Effect of carbon to nitrogen ratio on the physical and chemical properties of activated sludge

Date

2003-11-01

Author

Durmaz, B
Sanin, Faika Dilek

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The effect of carbon to nitrogen ratio (C/N) of the feed on the physical and surface chemical properties of activated sludge is investigated. Semi-continuous reactors with 2 liters volume were operated at a mean cell residence time of 8 days. These mixed culture reactors were operated at 3 different carbon to nitrogen ratio. The operation of conventional activated sludge plants treating municipal wastewater is represented with reactors having a C/N ratio of 21 (in terms of the ratio of COD to TKN). Carbon and nitrogen limited activated sludge systems are represented by reactors with a C/N ratio of 9 and 43, respectively. The results show that C/N ratio has a profound effect on the ultimate physical and surface chemical properties of activated sludge. Both the steady state microorganism concentration and the amount of microbial extracellular polymers produced increase with increasing C/N ratio. The sludge becomes much harder to dewater and settle and it becomes more viscous as the C/N ratio increases. A decrease in surface hydrophobicity and an increase in surface charge of the sludge accompany these physical changes.

Subject Keywords

Activated sludge, Carbon to nitrogen ratio, Extracellular polymers, Physical properties, Surface characteristics

URI

https://hdl.handle.net/11511/49022

Journal

ENVIRONMENTAL TECHNOLOGY

DOI

https://doi.org/10.1080/09593330309385677

Collections

Department of Environmental Engineering, Article

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Citation Formats

B. Durmaz and F. D. Sanin, “Effect of carbon to nitrogen ratio on the physical and chemical properties of activated sludge,” ENVIRONMENTAL TECHNOLOGY, pp. 1331–1340, 2003, Accessed: 00, 2020. [Online]. Available: https://hdl.handle.net/11511/49022.