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Experimental investigation of the external nitrification biological nutrient removal activated sludge (ENBNRAS) system.
Biotechnol Bioeng. 2003 Aug 05; 83(3):260-73.BB

Abstract

A systematic lab-scale experimental investigation is reported for the external nitrification (EN) biological nutrient removal (BNR) activated sludge (ENBNRAS) system, which is a combined fixed and suspended medium system. The ENBNRAS system was proposed to intensify the treatment capacity of BNR-activated sludge (BNRAS) systems by addressing two difficulties often encountered in practice: (a) the long sludge age for nitrification requirement; and (b) sludge bulking. In the ENBNRAS system, nitrification is transferred from the aerobic reactor in the suspended medium activated sludge system to a fixed medium nitrification system. Thus, the sludge age of the suspended medium activated sludge system can be reduced from 20 to 25 days to 8 to 10 days, resulting in a decrease in reactor volume per ML wastewater treated of about 30%. Furthermore, the aerobic mass fraction can also be reduced from 50% to 60% to <30% and concommitantly the anoxic mass fraction can be increased from 25% to 35% to >55% (if the anaerobic mass fraction is 15%), and thus complete denitrification in the anoxic reactors becomes possible. Research indicates that both the short sludge age and complete denitrification could ameliorate anoxic aerobic (AA) or low food/microorganism (F/M) ratio filamentous bulking, and hence reduce the surface area of secondary settling tanks or increase the treatment capacity of existing systems. The lab-scale experimental investigations indicate that the ENBNRAS system can obtain: (i) very good chemical oxygen demand (COD) removal, even with an aerobic mass fraction as low as 20%; (ii) high nitrogen removal, even for a wastewater with a high total kjeldahl nitrogen (TKN)/COD ratio, up to 0.14; (iii) adequate settling sludge (diluted sludge volume index [DSVI] <100 mL/g); and (iv) a significant reduction in oxygen demand.

Authors+Show Affiliations

Water Research Group, Department of Civil Engineering, University of Cape Town, Rondebosch Cape, South Africa.No affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info available

Pub Type(s)

Comparative Study
Evaluation Study
Journal Article
Research Support, Non-U.S. Gov't
Validation Study

Language

eng

PubMed ID

12783482

Citation

Hu, Zhi-Rong, et al. "Experimental Investigation of the External Nitrification Biological Nutrient Removal Activated Sludge (ENBNRAS) System." Biotechnology and Bioengineering, vol. 83, no. 3, 2003, pp. 260-73.
Hu ZR, Sötemann S, Moodley R, et al. Experimental investigation of the external nitrification biological nutrient removal activated sludge (ENBNRAS) system. Biotechnol Bioeng. 2003;83(3):260-73.
Hu, Z. R., Sötemann, S., Moodley, R., Wentzel, M. C., & Ekama, G. A. (2003). Experimental investigation of the external nitrification biological nutrient removal activated sludge (ENBNRAS) system. Biotechnology and Bioengineering, 83(3), 260-73.
Hu ZR, et al. Experimental Investigation of the External Nitrification Biological Nutrient Removal Activated Sludge (ENBNRAS) System. Biotechnol Bioeng. 2003 Aug 5;83(3):260-73. PubMed PMID: 12783482.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Experimental investigation of the external nitrification biological nutrient removal activated sludge (ENBNRAS) system. AU - Hu,Zhi-Rong, AU - Sötemann,S, AU - Moodley,R, AU - Wentzel,M C, AU - Ekama,G A, PY - 2003/6/5/pubmed PY - 2004/3/12/medline PY - 2003/6/5/entrez SP - 260 EP - 73 JF - Biotechnology and bioengineering JO - Biotechnol Bioeng VL - 83 IS - 3 N2 - A systematic lab-scale experimental investigation is reported for the external nitrification (EN) biological nutrient removal (BNR) activated sludge (ENBNRAS) system, which is a combined fixed and suspended medium system. The ENBNRAS system was proposed to intensify the treatment capacity of BNR-activated sludge (BNRAS) systems by addressing two difficulties often encountered in practice: (a) the long sludge age for nitrification requirement; and (b) sludge bulking. In the ENBNRAS system, nitrification is transferred from the aerobic reactor in the suspended medium activated sludge system to a fixed medium nitrification system. Thus, the sludge age of the suspended medium activated sludge system can be reduced from 20 to 25 days to 8 to 10 days, resulting in a decrease in reactor volume per ML wastewater treated of about 30%. Furthermore, the aerobic mass fraction can also be reduced from 50% to 60% to <30% and concommitantly the anoxic mass fraction can be increased from 25% to 35% to >55% (if the anaerobic mass fraction is 15%), and thus complete denitrification in the anoxic reactors becomes possible. Research indicates that both the short sludge age and complete denitrification could ameliorate anoxic aerobic (AA) or low food/microorganism (F/M) ratio filamentous bulking, and hence reduce the surface area of secondary settling tanks or increase the treatment capacity of existing systems. The lab-scale experimental investigations indicate that the ENBNRAS system can obtain: (i) very good chemical oxygen demand (COD) removal, even with an aerobic mass fraction as low as 20%; (ii) high nitrogen removal, even for a wastewater with a high total kjeldahl nitrogen (TKN)/COD ratio, up to 0.14; (iii) adequate settling sludge (diluted sludge volume index [DSVI] <100 mL/g); and (iv) a significant reduction in oxygen demand. SN - 0006-3592 UR - https://www.unboundmedicine.com/medline/citation/12783482/Experimental_investigation_of_the_external_nitrification_biological_nutrient_removal_activated_sludge__ENBNRAS__system_ L2 - https://doi.org/10.1002/bit.10664 DB - PRIME DP - Unbound Medicine ER -