Operational Behaviour of an Industrial Fixed Bed Reactor for Biomethanation of Alcohol Slops from Different Crops

1990 ◽  
Vol 22 (1-2) ◽  
pp. 385-394 ◽  
Author(s):  
P. Weiland ◽  
H. Thomsen
Keyword(s):  
Fixed Bed ◽  
High Strength ◽  
Pilot Scale ◽  
Anaerobic Treatment ◽  
Fixed Bed Reactor ◽  
Two Phase ◽  
Fixed Bed Reactors ◽  
Industrial Unit ◽  
One Year ◽  
Better Than

Distillery slops from a multicrop ethanol plant are difficult to treat anaerobically, because the composition and load changes throughout the year due to processing of different sugar-and starch-containing crops. For achieving high COD removal efficiencies and good process stabilities at medium strength loading rates, a two-phase anaerobic treatment process with a fixed-bed reactor for biomethanation was developed and tested in pilot-scale. On the basis of these experiments a full-scale unit with 1,800 m3 reactor volume was erected, which has been in operation for more than one year. The fixed-bed reactor is operated with COD loads up to 10 kg COD/m3d at hydraulic retention times of about 5 days. A variety of highly concentrated slops can be treated successfully with COD removals from 85 % to over 90 %. The fixed-bed reactor withstood sudden changes in wastewater strength and composition and is able to handle hydraulic overloads. Operational data from the industrial unit show that the performance and reliability of the fixed-bed reactor is much better than a conventional contact system, which was operated in a parallel run in the same scale. The results show, that the application of fixed-bed reactors can be recommended for a wide variety of high-strength wastewaters with low suspended solids contents.

Application of Biofilm Kinetics to Anaerobic Fixed Bed Reactors

1991 ◽  
Vol 23 (7-9) ◽  
pp. 1319-1326 ◽  
Author(s):  
I. E. Gönenç ◽  
D. Orhon ◽  
B. Beler Baykal
Keyword(s):  
Removal Rate ◽  
Fixed Bed ◽  
Experimental Studies ◽  
Pilot Scale ◽  
Cod Removal ◽  
Experimental Results ◽  
Fixed Bed Reactor ◽  
Removal Mechanism ◽  
Term Operation ◽  
Fixed Bed Reactors

Two basic phenomena, reactor hydraulics and mass transport through biofilm coupled with kinetic expressions for substrate transformations were accounted for in order to describe the soluble COD removal mechanism in anaerobic fixed bed reactors. To provide necessary verification, experimental results from the long term operation of the pilot scale anaerobic reactor treating molasses wastewater were used. Theoretical evaluations verified by these experimental studies showed that a bulk zero-order removal rate expression modified by diffusional resistance leading to bulk half-order and first-order rates together with the particular hydraulic conditions could adequately define the overall soluble COD removal mechanism in an anaerobic fixed bed reactor. The experimental results were also used to determine the kinetic constants for practical application. In view of the complexity of the phenomena involved it is found remarkable that a simple simulation model based on biofilm kinetics is a powerful tool for design and operation of anaerobic fixed bed reactors.

Calcium Carbonate Precipitation in Anaerobic Waste Water Treatment

1991 ◽  
Vol 23 (7-9) ◽  
pp. 1239-1248 ◽  
Author(s):  
K. Svardal
Keyword(s):  
Equilibrium Constants ◽  
Waste Water Treatment ◽  
Fixed Bed ◽  
Pilot Scale ◽  
Anaerobic Treatment ◽  
Carbonate Precipitation ◽  
Waste Waters ◽  
Calcium Carbonate Precipitation ◽  
Severe Problem ◽  
Fixed Bed Reactors

Precipitation of calcium in anaerobic treatment can be a severe problem, especially for fixed bed reactors. In order to assess calcium precipitation quantitatively, an equilibrium model has been developed. It is based on concentrations in the influent (COD, TOC, TIC, alkalinity, Ca2+,TKN) conditions in the reactor (pH, temperature) and equilibrium constants. The model has been verified for different waste waters in pilot scale and full scale investigations.

An Anaerobic Fixed Bed Reactor with a Porous Ceramic Carrier

1989 ◽  
Vol 21 (4-5) ◽  
pp. 77-86 ◽  
Author(s):  
Mitsuo Kawase ◽  
Tadashi Nomura ◽  
Tsuyoshi Majima
Keyword(s):  
Loading Rate ◽  
Unit Area ◽  
Porous Ceramic ◽  
Fixed Bed ◽  
Anaerobic Treatment ◽  
Fixed Bed Reactor ◽  
Operational Conditions ◽  
Treatment Performance ◽  
Fixed Bed Reactors ◽  
Highly Loaded

To date, a large number of studies on anaerobic fixed bed reactors have been reported, but there have been few studies on the application of this technology to thermophilic anaerobic treatment. One of the reasons for the small number of applications is the difficulty of attaching thermophilic anaerobic organisms to carriers. The study reported in this paper was conducted to examine the thermophilic treatment performance of an anaerobic fixed bed reactor containing a porous ceramic carrier (‘microbe immobilized ceramic', MIC) developed for the immobilization of anaerobic organisms. When boiled soybean wastewater (55,000 mg/l COD) was treated anaerobically at a high temperature (54°C) in a reactor where 31% of the volume was filled with the MIC carrier, it was found that highly loaded operation with up to 65 kg COD/m3/d was possible. The COD load per unit area of carrier surface under these operational conditions reached 0.397 kg COD/m3/d, and the performance of the reactor was excellent. Stable anaerobic treatment was achieved when the COD loading rate fluctuated from 26 to 51 kg COD/m3/d.

Design of Pre-Acidification Reactors for the Anaerobic Treatment of Industrial Wastewaters

1994 ◽  
Vol 29 (9) ◽  
pp. 199-204 ◽  
Author(s):  
I. E. Alexiou ◽  
G. K. Anderson ◽  
L. M. Evison
Keyword(s):  
Industrial Wastewater ◽  
Volatile Fatty Acids ◽  
High Strength ◽  
Pilot Scale ◽  
Anaerobic Treatment ◽  
Coffee Production ◽  
Two Phase ◽  
Industrial Wastewaters ◽  
Wide Range ◽  
Pre Treatment

Two-phase anaerobic digestion has often been considered beneficial for the treatment of high strength industrial wastewaters, especially when the first phase is used as a pre-treatment system known as pre-acidification. Several applications in the field of industrial wastewater treatment have been reviewed in order to evaluate the advantages of the pre-acidification process and its effects on the methanogenic reactor. Although pre-acidification has obvious advantages, complete acidification may be detrimental to the efficiency of the overall process. The use of balancing tanks at full-scale has been common practice for the pre-acidification of a wide range of wastewaters yet no accepted design criteria for acidogenic reactors have been formulated and two-phase applications are generally based upon previous experience. The paper summarizes the results of a two year investigation into pre-acidification at both bench- and pilot-scale, presents the results of instant coffee production wastewaters and discusses a wide range of parameters which have been evaluated. Operating criteria will be discussed and guidelines for the design of pre-acidification reactors will be presented. Finally alternatives to using the total VFA (volatile fatty acids) concentrations for expressing the efficiency of acidogenesis will be introduced.

Role of filter media in an anaerobic fixed-bed reactor

1995 ◽  
Vol 31 (9) ◽  
pp. 137-144 ◽  
Author(s):  
T. Miyahara ◽  
M. Takano ◽  
T. Noike
Keyword(s):  
Anaerobic Bacteria ◽  
Fixed Bed ◽  
Methanogenic Bacteria ◽  
The Other ◽  
Fixed Bed Reactor ◽  
Filter Media ◽  
Fixed Bed Reactors ◽  
Attached Bacteria ◽  
The Relationship

The relationship between the filter media and the behaviour of anaerobic bacteria was studied using anaerobic fixed-bed reactors. At an HRT of 48 hours, the number of suspended acidogenic bacteria was higher than those attached to the filter media. On the other hand, the number of attached methanogenic bacteria was more than ten times as higher than that of suspended ones. The numbers of suspended and deposited acidogenic and methanogenic bacteria in the reactor operated at an HRT of 3 hours were almost the same as those in the reactor operated at an HRT of 48 hours. Accumulation of attached bacteria was promoted by decreasing the HRT of the reactor. The number of acidogenic bacteria in the reactor packed sparsely with the filter media was higher than that in the closely packed reactor. The number of methanogenic bacteria in the sparsely packed reactor was lower than that in the closely packed reactor.

Modeling of aerated upflow fixed bed reactors for nitrification

1999 ◽  
Vol 39 (4) ◽  
pp. 85-92 ◽  
Author(s):  
J. Behrendt
Keyword(s):  
Mathematical Model ◽  
Mass Transfer ◽  
Liquid Phase ◽  
Gas Phase ◽  
Fixed Bed ◽  
Fixed Bed Reactor ◽  
Bulk Liquid ◽  
Initial Value ◽  
Fixed Bed Reactors ◽  
Number Of Cells

A mathematical model for nitrification in an aerated fixed bed reactor has been developed. This model is based on material balances in the bulk liquid, gas phase and in the biofilm area. The fixed bed is divided into a number of cells according to the reduced remixing behaviour. A fixed bed cell consists of 4 compartments: the support, the gas phase, the bulk liquid phase and the stagnant volume containing the biofilm. In the stagnant volume the biological transmutation of the ammonia is located. The transport phenomena are modelled with mass transfer formulations so that the balances could be formulated as an initial value problem. The results of the simulation and experiments are compared.

scholarly journals Evaluation of Fixed-Bed Cultures with Immobilized Lactococcus Lactis ssp. Lactis on Different Scales

2017 ◽  
Vol 11 (1) ◽  
pp. 16-25 ◽  
Author(s):  
Rebecca Faschian ◽  
Ilyas Eren ◽  
Steven Minden ◽  
Ralf Pörtner
Keyword(s):  
Dilution Rate ◽  
Lactococcus Lactis ◽  
Scale Up ◽  
Fixed Bed ◽  
Pilot Scale ◽  
Fixed Bed Reactor ◽  
Batch Mode ◽  
Promising Alternative ◽  
Fixed Beds ◽  
Pilot Scale Reactor

Fixed-bed processes, where cells are immobilized within macroporous carriers, are a promising alternative to processes with suspended cells. A scale-up concept is presented in order to evaluate the performance as part of process design of fixed-bed processes. Therefore,Lactococcus lactiscultivation in chemostat and batch mode was compared to fixed bed cultures on three different scales, the smallest being the downscaledMultifermwith 10 mL fixed bed units, the second a 100 mL fixed-bed reactor and the third a pilot scale reactor with 1 L fixed bed volume. As expected, the volume specific lactate productivity of all cultivations was dependent on dilution rate. In suspension chemostat culture a maximum of 2.3 g·L-1·h-1was reached. Due to cell retention in the fixed-beds, productivity increased up to 8.29 g·L-1·h-1at a dilution rate of D = 1.16 h-1(corresponding to 2.4·µmax) on pilot scale. For all fixed bed cultures a common spline was obtained indicating a good scale-up performance.

scholarly journals Simulation of CO2 Conversion into Methanol in Fixed-bed Reactors: Comparison of Isothermal and Adiabatic Configurations

REAKTOR ◽  
2019 ◽  
Vol 19 (3) ◽  
pp. 131-135
Author(s):  
Fadilla Noor Rahma
Keyword(s):  
Fixed Bed ◽  
Value Added ◽  
Fixed Bed Reactor ◽  
Inlet Temperature ◽  
Methanol Production ◽  
Greenhouse Gases Emissions ◽  
Fixed Bed Reactors ◽  
Adiabatic Reactor ◽  
Co2 Conversion Into Methanol ◽  
Feed Inlet

CO2 capture and utilization (CCU) has been widely considered as a potential solution to overcome global warming. Conversion of CO2 into methanol is an interesting option to transform waste into value-added chemical while also reducing greenhouse gases emissions in the atmosphere. In this paper, utilization of CO2 into methanol was simulated using Aspen Plus software. The reaction between CO2 and H2 to produce methanol and water was carried out in a simulated fixed-bed reactor with Cu/ZnO/Al2O3 commercial catalyst, following LHHW (Langmuir – Hinshelwood – Hougen – Watson) kinetic model. Isothermal and adiabatic reactor configurations were compared under similar feed conditions and the concentration profile along the reactor was observed. The result showed that isothermal configuration converted 3.23% more CO2 and provided 16.34% higher methanol yield compared to the adiabatic reactor. Feed inlet temperature variation was applied and the effect to methanol production on both configurations was studied. The highest methanol yield for adiabatic and isothermal reactor was obtained at 200 oC and 240 oC respectively.

Improvement of anaerobic treatment of tannery beamhouse wastewater by an integrated sulphide elimination process

1999 ◽  
Vol 40 (1) ◽  
pp. 245-252 ◽  
Author(s):  
H. Schenk ◽  
M. Wiemann ◽  
W. Hegemann
Keyword(s):  
Hydrogen Sulphide ◽  
Fixed Bed ◽  
Anaerobic Treatment ◽  
Methanogenic Bacteria ◽  
Cod Removal ◽  
Batch Tests ◽  
Treatment Processes ◽  
Fixed Bed Reactors ◽  
Sulphide Toxicity ◽  
High Concentrations

Sulphide, and especially the undissociated form, hydrogen sulphide, is inhibitory to anaerobic wastewater treatment processes. Tannery beamhouse wastewater contains high concentrations of organic material which make an anaerobic treatment favourable, but it also contains high concentrations of sulphide which cause difficulties for anaerobic treatment. The success of an anaerobic treatment will depend on reliable elimination of the sulphide. In batch tests stripping was the most effective process for sulphide removal compared to precipitation. The chemical-physical COD removal caused by the stripping was negligible, while precipitation caused a COD-removal of 26%. Also, anaerobic degradation velocity was higher if sulphide was removed by stripping. In fixed bed reactors operated continuously, stripping was shown to be a reliable method for eliminating hydrogen sulphide toxicity. Hydrogen sulphide caused an inhibition of 0.2% per mg 1−1 for methanogenic bacteria. Acidogenic bacteria were not inhibited by hydrogen sulphide. The gas-liquid equilibrium was shown to deviate from theoretical values taken from literature.

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