Full scale experience of two stage thermophilic/mesophilic sludge digestion

1997 ◽  
Vol 36 (6-7) ◽  
pp. 449-456 ◽  
Author(s):  
Jürgen Oles ◽  
Norbert Dichtl ◽  
Hans-hermann Niehoff
Keyword(s):  
Degradation Process ◽  
Pilot Scale ◽  
Full Scale ◽  
Process Efficiency ◽  
Anaerobic Sludge ◽  
Process Conditions ◽  
Two Stage ◽  
Operational Conditions ◽  
Digestion Process ◽  
General Goals

The general goals of anaerobic sludge stabilisation are degradation of organic substances, reduction of solids, decrease of pathogenic bacterias, improvement of dewatering capabilities and production of biogas. The anaerobic degradation process can be divided in several steps with different optimum operational conditions. This gives the possibility to design treatment plants as a two-stage process, optimizing the process conditions in each step and thereby leading to an overall increase in process efficiency. Research results in lab scale and pilot scale have shown that a two-stage digestion process with a high loaded first thermophilic (50-55°C) stage and a second stage under mesophilic (35-37°C) conditions with sufficient retention time will lead to the best results. After giving a short summary of the development of the two-stage thermophilic/mesophilic digestion process the paper will present full scale experiences with this system in Germany.

scholarly journals Indicative Marker Microbiome Structures Deduced from the Taxonomic Inventory of 67 Full-Scale Anaerobic Digesters of 49 Agricultural Biogas Plants

2021 ◽  
Vol 9 (7) ◽  
pp. 1457
Author(s):  
Julia Hassa ◽  
Johanna Klang ◽  
Dirk Benndorf ◽  
Marcel Pohl ◽  
Benedikt Hülsemann ◽  
...  
Keyword(s):  
Stable Process ◽  
Process Condition ◽  
Full Scale ◽  
Process Models ◽  
Process Efficiency ◽  
Process Conditions ◽  
Rrna Gene ◽  
General Process ◽  
Specific Distribution ◽  
Biogas Plants

There are almost 9500 biogas plants in Germany, which are predominantly operated with energy crops and residues from livestock husbandry over the last two decades. In the future, biogas plants must be enabled to use a much broader range of input materials in a flexible and demand-oriented manner. Hence, the microbial communities will be exposed to frequently varying process conditions, while an overall stable process must be ensured. To accompany this transition, there is the need to better understand how biogas microbiomes respond to management measures and how these responses affect the process efficiency. Therefore, 67 microbiomes originating from 49 agricultural, full-scale biogas plants were taxonomically investigated by 16S rRNA gene amplicon sequencing. These microbiomes were separated into three distinct clusters and one group of outliers, which are characterized by a specific distribution of 253 indicative taxa and their relative abundances. These indicative taxa seem to be adapted to specific process conditions which result from a different biogas plant operation. Based on these results, it seems to be possible to deduce/assess the general process condition of a biogas digester based solely on the microbiome structure, in particular on the distribution of specific indicative taxa, and without knowing the corresponding operational and chemical process parameters. Perspectively, this could allow the development of detection systems and advanced process models considering the microbial diversity.

scholarly journals A Review of the Chemistry of Anaerobic Digestion: Methods of Accelerating and Optimizing Process Efficiency

Processes ◽  
2019 ◽  
Vol 7 (8) ◽  
pp. 504 ◽  
Author(s):  
Anthony Anukam ◽  
Ali Mohammadi ◽  
Muhammad Naqvi ◽  
Karin Granström
Keyword(s):  
Anaerobic Digestion ◽  
Energy System ◽  
Process Efficiency ◽  
Process Conditions ◽  
Future Directions ◽  
Digestion Process ◽  
Process Chemistry ◽  
Depth Analysis ◽  
Sustainable Energy System ◽  
Digestion Methods

The anaerobic digestion technology has been in existence for centuries and its underlying theory established for decades. It is considered a useful technology for the generation of renewable energy, and provides means to alleviate problems associated with low access to energy. However, a great deal of current research is targeted towards the optimization of this technology under diverse digestion process conditions. This review presents an in-depth analysis of the chemistry of anaerobic digestion and discusses how process chemistry can be used to optimize system performance through identification of methods that can accelerate syntrophic interactions of different microorganisms for improved methanogenic reactions. Recent advances in addition to old research are discussed in order to offer a general but comprehensive synopsis of accumulated knowledge in the theory of anaerobic digestion, as well as an overview of previous research and future directions and opportunities of the AD technology. Achieving a sustainable energy system requires comprehensive reforms in not just economic, social and policy aspects, but also in all technical aspects, which represents one of the most crucial future investments for anaerobic digestion systems.

The effect of operational conditions on the sludge specific methanogenic activity and sludge biodegradability

2009 ◽  
Vol 59 (9) ◽  
pp. 1847-1853 ◽  
Author(s):  
R. C. Leitão ◽  
S. T. Santaellla ◽  
A. C. van Haandel ◽  
G. Zeeman ◽  
G. Lettinga
Keyword(s):  
Municipal Wastewater ◽  
Pilot Scale ◽  
Upflow Anaerobic Sludge Blanket ◽  
Uasb Reactor ◽  
Anaerobic Sludge ◽  
Treatment Unit ◽  
Methanogenic Activity ◽  
Operational Conditions ◽  
Anaerobic Reactors ◽  
Specific Methanogenic Activity

The effects of hydraulic retention time (HRT) and influent COD concentration (CODInf) on Specific Methanogenic Activity (SMA) and the biodegradability of an anaerobic sludge need to be elucidated because of the discordant results available in literature. This information is important for the operation of anaerobic reactors and design of the sludge post-treatment unit. For this study, sludge samples obtained from eight pilot-scale Upflow Anaerobic Sludge Blanket (UASB) reactors were tested. The reactors were fed with municipal wastewater and operated with different sets of HRT and influent concentrations until the steady state was established. The results show that at a lower HRT, sludge with relatively higher SMA develops. A slight trend of declining SMA at increasing CODInf was found for reactors operated at longer HRTs; however, further experiments are necessary for more definitive conclusions. The sludge from reactors operated at longer HRTs and with lower CODInf resulted in lower biodegradability. Results also showed that it is ineffective to design a UASB reactor with a longer HRT to cope with organic shock loads.

The effect of operational conditions on the performance of UASB reactors for domestic wastewater treatment

2005 ◽  
Vol 52 (1-2) ◽  
pp. 299-305 ◽  
Author(s):  
R.C. Leitão ◽  
J.A. Silva-Filho ◽  
W. Sanders ◽  
A.C. van Haandel ◽  
G. Zeeman ◽  
...  
Keyword(s):  
Removal Efficiency ◽  
Municipal Wastewater ◽  
Domestic Wastewater ◽  
Pilot Scale ◽  
Cod Removal ◽  
Upflow Anaerobic Sludge Blanket ◽  
Anaerobic Sludge ◽  
Operational Conditions ◽  
Cod Removal Efficiency ◽  
Uasb Reactors

In this investigation, the performance of Upflow Anaerobic Sludge Blanket (UASB) reactors treating municipal wastewater was evaluated on the basis of: (i) COD removal efficiency, (ii) effluent variability, and (iii) pH stability. The experiments were performed using 8 pilot-scale UASB reactors (120 L) from which some of them were operated with different influent COD (CODInf ranging from 92 to 816 mg/L) and some at different hydraulic retention time (HRT ranging from 1 to 6 h). The results show that decreasing the CODInf, or lowering the HRT, leads to decreased efficiencies and increased effluent variability. During this experiment, the reactors could treat efficiently sewage with concentration as low as 200 mg COD/L. They could also be operated satisfactorily at an HRT as low as 2 hours, without problems of operational stability. The maximum COD removal efficiency can be achieved at CODInf exceeding 300 mg/L and HRT of 6 h.

Biofilter Response to Upsets in Process Conditions

2009 ◽  
Vol 4 (1) ◽  
Author(s):  
Zarook M Shareefdeen
Keyword(s):  
Process Control ◽  
Dynamic Behavior ◽  
Flow Rate ◽  
Environmental Conditions ◽  
Full Scale ◽  
Axial Dispersion ◽  
Process Conditions ◽  
Operational Conditions ◽  
Dispersion Effects ◽  
Component Adsorption

Full scale biofilter systems are often subjected to variations in operational and environmental conditions. Occasional fluctuations in the flow rate, temperature, concentrations of process emissions, and pH drops are commonly encountered. In this work, a general transient biofilter model which incorporates axial dispersion effects, interactive kinetics, multi-component adsorption effects and oxygen limitations aspects have been used to study the dynamic behavior of biofilters to process upsets. Biofilter performance under sinusoidal and triangular perturbations of concentrations, flow rate, and media pH are presented. The results of this study will be useful in the designing and process control of biofilter systems that are exposed to varying operational conditions.

scholarly journals Improvement of Digestate Stability Using Dark Fermentation and Anaerobic Digestion Processes

Energies ◽  
2019 ◽  
Vol 12 (18) ◽  
pp. 3552 ◽  
Author(s):  
Elena Albini ◽  
Isabella Pecorini ◽  
Giovanni Ferrara
Keyword(s):  
Anaerobic Digestion ◽  
Pilot Scale ◽  
Dark Fermentation ◽  
Second Phase ◽  
Reference Scenario ◽  
Biological Stability ◽  
Two Stage ◽  
Anaerobic Digestion Process ◽  
Digestion Process ◽  
Stage Process

This paper assessed the effect of dark fermentation, the fermentative phase in a two-stage anaerobic digestion system, in terms of digestate biostabilization efficiency. The digestates analyzed in this study were obtained from a pilot-scale system in which two different substrates were used in order to simulate both the digestion and co-digestion process. Biostabilization performances were evaluated by measuring the specific oxygen uptake rate (SOUR) of the outgoing digestates. This index allowed us to define the degree of effectiveness in terms of stabilization of organic matter, between the traditional anaerobic digestion process and the two-stage configuration. Considering the traditional process as a reference scenario, the results highlighted an increase in biological stability for the two-stage co-digestion process, consisting of a dark fermentation stage, followed by an anaerobic digestion one. Digestates biostabilization efficiency increased up from 6.5% to 40.6% from the traditional one-stage configuration to the two-stage one by improving the anaerobic digestion process through a preliminary fermentative stage. The advantages of the two-stage process were due to the role of dark fermentation as a biological pre-treatment. Considering the partial stability results related to the second stage, biological stability was improved in comparison to a single-stage process, reaching an efficiency of 42.2% and 55.8% for the digestion and co-digestion scenario respectively. The dark fermentation phase allowed for a higher hydrolysis of the substrate, making it more easily degradable in the second phase. Results demonstrated better biostabilization performances of the outgoing digestates with the introduction of dark fermentation, resulting in more stable digestates for both the digestion and co-digestion process.

Treatment of natural rubber processing wastewater using a combination system of a two-stage up-flow anaerobic sludge blanket and down-flow hanging sponge system

2016 ◽  
Vol 73 (8) ◽  
pp. 1777-1784 ◽  
Author(s):  
D. Tanikawa ◽  
K. Syutsubo ◽  
M. Hatamoto ◽  
M. Fukuda ◽  
M. Takahashi ◽  
...  
Keyword(s):  
Natural Rubber ◽  
Oxygen Demand ◽  
Pilot Scale ◽  
Organic Loading Rate ◽  
Anaerobic Sludge ◽  
Activity Measurement ◽  
Two Stage ◽  
Combination System ◽  
Scale Experiment ◽  
Anaerobic Sludge Blanket

A pilot-scale experiment of natural rubber processing wastewater treatment was conducted using a combination system consisting of a two-stage up-flow anaerobic sludge blanket (UASB) and a down-flow hanging sponge (DHS) reactor for more than 10 months. The system achieved a chemical oxygen demand (COD) removal efficiency of 95.7% ± 1.3% at an organic loading rate of 0.8 kgCOD/(m3.d). Bacterial activity measurement of retained sludge from the UASB showed that sulfate-reducing bacteria (SRB), especially hydrogen-utilizing SRB, possessed high activity compared with methane-producing bacteria (MPB). Conversely, the acetate-utilizing activity of MPB was superior to SRB in the second stage of the reactor. The two-stage UASB–DHS system can reduce power consumption by 95% and excess sludge by 98%. In addition, it is possible to prevent emissions of greenhouse gases (GHG), such as methane, using this system. Furthermore, recovered methane from the two-stage UASB can completely cover the electricity needs for the operation of the two-stage UASB–DHS system, accounting for approximately 15% of the electricity used in the natural rubber manufacturing process.

Robust interval-based regulation for anaerobic digestion processes

2005 ◽  
Vol 52 (1-2) ◽  
pp. 449-456 ◽  
Author(s):  
V. Alcaraz-González ◽  
J. Harmand ◽  
A. Rapaport ◽  
J.P. Steyer ◽  
V. González-Álvarez ◽  
...  
Keyword(s):  
Anaerobic Digestion ◽  
Oxygen Demand ◽  
Pilot Scale ◽  
Set Point ◽  
Operational Conditions ◽  
Digestion Process ◽  
Biochemical Reactors ◽  
Highly Nonlinear ◽  
Distillery Wastewater ◽  
Robust Regulation

A robust regulation law is applied to the stabilization of a class of biochemical reactors exhibiting partially known highly nonlinear dynamic behavior. An uncertain environment with the presence of unknown inputs is considered. Based on some structural and operational conditions, this regulation law is shown to exponentially stabilize the aforementioned bioreactors around a desired set-point. This approach is experimentally applied and validated on a pilot-scale (1 m3) anaerobic digestion process for the treatment of raw industrial wine distillery wastewater where the objective is the regulation of the chemical oxygen demand (COD) by using the dilution rate as the manipulated variable. Despite large disturbances on the input COD and state and parametric uncertainties, this regulation law gave excellent performances leading the output COD towards its set-point and keeping it inside a pre-specified interval.

Feasibility analysis of print pastes co-disposal in anaerobic sludge digesters

1997 ◽  
Vol 36 (2-3) ◽  
pp. 181-188
Author(s):  
L. Bonomo ◽  
A. Rozzi ◽  
F. Malpei
Keyword(s):  
Sewage Sludge ◽  
Industrial Wastewater ◽  
Pilot Scale ◽  
Treatment Costs ◽  
Full Scale ◽  
Feasibility Analysis ◽  
Anaerobic Sludge ◽  
Technical Feasibility ◽  
The Future ◽  
The Impact

Significant amounts of residual print pastes are produced by the industrial textile settlements of the Como area (Italy). Currently, these wastes are directly discharged in the sewer but it is unlikely that in the future this treatment through POTW will be further allowed. Therefore alternative ways of collection and disposal must be evaluated. The most suitable processes appear to be: drying, followed by incineration or landfilling, or anaerobic co-treatment with sewage sludge. The latter option was investigated at pilot scale and a technical feasibility analysis of the full-scale solution was carried out. Results are presented and discussed with reference to the impact that this solution would have on the performance of POTW and on the treatment costs of textile industrial wastewater.

scholarly journals Two-Stage Anaerobic Digestion Process Combining Pre-digestion with Methanization

2015 ◽  
Vol 9 (2) ◽  
pp. 55-60
Author(s):  
Mohammed Mohaibes
Keyword(s):  
Anaerobic Digestion ◽  
Detectable Level ◽  
Process Efficiency ◽  
Two Stage ◽  
Biogas Yield ◽  
Digestion Process ◽  
Vs Removal ◽  
Mesophilic Digestion ◽  
Thermophilic Digestion ◽  
Biogas Process

Anaerobic digestion of a mixture of manure and sewage sludge by combination of the biological predigestion at 73°C with methanization at 55°C was studied with regard to the biogas process efficiency,energy balance and sanitation effect. Performance of the two-stage digestion was compared with theconventional, one-stage moderate thermophilic digestion at 55°C and mesophilic digestion at 37°C,respectively. The best performance was achieved by the two-stage treatment both in terms of VolatileSolids (VS) removal and biogas yield. Up to 60% of VS was removed and a specific methane yield of 300ml CH4 gVS-1 was achieved. Sanitation effect was measured as inactivation of the indicators of bacterialpathogens - the faecal enterococci and spores of Clostridium perfringens. Elimination of faecal enterococcito non-detectable level occurred only during treatments at 73°C and 55°C. Numbers of Clostridiumperfringens spores were reduced solely by the combined 73°C/55°C treatment.

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