Physical granular sludge formed by dewatering as seed sludge, significantly enhanced aerobic granulation. On day 20, there was 90% of sludge larger than 0.2mm in R2 seeded with physical granular sludge,and only 26.7% was in R1 seeded with flocculent sludge. The SVI of R2 maintained below 80mL/g meaning better settleability.Compared with 3200mg/L of MLSS in R1, R2 had a much higher MLSS at 6300 mg/L on day 25.In the whole process, COD removal rate of both reactor exceeded 90%, suggesting sludge activity was not obviously decreased by dewatering, but TN removal rate was about 70% in R2 superior than the 55% in R1on account of the lager particles size in R2. Experienced 5 days shearing, 39.8% of physical granular sludge were still larger than 0.2 mm providing plentiful cores for aerobic granulation, and nutrition transmission channel was formed inside physical granular sludge by endogenous digestion of EPS and gas escaping of denitrification.
Adav S S, Lee D J, Show K Y, et al. Aerobic granular sludge:Recent advances[J]. Biotechnology Advances, 2008,26(5):411-423.
[2]
Ni B, Yu H. Mathematical modeling of aerobic granular sludge:A review[J]. Biotechnology Advances, 2010,28(6):895-909.
[3]
Gao D, Liu L, Liang H, et al. Aerobic granular sludge:characterization, mechanism of granulation and application to wastewater treatment.[J]. Critical Reviews in Biotechnology, 2011,31(2):137-152.
[4]
Liu Y, Xu H, Yang S, et al. Mechanisms and models for anaerobic granulation in upflow anaerobic sludge blanket reactor[J]. Water Research, 2003,37(3):661-673.
[5]
Caudan C, Filali A, Spérandio M, et al. Multiple EPS interactions involved in the cohesion and structure of aerobic granules[J]. Chemosphere, 2014,117:262-270.
[6]
Sheng G, Yu H, Li X. Extracellular polymeric substances (EPS) of microbial aggregates in biological wastewater treatment systems:A review[J]. Biotechnology Advances, 2010,28(6):882-894.
[7]
More T T, Yadav J S S, Yan S, et al. Extracellular polymeric substances of bacteria and their potential environmental applications[J]. Journal of Environmental Management, 2014, 144:1-25.
Liu Z, Liu Y, Kuschk P, et al. Poly aluminum chloride (PAC) enhanced formation of aerobic granules:Coupling process between physicochemical-biochemical effects[J]. Chemical Engineering Journal, 2016,284:1127-1135.
[10]
Sajjad M, Kim K S. Studies on the interactions of Ca2+ and Mg2+ with EPS and their role in determining the physicochemical characteristics of granular sludges in SBR system[J]. Process Biochemistry, 2015,50(6):966-972.
[11]
Konczak B, Karcz J, Miksch K. Influence of calcium, magnesium, and iron ions on aerobic granulation[J]. Appl. Biochem. Biotechnol., 2014,174(8):2910-2918.
Gao D, Liu L, Liang H, et al. Comparison of four enhancement strategies for aerobic granulation in sequencing batch reactors[J]. Journal of Hazardous Materials, 2011,186(1):320-327.
[14]
Liu Y, Tay J. Fast formation of aerobic granules by combining strong hydraulic selection pressure with overstressed organic loading rate[J]. Water Research, 2015,80:256-266.
Zhang B, Chen Z, Qiu Z, et al. Dynamic and distribution of ammonia-oxidizing bacteria communities during sludge granulation in an anaerobic-aerobic sequencing batch reactor[J]. Water Research, 2011,45(18):6207-6216.
[18]
Tay J H, Liu Q S, Liu Y. Characteristics of aerobic granules grown on glucose and acetate in sequential aerobic sludge blanket reactors.[J]. Environmental Technology, 2002,23(8):931-936.
de Kreuk M K, Kishida N, van Loosdrecht M C M. Aerobic granular sludge-state of the art[J]. Water Science & Technology, 2007,55(8/9):75-81.
[21]
Verawaty M, Pijuan M, Yuan Z, et al. Determining the mechanisms for aerobic granulation from mixed seed of floccular and crushed granules in activated sludge wastewater treatment[J]. Water Research, 2012,46(3):761-771.
[22]
Pijuan M, Werner U, Yuan Z. Reducing the startup time of aerobic granular sludge reactors through seeding floccular sludge with crushed aerobic granules[J]. Water Research, 2011,45(16):5075-5083.
[23]
Huang L, Yang T, Wang W, et al. Effect of Mn2+ augmentation on reinforcing aerobic sludge granulation in a sequencing batch reactor[J]. Appl. Microbiol. Biotechnol., 2012,93(6):2615-2623.
[24]
He-Long Jiang J T Y L. Ca2+ augmentation for enhancement of aerobically grown microbial[J]. Biotechnology Letters, 2003, 25(2):95-99.
[25]
Wang Z W, Li Y, Liu Y. Mechanism of calcium accumulation in acetate-fed aerobic granule[J]. Appl. Microbiol. Biotechnol., 2007, 74(2):467-473.
Bella G D, Torregrossa M. Simultaneous nitrogen and organic carbon removal in aerobic granular sludge reactors operated with high dissolved oxygen concentration[J]. Bioresource Technology, 2013,142(8):706-713.