| Author | Uddin, Md. Salim |
| Call Number | AIT Thesis no. 440 |
| Subject(s) | Factory and trade waste
|
| Note | A thesis submitted in partial fulfillment of the requirements
for the degree of Master of Engineering in the Asian Institute
of Technology, Bangkok, Thailand. |
| Publisher | Asian Institute of Technology |
| Abstract | Wastes from the production of tapioca starch in Thailand have a very high BOD and low pH. The economic position of the industry makes it necessary to find a low cost solution to this difficult waste treatment
problem. Anaerobic ponds are considered the most applicable form of treatment for this waste in the tropics, minimizing land use and plant operational costs. This research was aimed at evaluating design parameters for anaerobic ponds and arriving at a basis for estimating their performance. The effects of BOD loading, detention time and pH on anaerobic pond
performance were evaluated outdoors in 3ft. deep experimental units using
tapioca starch waste as influent. Initially, it was found that these
three factors, and also BOD loading and pH interaction, were significant in BOD removal. The optimum BOD loading on first-stage anaerobic ponds was found to be about 6000 Ib/acre-day (6720 Kg/ha day) for this waste and maximum detention period of 5 days covered in the studies gave best BOD removal. BOD removal at optimum loading conditions and 5 days
detention period was 3680 Ib/acre day (4130 Kg/ha day). Above 6000 Ib/acre day (6720 Kg/ha day) BOD loading, effluent pH was normally below
6, alkalinity was relatively low and volatile acids concentration was very high. Second and third-stage anaerobic ponds in series with first first stage anaerobic ponds gave lower areal BOD removal than first-stage ponds, when BOD loading were lower and detention times similar. However, a second-stage anaerobic pond loaded at 6570 Ib/acre day (7700 Kg/ha day) gave a BOD removal of 2650 Ib/acre day (2960 Kg/ha day) which was close to
first-stage BOD removal at a similar loading. Third-stage facultative ponds with lower BOD loadings and longer detention times than third stage anaerobic ponds, gave less areal BOD removals. A prototype design for treatment of 1 mgd of tapioca starch waste with BOD concentration of 3000 mg/1 suggested that five stages of
anaerobic ponds followed by a sixth-stage facultative pond would give a BOD removal efficiency approaching 99 per cent for minimum investment. |
| Year | 1970 |
| Type | Thesis |
| School | Student Research Before 1980 |
| Department | Other Field of Studies (No Department) |
| Academic Program/FoS | Thesis (Year <=1979) |
| Chairperson(s) | Pescod, M.B. |
| Examination Committee(s) | McGarry, M.G. |
| Degree | Thesis (M. Eng.) - Asian Institute of Technology, 1970 |
