Novel feast-fast technique for filamentous foam control in the activated sludge process - introducing a new foam-measurement method

Citation
H. Chua et al., Novel feast-fast technique for filamentous foam control in the activated sludge process - introducing a new foam-measurement method, WATER SCI T, 42(3-4), 2000, pp. 95-102
Citations number
22
Categorie Soggetti
Environment/Ecology
Journal title
WATER SCIENCE AND TECHNOLOGY
ISSN journal
02731223 → ACNP
Volume
42
Issue
3-4
Year of publication
2000
Pages
95 - 102
Database
ISI
SICI code
0273-1223(2000)42:3-4<95:NFTFFF>2.0.ZU;2-8
Abstract
Overgrowth of filamentous Nocardia spp. in the activated sludge microbial e cosystem was previously identified as the cause of foaming problems in Hong Kong. in this work, the specific growth rate of N. amarae was found to be significantly higher than that of non-filamentous bacteria under food-to-mi croorganism (FIM) ratios lower than 0.5 mgBOD/mgMLSS-day, and was used as t he basis for the development of a novel Feast-Fast Operation (FFO) for the prevention and control of foaming problems. The F/M ratio in the "feasting" aeration unit was 0.8 mgBOD/mgMLSS-day while that in the "fasting" aeratio n unit was 0.2 mgBOD/mgMLSS-day, resulting in an overall process F/M ratio that remained within the normal range, while avoided prolonged exposure of the sludge ecosystem to an F/M ratio below 0.5 mgBOD/mgMLSS-day. The FFO su ppressed filamentous overgrowth and foaming without adversely affecting the organic treatment efficiency of the modified process. A new and convenient measurement method was developed for quantifying the degree of foaming and foam stability in activated sludge.