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Impact of food-to-microorganisms ratio on the stability of aerobic granular sludge treating high-strength organic wastewater.
Water Res. 2018 12 15; 147:287-298.WR

Abstract

This work investigated the long-term stability of aerobic granular sludge treating high-strength organic wastewater in a semi-pilot scale sequential batch reactor (SBR). The reactor was operated for 316 days under different operational conditions. It was found that the F/M ratio is an important parameter affecting granules formation and stability. Three selection mechanisms were investigated: (1) cultivation and maturation at moderately high influent COD concentration (2500 mg/L) followed by increase in influent COD concentration to 7500 mg/L; (2) stressed cultivation and operation at high influent COD concentration of 4500 mg/L; and (3) alternate feed loading strategy (variable influent COD concentration across the daily schedule of cycles at 50%, 75%, and 100% of the peak concentration of 5000 mg/L). It was found that adopting high OLR at the reactor start-up accelerated the formation of granules. However, the overgrowth of biomass under high organics concentration negatively affected the stability of granules and led to disintegration due to the presence of methanogens in the granule core. Cultivation at high organics concentration resulted in a rapid loss of microbial diversity and reactor failure. Under alternate feed loading, adequate selection of microbial community was maintained and resulted in stable reactor performance. Moreover, a strong correlation between F/M ratio and the granules settling ability was observed. When F/M ratio exceeded 1.5 gCOD/gSS.d, granules showed poor settleability and under very high sludge loading rates (above 2.5), sludge bulking occurred and led to washout of sludge due to the strong selection pressure of short settling time. Operating the reactor at F/M ratio of 0.5-1.4 gCOD/gSS.d appears to favor stable long-term granule stability.

Authors+Show Affiliations

Department of Civil Engineering, University of Calgary, 2500 University Drive NW, Calgary, AB, T2N 1N4, Canada. Electronic address: rania.sayedeid@ucalgary.ca.Department of Civil Engineering, University of Calgary, 2500 University Drive NW, Calgary, AB, T2N 1N4, Canada.Department of Civil Engineering, University of Calgary, 2500 University Drive NW, Calgary, AB, T2N 1N4, Canada.Department of Civil Engineering, University of Calgary, 2500 University Drive NW, Calgary, AB, T2N 1N4, Canada.Department of Civil Engineering, University of Calgary, 2500 University Drive NW, Calgary, AB, T2N 1N4, Canada.

Pub Type(s)

Journal Article
Research Support, Non-U.S. Gov't

Language

eng

PubMed ID

30317038

Citation

Hamza, Rania Ahmed, et al. "Impact of Food-to-microorganisms Ratio On the Stability of Aerobic Granular Sludge Treating High-strength Organic Wastewater." Water Research, vol. 147, 2018, pp. 287-298.
Hamza RA, Sheng Z, Iorhemen OT, et al. Impact of food-to-microorganisms ratio on the stability of aerobic granular sludge treating high-strength organic wastewater. Water Res. 2018;147:287-298.
Hamza, R. A., Sheng, Z., Iorhemen, O. T., Zaghloul, M. S., & Tay, J. H. (2018). Impact of food-to-microorganisms ratio on the stability of aerobic granular sludge treating high-strength organic wastewater. Water Research, 147, 287-298. https://doi.org/10.1016/j.watres.2018.09.061
Hamza RA, et al. Impact of Food-to-microorganisms Ratio On the Stability of Aerobic Granular Sludge Treating High-strength Organic Wastewater. Water Res. 2018 12 15;147:287-298. PubMed PMID: 30317038.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Impact of food-to-microorganisms ratio on the stability of aerobic granular sludge treating high-strength organic wastewater. AU - Hamza,Rania Ahmed, AU - Sheng,Zhiya, AU - Iorhemen,Oliver Terna, AU - Zaghloul,Mohamed Sherif, AU - Tay,Joo Hwa, Y1 - 2018/10/06/ PY - 2018/07/04/received PY - 2018/08/30/revised PY - 2018/09/18/accepted PY - 2018/10/15/pubmed PY - 2019/9/26/medline PY - 2018/10/15/entrez KW - Aerobic granular sludge KW - Food-to-microorganism ratio KW - High-strength organic wastewater KW - Microbial diversity KW - Wastewater treatment SP - 287 EP - 298 JF - Water research JO - Water Res. VL - 147 N2 - This work investigated the long-term stability of aerobic granular sludge treating high-strength organic wastewater in a semi-pilot scale sequential batch reactor (SBR). The reactor was operated for 316 days under different operational conditions. It was found that the F/M ratio is an important parameter affecting granules formation and stability. Three selection mechanisms were investigated: (1) cultivation and maturation at moderately high influent COD concentration (2500 mg/L) followed by increase in influent COD concentration to 7500 mg/L; (2) stressed cultivation and operation at high influent COD concentration of 4500 mg/L; and (3) alternate feed loading strategy (variable influent COD concentration across the daily schedule of cycles at 50%, 75%, and 100% of the peak concentration of 5000 mg/L). It was found that adopting high OLR at the reactor start-up accelerated the formation of granules. However, the overgrowth of biomass under high organics concentration negatively affected the stability of granules and led to disintegration due to the presence of methanogens in the granule core. Cultivation at high organics concentration resulted in a rapid loss of microbial diversity and reactor failure. Under alternate feed loading, adequate selection of microbial community was maintained and resulted in stable reactor performance. Moreover, a strong correlation between F/M ratio and the granules settling ability was observed. When F/M ratio exceeded 1.5 gCOD/gSS.d, granules showed poor settleability and under very high sludge loading rates (above 2.5), sludge bulking occurred and led to washout of sludge due to the strong selection pressure of short settling time. Operating the reactor at F/M ratio of 0.5-1.4 gCOD/gSS.d appears to favor stable long-term granule stability. SN - 1879-2448 UR - https://www.unboundmedicine.com/medline/citation/30317038/Impact_of_food_to_microorganisms_ratio_on_the_stability_of_aerobic_granular_sludge_treating_high_strength_organic_wastewater_ L2 - https://linkinghub.elsevier.com/retrieve/pii/S0043-1354(18)30802-9 DB - PRIME DP - Unbound Medicine ER -