Simulation of a periodic anaerobic baffled reactor (PABR): steady state and dynamic response

2002 ◽  
Vol 45 (10) ◽  
pp. 81-86 ◽  
Author(s):  
K. Stamatelatou ◽  
G. Lyberatos
Keyword(s):  
A Priori ◽  
Operation Mode ◽  
Biomass Concentration ◽  
Biomass Accumulation ◽  
Operating Conditions ◽  
High Rate ◽  
Organic Loading Rate ◽  
Experimental Conditions ◽  
Anaerobic Baffled Reactor ◽  
Reactor Dynamics

The Periodic Anaerobic Baffled Reactor (PABR) is a novel high-rate configuration for wastewater treatment. The reactor resembles an ABR with the compartments arranged in a circular manner. The feeding and effluent points are periodically set in different compartments by proper manipulation of valves that determine the flow pattern. This way of feeding makes the reactor response oscillating and gives the PABR a great flexibility in the operation mode. A 15 litre PABR was operated on a gelatin based medium under steady and variable organic loading rate. The experimental conditions were simulated using a mathematical model whose primary feature was that each compartment was considered as a two-section tank, each section with a different biomass concentration in them. The degree of biomass accumulation was determined indirectly by the operating conditions and the reactor dynamics and was not set a-priori.

The circulating floating bed reactor: effect of particle size distribution of the carrier on ammonia conversion

2000 ◽  
Vol 41 (4-5) ◽  
pp. 393-400 ◽  
Author(s):  
J.M. Garrido-Fernandez ◽  
R. Méndez ◽  
J.M. Lema ◽  
V. Lazarova
Keyword(s):  
Particle Size ◽  
Size Distribution ◽  
G Protein ◽  
Biomass Concentration ◽  
Biomass Accumulation ◽  
Ammonia Removal ◽  
Operating Conditions ◽  
Nitrification Rate ◽  
Ammonia Conversion ◽  
Biomass Activity

Three Circulating Floating Bed Reactors (CFBR) R1, R2 and R3 with 20% v/v of a plastic carrier with different size distribution were operated to study the effect of the particles size of the carrier on biomass accumulation and nitrification performance. Operating conditions were similar in the three systems: ammonia concentrations around 50 mg-N–NH4+/ L, ammonia loading rates up to 1.2 kg N–NH4+/m3·d and temperatures between 14 and 27°C. Accumulation of nitrite was observed until day 65th. This w as result both of the inhibition of nitrite oxidation by free ammonia until day 20th and the insignificant accumulation of a biomass with low nitrite oxidising capacity between days 20 and 65th. Ammonia conversion rate and removal efficiency were higher in the reactor with lower particle size, R3 (nitrification rate of 1.1 kg N–NH4+/m3·d and ammonia removal of 97% at 16°C), than in R2 or R1 (nitrification rate of 1.0 kg N–NH4+/m3·d and ammonia removal of 90% at 16°C). The better efficiency in R3 was obtained as a result of the higher specific surface of the biofilm developed. Biomass activity was similar in the three reactors (2.2 and 1.12 g N/g protein · d at 30 and 15°C, respectively). Both the biomass evolution with time and biomass retention in the systems was practically not influenced by the size of particle. Biomass concentration of 1.2 g protein/L was retained in the carrier and up to 20% of the newly produced biomass was retained in the CFBRs.

scholarly journals Anaerobic digestion of dried/shredded food waste in a periodic anaerobic baffled reactor

2021 ◽  
Author(s):  
D. Mathioudakis ◽  
I. Michalopoulos ◽  
K. Kalogeropoulos ◽  
K. Papadopoulou ◽  
G. Lyberatos
Keyword(s):  
Food Waste ◽  
High Rate ◽  
Upflow Anaerobic Sludge Blanket ◽  
Organic Loading Rate ◽  
Anaerobic Sludge ◽  
Operational Parameters ◽  
Operational Parameter ◽  
Anaerobic Baffled Reactor ◽  
Food Residue ◽  
The Impact

Abstract The objective of the current work is to study the impact of the operational parameters' variation (HRT, OLR and T) on biomethane productivity in a Periodic Anaerobic Baffled Reactor (PABR). The feedstock used was a biomass product named FORBI (Food Residue Biomass), which is dried and shredded source-separated household food waste. The Periodic Anaerobic Baffled Reactor (PABR) is an innovative, high-rate bioreactor. Apart from the Hydraulic Retention Time (HRT) and the Organic Loading Rate (OLR), an important operational parameter is the Switching Period (T) of the feeding compartment: when T is high, the bioreactor operation is similar to an Anaerobic baffled reactor (ABR), while when it is low, the operation approaches that of an Upflow Anaerobic Sludge Blanket Reactor (UASBR). Nine distinct experimental phases were conducted, during which the operational parameters of the PABR were consecutively modified: the HRT varied from 9 to 2.5 days, T between 2 days and 1 and finally the OLR from 1.24 gCOD/Lbioreactor*d to 8.08 gCOD/Lbioreactor*d. The maximum biomethane yield was 384 LCH4/kgFORBI corresponding to the operation at HRT = 5 d, OLR = 2.14 gCOD/Lbioreactor*d and T = 2 days. Similar efficiency (333 LCH4/kg­FORBI) was achieved at higher OLR (4.53 gCOD/Lbioreactor*d).

Solid waste digestors: process performance and practice for municipal solid waste digestion

2001 ◽  
Vol 44 (8) ◽  
pp. 91-102 ◽  
Author(s):  
G. Lissens ◽  
P. Vandevivere ◽  
L. De Baere ◽  
E.M. Biey ◽  
W. Verstraete
Keyword(s):  
Solid Waste ◽  
Biomass Concentration ◽  
Biomass Accumulation ◽  
Industrial Applications ◽  
Organic Loading Rate ◽  
Organic Loading ◽  
Two Stage ◽  
Technical Performance ◽  
Second Stage ◽  
Biological Performance

The most common types of anaerobic digesters for solid wastes have been compared based on biological and technical performance and reliability. Batch systems have the most simple designs and are the least expensive solid waste digesters. They have high potential for application in developing countries. Two-stage systems are the most complex and most expensive systems. Their greatest advantage lies in the equalisation of the organic loading rate in the first stage, allowing a more constant feeding rate of the methanogenic second stage. Two-stage systems with biomass accumulation devices in the second stage display a larger resistance toward toxicants and inhibiting substances such as ammonia. However, the large majority of industrial applications use one-stage systems and these are evenly split between ‘dry’ systems (wastes are digested as received) and ‘wet’ systems (wastes are slurried to about 12% total solids). Regarding biological performance, this study compares the different digester systems in terms of organic loading rates and biogas yields considering differences in input waste composition. As a whole, ‘dry’ designs have proven reliable due to their higher biomass concentration, controlled feeding and spatial niches. Moreover, from a technical viewpoint the ‘dry’ systems are more robust and flexible than ‘wet’ systems.

scholarly journals Anaerobic membrane bioreactor for high-strength wastewater treatment: batch and continuous operation comparison

2015 ◽  
Vol 5 (2) ◽  
pp. 95-103 ◽  
Author(s):  
D. Hufnagel ◽  
S. Chang ◽  
Y. Hong ◽  
P. Wu ◽  
R. G. Zytner
Keyword(s):  
Membrane Filtration ◽  
Membrane Bioreactor ◽  
Biomass Concentration ◽  
High Strength ◽  
High Rate ◽  
Organic Loading Rate ◽  
Brewery Wastewater ◽  
Batch Operation ◽  
Anaerobic Membrane Bioreactor ◽  
Continuous Feeding

The anaerobic membrane bioreactor (AnMBR) is a recent development in high-rate anaerobic bioreactors. This study assessed the treatment of high-strength wastewater by an AnMBR using batch and continuous feeding operation. The results showed that the AnMBR could establish a biomass concentration of 6–8 g/L in approximately 20 days due to retention of micro-organisms by the membrane, resulting in 86% chemical oxygen demand (COD) removal efficiency in the treatment of high-strength brewery wastewater. Batch operation was proven to be effective for an organic loading rate (OLR) up to 2 gCOD/L/day and was beneficial to the membrane filtration. However, the treatment capacity of the AnMBR with batch feeding was limited by the high instantaneous OLR during the feeding period. Compared to batch operation, continuous feeding can achieve improved stability and better effluent quality, but prolonged continuous permeation may make the membrane more susceptible to fouling. Although a critical flux of 22 L/m2/h was determined for the membrane filtration in the AnMBR tested, a decrease in the membrane permeability was still observed in the long-term filtration at a flux of approximately 10 L/m2/h.

scholarly journals Field-scale anaerobic baffled reactor for domestic wastewater treatment: effect of dynamic operating conditions

2020 ◽  
Author(s):  
S. S. Yenji ◽  
G. R. Munavalli ◽  
M. M. Koli
Keyword(s):  
Loading Rate ◽  
Organic Content ◽  
Operating Conditions ◽  
Aluminium Chloride ◽  
Organic Loading Rate ◽  
Phase System ◽  
Field Scale ◽  
Two Phase ◽  
Anaerobic Baffled Reactor ◽  
Sludge Granulation

Abstract A 45 m3/d field-scale anaerobic baffled reactor (ABR) was studied for its performance to remove carbonaceous organic content and suspended solids under a dynamic hydraulic loading rate (HLR) and organic loading rate (OLR). Sludge granulation effect was also assessed with and without sand as a bio-carrier aided with poly aluminium chloride. ABR was subjected to a significant variation in HLR (0.26 to 7.72 m3/m2.d) and OLR (0.03 to 8 kg COD/m3.d). Tracer study showed flow-through time was 50% of theoretical hydraulic retention time. The initial compartments of ABR were more effective for the removal of organic carbon. An overall CODTotal removal of 60 to 90% was possible for OLR in the range 1 to 8 kg COD/m3.d irrespective of low/high HLR. OLR dominated the performance of ABR compared to HLR. The compartmentalized nature of ABR was visualized through a two-phase system of anaerobic digestion as alkalinity increased while VFA decreased from the first to last compartment even under dynamic conditions. Sludge granulation with sand and PAC increased the size of granule from 629 to 1,471 μm, decreased sludge depth by 20% and enhanced CODTotal removal within a month. ABR is sturdy to sustain low/high HLR with low/high OLR conditions without impairing CODTotal removal efficiency significantly.

Performance of an anaerobic baffled reactor (ABR) as a hydrolysis-acidogenesis unit in treating landfill leachate mixed with municipal sewage

2000 ◽  
Vol 42 (12) ◽  
pp. 115-121 ◽  
Author(s):  
B. Wang ◽  
Y. Shen
Keyword(s):  
Landfill Leachate ◽  
Loading Rate ◽  
Granular Sludge ◽  
Operational Performance ◽  
Municipal Sewage ◽  
Organic Loading Rate ◽  
Stable Operation ◽  
Organic Loading ◽  
Anaerobic Baffled Reactor ◽  
Biological Treatability

A study on the performance of an Anaerobic Baffled Reactor(ABR) as a hydrolysis-acidogenesis unit in treating the mixed wastewater of landfill leachate and municipal sewage in different volumetric ratios was carried out. The results showed that ABR substantially improved the biological treatability of the mixed wastewater by increasing its BOD5/COD ratio to 0.4–0.6 from the initial values of 0.15–0.3. The formation of bar-shaped granular sludge of 0.5–5 mm both in diameter and length with an SVI of 7.5–14.2 ml/g was observed in all compartments of the ABR when the organic loading rate reached 4.71 kgCOD/m3 · d. The effects of the ratios of NH4+-N/COD and COD/TP in mixed wastewater on the operational performance were also studied, from which it was found that a reasonable NH4+-N/COD ratio should be lower than 0.02, and the phosphorus supplement was needed when the volumetric ratio was higher than 4:6 for stable operation of ABR.

scholarly journals Zeolite addition to improve biohydrogen production from dark fermentation of C5/C6-sugars and Sargassum sp. biomass

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
R. M. Silva ◽  
A. A. Abreu ◽  
A. F. Salvador ◽  
M. M. Alves ◽  
I. C. Neves ◽  
...  
Keyword(s):  
Hydrogen Production ◽  
Anaerobic Bacteria ◽  
Dark Fermentation ◽  
Inorganic Materials ◽  
Biohydrogen Production ◽  
High Rate ◽  
Continuous Reactor ◽  
Organic Loading Rate ◽  
Fermentation Products ◽  
Zeolite Type

AbstractThermophilic biohydrogen production by dark fermentation from a mixture (1:1) of C5 (arabinose) and C6 (glucose) sugars, present in lignocellulosic hydrolysates, and from Sargassum sp. biomass, is studied in this work in batch assays and also in a continuous reactor experiment. Pursuing the interest of studying interactions between inorganic materials (adsorbents, conductive and others) and anaerobic bacteria, the biological processes were amended with variable amounts of a zeolite type-13X in the range of zeolite/inoculum (in VS) ratios (Z/I) of 0.065–0.26 g g−1. In the batch assays, the presence of the zeolite was beneficial to increase the hydrogen titer by 15–21% with C5 and C6-sugars as compared to the control, and an increase of 27% was observed in the batch fermentation of Sargassum sp. Hydrogen yields also increased by 10–26% with sugars in the presence of the zeolite. The rate of hydrogen production increased linearly with the Z/I ratios in the experiments with C5 and C6-sugars. In the batch assay with Sargassum sp., there was an optimum value of Z/I of 0.13 g g−1 where the H2 production rate observed was the highest, although all values were in a narrow range between 3.21 and 4.19 mmol L−1 day−1. The positive effect of the zeolite was also observed in a continuous high-rate reactor fed with C5 and C6-sugars. The increase of the organic loading rate (OLR) from 8.8 to 17.6 kg m−3 day−1 of COD led to lower hydrogen production rates but, upon zeolite addition (0.26 g g−1 VS inoculum), the hydrogen production increased significantly from 143 to 413 mL L−1 day−1. Interestingly, the presence of zeolite in the continuous operation had a remarkable impact in the microbial community and in the profile of fermentation products. The effect of zeolite could be related to several properties, including the porous structure and the associated surface area available for bacterial adhesion, potential release of trace elements, ion-exchanger capacity or ability to adsorb different compounds (i.e. protons). The observations opens novel perspectives and will stimulate further research not only in biohydrogen production, but broadly in the field of interactions between bacteria and inorganic materials.

scholarly journals Data-driven Modelling of Microfiltration Process with Embedded Static Mixer for Steepwater from Corn Starch Industry

2017 ◽  
Author(s):  
Laslo Šereš ◽  
Ljubica Dokić ◽  
Bojana Ikonić ◽  
Dragana Šoronja-Simović ◽  
Miljana Djordjević ◽  
...  
Keyword(s):  
Corn Starch ◽  
Desirability Function ◽  
Specific Energy Consumption ◽  
Cross Flow ◽  
Operating Conditions ◽  
Transmembrane Pressure ◽  
Static Mixer ◽  
Permeate Flux ◽  
Experimental Conditions ◽  
Starch Industry

Cross-flow microfiltration using ceramic tubular membrane was applied for treatment of steepwater from corn starch industry. Experiments are conducted according to the faced centered central composite design at three different transmembrane pressures (1, 2 and 3 bar) and cross-flow velocities (100, 150 and 200 L/h) with and without the usage of Kenics static mixer. For examination of the influence of the selected operating conditions at which usage of the static mixer is justified, a response surface methodology and desirability function approach were used. Obtained results showed improvement in the average permeate flux by using Kenics static mixer for 211 % to 269 % depending on experimental conditions when compared to the system without the static mixer. As a result of optimization, the best results considering flux improvement as well as reduction of specific energy consumption were obtained at low transmembrane pressure and lower feed cross-flow rates.

scholarly journals The Influence of Carrier Air Preheating on Autoignition of Inline-Injected Hydrogen–Nitrogen Mixtures in Vitiated Air of High Temperature

2017 ◽  
Vol 140 (3) ◽  
Author(s):  
Christoph A. Schmalhofer ◽  
Peter Griebel ◽  
Manfred Aigner
Keyword(s):  
Hydrogen Content ◽  
Gas Turbines ◽  
High Speed ◽  
Flame Stabilization ◽  
Operating Conditions ◽  
Promoting Effect ◽  
Experimental Conditions ◽  
Lean Premixed Combustion ◽  
Image Velocimetry ◽  
Fuel Mixtures

The use of highly reactive hydrogen-rich fuels in lean premixed combustion systems strongly affects the operability of stationary gas turbines (GT) resulting in higher autoignition and flashback risks. The present study investigates the autoignition behavior and ignition kernel evolution of hydrogen–nitrogen fuel mixtures in an inline co-flow injector configuration at relevant reheat combustor operating conditions. High-speed luminosity and particle image velocimetry (PIV) measurements in an optically accessible reheat combustor are employed. Autoignition and flame stabilization limits strongly depend on temperatures of vitiated air and carrier preheating. Higher hydrogen content significantly promotes the formation and development of different types of autoignition kernels: More autoignition kernels evolve with higher hydrogen content showing the promoting effect of equivalence ratio on local ignition events. Autoignition kernels develop downstream a certain distance from the injector, indicating the influence of ignition delay on kernel development. The development of autoignition kernels is linked to the shear layer development derived from global experimental conditions.

Control-Oriented Modelling and Optimal Adaptive Control of Parallel Compressors

2021 ◽  
Author(s):  
Ayman Ismail Al Zawaideh ◽  
Khalifa Hassan Al Hosani ◽  
Igor Boiko ◽  
Abdulla AlQassab ◽  
Ibrahim Khan
Keyword(s):  
Energy Consumption ◽  
Optimization Algorithm ◽  
Dynamic Control ◽  
Operating Conditions ◽  
High Rate ◽  
Total Energy Consumption ◽  
Process Industries ◽  
Gas Processing ◽  
Processing Plants ◽  
Efficient Power

Abstract Compressors are widely used to transport gas offshore and onshore. Oil rigs and gas processing plants have several compressors operating either alone, in parallel or in trains. Hence, compressors must be controlled optimally to insure a high rate of production, and efficient power consumption. The aim of this paper is to provide a control algorithm to optimize the compressors operation in parallel in process industries, to minimize energy consumption in variable operating conditions. A dynamic control-oriented model of the compression system has been developed. The optimization algorithm is tested on an experimental prototype having two compressors connected in parallel. The developed optimization algorithm resulted in a better performance and a reduction of the total energy consumption compared to an equal load sharing scheme.

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