Effects of biomass addition and fermentation on the energy content of hydrochar produced by hydrothermal carbonization (HTC) with faecal sludge | |
| Author | Pradeep, Sangeetha Vani |
| Call Number | AIT Thesis no.UWEM-15-03 |
| Subject(s) | Sewage sludge Biomass energy Carbonization |
| Note | 93 p. : ill. |
| Publisher | Asian Institute of Technology |
| Series Statement | Thesis ; no. UWEM-15-03 |
| Abstract | At a global level, faecal sludge management (FSM) is in need of the effective technologies that have to accomplish the basic sanitation problems such as pathogen removals, pre/post treatment, large foot print etc. Additionally, the proposed technology has to overwhelm all the deficiencies from the current practices. Hydrothermal carbonization (HTC) successfully aids to solve the issues, which effectively converts the feedsto ck into a char coal like hydrochar within few hours at high temperature. Moreover, HTC is most favorable for the wet biomass that produces hydrochar with its energy content. Previous studies were carried out to investigate the effects of faecal sludge (FS) as feedstock, which generally holds higher moisture content. The results prove that HTC is also effective for FS. Although, it shows good results to treat FS, the energy content of hydrochar produced is quiet low while compared with other biomass. Therefo re, external biomass such as cassava pulp (CP), dried leaves/grass cuttings (DL) , pig manure (PM) and rice husk (RH) were added with FS. It was investigated its effects on the energy content for different mixing ratio at 220 ° C for 5h. Relatively, all the biomasses used in this study helped to increase the energy content from 3 – 16%. From the results, an effective biomass of cassava pulp had selected that increase the energy content from 19.50 MJ/kg to 22.66 MJ/kg. In the se cond phase, to unravel the effects of process parameters on the maximum energy content that can be yielded when FS and CP are involved in the HTC process, parameters such as temperature and operation time were varied and studied the results obtained. As a result, FS: CP produced hydrochar with 23.75 MJ/kg at 250 ° C for 3 h. Furthermore, the research was extended to examine the characteristics of the produced hydrochar and validated with previous studies. Apart from the energy content, biomass addition also s ignificantly enhanced the carbon content up to 7.23% in hydrochar. Moreover, the emission of CO 2 from HTC was extremely lower, when compared with other technologies. In order to satisfy the economic beneficial aspects, energy balance were carried out for t he optimum conditions. Apart from the biomass addition, HTC is also capable to increase the energy content in the presence of catalyst. Literature reviews revealed that acetic acid as a catalyst significantly gains the energy content. Therefore, in order to produce acetic acid from acidogenesis process, fermentation process was studied by using FS: CP for 35 days as total SRT . HTC experiments were conducted to study the performance of digested sludge, which segregated acetic acid during fermentation. Expec ted results could not be achieved in this phase, since produced acetic acid through fermentation is too lower. But, HTC was also effective to convert the digested sludge into hydrochar by varying its energy content from 21 - 17.36 MJ/kg. In conclusion, inc rement on energy content was achieved by addition of biomass with FS and its optimum process parameters were also found. Finally, recommendations for the further research were suggested. |
| Year | 2015 |
| Corresponding Series Added Entry | Asian Institute of Technology. Thesis ; no. UWEM-15-03 |
| Type | Thesis |
| School | School of Engineering and Technology |
| Department | Department of Civil and Infrastucture Engineering (DCIE) |
| Academic Program/FoS | Urban Water Engineering and Management (UWEM) |
| Chairperson(s) | Thammarat Koottatep;Hooijmans, C.M. (Tineke). |
| Examination Committee(s) | Shrestha, Sangam;Chongrak Polprasert |
| Scholarship Donor(s) | Bill & Melinda Gates Foundation under the framework of the SaniUP Project / UNESCO - IHE - AIT |
| Degree | Thesis (M.Sc.) - Asian Institute of Technology - UNESCO-IHE, 2015 |