digestion processes. In order to further illustrate the advantages of using such a technique, on-line measurements recorded during an accident of the pH regulation in the input (pH in the reactor went above 11 and biomass activity stopped) are shown. They demonstrate that, if carefully performed, the calibration can be extended outside its range while being still compatible with requirements of wastewater treatment processes.

Alkali pre-treatment of Sorghum Moench for biogas production

2013 ◽  
Vol 67 (9) ◽  
Author(s):  
Karina Michalska ◽  
Stanisław Ledakowicz
Keyword(s):  
Anaerobic Digestion ◽  
Chemical Oxygen Demand ◽  
Volatile Fatty Acids ◽  
Biogas Production ◽  
Oxygen Demand ◽  
Total Phenolic ◽  
Methane Generation ◽  
Pre Treatment ◽  
Alkali Hydrolysis ◽  
Almost All

AbstractThis work studies the influence of the alkali pre-treatment of Sorghum Moench — a representative of energy crops used in biogas production. Solutions containing various concentrations of sodium hydroxide were used to achieve the highest degradation of lignocellulosic structures. The results obtained after chemical pre-treatment indicate that the use of NaOH leads to the removal of almost all lignin (over 99 % in the case of 5 mass % NaOH) from the biomass, which is a prerequisite for efficient anaerobic digestion. Several parameters, such as chemical oxygen demand, total organic carbon, total phenolic content, volatile fatty acids, and general nitrogen were determined in the hydrolysates thus obtained in order to define the most favourable conditions. The best results were obtained for the Sorghum treated with 5 mass % NaOH at 121°C for 30 min The hydrolysate thus achieved consisted of high total phenolic compounds concentration (ca. 4.7 g L−1) and chemical oxygen demand value (ca. 45 g L−1). Although single alkali hydrolysis causes total degradation of glucose, a combined chemical and enzymatic pre-treatment of Sorghum leads to the release of large amounts of this monosaccharide into the supernatant. This indicates that alkali pre-treatment does not lead to complete cellulose destruction. The high degradation of lignin structure in the first step of the pre-treatment rendered the remainder of the biomass available for enzymatic action. A comparison of the efficiency of biogas production from untreated Sorghum and Sorghum treated with the use of NaOH and enzymes shows that chemical hydrolysis improves the anaerobic digestion effectiveness and the combined pre-treatment could have great potential for methane generation.

Effect of Ultrasonic Pretreatment for the Anaerobic Digestion of Sewage Sludge

2012 ◽  
Vol 531 ◽  
pp. 528-531 ◽  
Author(s):  
Na Wei
Keyword(s):  
Anaerobic Digestion ◽  
Sewage Sludge ◽  
Volatile Fatty Acids ◽  
Biogas Production ◽  
Oxygen Demand ◽  
High Concentration ◽  
Ultrasonic Pretreatment ◽  
Soluble Chemical Oxygen Demand ◽  
Pre Treatment ◽  
Settling Characteristics

Anaerobic digestion is an economic and environmentally friendly technology for treating the biomass material-sewage sludge, but has some limitations, such as the low efficient biogass production. In this paper ultrasound was proposed as pre-treatment for effective sludge anaerobic digestion. Sludge anaerobic digestion experiments with ultrasonic pretreatment was investigated. It can be seen that this treatment effectively leaded to the increase of soluble chemical oxygen demand(SCOD) and volatile fatty acids(VFA)concentration. High concentration of VFA leaded to a increase in biogas production. Besides, the SV of sludge was reduced and the settling characteristics of sludge was improved after ultrasonic pretreatment. It can be concluded that sludge anaerobic digestion with ultrasonic pretreatment is an effective method for biomass material transformation.

Temperature effects on the trophic stages of perennial rye grass anaerobic digestion

2011 ◽  
Vol 64 (1) ◽  
pp. 70-76 ◽  
Author(s):  
D. Cysneiros ◽  
A. Thuillier ◽  
R. Villemont ◽  
A. Littlestone ◽  
T. Mahony ◽  
...  
Keyword(s):  
Anaerobic Digestion ◽  
Low Temperature ◽  
Methane Production ◽  
Volatile Fatty Acids ◽  
Oxygen Demand ◽  
Production Performance ◽  
Batch Mode ◽  
Rye Grass ◽  
Long Term Experiment ◽  
Rate Limiting

Continuous Stirred Tank Reactors (CSTRs), operated in batch mode, were used to evaluate the feasibility of psychrophilic (low temperature) digestion of perennial rye grass in a long term experiment (150 days) for the first time. The reactors were operated in parallel at 3 different temperatures, 10, 15 and 37 °C. Hydrolysis, acidification and methanogenesis were assessed by VS degradation, by soluble chemical oxygen demand (SCOD) and volatile fatty acids (VFA) production, and by methane production, respectively. Hydrolysis was the rate-limiting step at all temperatures and the rates and extent of hydrolysis were considerably lower at 15 and 10 °C, than at 37 °C. The total VS degradation was 53%, 34% and 19% at 37, 15 and 10 °C, respectively. Acidification was not affected by temperature and VFA production and consumption was balanced in all cases, except at 10 °C. Methane yields were 0.215 m3 CH4 kg−1 VS−1 added, 0.160 m3 CH4 kg−1 VS−1 added and 0.125 m3 CH4 kg−1 VS−1 added at 37, 15 and 10 °C, respectively. Methanogenesis was not strongly affected at 15 °C but it became rate-limiting at 10 °C. Overall, the solid degradation and methane production performance under psychrophilic conditions was encouraging and greater than previously reported. Considering the non-acclimated, mesophilic nature of the inoculum, there are grounds to believe that low-temperature anaerobic digestion of grass could be feasible if coupled to efficient hydrolysis of the biomass.

Sludge electrooxidation as pre-treatment for anaerobic digestion

2016 ◽  
Vol 75 (4) ◽  
pp. 775-781 ◽  
Author(s):  
J. A. Barrios ◽  
U. Duran ◽  
A. Cano ◽  
M. Cisneros-Ortiz ◽  
S. Hernández
Keyword(s):  
Anaerobic Digestion ◽  
Volatile Fatty Acids ◽  
Biogas Production ◽  
Oxygen Demand ◽  
Wastewater Sludge ◽  
Boron Doped Diamond ◽  
Boron Doped ◽  
Treatment Conditions ◽  
Volatile Solids ◽  
Pre Treatment

Anaerobic digestion of wastewater sludge is the preferred method for sludge treatment as it produces energy in the form of biogas as well as a stabilised product that may be land applied. Different pre-treatments have been proposed to solubilise organic matter and increase biogas production. Sludge electrooxidation with boron-doped diamond electrodes was used as pre-treatment for waste activated sludge (WAS) and its effect on physicochemical properties and biomethane potential (BMP) was evaluated. WAS with 2 and 3% total solids (TS) achieved 2.1 and 2.8% solubilisation, respectively, with higher solids requiring more energy. After pre-treatment, biodegradable chemical oxygen demand values were close to the maximum theoretical BMP, which makes sludge suitable for energy production. Anaerobic digestion reduced volatile solids (VS) by more than 30% in pre-treated sludge with a food to microorganism ratio of 0.15 g VSfed g−1 VSbiomass. Volatile fatty acids were lower than those for sludge without pre-treatment. Best pre-treatment conditions were 3% TS and 28.6 mA cm−2.

scholarly journals Temperature-Phased Biological Hydrolysis and Thermal Hydrolysis Pretreatment for Anaerobic Digestion Performance Enhancement

Water ◽  
2018 ◽  
Vol 10 (12) ◽  
pp. 1812 ◽  
Author(s):  
Beraki Bahre Mehari ◽  
Sheng Chang ◽  
Youngseck Hong ◽  
Han Chen
Keyword(s):  
Anaerobic Digestion ◽  
Volatile Fatty Acids ◽  
Municipal Wastewater ◽  
Performance Enhancement ◽  
Treatment Plant ◽  
Oxygen Demand ◽  
Wastewater Sludge ◽  
Thermal Hydrolysis ◽  
Soluble Chemical Oxygen Demand ◽  
Effects Of Temperature

Thermal hydrolysis (TH) and biological hydrolysis (BH) are two main and growing anaerobic digestion pretreatment technologies. In this study, municipal wastewater sludge samples were collected from the Guelph Wastewater Treatment Plant (WWTP) in Ontario, Canada. The effects of temperature on BH treatment, including BH at 42 °C (BH42), 42 °C followed by 55 °C (BH42+55), 55 °C followed by 42 °C (BH55+42), and 55 °C (BH55) were evaluated for anaerobic digestion performance enhancement and compared with TH treatment at 165 °C. The TH, BH42, BH42+55, BH55+42, and BH55 treatments caused the reduction of volatile suspended solids (VSS) by 22.6%, 17.5%, 24.6%, 23.1%, and 25.9%, respectively. The soluble chemical oxygen demand (sCOD) content of the sludge increased by 377.5%, 323.8%, 301.3%, 286.9%, and 221.7% by the TH, BH55, BH42+55, BH55+42, and BH42 treatments, respectively. Volatile fatty acids (VFA) constituted around 40% of the sCOD in the BH-treated sludge and 6% in the TH-treated sludge. The cumulative methane yields (NmLCH4/g COD fed) of sludge treated by BH55+42 and TH were respectively 23% and 20% higher than that of the untreated sludge. For BH pretreatment, sludge treated by BH55+42 produced more methane than those treated by BH42+55, BH55, and BH42. The methane yields of the combined sludge treated by the TH and BH55+42 treatments were in the ranges of 248.9 NmLCH4/g COD to 266.1 NmLCH4/g COD fed, and 255.3 NmLCH4/g COD to 282.2 NmLCH4/g COD fed, respectively.

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.

Experimental and Artificial Neural Network Modeling of a Upflow Anaerobic Contactor (UAC) for Biogas Production from Vinasse

2016 ◽  
Vol 14 (6) ◽  
pp. 1241-1254 ◽  
Author(s):  
Ousman R. Dibaba ◽  
Sandip K. Lahiri ◽  
Stephan T’Jonck ◽  
Abhishek Dutta
Keyword(s):  
Neural Network ◽  
Artificial Neural Network ◽  
Anaerobic Digestion ◽  
Volatile Fatty Acids ◽  
Biogas Production ◽  
Oxygen Demand ◽  
Pilot Scale ◽  
Organic Loading Rate ◽  
Neural Network Modeling ◽  
Artificial Neural

Abstract A pilot scale Upflow Anaerobic Contactor (UAC), based on upflow sludge blanket principle, was designed to treat vinasse waste obtained from beet molasses fermentation. An assessment of the anaerobic digestion of vinasse was carried out for the production of biogas as a source of energy. Average Organic loading rate (OLR) was around 7.5 gCOD/m3/day in steady state, increasing upto 8.1 gCOD/m3/day. The anaerobic digestion was conducted at mesophilic (30–37 °C) temperature and a stable operating condition was achieved after 81 days with average production of 65 % methane which corresponded to a maximum biogas production of 85 l/day. The optimal performance of UAC was obtained at 87 % COD removal, which corresponded to a hydraulic retention time of 16.67 days. The biogas production increased gradually with OLR, corresponding to a maximum 6.54 gCOD/m3/day (7.4 % increase from initial target). A coupled Artificial Neural Network-Differential Evolution (ANN-DE) methodology was formulated to predict chemical oxygen demand (COD), total suspended solids (TSS) and volatile fatty acids (VFA) of the effluent along with the biogas production. The method incorporated a DE approach for the efficient tuning of ANN meta-parameters such as number of nodes in hidden layer, input and output activation function and learning rate. The model prediction indicated that it can learn the nonlinear complex relationship between the parameters and able to predict the output of the contactor with reasonable accuracy. The utilization of the coupled ANN-DE model provided significant improvement to the study and helps to study the parametric effect of influential parameters on the reactor output.

scholarly journals Cadmium Addition Effects on Anaerobic Digestion with Elevated Temperatures

Energies ◽  
2019 ◽  
Vol 12 (12) ◽  
pp. 2367
Author(s):  
Yonglan Tian ◽  
Shusen Li ◽  
Ying Li ◽  
Huayong Zhang ◽  
Xueyue Mi ◽  
...  
Keyword(s):  
Heavy Metals ◽  
Anaerobic Digestion ◽  
Volatile Fatty Acids ◽  
Elevated Temperatures ◽  
Anaerobic Fermentation ◽  
Oxygen Demand ◽  
Future Research ◽  
Coenzyme F420 ◽  
Peak Period ◽  
The Impact

Anaerobic fermentation with biogas as an energy source is influenced by the presence of heavy metals. However, the availability of the heavy metals is dependent on the digestion temperature. In this study, the impacts of Cd on the characteristics of biogas, substrate biodegradation, and enzyme activity during anaerobic co-digestion were investigated under varying digestion temperatures. The results showed that 1 mg/L initial Cd concentration improved cumulative biogas yields by 404.96%, 16.93%, and 5.56% at 55 °C, 45 °C, and 35 °C, respectively. In contrast, at low temperatures (25 °C), the yield decreased by 0.77%. In the 55 °C group, Cd addition improved the activity of cellulase (p < 0.05) and coenzyme F420 (p < 0.01). The total chemical oxygen demand (COD) during the peak period and the transformation of hydrolytic organic components into volatile fatty acids (VFAs) influenced the CH4 and biogas yields. There were no significant differences in cellulase, dehydrogenase, and coenzyme F420 activities with or without Cd addition when the digestion temperature was 45 °C, 35 °C, and 25 °C. Therefore, thermophilic digestion is recommended for the efficient degradation of Cd-contaminated biowaste. Moreover, the impact of metals on the performance of anaerobic digestion should be considered together with temperature conditions in future research and practice.

Lessons learnt from 15 years of ICA in anaerobic digesters

2006 ◽  
Vol 53 (4-5) ◽  
pp. 25-33 ◽  
Author(s):  
J.P. Steyer ◽  
O. Bernard ◽  
D.J. Batstone ◽  
I. Angelidaki
Keyword(s):  
Wastewater Treatment ◽  
Anaerobic Digestion ◽  
Energy Production ◽  
Control Strategies ◽  
Operating Conditions ◽  
High Rate ◽  
Anaerobic Digesters ◽  
Treatment Processes ◽  
On Line ◽  
Rate Processes

Anaerobic digestion plants are highly efficient wastewater treatment processes with inherent energy production. Despite these advantages, many industries are still reluctant to use them because of their instability confronted with changes in operating conditions. There is therefore great potential for application of instrumentation, control and automation (ICA) in the field of anaerobic digestion. This paper will discuss the requirements (in terms of on-line sensors needed, modelling efforts and mathematical complexity) but also the advantages and drawbacks of different control strategies that have been applied to AD high rate processes over the last 15 years.

scholarly journals Kraft Lignin Grafted with Polyvinylpyrrolidone as a Novel Microbial Carrier in Biogas Production

Energies ◽  
2018 ◽  
Vol 11 (12) ◽  
pp. 3246 ◽  
Author(s):  
Agnieszka A. Pilarska ◽  
Agnieszka Wolna-Maruwka ◽  
Krzysztof Pilarski
Keyword(s):  
Anaerobic Digestion ◽  
Sewage Sludge ◽  
Volatile Fatty Acids ◽  
Biogas Production ◽  
Kraft Lignin ◽  
Physicochemical Analysis ◽  
Process Efficiency ◽  
Total Alkalinity ◽  
Elementary Analysis ◽  
Biochemical Analyses

The objective of this study was to verify the effect of kraft lignin as a microbial carrier on biogas/methane yield. An anaerobic co-digestion test process was carried out, in which confectionery waste was used with sewage sludge. At the first stage of the study pure lignin and lignin combined with polyvinylpyrrolidone (PVP) were subjected to an extensive physicochemical analysis. Their morphology, dispersion and adsorption properties were determined. The two materials were also subjected to thermal, spectroscopic and elementary analysis. The anaerobic digestion of the two substrates was carried out with and without the addition of the carrier, under mesophilic conditions and in periodic operation. The monitoring and analysis of the two essential parameters, i.e., pH and volatile fatty acids/total alkalinity (VFA/TA) ratio, revealed that the process was stable in both tests. Microbial and biochemical analyses showed intensified proliferation of eubacteria and increased dehydrogenase activity in samples prepared with the lignin + PVP material. The cell count increased by 46% in the stuffed wafers (WAF) + sewage sludge (SS) variant with the carrier, whereas the enzyme activity increased by 43%. Cell immobilisation noticeably improved the process efficiency. The biogas production increased from 722 m3 Mg−1 VS to 850 m3 Mg−1 VS (VS – volatile solids), whereas the methane production increased from 428 m3 Mg−1 VS to 503 m3 Mg−1 VS (by about 18%). The research proved that lignin could be used as a very effective microbial carrier in anaerobic digestion (AD).

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