AICAR (bulking) 10,000 mg/l MLSS COD COD (AICAR) activated sludge bacteria protozoa rotifer fungi substrate mass transfer secondary clarifier bioflocculation
excess sludge 1 inflow outflow recycle 1. 2 2 (Sezgin, Jenkins and Parker,1978) (microbial ecology) (extra-celluar polymer, ECP) (Liao et. al.,2001) (Kim and Pipes, 1999) (filamentous microorganisms) (non-filamentous microorganisms) 2 (Sezgin et. al., 1978)
MLSS : (1) (2) (3) NocardiaMicrothrix parcicella type021n type1701 (1) ph (2) (F/M) (sludge retention time, SRT) 3 SRT (Microthrix parvicella Thiothrix spp.) SRT(Sphaerotilus natuns type 0092) Table1. Comparisn of dominant filamentous organisms in bulking and foaming acivated sludge form several geographical areas (ranking in order of prevalence) Filamentous Organism USA Netherlands Germany South Africa Colorado USA Nocardia spp 1 7 2 Type 1701 2 5 8 _ 1 Type021N 3 2 1 _ 10 Type 0041 4 6 3 6 7 Thiothrix spp. 5 19 - _ 5 Sphaerotilus natans 6 7 4-8 Microthrix parvicella 7 1 2-3 2 Type0092 8 4 6 1 8 Haliscomenobacter hydrossis 9 3 - Type 0675 10 _ 10 5 5 Type 0803 11 9 7 8 _ Nostocoida limicola 12 11 - Type 1851 13 12 9 4 4 Type 0961 14 10 _ Type 0581 15 8 _ Beggiatoa spp 16 18 - Fungi 17 15 _ Type 0914 18 - - 2 _
Table 2. Causes of filamentous bacteria filaments Sphaerotilus natans, Type 1701, Haliscomenibacter hydrossis. Favored operational parameter Low levels of dissolved oxygen. Low F / M, Longer sludge ages or higher mean cell residence times. Microthrix parvicella, Nocardia spp. High F / M, Short sludge age ( <5 days ) Haliscomenibacter hydrossis, Type 021N, OO41/ 0675, 0092, 0581, 0961, 0803, 0914. Type 1863 Thiothrix spp. Sphaerotilus natans, Type 021N, Haliscomenibacter hydrossis, Type OO41/ 0675. Sphaerotilus natans, Thiothrix spp. Type 1851, Nitrogen or phosphorus deficiency in mixed liquors. Readily biodegradable soluble substrates. Slowly biodegradable or particulate substrates. Low ph ( < 6 ) Presence of H2S and septic wastewater provides energy source for mixotrophic growth 3 Jenkins et. al., 1993) Eikelboom ( 3) :
Table 3 Characteristic for identification of filamentous microorganisms Test No Remarks Branching 1 No Branching(-), false branching(fb), real branching(rb) Motility 2 Non-motile(-), motile(+) Filament Shape 3 Curved, strait, bent, coiled etc. Filament Length 4 Expressed in m Morphological Characteristics Attached Growth Other bacterial cells attached to filaments surface(+) no 5 attached growth(-) (Eikelboom and van Sheath 6 Visible reaction(+), invisible(-) Buijsen, 1981 and Crosswalls Visibility 7 Visible reaction(+), invisible(-) Kohno, 1987) Cell Diameter 8 Expressed in m Cell Length 9 Expressed in m Cell Shape 10 Coccus, square, discus-shaped, rectangular, rod-shaped Constrictions 11 Visible reaction(+), invisible(-) Staining(Eikelboom Gram Staining 12 Positive reaction(+), negative reaction(-) and van Buijsen, 1981) Neisser Staining 13 Positive reaction(+), negative reaction(-) Physiological Characteristics (Kohno, 1987) Sulfur Test 14 Sulfur deposits formed(+), no sulfur deposits(-) MLSS DO 4 (selector) NaOCl H 2 O 2 4 AICAR AICAR AICAR
:(1). ( / )(2). (3). (4). (5). 2.AICAR AICAR :(1). (2). (3). DO COD MLSS (4). (5). (6). (7). AICAR 5 6 (5) ( 6) 5 AICAR 3. (1).
a. b. SRT (2). a. b. c. (, 7) 6 AICAR 7 AICAR
1. ( AICAR) : a. : b. : 4000 m 3 /day c. : UASB+AICAR d.aicar : 1200-1600 mg/l e. : two plug flow reactors (6000 m 3 ) SVI 180 210 ml/g-mlss SVI 100120 ml/g-mlss SS 150300 mg/l SS 30 mg/lcod 25% COD 250 400 mg/l 120200 mg/l ( 8) AICAR 60-80 mg/lsvi 80-100 ml/g-mlss 6500~7500 mg MLSS/L 0.07 kg COD/kg-MLSS-dayAICAR 4 2000 1500 COD 1000 500 Influent COD Effluent COD 0 0-Jan-00 5-Jan-00 10-Jan-00 15-Jan-00 Time 8 PTA AICAR COD
4. (CASR) AICAR Item CASR AICAR Parameter HRT days 2 2 MLSS mg/l 1,800~2,200 4,000~5,000 VLR Kg COD/m 3 -d 0.89~0.72 0.89~0.72 F/M Kg COD/kg 0.48~0.36 0.15~0.20 VSS-d SVI ml/g-mlss 200~250 50~80 Performance COD efficiency % 90 99 TA efficiency % 40 99.5 p-tol efficiency % 70 99.8 HRT: Hydraulic Retention time VLR: Volumetric Loading Rate 2. ( AICAR) PU : a.: PU b.: 1000 m3/day c.: d.aicar : 4000-5000 mg/l e.aicar :400-550 mg/l f.: 1000 4 reactors m 3 )( g.svi=320 ml/g-mlss AICAR 9 AICAR COD MLSS COD 150 mg/l MLSS 8,000 mg/l 0.15 kg COD/kg-MLSS-day 9 PU AICAR COD
PC/PLC V-SCADA 10 ph 600 DO 0 mg/lph ( ph 8.1) 600 DO 6.0 mg/l ph 11 ORP 10 AICAR DO ph 11 AICAR ORP
3. (AICAR) AICAR : a.: b.: 4000 c.: m3/day UASB+AICAR d.aicar :200-150 mg/l e.aicar : COD=50 mg/l f.: two plug flow 800m reactors( 3 ) g.svi= 100 ml/g-mlss AICAR COD MLSS (1). AICAR 1kg COD/m 3 -day BOD (F/M) 0.2-0.5kg BOD/kg MLVSS-day (2).pH ph 6.0 8.5 ph ph ph 6.8 7.2 (3).(Dissolved oxygen) DO COD DO DO DO 6mg/L DO COD (4). MLSS(Mixed Liquor Suspended Solid) MLSS SBR MLSS 2000~8000mg/L 8000mg/L MLSS (5).(Sludge Volume Index, SVI) SVI SBR SVI 50 150ml/g
MLSS SVI 50 SVI 150 SVI 50 150 (7). SBR 12 13 12 13 AICAR AICAR COD 1. Jenkins, D., Richard M. G. and Daigger T. D. (1993) Manual on the causes
and control of sludge bulking and foaming, 2 nd Chelsea. ed. Lewis Publisher, 2. Kim, Y. and Pipes, W. O. (1999) Factors influencing suspended solids concentrations in activated sludge settling tanks, J. Hazardous Materials, B67, pp95-109. 3. Liao, B. Q., Allen, D.G., Droppo, I. G., Leppard, G. G. and Liss, S. N. (2001) Surface properties of sludge and their role in bioflocculation and settleability, Wat. Res., Vol. 35, No. 2, pp.339-350. 4. Sezgin, M., Jenkins, D. and Parker, D. S. (1978) A unified theory of filamentous activated sludge bulking, JWPCF, 50, 2, pp362-381. 5.,1998 6. Mino, T. (1995) Survey on filamentous microorganisms in activated sludge processes in Bangkok, Thailand. Wat. Sci. Tech. 31 (9), pp.193-202. 7. Madoni, P., Davoli, D. and Gibin, G. (2000) Survey of filamentous microorganisms from bulking and forming activated-sludge plants in Italy. Wat. Res. 34(6), pp.1767-1772. 8. Eikelboom, D. H., van Buijsen, H.J.J. (1981) Microscopic Sludge Investigation Manual. TNO Research Institute for Environmental Hygiene. 9. Eikelboom, D.H., (2000) Process Control of Activated Sludge Plants by Microscopic Investigation, 1 st ed, IWA publishing, UK, pp43-84. 10. Wanner, J., (1994) Activated Sludge Bulking and Foaming Control, 1 st ed, Technomic Publishing Co., Inc, Lancaster, USA, pp129-206. 11. Seviour, R.J. and L.L. Blackall, (1999) The Microbiology of Activated Sludge, Kluwer Academic Publishers, Dordrecht, The Netherlands, pp99-121.