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Study of the Effects of Temperature and pH on Acidogenic - - PowerPoint PPT Presentation

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6 th International Conference on Sustainable Solid Waste Management Study of the Effects of Temperature and pH on Acidogenic Fermentation Process from Organic Fraction of Municipal Solid Waste Y.K. Cheah 1 , C. Vidal-Antich 1 , J. Dosta 1 , J.

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6th International Conference on Sustainable Solid Waste Management

Study of the Effects of Temperature and pH

  • n Acidogenic Fermentation Process from

Organic Fraction of Municipal Solid Waste

Y.K. Cheah1, C. Vidal-Antich1, J. Dosta1, J. Mata-Álvarez1,2

1Department of Chemical Engineering and Analytical Chemistry,

University of Barcelona, Barcelona, Catalonia, 08028, Spain.

2Water Research Institute, University of Barcelona, Catalonia, 08001,

Spain.

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Contents

2

  • 1. Introduction
  • 2. Objectives
  • 4. Results & Discussions
  • 3. Materials & Methods
  • 5. Conclusions
  • Waste to resource
  • OFMSW
  • Anaerobic digestion
  • Batch test
  • Continuous reactor
  • Effects of temperature
  • Effects of pH
  • VFA distribution
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SLIDE 3

Waste to resource

3

Introduction

Source sorted OFMSW Mechanically sorted OFMSW

VFA

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SLIDE 4

World Bank, 2012 4

Introduction

OFMSW

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SLIDE 5

Hydrolysis Acidogenesis Acetogenesis Methanogenesis

Lipid Proteins Carbohydrates Fatty acids Amino acids Sugars Intermediate products (VFA: propionic acid, butyric acid…) Acetic acid CO2 & H2 CH4 + CO2

Anaerobic Digestion

5

Introduction

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SLIDE 6

Research goals

  • To

evaluate the VFA production in acidogenic fermentation of OFMSW by manipulating pH and temperature conditions which can be performed in continuous reactors.

  • To assess the distribution of individual VFA (acetic,

propionic, butyric and valeric acids) in the effluent which will be used for PHA production.

6

Objectives

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SLIDE 7

Experimental Set-up

Batch test

Effects of Temperature (A1) Effects of pH (A2)

T = 35, 55, 70 ºC Without pH control Period = 6 d T = 70 ºC pH = 3, 4, 5, 8, 9, 10, 12, without pH control Period = 6 d

7

OFMSW Inoculum Materials and Methods

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Experimental Set-up

Continuous

Effects of Temperature B1, B2 Effects of pH B2, B3, B4

T = 35, 70 ºC Without pH control HRT = 3.5 d T = 35, 70 ºC pH = 10, without pH control HRT = 3.5 d

8

OFMSW Inoculum Materials and Methods

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Characterization

9

Results and Discussions Source sorted OFMSW from a mechanical-biological treatment plant (Ecoparc) of the Barcelona Metropolitan Area

OFMSW

(from Trommel)

Rejected solids DIGESTATE BIOGAS Purged Wastewater S/L SEPARATOR PREPARATION TANK (Mixer + Shredder) ANAEROBIC DIGESTION Prefermented OFMSW Sampling

Characterization of OFMSW Units Value Total Solids (TS) % w/w 6.21 ± 1.29 Volatile Solids (VS) % w/w 4.76 ± 1.13 Soluble Chemical Oxygen Demand (SCOD) g/L 72.53 ± 12.98 Volatile Fatty Acids (VFA) g/L 9.57 ± 1.05 Alkalinity gCaCO3/L 4.99 ± 0.51 Ammonium‐nitrogen concentration gNH4

+‐N/L

2.84 ± 0.66 pH ‐ 6.28 ± 0.36

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SLIDE 10

Effects of temperature

10

Results and Discussions

Batch

5 10 15 1 2 3 4 5 6 VFA concentration (g/L) Time (d) 35 ⁰C 55 ⁰C 70 ⁰C

Temperature Temperature 35ºC 35ºC 55ºC 55ºC 70ºC 70ºC Inoculum Inoculum Sludge from acidogenic fermenter at 35 ºC Sludge from acidogenic fermenter at 70 ºC Sludge from acidogenic fermenter at 70 ºC Ra Ratio tio VS VS feed

eed/VS

/VS slu

sludge

1 1 1 pH con pH control rol No No No

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SLIDE 11

Effects of temperature

11

Results and Discussions

Continuous

5 10 15 20 25 10 20 30 40 50 60 70 80 VFA concentration (g/L) Time (d) 35 °C 70 °C

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Effects of temperature

Parameters Units B1 (35ºC, without pH control) B2 (70ºC, without pH control) Alk gCaCO3/L 3.01 ± 2.82 7.34 ± 1.42 NH4

+‐N

gNH4

+‐N/L

3.14 ± 0.10 4.83 ± 0.81 Free ammonia gNH3‐N/L 0.003 ± 0.000 0.07 ± 0.01 pH ‐ 5.96 ± 0.32 6.17 ± 0.33 sCOD g/L 76.66 ± 12.48 95.10 ± 16.00

VFACOD/sCOD

% 22.59 ± 3.78 21.32 ± 4.22 VFA g/L 10.91 ± 1.08 14.59 ± 2.54 Acetic % 38.16 ± 4.21 39.81 ± 2.67 Propionic % 20.93 ± 1.83 21.65 ± 0.91 Butyric % 18.67 ± 2.06 19.19 ± 2.52 Valeric % 10.83 ± 1.27 9.93 ± 0.82 (C2+C4)/(C3+C5) ‐ 1.76 ± 0.23 1.85 ± 0.09

12

Results and Discussions

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SLIDE 13

Effects of pH

13

Results and Discussions

Batch

2 4 6 8 10 12 14 16 1 2 3 4 5 6 VFA concentration (g/L) Time (d) pH 3 pH 4 pH 5 pH 8 pH 9 pH 10 pH 12 Blank

pH ≤ 5 pH ≥ 10

T = 70 ºC; Experiments were carried out in duplicate Inoculum: Sludge from B2 (70 ºC without pH control)

pH ≤ 5 pH ≤ 5 pH ≤ 5 pH ≤ 5 pH ≤ 5 pH ≥ 10 pH ≥ 10 pH ≥ 10 pH ≥ 10 pH ≥ 10

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SLIDE 14

Effects of pH

14

Results and Discussions

Continuous

1 2 5 6 7 8 9 12 13 14 16 19 20 21 22 30 2 4 6 8 10 12 14 16 18 Time (d) VFA concentration (g/L)

Without pH control With pH control

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SLIDE 15

VFA distribution

Parameters Units B1 (35 ºC, without pH control) B2 (70 ºC, without pH control) B3* (70 ºC, pH=10) B4 (35 ºC, pH=10) Alk gCaCO3/L 3.01 ± 2.82 7.34 ± 1.42 9.36 ± 0.30 10.10 ± 0.82 NH4

+‐N

gNH4

+‐N/L

3.14 ± 0.10 4.83 ± 0.81 1.42 ± 0.67 1.97 ± 0.59 Free ammonia gNH3‐N/L 0.003 ± 0.000 0.07 ± 0.01 1.40 ± 0.66 1.77 ± 0.53 pH ‐ 5.96 ± 0.32 6.17 ± 0.33 9.95 ± 0.18 9.90 ± 0.16 sCOD g/L 76.66 ± 12.48 95.1 ± 16.0 84.72 ± 15.41 88.21 ± 21.99

VFACOD/sCOD

% 22.59 ± 3.78 21.32 ± 4.22 19.19 ± 5.07 18.05 ± 3.29 VFA g/L 10.91 ± 1.08 14.59 ± 2.54 9.85 ± 1.04 10.43 ± 1.13 Acetic % 38.16 ± 4.21 39.81 ± 2.67 38.77 ± 1.61 40.08 ± 4.49 Propionic % 20.93 ± 1.83 21.65 ± 0.91 22.10 ± 1.26 20.22 ± 2.07 Butyric % 18.67 ± 2.06 19.19 ± 2.52 16.29 ± 1.89 18.12 ± 3.97 Valeric % 10.83 ± 1.27 9.93 ± 0.82 9.92 ± 0.96 9.86 ± 1.95 (C2+C4)/(C3+C5) ‐ 1.76 ± 0.23 1.85 ± 0.09 1.79 ± 0.09 1.93 ± 0.13

15

Results and Discussions * 30 days of operation

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0% 10% 20% 30% 40% 50%

1 2 5 6 7 8 9 12 13 14 16 19 20 21 22 30 VFA composition (%) Time (d)

Acetic Propionic Butyric Valeric

VFA distribution

16

Results and Discussions

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Conclusive remarks

 Collected OFMSW was prefermented at pH 6.2 and the distribution of VFA was even suitable for PHA production.  Without pH control, the hyperthermophilic range at 70 ºC is more favourable for maximum VFA production.  Generally, the composition of individual VFA in all reactors were similar to that of influent (OFMSW from Ecoparc).  Fermenters at 35 ºC and 70 ºC working at pH 10 did not produce a higher VFA quantity than the fermenters working at acidic pH, probably due to the free ammonia inhibition.  Effluents from the fermenters has a proportion

  • ≈ 1.8;
  • ≈ 18-22 % and high NH4

+-N ≥ 1.4 g/L.

17

Conclusions

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Acknowledgement

18

Thank you for your attention

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6th International Conference on Sustainable Solid Waste Management

Study of the Effects of Temperature and pH

  • n Acidogenic Fermentation Process from

Organic Fraction of Municipal Solid Waste

Y.K. Cheah1, C. Vidal-Antich1, J. Dosta1, J. Mata-Álvarez1,2

1Department of Chemical Engineering and Analytical Chemistry,

University of Barcelona, Barcelona, Catalonia, 08028, Spain.

2Water Research Institute, University of Barcelona, Catalonia, 08001,

Spain.