| Author | Pham Thi Hoa |
| Call Number | AIT Thesis no. EV-02-20 |
| Subject(s) | Sewage--Purification--Nutrient removal
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| Note | A thesis submitted in partial fulfilment of the requirement for the Degree of Master of Engineering. School of Environment, Resources and Development |
| Publisher | Asian Institute of Technology |
| Series Statement | Thesis ; no. EV-02-20 |
| Abstract | This study aimed to investigate the effects of nutrients (nitrogen and phosphorus) on EPS production, sludge settling and dewatering. Several sludge and wastewater samples were collected to analyze. The relationship between the involving factors and EPS production, the effects of EPS on sludge properties, and the effects of nutrients on EPS were investigated. The survey study revealed that although filamentous microorganism was found in most sludge samples, they did not always cause sludge bulking. It could be served as backbone for the sludge floes. EPS production was different at various operational conditions. EPS production was found lower in anaerobic processes than in aerobic ones. It was also observed that attached growth system produced lower EPS than suspended growth. The reduction ofEPS in attached growth could be caused by the absorption ofEPS on the media and/or the reduction of excretion EPS from the attached microorganism. Nutrient content in feed seemed to have no direct correlation with EPS production and sludge properties. EPS variation could be directly linked to SVI values, but not with CST and effluent quality. Several lab-scale batch experiments were conducted to investigate the more detailed effect of nitrogen and phosphorus content on EPS and its components related to sludge settling and dewatering. Nutrient effect was done in the wide range of nutrient deficiency and excess. COD removal was found stable and average reached 93% for all reactors. From the sludge analysis, it was apparent that EPS components (protein and carbohydrate) affected sludge properties more than total EPS. Within two EPS components, protein affected sludge properties more than carbohydrate. Nitrogen affected both protein and carbohydrate while phosphorus only affected carbohydrate. Both nitrogen deficiency (COD:N < 100:2) and nitrogen excess (COD:N > 100:10) improves sludge properties. Nitrogen excess caused another problem with high nitrogen content in the effluent. Optimum phosphorus ratio was in the range of COD:P of 100:3 to 100:5 at which sludge properties including settling, dewatering and clarifying were improved. |
| Year | 2002 |
| Corresponding Series Added Entry | Asian Institute of Technology. Thesis ; no. EV-02-20 |
| 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) | Visvanathan, C. |
| Examination Committee(s) | Rakshit, Sudip K ;Lee, Seung-Ruan |
| Scholarship Donor(s) | Asian Development Bank |
| Degree | Thesis (M.Eng.) - Asian Institute of Technology, 2002 |