Evidence for resistance of activated sludge flocs to deflocculative DO stress
| Autor: | Leong Soon Poh, Ewa Grygolowicz-Pawlak, Maszenan bin Abdul Majid, Wun Jern Ng, Xin Gao, Thomas Vistisen Bugge, Dominik Dominiak, Akshaykumar Suresh |
|---|---|
| Přispěvatelé: | Interdisciplinary Graduate School (IGS), School of Civil and Environmental Engineering, Nanyang Environment and Water Research Institute |
| Jazyk: | angličtina |
| Rok vydání: | 2019 |
| Předmět: |
Flocculation
Environmental Engineering Chemistry 0208 environmental biotechnology 02 engineering and technology 020801 environmental engineering Environmental engineering [Engineering] Stress (mechanics) Activated Sludge Activated sludge Extracellular polymeric substance Chemical engineering Activated sludge flocs Environmental Chemistry Low dissolved oxygen General Environmental Science Civil and Structural Engineering |
| Popis: | In the published literature, deflocculation of aerobic biological flocs under low dissolved oxygen (DO) (< 0.5 mg/L) conditions is typically reported as occurring as early as after 1 h of oxygen deficiency. However, results of this study involving aerobic sludge from three different sources repeatedly indicated a lack of deflocculation after 24 h of low DO conditions. This finding has led to the conclusion that low DO might not be a direct cause of deflocculation. In addition to the low DO conditions, the sludge samples were not re-fed throughout the experiment, but deflocculation was still not observed. An analysis of the soluble microbial products (SMP) and loosely and tightly bound extracellular polymeric substances (EPS) was performed to improve understanding of the sludge’s behavior in response to low DO conditions. Results indicated no increase in SMP content or change in the tightly bound EPS content upon extended periods of low DO. It was concluded that high proteins concentration in the bound EPS improved flocs stability, and so contributed to the maintenance of floc integrity during extended periods of low DO conditions. This project was supported by funding from Grundfos Holdings through project Understanding and Mitigation of Sludge Deflocculation During Nitrogen Removal Process. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|