Thermophilic versus Mesophilic Anaerobic Digestion of Sewage Sludge: A Comparative Review
During advanced biological wastewater treatment, a huge amount of sludge is produced as a by-product of the treatment process. Hence, reuse and recovery of resources and energy from the sludge is a big technological challenge. The processing of sludge produced by Wastewater Treatment Plants (WWTPs)...
| Main Authors: | , |
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| Format: | Article |
| Language: | English |
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MDPI AG
2016-06-01
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| Series: | Bioengineering |
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| Online Access: | http://www.mdpi.com/2306-5354/3/2/15 |
| _version_ | 1797764177703469056 |
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| author | Getachew D. Gebreeyessus Pavel Jenicek |
| author_facet | Getachew D. Gebreeyessus Pavel Jenicek |
| author_sort | Getachew D. Gebreeyessus |
| collection | DOAJ |
| description | During advanced biological wastewater treatment, a huge amount of sludge is produced as a by-product of the treatment process. Hence, reuse and recovery of resources and energy from the sludge is a big technological challenge. The processing of sludge produced by Wastewater Treatment Plants (WWTPs) is massive, which takes up a big part of the overall operational costs. In this regard, anaerobic digestion (AD) of sewage sludge continues to be an attractive option to produce biogas that could contribute to the wastewater management cost reduction and foster the sustainability of those WWTPs. At the same time, AD reduces sludge amounts and that again contributes to the reduction of the sludge disposal costs. However, sludge volume minimization remains, a challenge thus improvement of dewatering efficiency is an inevitable part of WWTP operation. As a result, AD parameters could have significant impact on sludge properties. One of the most important operational parameters influencing the AD process is temperature. Consequently, the thermophilic and the mesophilic modes of sludge AD are compared for their pros and cons by many researchers. However, most comparisons are more focused on biogas yield, process speed and stability. Regarding the biogas yield, thermophilic sludge AD is preferred over the mesophilic one because of its faster biochemical reaction rate. Equally important but not studied sufficiently until now was the influence of temperature on the digestate quality, which is expressed mainly by the sludge dewateringability, and the reject water quality (chemical oxygen demand, ammonia nitrogen, and pH). In the field of comparison of thermophilic and mesophilic digestion process, few and often inconclusive research, unfortunately, has been published so far. Hence, recommendations for optimized technologies have not yet been done. The review presented provides a comparison of existing sludge AD technologies and the gaps that need to be filled so as to optimize the connection between the two systems. In addition, many other relevant AD process parameters, including sludge rheology, which need to be addressed, are also reviewed and presented. |
| first_indexed | 2024-03-12T19:52:55Z |
| format | Article |
| id | doaj.art-48e9eeadf8b2490984cd1b9f7980dceb |
| institution | Directory Open Access Journal |
| issn | 2306-5354 |
| language | English |
| last_indexed | 2024-03-12T19:52:55Z |
| publishDate | 2016-06-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Bioengineering |
| spelling | doaj.art-48e9eeadf8b2490984cd1b9f7980dceb2023-08-02T03:01:43ZengMDPI AGBioengineering2306-53542016-06-01321510.3390/bioengineering3020015bioengineering3020015Thermophilic versus Mesophilic Anaerobic Digestion of Sewage Sludge: A Comparative ReviewGetachew D. Gebreeyessus0Pavel Jenicek1Urban Environmental Management, Kotebe University College, 31248, Addis Ababa, EthiopiaWater Technology and Environmental Engineering, University of Chemistry and Technology, Technická 5, 166 28 Prague 6—Dejvice, Czech RepublicDuring advanced biological wastewater treatment, a huge amount of sludge is produced as a by-product of the treatment process. Hence, reuse and recovery of resources and energy from the sludge is a big technological challenge. The processing of sludge produced by Wastewater Treatment Plants (WWTPs) is massive, which takes up a big part of the overall operational costs. In this regard, anaerobic digestion (AD) of sewage sludge continues to be an attractive option to produce biogas that could contribute to the wastewater management cost reduction and foster the sustainability of those WWTPs. At the same time, AD reduces sludge amounts and that again contributes to the reduction of the sludge disposal costs. However, sludge volume minimization remains, a challenge thus improvement of dewatering efficiency is an inevitable part of WWTP operation. As a result, AD parameters could have significant impact on sludge properties. One of the most important operational parameters influencing the AD process is temperature. Consequently, the thermophilic and the mesophilic modes of sludge AD are compared for their pros and cons by many researchers. However, most comparisons are more focused on biogas yield, process speed and stability. Regarding the biogas yield, thermophilic sludge AD is preferred over the mesophilic one because of its faster biochemical reaction rate. Equally important but not studied sufficiently until now was the influence of temperature on the digestate quality, which is expressed mainly by the sludge dewateringability, and the reject water quality (chemical oxygen demand, ammonia nitrogen, and pH). In the field of comparison of thermophilic and mesophilic digestion process, few and often inconclusive research, unfortunately, has been published so far. Hence, recommendations for optimized technologies have not yet been done. The review presented provides a comparison of existing sludge AD technologies and the gaps that need to be filled so as to optimize the connection between the two systems. In addition, many other relevant AD process parameters, including sludge rheology, which need to be addressed, are also reviewed and presented.http://www.mdpi.com/2306-5354/3/2/15dewaterabilitymesophilic anaerobic digestionreject waterrheologysludgethermophilic anaerobic digestion |
| spellingShingle | Getachew D. Gebreeyessus Pavel Jenicek Thermophilic versus Mesophilic Anaerobic Digestion of Sewage Sludge: A Comparative Review Bioengineering dewaterability mesophilic anaerobic digestion reject water rheology sludge thermophilic anaerobic digestion |
| title | Thermophilic versus Mesophilic Anaerobic Digestion of Sewage Sludge: A Comparative Review |
| title_full | Thermophilic versus Mesophilic Anaerobic Digestion of Sewage Sludge: A Comparative Review |
| title_fullStr | Thermophilic versus Mesophilic Anaerobic Digestion of Sewage Sludge: A Comparative Review |
| title_full_unstemmed | Thermophilic versus Mesophilic Anaerobic Digestion of Sewage Sludge: A Comparative Review |
| title_short | Thermophilic versus Mesophilic Anaerobic Digestion of Sewage Sludge: A Comparative Review |
| title_sort | thermophilic versus mesophilic anaerobic digestion of sewage sludge a comparative review |
| topic | dewaterability mesophilic anaerobic digestion reject water rheology sludge thermophilic anaerobic digestion |
| url | http://www.mdpi.com/2306-5354/3/2/15 |
| work_keys_str_mv | AT getachewdgebreeyessus thermophilicversusmesophilicanaerobicdigestionofsewagesludgeacomparativereview AT paveljenicek thermophilicversusmesophilicanaerobicdigestionofsewagesludgeacomparativereview |