Sewage sludge is widely used as an important source for biogas production through digestion. Developing the high performance processes has a significant goal in order to promote energy efficiency and reduce the cost sewage sludge treatment. The problem of sewage sludge disposal is becoming top one which almost cost 50 % of running fee for a municipal wastewater treatment plant. This paper basically introduces three methods to improve the conventional digestion. However, they enhance the conventional digestion from different aspects. For examples, Two-phase anaerobic digestion enables to exhibit the merit of thermophilic anaerobic digestion and avoid the weak points of conventional digestion regarding odor problem. In two-phase anaerobic digestion, the acid and methane producing stages are separated. Extended solids retention time is an approach to separate the hydraulic retention time and solids retention time in an anaerobic digester by using recycle thickening. This method could benefit further de-composing the organics and increase methane formation. Dewaterability is the final step of anaerobic digestion process. Enhancing this part of process is an efficient way to increase the solid content of sludge that would reduce the transportation costs. In a nutshell, no matter on saving cost or energy perspectives, these three methods all promote biogas production efficiency up to a better performance, but various requirement of energy and cost are demanded. The paper displays and compares the advantages and disadvantages among three methods. There is no certain answer to which method is the best one; however, they can be chose to enhance digestion in different condition.
| Identifer | oai:union.ndltd.org:UPSALLA1/oai:DiVA.org:kth-99357 |
| Date | January 2012 |
| Creators | Wang, Kai |
| Publisher | KTH, VA-teknik, Vatten, Avlopp och Avfall |
| Source Sets | DiVA Archive at Upsalla University |
| Language | English |
| Detected Language | English |
| Type | Student thesis, info:eu-repo/semantics/bachelorThesis, text |
| Format | application/pdf |
| Rights | info:eu-repo/semantics/openAccess |
| Relation | TRITA-LWR Degree Project, 1651-064X ; LWR-EX-12-15 |
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