scholarly journals Morphological study of biomass during the start-up period of a fixed-bed anaerobic reactor treating domestic sewage

2005 ◽  
Vol 48 (5) ◽  
pp. 841-849 ◽  
Author(s):  
Cláudio Antonio Andrade Lima ◽  
Rogers Ribeiro ◽  
Eugenio Foresti ◽  
Marcelo Zaiat
Keyword(s):  
Polyurethane Foam ◽  
Morphological Study ◽  
Extracellular Polymeric Substances ◽  
Fixed Bed ◽  
Morphological Characteristics ◽  
Morphological Diversity ◽  
Domestic Sewage ◽  
Fixed Bed Reactor ◽  
Start Up ◽  
Colonization Process

This work focused on a morphological study of the microorganisms attached to polyurethane foam matrices in a horizontal-flow anaerobic immobilized biomass (HAIB) reactor treating domestic sewage. The experiments consisted of monitoring the biomass colonization process of foam matrices in terms of the amount of retained biomass and the morphological characteristics of the cells attached to the support during the start-up period. Non-fluorescent rods and cocci were found to predominate in the process of attachment to the polyurethane foam surface. From the 10th week of operation onwards, an increase was observed in the morphological diversity, mainly due to rods, cocci, and Methanosaeta-like archaeal cells. Hydrodynamic problems, such as bed clogging and channeling occurred in the fixed-bed reactor, mainly due to the production of extracellular polymeric substances and their accumulation in the interstices of the bed causing a gradual deterioration of its performance, which eventually led to the system's collapse. These results demonstrated the importance and usefulness of monitoring the dynamics of the formation of biofilm during the start-up period of HAIB reactors, since it allowed the identification of operational problems.

scholarly journals Start-up of anaerobic reactors for slaughterhouse wastewater treatment

2015 ◽  
Vol 35 (2) ◽  
pp. 331-339 ◽  
Author(s):  
RONALDO FIA ◽  
ERLON L. PEREIRA ◽  
FÁTIMA R. L. FIA ◽  
DÉBORA G. EMBOABA ◽  
EMANUEL M. GOMES
Keyword(s):  
Wastewater Treatment ◽  
Fixed Bed ◽  
Fixed Bed Reactor ◽  
Upflow Anaerobic Sludge Blanket ◽  
Organic Loading Rate ◽  
Anaerobic Sludge ◽  
Stable Operation ◽  
Slaughterhouse Wastewater ◽  
Start Up ◽  
Bicarbonate Alkalinity

This study aimed to evaluate the start-up of a horizontal anaerobic fixed bed reactor (HAFBR) followed by an upflow anaerobic sludge blanket (UASB) for the slaughterhouse wastewater treatment. HAFBR was filled with bamboo rings and had 1.2 m in length, 0.10 m in diameter and volume of 7.5 L. The UASB had the volume of 15 L. The HAFBR and UASB operated at organic loading rate and hydraulic retention time average of 8.46 and 3.77 kg m-3 d-1 of COD and 0.53 and 0.98 days, respectively. During 150 days of monitoring system it was found pH 6.8, relatively high values of bicarbonate alkalinity (> 1000 mg L-1) and reduced values of volatile acids (70 to 150 mg L-1), which afforded average removal efficiencies of COD total and total suspended solids of the order of 31 and 23% in HAFBR and 79% and 63% in UASB. It can be concluded that the generation and consumption of bicarbonate alkalinity and total volatile acids, thereby maintaining the pH during the study indicated stable operation of the reactors. The COD removal in the reactors was satisfactory especially when it considers that the assessment was conducted in a period of adaptation of organisms to the effluent and also the high organic load applied during this period.

Electrical conductivity as a state indicator for the start-up period of anaerobic fixed-bed reactors

2016 ◽  
Vol 73 (9) ◽  
pp. 2294-2300 ◽  
Author(s):  
A. Robles ◽  
E. Latrille ◽  
J. Ribes ◽  
N. Bernet ◽  
J. P. Steyer
Keyword(s):  
Electrical Conductivity ◽  
Production Rate ◽  
Methane Production ◽  
Fixed Bed ◽  
Fixed Bed Reactor ◽  
Bicarbonate Concentration ◽  
Fixed Bed Reactors ◽  
Start Up ◽  
On Line ◽  
Methane Production Rate

The aim of this work was to analyse the applicability of electrical conductivity sensors for on-line monitoring the start-up period of an anaerobic fixed-bed reactor. The evolution of bicarbonate concentration and methane production rate was analysed. Strong linear relationships between electrical conductivity and both bicarbonate concentration and methane production rate were observed. On-line estimations of the studied parameters were carried out in a new start-up period by applying simple linear regression models, which resulted in a good concordance between both observed and predicted values. Electrical conductivity sensors were therefore identified as an interesting method for monitoring the start-up period of anaerobic fixed-bed reactors due to its reliability, robustness, easy operation, low cost, and minimum maintenance compared with the currently used sensors.

The use of an upflow fixed bed reactor for treatment of a primary settled domestic sewage

1986 ◽  
Vol 20 (1) ◽  
pp. 9-14 ◽  
Author(s):  
D. Amar ◽  
J. Partos ◽  
C. Granet ◽  
G.M. Faup ◽  
J.M. Audic
Keyword(s):  
Fixed Bed ◽  
Domestic Sewage ◽  
Fixed Bed Reactor

scholarly journals CO2methanation: Optimal start-up control of a fixed-bed reactor for power-to-gas applications

AIChE Journal ◽  
2016 ◽  
Vol 63 (1) ◽  
pp. 23-31 ◽  
Author(s):  
Jens Bremer ◽  
Karsten H. G. Rätze ◽  
Kai Sundmacher
Keyword(s):  
Fixed Bed ◽  
Fixed Bed Reactor ◽  
Start Up ◽  
Power To Gas

Start-up performance of Anammox process in a fixed bed reactor (FBR) filled with honeycomb-like polypropylene carriers

2016 ◽  
Vol 73 (8) ◽  
pp. 1848-1854 ◽  
Author(s):  
Tao Wang ◽  
Boxiong Shen ◽  
Sha Zhang ◽  
Zhiqiang Wang ◽  
Li Tian
Keyword(s):  
Shock Loading ◽  
Nitrogen Concentration ◽  
Fixed Bed ◽  
Fixed Bed Reactor ◽  
Nitrite Accumulation ◽  
Reactor Performance ◽  
Retention Capacity ◽  
Positive Role ◽  
Start Up ◽  
Anammox Activity

Novel honeycomb-like carriers, made of polypropylene, were applied to enhance biomass retention capacity so as to improve Anammox start-up performance in a fixed bed reactor (FBR). The reactor was operated for 3 months. On day 45, Anammox activity appeared. After 61 days' operation, the removal efficiencies of ammonium and nitrite were both over 91% based on 70 mg N L−1 of the influent ammonium and influent nitrite, indicating that a remarkable Anammox activity was attained. A final specific Anammox activity of 0.12 g NH4+-N gVSS−1 d−1 was reached (VSS: volatile suspended solids). The FBR showed a good capacity for resisting shock loading and was more able to resist shock loading of nitrogen concentration than resist hydraulic shock loading. Phylogenetic analysis showed that Candidatus Brocadia anammoxidans' and Candidatus Kuenenia stuttgartiensis' were detected in the mature biofilm, and Candidatus Brocadia anammoxidans' was the dominant Anammox strain. Candidatus Kuenenia stuttgartiensis' played a positive role in the reactor performance, as it could consumed nitrite quickly and efficiently so as to avoid an adverse effect of temporary nitrite accumulation. The results showed that the honeycomb-like carriers were suitable for start-up of Anammox.

On-board conversion of alcohols to ethers for fumigation in compression ignition engines

2003 ◽  
Vol 217 (3) ◽  
pp. 155-164 ◽  
Author(s):  
H Armbruster ◽  
S Stucki ◽  
E Olsson ◽  
S Gjirja
Keyword(s):  
Mass Transfer ◽  
Catalytic Converter ◽  
Fixed Bed ◽  
Methanol Conversion ◽  
Bifunctional Catalyst ◽  
Fixed Bed Reactor ◽  
Compression Ignition ◽  
Warm Start ◽  
Compression Ignition Engines ◽  
Start Up

Fumigation of dimethyl ether (DME) is an interesting option for using methanol as a fuel in compression ignition engines. In this concept, a fraction of the methanol used as a fuel is catalytically converted on-board to DME and water, and the products of the conversion are introduced into the engine via the combustion air. With an optimized engine the performance as well as emissions are comparable with those obtained when running the engine on alcohol with polyethylene glycol as ignition improver. The methanol conversion has been tested with different catalysts under various conditions. Because of its superior thermal stability and the low costs, γ-Al2O3 has been selected as the most promising catalyst for converting methanol to DME in suffcient rates for an on-board application. The chemical kinetics and the mass transfer limitations of the γ-Al2O3 catalyst used for the methanol dehydration were evaluated. The rate-determining step of the catalytic reaction is found to be the reaction of adsorbed intermediates (the Langmuir-Hinshelwood mechanism); mass transfer is limited by Knudsen diffusivity. The kinetic data were used to design a catalytic converter for fuel processing on-board. Providing DME for fumigation in a 180 kW engine will require approximately 0.7 kg of catalyst. The compact catalyst is necessary for an effcient and fast start-up of the process. The transient behaviour (cold/warm start-up; load changes) of a fixed-bed reactor with γ-Al2O3 has been estimated using simplified models, which show that the cold start problem should be manageable in less than 1 min. With the hot gas of a methanol burner in front of the fixed bed or a bifunctional catalyst, the catalyst bed can be heated to 250 °C and the reaction of methanol to DME started within 25 s. This is an acceptable time for cold-starting an engine in heavy-duty vehicles.

Start-up and long-term operation of the Anammox process in a fixed bed reactor (FBR) filled with novel non-woven ring carriers

Chemosphere ◽  
2013 ◽  
Vol 91 (5) ◽  
pp. 669-675 ◽  
Author(s):  
Tao Wang ◽  
Hanmin Zhang ◽  
Fenglin Yang ◽  
Yifei Li ◽  
Guangyi Zhang
Keyword(s):  
Fixed Bed ◽  
Fixed Bed Reactor ◽  
Term Operation ◽  
Start Up ◽  
Anammox Process
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