Hydrolysis of organic wastewater particles in laboratory scale and pilot scale biofilm reactors under anoxic and aerobic conditions

1998 ◽  
Vol 38 (8-9) ◽  
pp. 179-188 ◽  
Author(s):  
K. F. Janning ◽  
X. Le Tallec ◽  
P. Harremoës
Keyword(s):  
Organic Matter ◽  
Mass Balance ◽  
Particulate Organic Matter ◽  
Removal Rate ◽  
Pilot Scale ◽  
Laboratory Scale ◽  
Synthetic Wastewater ◽  
Aerobic Conditions ◽  
Biofilm Reactors ◽  
Hydrolysis Of

Hydrolysis and degradation of particulate organic matter has been isolated and investigated in laboratory scale and pilot scale biofilters. Wastewater was supplied to biofilm reactors in order to accumulate particulates from wastewater in the filter. When synthetic wastewater with no organic matter was supplied to the reactors, hydrolysis of the particulates was the only process occurring. Results from the laboratory scale experiments under aerobic conditions with pre-settled wastewater show that the initial removal rate is high: rV, O2 = 2.1 kg O2/(m3 d) though fast declining towards a much slower rate. A mass balance of carbon (TOC/TIC) shows that only 10% of the accumulated TOC was transformed to TIC during the 12 hour long experiment. The pilot scale hydrolysis experiment was performed in a new type of biofilm reactor - the B2A® biofilter that is characterised by a series of decreasing sized granular media (80-2.5 mm). When hydrolysis experiments were performed on the anoxic pilot biofilter with pre-screened wastewater particulates as carbon source, a rapid (rV, NO3=0.7 kg NO3-N/(m3 d)) and a slowler (rV, NO3 = 0.3 kg NO3-N/(m3 d)) removal rate were observed at an oxygen concentration of 3.5 mg O2/l. It was found that the pilot biofilter could retain significant amounts of particulate organic matter, reducing the porosity of the filter media of an average from 0.35 to 0.11. A mass balance of carbon shows that up to 40% of the total incoming TOC accumulates in the filter at high flow rates. Only up to 15% of the accumulated TOC was transformed to TIC during the 24 hour long experiment.

scholarly journals Cooperation and spatial self-organization determine rate and efficiency of particulate organic matter degradation in marine bacteria

2019 ◽  
Vol 116 (46) ◽  
pp. 23309-23316 ◽  
Author(s):  
Ali Ebrahimi ◽  
Julia Schwartzman ◽  
Otto X. Cordero
Keyword(s):  
Organic Matter ◽  
Public Goods ◽  
Social Interactions ◽  
Particulate Organic Matter ◽  
High Efficiency ◽  
Cell Aggregation ◽  
Self Organization ◽  
Turnover Rates ◽  
Particulate Carbon ◽  
Hydrolysis Of

The recycling of particulate organic matter (POM) by microbes is a key part of the global carbon cycle. This process is mediated by the extracellular hydrolysis of polysaccharides, which can trigger social behaviors in bacteria resulting from the production of public goods. Despite the potential importance of public good-mediated interactions, their relevance in the environment remains unclear. In this study, we developed a computational and experimental model system to address this challenge and studied how the POM depolymerization rate and its uptake efficiency (2 main ecosystem function parameters) depended on social interactions and spatial self-organization on particle surfaces. We found an emergent trade-off between rate and efficiency resulting from the competition between oligosaccharide diffusion and cellular uptake, with low rate and high efficiency being achieved through cell-to-cell cooperation between degraders. Bacteria cooperated by aggregating in cell clusters of ∼10 to 20 µm, in which cells were able to share public goods. This phenomenon, which was independent of any explicit group-level regulation, led to the emergence of critical cell concentrations below which degradation did not occur, despite all resources being available in excess. In contrast, when particles were labile and turnover rates were high, aggregation promoted competition and decreased the efficiency of carbon use. Our study shows how social interactions and cell aggregation determine the rate and efficiency of particulate carbon turnover in environmentally relevant scenarios.

Oxygen reduces denitrification in biofilm reactors

1994 ◽  
Vol 29 (10-11) ◽  
pp. 83-91 ◽  
Author(s):  
C. Hagedorn-Olsen ◽  
I. H. Møller ◽  
H. Tøttrup ◽  
P. Harremoës
Keyword(s):  
Organic Matter ◽  
Oxygen Concentration ◽  
Nitrate Removal ◽  
Full Scale ◽  
Laboratory Scale ◽  
Oxygen Penetration ◽  
Biofilm Reactors ◽  
Fixed Film ◽  
Half Power ◽  
Denitrification Process

The mechanism for the nitrate removal from wastewater in a submerged fixed film filter is reviewed and evaluated to demonstrate that the denitrification process is significantly reduced by the presence of oxygen. The kinetics were developed for a fully nitrate penetrated biofilm, influenced by oxygen. It was demonstrated that there is a linear reduction of the denitrification rate with depth of oxygen penetration, proportional to the oxygen concentration to the half power. For a partly nitrate penetrated biofilm the influence of oxygen is a function of the ratio between the penetration of oxygen and the penetration of nitrate without the influence of oxygen. The phenomenon was investigated in laboratory scale with biocarbone and biostyr as media and at a full scale biocarbone plant. The investigation was performed with organic matter in excess on a thin biofilm taken directly from a full scale plant. The results of the experiments with influence of oxygen fit the kinetic concepts well.

Effect of temperature and salinity on the wastewater treatment performance of aerobic submerged fixed bed biofilm reactors

2007 ◽  
Vol 55 (8-9) ◽  
pp. 159-164 ◽  
Author(s):  
G. Chapanova ◽  
M. Jank ◽  
S. Schlegel ◽  
H. Koeser
Keyword(s):  
Removal Rate ◽  
Fixed Bed ◽  
Synthetic Wastewater ◽  
Effect Of Temperature ◽  
Wastewater Purification ◽  
Ammonium Removal ◽  
Biofilm Reactors ◽  
Operation Conditions ◽  
C And N ◽  
German Association

The influence of temperature (5–35 °C) and salinity (up to 20 g/l NaCl) on the wastewater purification process in completely mixed and aerated submerged fixed bed biofilm reactors (SFBBRs) was studied. C- and N-conversion in SFBBRs designed according to the DWA (German Association for Water, Wastewater and Waste) rules for carbon removal was investigated for several months on synthetic wastewater. The DOC degradation rate was even at, according to the DWA, high DOC/BOD loading rates not much affected by temperatures between 5–35 °C and salt contents up to 20 g/L NaCl. At these high DOC loadings an appreciable ammonium conversion could also be observed. The ammonium conversion proved to be sensitive to temperature and salinity. At 5 °C the ammonium removal rate decreased by a factor of five compared to 25–35 °C. Under many operation conditions investigated more than 50% of the converted ammonium was transformed into gaseous nitrogen. The addition of 20 g/L NaCl caused a strong inhibition of the ammonium removal rate over the whole temperature range investigated.

Primary fermentation of soluble and particulate organic matter for wastewater treatment

1994 ◽  
Vol 30 (6) ◽  
pp. 53-62 ◽  
Author(s):  
Ricardo Françi GonÇalves ◽  
Anne Catherine Charlier ◽  
François Sammut
Keyword(s):  
Organic Matter ◽  
Particulate Organic Matter ◽  
Volatile Fatty Acids ◽  
Soluble Fraction ◽  
Domestic Wastewater ◽  
Pilot Scale ◽  
Primary Treatment ◽  
Operating Conditions ◽  
Optimum Conditions ◽  
Hydraulic Load

A new reactor based on upflow sludge blanket technology (USB) for fermentation of both the particulate and soluble fractions of domestic wastewater is presented. The process is fed with the total wastewater flow, and carries out suspended solids (SS) retention, fermentation and clarification of the fermented effluent in a single reactor. The study was carried out using pilot scale reactors, under six different operating conditions with regards to hydraulic load (hydraulic retention time, HRT, varying between 1.1 and 4.3 hours) and at a constant temperature (20 ± 1°C). With regards to primary treatment, the process has been shown to ensure low SS residuals in the fermented effluent under all operating conditions tested. Very low residuals, with an average below 50 mg SS/l, were obtained with an upflow velocity of between 0.75 and 0.9 m/h. These trials have also highlighted the important role played by the adsorption of particulate organic matter on the biological flocs of the sludge blanket in the elimination of SS. Fermentation efficiencies are superior to those of existing fermenters, the results clearly proving that a majority of the volatile fatty acids produced originate from the soluble fraction of the wastewater. Under the optimum conditions tested, with an HRT = 2.8 hours, 0.17 mg HAc/mg total COD are produced, over 60% of which is generated by the fermentation of the influent soluble organic matter. Under these operating conditions, maximum solubilisation of the particulate fraction has been estimated at 0.13 mg of filtered COD/mg particulate COD (total COD-filtered COD).

High biofilm activity under increased oxygen concentrations in a pressurised biofilm system

2005 ◽  
Vol 52 (7) ◽  
pp. 69-75 ◽  
Author(s):  
K.F. Janning ◽  
S.N. Bak ◽  
M. Andersen ◽  
G.H. Kristensen
Keyword(s):  
Liquid Film ◽  
Reaction Rate ◽  
Removal Rate ◽  
Fold Increase ◽  
Order Rate Constant ◽  
Pilot Scale ◽  
Biofilm Reactor ◽  
Synthetic Wastewater ◽  
Film Diffusion ◽  
Zero Order Reaction

A new pressurised biofilm reactor (PBR) process with a patented disc system that enables constant biofilm control has been developed to treat concentrated wastewater with respect to easily degradable organic matter under pressures of up to 6 bar. The pressurisation enables a six-fold increase of the O2 saturation level and aeration capacity, which potentially increases the reaction rate of COD as long as O2 is limiting the reaction rate. Experiments performed in a pilot-scale PBR-reactor fed by synthetic wastewater were conducted to verify the potential and kinetics of heterotrophic conversion of O2 and acetate. Under O2-limited conditions the maximum removal rate of O2 and CODf was measured to rA,O2=60 g O2/m2/d and rA,CODf=150 g CODf/m2/d at 70 mg O2/l. Experiments verified that half-order kinetics could be applied but liquid film diffusion apparently influenced the reaction rate considerably. The observed half-order rate constant was experimentally determined to K½A,O2=7.0 (g O2)1/2m−1/2d−1 but this value is underestimated by 15% due to the observed liquid film diffusion. Based on this the intrinsic zero-order reaction rate was estimated at k0f,O2=190 kg O2/m3 biofilm/d when both liquid film and biofilm diffusion were taken into account.

Study on the Impact of DO and Organic Matter on Aerobic Granular Sludge Treating Municipal Sewage

2014 ◽  
Vol 989-994 ◽  
pp. 603-606 ◽  
Author(s):  
Yang Yu ◽  
Hai Jiao Yu ◽  
Chen Ci Ma
Keyword(s):  
Organic Matter ◽  
Total Nitrogen ◽  
Removal Rate ◽  
Granular Sludge ◽  
Ammonia Nitrogen ◽  
Aerobic Granular Sludge ◽  
Municipal Sewage ◽  
Aerobic Conditions ◽  
Do Concentration ◽  
The Impact

The experiment uses municipal sewage as the research object and runs SBR reactor in completely aerobic conditions. Through controlling different of DO concentration and COD concentration, we study spreading comparison. The results show that when DO concentration was 1mg/L, the removal effect of aerobic granular sludge process in SBR treating municipal sewage was best, the average removal rate of COD, ammonia nitrogen, total nitrogen and phosphorous was 90.12%,98.95%,87.65% and 83.74% respectively. When COD concentration of influent was about 400mg/L, the treatment effects of aerobic granular sludge for COD, ammonia nitrogen, total nitrogen and phosphorous were all better, the average removal rate was up to 92.33%,98.83%,88.17% and 80.25% respectively.

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