Enhanced Mesophilic Anaerobic Digestion of Primary Sewage Sludge

Water ◽  
2021 ◽  
Vol 13 (3) ◽  
pp. 348
Author(s):  
Foteini Sakaveli ◽  
Maria Petala ◽  
Vasilios Tsiridis ◽  
Efthymios Darakas
Keyword(s):  
Anaerobic Digestion ◽  
Methane Production ◽  
Sewage Treatment ◽  
Cationic Polyelectrolyte ◽  
Hydrolysis Rate ◽  
Primary Sludge ◽  
Secondary Sludge ◽  
Adequate Quality ◽  
Production Capacities ◽  
Efficiency And Productivity

Processing of the produced primary and secondary sludge during sewage treatment is demanding and requires considerable resources. Most common practices suggest the cotreatment of primary and secondary sludge starting with thickening and anaerobic digestion. The aim of this study is to investigate the anaerobic digestion of the primary sludge only and estimate its impact on sludge treatment and energy recovery. Within this context, the performance of the anaerobic digestion of primary sludge is explored and focused on practices to further enhance the methane production by using additives, e.g., a cationic polyelectrolyte and attapulgite. The results showed that the overall yield in methane production during anaerobic digestion of primary sludge alone was higher than that obtained by the anaerobic digestion of mixed primary and secondary sludge (up to 40%), while the addition of both organic polyelectrolyte and attapulgite enhanced further the production of methane (up to 170%). Attapulgite increased the hydrolysis rate of biosolids and produced relatively stabilized digestate, though of lower dewaterability. Moreover, the results suggest that single digestion of primary sludge may accomplish higher methane production capacities at lower digestors’ volume increasing their overall efficiency and productivity, while the produced digestates are of adequate quality for further utilization mainly in agricultural or energy sectors.

scholarly journals Pretreatment, Anaerobic Codigestion, or Both? Which Is More Suitable for the Enhancement of Methane Production from Agricultural Waste?

Molecules ◽  
2021 ◽  
Vol 26 (14) ◽  
pp. 4175
Author(s):  
Lütfiye Dumlu ◽  
Asli Seyhan Ciggin ◽  
Stefan Ručman ◽  
N. Altınay Perendeci
Keyword(s):  
Anaerobic Digestion ◽  
Methane Production ◽  
Agricultural Waste ◽  
Kinetic Studies ◽  
Antagonistic Effect ◽  
Hydrolysis Rate ◽  
Order Kinetic ◽  
Maximum Enhancement ◽  
Mixing Ratios ◽  
Anaerobic Codigestion

Pretreatment and codigestion are proven to be effective strategies for the enhancement of the anaerobic digestion of lignocellulosic residues. The purpose of this study is to evaluate the effects of pretreatment and codigestion on methane production and the hydrolysis rate in the anaerobic digestion of agricultural wastes (AWs). Thermal and different thermochemical pretreatments were applied on AWs. Sewage sludge (SS) was selected as a cosubstrate. Biochemical methane potential tests were performed by mixing SS with raw and pretreated AWs at different mixing ratios. Hydrolysis rates were estimated by the best fit obtained with the first-order kinetic model. As a result of the experimental and kinetic studies, the best strategy was determined to be thermochemical pretreatment with sodium hydroxide (NaOH). This strategy resulted in a maximum enhancement in the anaerobic digestion of AWs, a 56% increase in methane production, an 81.90% increase in the hydrolysis rate and a 79.63% decrease in the technical digestion time compared to raw AWs. On the other hand, anaerobic codigestion (AcoD) with SS was determined to be ineffective when it came to the enhancement of methane production and the hydrolysis rate. The most suitable mixing ratio was determined to be 80:20 (Aws/SS) for the AcoD of the studied AWs with SS in order to obtain the highest possible methane production without any antagonistic effect.

scholarly journals Effect of Biochar Addition on the Microbial Community and Methane Production in the Rapid Degradation Process of Corn Straw

Energies ◽  
2021 ◽  
Vol 14 (8) ◽  
pp. 2223
Author(s):  
Zhi Wang ◽  
Ying Guo ◽  
Weiwei Wang ◽  
Liumeng Chen ◽  
Yongming Sun ◽  
...  
Keyword(s):  
Microbial Community ◽  
Anaerobic Digestion ◽  
Methane Production ◽  
Biogas Production ◽  
Degradation Process ◽  
Hydrolysis Rate ◽  
Control Group ◽  
Corn Straw ◽  
High Concentration ◽  
Fermentation Time

Anaerobic digestion with corn straw faces the problems of difficult degradation, long fermentation time and acid accumulation in the high concentration of feedstocks. In order to speed up the process of methane production, corn straw treated with sodium hydroxide was used in thermophilic (50 °C) anaerobic digestion, and the effects of biochar addition on the performance of methane production and the microbial community were analyzed. The results showed that the cumulative methane production of all treatment groups reached over 75% of the theoretical methane yield in 7 days and the addition of 4% biochar increased the cumulative methane production by 6.75% compared to the control group. The addition of biochar also decreased the number of biogas and methane production peaks from 2 to 1, and had a positive effect on shortening the digestion start-up period and reducing the fluctuation of biogas production during the digestion process. The addition of 4% biochar increased the abundance of the bacterial family Peptococcaceae throughout the digestion period, promoting the hydrolysis rate of corn straw. The dominant archaeal genus Methanosarcina was significantly more abundant at the peak stage and the end of methane production with 4% biochar added compared to the control group.

scholarly journals Zero valent iron enhances methane production from primary sludge in anaerobic digestion

2018 ◽  
Vol 351 ◽  
pp. 1159-1165 ◽  
Author(s):  
Wei Wei ◽  
Zhengqing Cai ◽  
Jie Fu ◽  
Guo-Jun Xie ◽  
Ang Li ◽  
...  
Keyword(s):  
Anaerobic Digestion ◽  
Methane Production ◽  
Zero Valent Iron ◽  
Primary Sludge

The Behaviour of Chlorinated Organics during Activated Sludge Treatment and Anaerobic Digestion

1988 ◽  
Vol 20 (11-12) ◽  
pp. 353-359 ◽  
Author(s):  
P. W. W. Kirk ◽  
J. N. Lester
Keyword(s):  
Biological Activity ◽  
Anaerobic Digestion ◽  
Activated Sludge ◽  
Sewage Treatment ◽  
Chemical Degradation ◽  
Organic Micropollutants ◽  
Sludge Treatment ◽  
Primary Sludge ◽  
Chlorinated Organic ◽  
Rapid Removal

An activated sludge pilot plant was operated at 4,6 and 9d sludge ages with influent settled sewage from a full scale treatment works. The behaviour of the chlorinated organic micropollutants was examined at their background levels in sewage and significant removal was seen for dieldrin, Y-HCH, DDE, PCB and 2,4-DCPol at all sludge ages. Dieldrin, Y-HCH, DDE PCB, 2,4,5-TCPol, 2,4,6-TCPol and 2,4-DCPol were found to associate with activated sludge solids. 2,4-DCPol and 4-C-2MPol were found to be biologically degraded. Mixed primary sludge from the same sewage treatment works was incubated anaerobically with and without azide addition to prevent biological activity. Rapid removal of Y-HCH was concluded to be due to chemical degradation, while biological activity was concluded to be the mechanism for the removals of 2,4-D, 2,4,5-T, 2,4,6-TCPol and 2,3,4,6-TeCPol. Statistically significant increases were observed for 2,3,4,6-TeCPol in azide treated incubations and for 2,4,5-TCPol and 2,4-DCPol in both treated and untreated anaerobic sludges.

Thermal pre-treatment of primary and secondary sludge at 70 °°C prior to anaerobic digestion

2005 ◽  
Vol 52 (1-2) ◽  
pp. 161-166 ◽  
Author(s):  
I.V. Skiadas ◽  
H.N. Gavala ◽  
J. Lu ◽  
B.K. Ahring
Keyword(s):  
Organic Matter ◽  
Anaerobic Digestion ◽  
Low Cost ◽  
Methane Recovery ◽  
Primary Sludge ◽  
Thermophilic Anaerobic Digestion ◽  
Secondary Sludge ◽  
Thermophilic Digestion ◽  
Pre Treatment ◽  
Digestion Step

In general, mesophilic anaerobic digestion of sewage sludge is more widely used compared to thermophilic digestion, mainly because of the lower energy requirements and higher stability of the process. However, the thermophilic anaerobic digestion process is usually characterised by accelerated biochemical reactions and higher growth rate of microorganisms resulting in an increased methanogenic potential at lower hydraulic retention times. Furthermore, thermal pre-treatment is suitable for the improvement of stabilization and could be realized at relatively low cost especially at low temperatures. The present study investigates the effect of the pre-treatment at 70 °C on thermophilic (55 °C) anaerobic digestion of primary and secondary sludge in continuously operated digesters. Thermal pre-treatment of primary and secondary sludge at 70 °C enhanced the removal of organic matter and the methane production during the subsequent anaerobic digestion step at 55 °C. It also greatly contributed to the destruction of pathogens present in primary sludge. Finally it results in enhanced microbial activities of the subsequent anaerobic step suggesting that the same efficiencies in organic matter removal and methane recovery could be obtained at lower HRTs.

Influence of wastewater treatment on sludge production and processing

2015 ◽  
Vol 10 (1) ◽  
pp. 178-186 ◽  
Author(s):  
W. P. F. Barber
Keyword(s):  
Wastewater Treatment ◽  
Anaerobic Digestion ◽  
Thermal Energy ◽  
Energy Recovery ◽  
Energy Content ◽  
Primary Sludge ◽  
Secondary Sludge ◽  
Configuration Changes ◽  
Chemical Sludge ◽  
Sludge Production

The challenge of stricter wastewater standards is resulting in configuration changes to wastewater treatment. As facilities upgrade, the type of sludge produced is changing, with growing quantities of secondary and chemical sludge at the expense of primary sludge. It is already understood that secondary sludge is harder to treat than its primary equivalent; therefore, increasing the quantity of this type of sludge will have detrimental impacts downstream. As legislation tightens further, extended aeration times may be required during processing to remove more nutrients. Work has shown that extended aeration further exacerbates the difficulty of treating secondary sludge. This paper explains how tightening wastewater legislation fundamentally alters the nature of the sludge produced and how this affects further processing, especially with respect to sludge production and type; sludge energy content; performance of anaerobic digestion and dewatering, and potential for thermal energy recovery.

scholarly journals Evaluation of batch mesophilic anaerobic digestion of raw and trampled llama and dromedary dungs: methane potential and kinetic study

2022 ◽  
Author(s):  
M. J. Fernández-Rodríguez ◽  
J. M. Mancilla-Leytón ◽  
D. de la Lama-Calvente ◽  
R. Borja
Keyword(s):  
Anaerobic Digestion ◽  
Methane Production ◽  
Hydrolysis Rate ◽  
Order Kinetic ◽  
Batch Mode ◽  
First Order ◽  
Volatile Solids ◽  
Order Kinetic Model ◽  
Methane Potential ◽  
Methane Production Rate

AbstractThis research was carried out with the aim to evaluate the anaerobic digestion (AD) of llama and dromedary dungs (both untreated and trampled) in batch mode at mesophilic temperature (35 °C). The biochemical methane potential (BMP) tests with an inoculum to substrate ratio of 2:1 (as volatile solids (VS)) were carried out. The methane yield from trampled llama dung (333.0 mL CH4 g−1 VSadded) was considerably higher than for raw llama, raw and trampled dromedary dungs (185.9, 228.4, 222.9 mL CH4 g−1 VSadded, respectively). Therefore, trampled llama dung was found to be the best substrate for methane production due to its high content of volatile solids as well as its high nitrogen content (2.1%) and more appropriate C/N ratio (23.6) for AD. The experimental data was found to be in accordance with both first-order kinetic and transference function mathematical models, when evaluating the experimental methane production against time. By applying the first-order kinetic model, the hydrolysis rate constants, kh, were found to be 19% and 11% higher for trampled dungs in comparison with the raw dung of dromedary and llama, respectively. In addition, the maximum methane production rate (Rm) derived from the transference function model for trampled llama dung (22.0 mL CH4 g−1 VS d−1) was 83.3%, 24.4% and 22.9% higher than those obtained for raw llama manure and for raw and trampled dromedary dungs, respectively.

Two combined techniques to enhance anaerobic digestion of sludge

2002 ◽  
Vol 46 (10) ◽  
pp. 167-172 ◽  
Author(s):  
G. Moeller-Chávez ◽  
S. González-Martínez
Keyword(s):  
Anaerobic Digestion ◽  
Yeast Extract ◽  
Methane Production ◽  
Influencing Factor ◽  
Removal Rates ◽  
Primary Sludge ◽  
Methanogenic Activity ◽  
Iron Nickel ◽  
Pre Treatment ◽  
Treatment Procedures

The rate-limiting step during anaerobic digestion is the hydrolysis of the particulate organic matter and methanogenesis. Certain elements, such as iron, nickel and cobalt and some growth factors such as coenzymes are needed for the adequate growth of the organisms. The main objective of this research was to enhance anaerobic digestion of primary sludge combining thermal and alkaline pre-treatment with stimulation of the methanogenic activity by adding yeast extract. Primary sludge was exposed, separately, to alkaline and thermal pre-treatment procedures. After this pre-treatment, different amounts of yeast extract were added to the sludge. The best COD, TSS and VSS removal rates were observed without pre-treatment and with the addition of 0.1% in weight of yeast extract. The highest specific methane production was obtained with thermal pre-treatment and 0.1% yeast addition. A second experimental stage was run for a closer analysis of the preliminary results. Thermal pre-treatment and 0.1% yeast addition was tested. The best results regarding both COD, TSS and VSS removal rates and methane production were obtained without thermal pre-treatment and with addition of yeast extract. The calculated F-values for the ANOVA-test show that the main influencing factor was the addition of yeast extract where the Biochemical Methane Production was doubled compared with the blank. The highest values for the hydrolysis constants were obtained at hydraulic retention times of six days after adding 0.1% of yeast extract.

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