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1 RATIONALE Figure 5.12 and Figure 5.13 show the diurnal variation of inflow and outflow COD, alkalinity and pH value for the 24 h sampling campaign. Values of Alkalinity and COD concentration in day time inflow samples were higher than night time samples. Outflow COD values showed much less variation than corresponding influent values; however, outflow alkalinity values showed a similar deceasing and then increasing trend to the inflow alkalinity values. It was proposed that high inflow alkalinity corresponded to high outflow values since the baffled configuration of the ABR promotes flow characteristics that approach those of a plug-flow reactor (Barber and Stuckey, 1999) and thus by matching the shape of the inflow and outflow alkalinity curves the fluid retention time (and therefore maximum possible contact time) experienced by the bulk of the fluid could be estimated. 1 The apparent hydraulic retention time is the time lapse between similar alkalinity profiles in influent and effluent. The rationale for this approach is as follows: • Outlet alkalinity is the sum of the inlet alkalinity and metabolism generated alkalinity (Section 2.1.6.3) • Considerable attenuation of the organic load oscillation is observed between inlet and outlet COD (Figure 5.13) • It is hypothesised that breakdown of biodegradable organic material and thus alkalinity generation proceeds at a relatively steady rate due to the first compartment acting as a buffering zone; in this compartment, solids retention reduces the amplitude of the oscillation in COD load to be treated in the remainder of the reactor • Thus the amount of alkalinity generated will be relatively constant and determined by the steady rate of hydrolysis of particulate components in the buffering zone • Thus the outlet alkalinity concentration will be the sum of the inlet alkalinity and a relatively constant value for metabolism generated alkalinity, and therefore the outlet alkalinity profile would have a similar shape to the inlet alkalinity profile. 2 COMPARISON OF INFLOW AND OUTFLOW DATA Correlation coefficients for corresponding inflow and outflow data were determined for apparent retention times between 8 and 22 hours. The significance of the correlation coefficients was determined from the number of degrees of freedom for each case. Correlation coefficients were calculated for comparison between inflow and outflow alkalinity values from the 24 h campaign (Section 5.5.2.3) at different apparent hydraulic retention times as shown in Figure A4. 2 below. 1 This is not the same as the mean residence time, and cannot be used to infer the apparent compartment volume, since it does not take into account eddy volumes within the reactor, or active space associated with microorganisms into and out of which components may diffuse, resulting in much longer retention times for fluid that passes through these zones. 202
19 h apparent HRT 14 h apparent HRT n = 21 n = 16 Alkalinity values Alkalinity values inflow sample time inflow outflow inflow sample time inflow outflow 5/27/03 10:00 254.0032 299.3122 5/27/03 10:00 254.0032 5/27/03 11:00 202.1441 5/27/03 11:00 202.1441 5/27/03 12:00 185.905 280.0952 5/27/03 12:00 185.905 5/27/03 13:00 173.9968 285.2678 5/27/03 13:00 173.9968 5/27/03 14:00 171.2507 278.0478 5/27/03 14:00 171.2507 5/27/03 15:00 169.1991 269.519 5/27/03 15:00 169.1991 299.3122 5/27/03 16:00 162.359 266.4764 5/27/03 16:00 162.359 5/27/03 17:00 254.2003 271.4025 5/27/03 17:00 254.2003 280.0952 5/27/03 18:00 203.4527 5/27/03 18:00 203.4527 285.2678 5/27/03 19:00 187.6578 249.3755 5/27/03 19:00 187.6578 278.0478 5/27/03 20:00 181.7426 268.7387 5/27/03 20:00 181.7426 269.519 5/27/03 21:00 179.8516 261.2244 5/27/03 21:00 179.8516 266.4764 5/27/03 22:00 171.4792 272.247 5/27/03 22:00 171.4792 271.4025 5/27/03 23:00 174.3711 275.0962 5/27/03 23:00 174.3711 5/28/03 0:00 175.9694 276.4672 5/28/03 0:00 175.9694 249.3755 5/28/03 1:00 173.6886 262.5183 5/28/03 1:00 173.6886 268.7387 5/28/03 2:00 163.8433 275.574 5/28/03 2:00 163.8433 261.2244 5/28/03 3:00 146.4356 265.2663 5/28/03 3:00 146.4356 272.247 5/28/03 4:00 149.2014 276.5242 5/28/03 4:00 149.2014 275.0962 5/28/03 5:00 164.3512 299.0592 5/28/03 5:00 164.3512 276.4672 5/28/03 6:00 286.8892 5/28/03 6:00 262.5183 5/28/03 7:00 208.4026 338.1573 5/28/03 7:00 208.4026 275.574 5/28/03 8:00 293.6795 300.4317 5/28/03 8:00 293.6795 265.2663 5/28/03 9:00 282.7434 286.2702 5/28/03 9:00 282.7434 276.5242 299.0592 286.8892 338.1573 300.4317 286.2702 Figure A4. 2: Construction of data tables for correlation analysis for 19 h and 14 h apparent hydraulic retention time. Dot-dash lines indicate the data sets to be compared. The correlation co-efficient r for each combination set was calculated according to Eq. A4- 2 (Davies and Goldsmith, 1977): r = ∑ n ∑ i n i n ( x − x) ( y − y) ∑ n 2 ( x − x) ( y − y) i i i ∑ i i i 2 203 Eq. A4- 2 Where xi and yi are values from the two data sets (x and y) to be compared and x and y are the average values of each of the data sets. The significance of the correlation coefficients describes the probability that two data sets are correlated and was calculated from a Student’s t-distribution: the t-statistic is determined from Eq. A4- 3, and the probability P was determined from the associated t-distribution with the appropriate number of degrees of freedom using Excel’s TDIST function for a 2-tailed application. t = 2 r φ 2 1 + r where φ is the degree of freedom and equals n-2. Eq. A4- 3
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ANALYSIS OF A PILOT-SCALE ANAEROBIC
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i DECLARATIONS I, Katherine Maria F
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My deepest thanks must be extended
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vii TABLE OF CONTENTS ANALYSIS OF A
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5.3 Feed characteristics and loadin
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xi LIST OF TABLES Table 1.1: List o
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xiii LIST OF FIGURES Figure 1.1: Gr
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Figure 5.1 Installation of the ABR
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Figure 6.8: WEST® representation o
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xix LIST OF ABBREVIATIONS A-HRT App
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1 1 INTRODUCTION The work presented
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obtained from anaerobic systems rel
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• Lalbahadur (MTech, 2005) perfor
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1.7 ORGANISATION OF THE THESIS This
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9 2 LITERATURE REVIEW A detailed re
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• Disintegration of composite par
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Homoacetogens are one of the most v
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Most of the control in anaerobic di
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therefore the sensitivity of the ov
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∆Gº (W) [kcal] -10 -8 -6 -4 -2 L
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For systems with low potential for
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design of the digester in which the
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2.2.2 Expanded granular sludge bed
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fact that for most non-ideal flow s
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hydrolysis steps to convert them to
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from the clarified zone between the
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Table 2.4: Typical pathogen surviva
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Table 2.5: Studies using anaerobic
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• There is no requirement for bio
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Kennedy and Barriault (2005) perfor
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methanogenic (Akunna and Clark, 200
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and 6 h with no significant differe
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2.5.1.12 Granule formation in ABRs
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• A baffled reactor is described
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2.5.3.4 Scanning electron microscop
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spacing on flow patterns in a singl
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Figure 3.5: Orthographic projection
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PLC calculated the fraction of that
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epresent buulk conditionns. Compart
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The rreactor was initially commmiss
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Phase I Phase II Phase III Phase IV
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Table 4.1: Characteristics of degri
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Table 4.2: Pilot-scale ABR approxim
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COD [mgCOD/ℓ] 2000 1800 1600 1400
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4.3.5 Phosphorus Figure 4.8 present
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Observation of sludge in compartmen
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Another interesting observation is
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4.4.3 pH pH measurements were perfo
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esult in low pH values. The reasons
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4.5 SUMMARY: PHASE I - OPERATION AT
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than the optimal range for methanog
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5 EXPERIMENTAL PHASES II-IV: KINGSB
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sludge on a number of occasions. Wh
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On days 99 and 100 of Phase III, a
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5.3.2 Analysis of variations in fee
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Table 5.2: Pilot-scale ABR average
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5.4.1.2 Phase III In Phase III, (Fi
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Phase II: Alkalinity [mgCaCO3/ℓ]
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Eq. 5-1 However, at a COD/SO4 2- ra
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wastewater was probably higher than
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5.5.2.2 Damping Figure 5.12 and Fig
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• The outflow COD values were not
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• Information about the volume of
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As with the total volume of sludge
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It is not clear why the rate of acc
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most compartments was exactly 6.5,
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Soluble COD [mg/ℓ] 600 500 400 30
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pathogens and parasites, which may
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% Probe of DAPI % Probe of DAPI % P
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later compartments at all. Furtherm
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and 4, with decreasing observations
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• The mechanism of sludge build-u
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Table 5.6: Inflow and outflow chara
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Behling et al. (1997) studied the p
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organisms in previous compartments.
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velocities. Unfortunately, these tw
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Thus for a fixed sludge load, at hi
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sampling was not possible since in
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Wentzel (2006) recommends a COD to
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6.2.1.4 Calculation of CH4 producti
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organically bound N) or that N accu
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All VFA is consumed in the process,
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However, these assumptions are clea
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The calculated pH value is compared
Page 176 and 177: influent alkalinity will increase d
Page 178 and 179: The original objective to develop a
Page 180 and 181: • It was not possible to simulate
Page 182 and 183: employed for a medium strength wast
Page 184 and 185: 6.6.4 Alternative baffle design Thi
Page 186 and 187: 6.7.3 Monitoring requirements The m
Page 188 and 189: compartments (Section 6.1.1) pH val
Page 190 and 191: generally about anaerobic digestion
Page 192 and 193: 7.1.1.6 Effect of sludge age on bio
Page 194 and 195: 7.1.2.4 Critical design parameters
Page 196 and 197: 172
Page 198 and 199: Batstone D. J., Keller J., Angelida
Page 200 and 201: Gopala K. G. V. T. (2007). Treatmen
Page 202 and 203: MacLeod F. A., Guiot S. R. and Cost
Page 204 and 205: Sasse L. (1998). Decentralised wast
Page 206 and 207: Wanasen (2003). Upgrading conventio
Page 209 and 210: METTHODS OFF SAMPLINNG AND ANNALYSI
Page 211 and 212: 3.6 Enumeration of total coliforms
Page 213 and 214: that the means are the same, or con
Page 215 and 216: And the significance of the regress
Page 217 and 218: ADDITIONAL RESULTS 193 APPENDIX A3
Page 219 and 220: Table A3. 1 cont. Phase I Phase II
Page 221 and 222: each of the eight compartments were
Page 223 and 224: 3.2 Pathogen indicator organisms A
Page 225: APPLIED VS. APPARENT HYDRAULIC RETE
Page 229 and 230: 205 APPENDIX A5 CALCULATION OF SOLI
Page 231 and 232: i.e. the average SRT of an accumula
Page 233: X X = P Inert ⋅ where Xinert is t
Page 236 and 237: iodegradable organic material may b
Page 238 and 239: Substituting Eq. A6- 1 in Eq. A6- 7
Page 240 and 241: 1.5 Implementation of steady-state
Page 242 and 243: X = 7⋅ Y = 7 Z = 7⋅ A = 7⋅ (
Page 244 and 245: Dama, P., Bell J., Naidoo, V., Foxo
Page 246: Lalbahadur T. (2004) Characterisati
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