Biological sulfate reduction in a pilot-scale UASB reactor under thermophilic conditions | |
| Author | Phan Thong Thai |
| Call Number | AIT Thesis no.EV-07-39 |
| Subject(s) | Spinning--Waste disposal--Thailand Sulphates-Environmental aspects Sulphides--Oxidation |
| Note | A thesis submitted in partial fulfillment of the requirements for the degree of Master of Engineering in Environmental Engineering and Management. |
| Publisher | Asian Institute of Technology |
| Series Statement | Thesis ; no. EV-07-39 |
| Abstract | Wastewater, from spinning process, contains high sulfate concentration of 11 ± 2 g/L, heavy metal zinc (concentrations ranging from 200 - 300 mg/L) and demonstrates a very low pH. Treatment of this waste stream is investigated by using pilot scale UASB reactor. Sludge from anaerobic lagoon treating tapioca starch wastewater is used as seed. The process starts up successfully with the up flow velocity of 0.06 m/h. Then sulfate reduction efficiency reaches the average value of 24% while the COD removal efficiency is quite high with the value of 76%. The sulfide concentration with the average value of 300 mg/L is more than enough to remove heavy metal zinc as zinc sulfide; recycling of UASB reactor effluent allows zinc removal. Optimized operation conditions for maximum sulfide production are studied. The maximum sulfide generation in the effluent of UASB reactor is achieved when the process operates under thermophilic condition (50 ± 2 °C). It is also found that there is no difference of sulfide generation even when the process operates under higher temperature (65 ± 2 °C). Consequently energy for heating the wastewater can be saved significantly. The highest sulfide concentration of 595 mg/L is produced under the following conditions: sulfate loading rate in range of 6.3 ± 0.7 Kg S04/m3.d, up flow velocity of 0.2 m/h and COD:SO4 ratio of 0.7:1.0. Cost and benefit analysis of sulfate reduction process is conducted. It is found that sulfate reduction followed by sulfide oxidation process is the most economical and promising process for treatment of rich sulfate wastewater containing heavy metals. This option can save energy front aeration process as well as used chemicals. |
| Year | 2007 |
| Corresponding Series Added Entry | Asian Institute of Technology. Thesis ; no. EV-07-39 |
| Type | Thesis |
| School | School of Environment, Resources, and Development (SERD) |
| Department | Department of Energy and Climate Change (Former title: Department of Energy, Environment, and Climate Change (DEECC)) |
| Academic Program/FoS | Environmental Engineering and Management (EV) |
| Chairperson(s) | Annachhatre, Ajit P.; |
| Examination Committee(s) | Visvanathan, C.;Preeda Parkpian; |
| Scholarship Donor(s) | Ministry of Education and Training of Vietnam; |
| Degree | Thesis (M.Eng.) - Asian Institute of Technology, 2007 |