Influence of Pretreatment on Anaerobic Stabilisation of Sewage Sludge

1984 ◽  
Vol 16 (12) ◽  
pp. 365-373 ◽  
Author(s):  
F Wechs
Keyword(s):  
Anaerobic Digestion ◽  
Sewage Sludge ◽  
Short Term ◽  
Digested Sludge ◽  
Digestion Process ◽  
Reference Process ◽  
Stage Process ◽  
Rate Limiting ◽  
Hydrolysis Of ◽  
Pretreatment Processes

In order to intensify anaerobic stabilisation of sewage sludge, several pretreatment processes have been tested. Pretreatment processes investigated are: prepasteurisation, separate acidification, short-term anaerobic digestion. Anaerobic stabilisation was performed in 500 1 digestors. All experiments were performed in parallel to a process operated with untreated raw sludge, the later serving as a reference process. Prepasteurisation turned out to improve solids degradation and dewaterability of the digested sludge, whereas acidification was found to be a rather slow and uncomplete process due to the rate limiting function of hydrolysis of sludge particulates. Using a short-term anaerobic digestion process before anaerobic stabilisation, the easily degradable organics were readily converted to methane. It was shown that this two-stage process improves stabilisation efficiency in comparison to a 20 day one-stage process very significantly.

Application of acidic thermal treatment for one- and two-stage anaerobic digestion of sewage sludge

2010 ◽  
Vol 62 (11) ◽  
pp. 2647-2654 ◽  
Author(s):  
M. Takashima ◽  
Y. Tanaka
Keyword(s):  
Anaerobic Digestion ◽  
Sewage Sludge ◽  
Thermal Treatment ◽  
Phosphorus Recovery ◽  
Attractive Alternative ◽  
Two Stage ◽  
Digested Sludge ◽  
One Stage ◽  
Stage Process ◽  
The One

The effectiveness of acidic thermal treatment (ATT) was examined in a 106-day continuous experiment, when applied to one- or two-stage anaerobic digestion of sewage sludge (4.3% TS). The ATT was performed at 170°C and pH 5 for 1 hour (sulfuric acid for lowering pH). The one-stage process was mesophilic at 20 days hydraulic retention time (HRT), and incorporated the ATT as pre-treatment. The two-stage process consisted of a thermophilic digester at 5 days HRT and a mesophilic digester at 15 days HRT, and incorporated the ATT as interstage-treatment. On average, VSS reduction was 48.7% for the one-stage control, 65.8% for the one-stage ATT, 52.7% for the two-stage control and 67.6% for the two-stage ATT. Therefore, VSS reduction was increased by 15–17%, when the ATT was combined in both one- and two-stage processes. In addition, the dewaterability of digested sludge was remarkably improved, and phosphate release was enhanced. On the other hand, total methane production did not differ significantly, and color generation was noted in the digested sludge solutions with the ATT. In conclusion, the anaerobic digestion with ATT can be an attractive alternative for sludge reduction, handling, and phosphorus recovery.

scholarly journals Improvement in the efficiency of hydrolysis of anaerobic digestion in sewage sludge by the use of enzymes

2010 ◽  
Vol 21 (1-3) ◽  
pp. 280-285 ◽  
Author(s):  
Ibrahim Gar Al-Alm Rashed ◽  
Joseph Akunna ◽  
Mohamed Mohamed El-Halwany ◽  
Ahmed Farag Fadil Abou Atiaa
Keyword(s):  
Anaerobic Digestion ◽  
Sewage Sludge ◽  
Hydrolysis Of

Breakthrough in hydrolysis of waste biomass by physico-chemical pretreatment processes for efficient anaerobic digestion

Chemosphere ◽  
2022 ◽  
pp. 133617
Author(s):  
Preethi ◽  
Rajesh Banu J ◽  
Sunita Varjani ◽  
Sivashanmugam P ◽  
Vinay Kumar Tyagi ◽  
...  
Keyword(s):  
Anaerobic Digestion ◽  
Waste Biomass ◽  
Chemical Pretreatment ◽  
Physico Chemical ◽  
Hydrolysis Of ◽  
Pretreatment Processes

Mesophilic and Thermophilic Digestion of Thickened Waste Activated Sludge: A Comparative Study

2010 ◽  
Vol 113-116 ◽  
pp. 450-458 ◽  
Author(s):  
Yong Zhi Chi ◽  
Yu You Li ◽  
Min Ji ◽  
Hong Qiang ◽  
Heng Wei Deng ◽  
...  
Keyword(s):  
Anaerobic Digestion ◽  
Activated Sludge ◽  
Municipal Wastewater ◽  
Treatment Plant ◽  
Methane Content ◽  
Waste Activated Sludge ◽  
Digested Sludge ◽  
Anaerobic Digestion Process ◽  
Digestion Process ◽  
Significant Difference

This paper presents an experimental study over 204 days on anaerobic degradation of thickened waste activated sludge (TWAS) from a municipal wastewater treatment plant (WWTP). The experiments were conducted under thermophilic (55°C) and mesophilic (35°C) condition, respectively, by using the semi-continuous flow completely mixed reactors. The influent total solids (TS), hydraulic retention time (HRT) and chemical oxygen demand (COD) loading levels were around 4%, 30 days and 1.67 kg-CODCr•m-3•d-1 , respectively. During the opration period, the thermophilic anaerobic digestion process (TADP) and the mesophilic anaerobic digestion process (MADP) were stable and well-functioned without ammonia inhibition. Particulate organic matters reduction of TADP was superior to that of MADP. This result implies that TADP has higher sludge reduction efficiency than MADP. According to the simulated chemical formula of TWAS, C5.85H9.75O3.96N, and the stoichiometric equation, the methane content and the ammonia yield in the anaerobic process could be calculated, which were consistent with the experimental results. The methane yield of TADP was a little higher than that of MADP. The statistical mean values of methane content for TADP and MADP were 60.97% and 62.38%, respectively.According to paired t-test, there was a significant difference in methane content between TADP and MADP(α=0.01, n=62). Compared with the mesophilic digested sludge, the dewaterability of thermophilic digested sludge was lower.

Potential of anaerobic digestion of complex waste(water)

2001 ◽  
Vol 44 (8) ◽  
pp. 115-122 ◽  
Author(s):  
G. Zeeman ◽  
W. Sanders
Keyword(s):  
Waste Water ◽  
Anaerobic Digestion ◽  
Order Relation ◽  
Organic Substrates ◽  
Reactor Technology ◽  
Rate Limiting Step ◽  
Treatment Technologies ◽  
Transport Complex ◽  
Rate Limiting ◽  
Hydrolysis Of

Although they differ greatly in origin complex waste(water)s mainly consist of proteins, lipids, carbohydrates and sometimes lignin in addition. Hydrolysis is the first and generally rate-limiting step in the process of anaerobic digestion of particulate organic substrates. Hydrolysis of particulate polymers can be described by Surface Based Kinetics, but for use in practice the empirical first order relation is advised. Unlike the hydrolysis of protein and carbohydrate, lipid hydrolysis is hardly occurring in the absence of methanogenesis. The latter is probably a physical rather than a biological process and affects the choice for either a one- or a two-step (phase) anaerobic reactor. In the chain of collection and transport, complex wastes often become complex wastewaters simply because of dilution. Dilution not only changes the reactor technology to be applied but also complicates the post-treatment and possibilities for resource recovery. Combining concentrated with diluted waste streams will almost always end up in much more complicated treatment technologies.

Inactivation of pathogenic bacteria under mesophilic and thermophilic conditions

1997 ◽  
Vol 36 (6-7) ◽  
pp. 25-32 ◽  
Author(s):  
Haruki Watanabe ◽  
Tomokazu Kitamura ◽  
Shuichi Ochi ◽  
Masaaki Ozaki
Keyword(s):  
Anaerobic Digestion ◽  
Fecal Coliform ◽  
Pathogenic Bacteria ◽  
Anaerobic Treatment ◽  
Digested Sludge ◽  
Primary Sludge ◽  
Digestion Process ◽  
Mesophilic Digestion ◽  
Thermophilic Digestion ◽  
Number Of Bacteria

This paper concerns field survey and laboratory experiment on the inactivation of pathogenic bacteria during sludge treatment processes with particular emphasis on anaerobic digestion process. We surveyed the inactivation of pathogenic bacteria processes by sampling various types of sludges from 17 wastewater treatment plants located in Japan and counting the number of bacteria in the sampled sludges. The bacteria we counted included fecal coliform groups, enterococcus and salmonella. The median number of fecal coliform groups in primary sludge was found to be 105 MPN/g, while the number of fecal coliform groups in digested sludge decreased to 103 MPN/g. We also confirmed that the treatments of dewatering using inorganic coagulant, drying and composting are also effective in inactivating pathogenic bacteria. In addition, we studied the performance conditions of anaerobic digestion and the degree of inactivation of pathogenic bacteria in the experiment of anaerobic treatment of the primary sludge. This study showed that the number of fecal coliform groups in mesophilic digestion sludge was in the range of 102 to 104 MPN/g regardless of the HRT, whereas the number of bacteria in thermophilic digestion sludge was of the order of 100 MPN/g, clearly indicating that the number of bacteria substantially decreases when the sludge is digested at thermophilic temperature. The number of enterococcus in digested sludge was in the range of 102 to 105 MPN/g after the sludge was subjected to mesophilic digestion while the number decreased to 100 MPN/g after the sludge was digested at thermophilic temperature. The number of salmonella in digested sludge was in the range of 1.8 to 30 MPN/4g after the sludge was digested at mesophilic temperature, but the number decreased to less than 1.8 MPN/4g after the sludge went through thermophilic digestion process. The thermophilic digestion is thus effective in inactivating pathogenic bacteria.

Microwave Thermal Hydrolysis Of Sewage Sludge As A Pretreatment Stage For Anaerobic Digestion

2008 ◽  
Author(s):  
W. Qiao ◽  
W. Wang ◽  
R. Xun ◽  
Kazuyuki Tohji ◽  
Noriyoshi Tsuchiya ◽  
...  
Keyword(s):  
Anaerobic Digestion ◽  
Sewage Sludge ◽  
Thermal Hydrolysis ◽  
Hydrolysis Of

Fate of nonylphenol polyethoxylates and nonylphenoxy acetic acids in an anaerobic digestion process for sewage sludge treatment

2006 ◽  
Vol 53 (11) ◽  
pp. 221-226 ◽  
Author(s):  
M. Minamiyama ◽  
S. Ochi ◽  
Y. Suzuki
Keyword(s):  
Wastewater Treatment ◽  
Anaerobic Digestion ◽  
Sewage Sludge ◽  
Treatment Process ◽  
Sludge Treatment ◽  
Testing Apparatus ◽  
Anaerobic Digestion Process ◽  
Digestion Process ◽  
Sewage Sludge Treatment ◽  
Acetic Acids

Many environmental problems caused by endocrine disruptors (EDs) have been reported. It is reported that EDs flow into sewage treatment plants, and it has been pointed out that these may be shifted from the wastewater treatment process to the sludge treatment process. Little is known about the fate of EDs accumulated in sewage sludge, so we carried out a study to clarify the fate of EDs in sewage sludge treatment processes, especially in an anaerobic digestion process. In this study, nonylphenol (NP) was selected as a target ED. Nonylphenol ethoxylates (NPnEO) or nonylphenoxy acetic acids (NPnEC), which were the precursor of NP, were added to an anaerobic digestion process, and mass balance was investigated. The following results were obtained from the anaerobic digestion experiments. (1) NP1EO was injected to an anaerobic digestion testing apparatus that was operated at a retention time of approximately 28 d and a temperature of 35 °C with thickened sludge sampled from an actual wastewater treatment plant. Approximately 40% of the injected NP1EO was converted to NP. (2) NP1EC was injected to an anaerobic digestion testing apparatus with thickened sludge. As a result, almost all injected NP1EC was converted to NP. When NP2EC was injected, NP2EC was not converted to NP until the 20th day.

scholarly journals Modelling and Multi-Criteria Analysis of Anaerobic Digestion Process to Get Upgraded Methane from Bio-Residues in the City of Reykjavik

Proceedings ◽  
2019 ◽  
Vol 30 (1) ◽  
pp. 46
Author(s):  
Finger ◽  
Stepanovic ◽  
Llano
Keyword(s):  
Anaerobic Digestion ◽  
Sewage Sludge ◽  
Food Waste ◽  
Organic Waste ◽  
Waste Treatment ◽  
Action Plan ◽  
Digestion Process ◽  
Climate Action ◽  
Climate Action Plan ◽  
The City

Anaerobic digestion of urban organic wastes, farming slurries or sewage sludge is a common practice in waste treatment plants. In the city of Reykjavik, the organic waste fraction constituted by 60% of biomass and 40% of food waste will be transformed by the local waste company SORPA providing biofuel for up to 10% of the cars. Such measures belong to the 2018-2030 Climate Action Plan from the Icelandic Government.

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.

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