17.12.2010 UNIVERSITÄT ROSTOCK AGRAR- UND UMWELTWISSENSCHAFTLICHE FAKULTÄT 1

Development of a test procedure for realistic assessment of the biology of

fermentation of NaWaRo-biogas plants

Nils Engler, Thomas Fritz, Michael Nelles, Ute Merrettig-Bruns, Adam Feher

3. Biogas-Innovationskongress Osnabrück 2010

17.12.2010 UNIVERSITÄT ROSTOCK | AGRAR- UND UMWELTWISSENSCHAFTLICHE FAKULTÄT 2

Content

1. Introduction

2. Development of the test procedure

3. First results and perspective

• Equipment and methods

• Realisation and prozess

• Analysis and interpretation of data

• Degradation kinetics of various substrates and biological activity of fermentation

samples

• Evaluation of effects of fermentation aids

• Detection of inhibitory effects

• Motive and purpose

Introduction

Growing number of biogas plants : medium to long term is to be expected of a shortage or

price increase of available substrates.

• Motive and purpose

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For both tasks process aids are already available on the market. Effectiveness is

difficult to assess in practice facilities

Molecular biological methods : time-consuming, expensive, no direct conclusions about the

actual degradation rate in the fermenter.

The activity is a manageable test procedures are developed,, which allows a

comparative quantification of the degradation rate of the fermenter biology.

Objectives: optimum utilization of available substrates, Development of new, in Anaerobic

fermentation unutilized biomass.

Development of the test procedure

Test procedure: The biogas production of a standard

substrate is measured under standardized conditions

with high temporal resolution.

• Equipment and methods

17.12.2010 4UNIVERSITÄT ROSTOCK | AGRAR- UND UMWELTWISSENSCHAFTLICHE FAKULTÄT

ANKOM ®Gas Production System:

• Compression-proof fermentation vessel.

• Module with pressure sensor , purge valve and vent

valve.

• Pressure sensor detects the actual pressure in the

head space and transmitted wirelessly to the PC

• Evaluation software (calculated by considering the

current air pressure) the cumulative increase in

pressure in the headspace of each fermentation

vessel.

Development of the test procedure

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Module in a water bath (top)

Daily homogenization using a magnetic stirrer (left)

Development of the test procedure

Requirement of the standard substrate:

• Reproducibility: Known and representable composition

• Quantification of the results: known gas yield

• Degradability: The composition of the major nutrients should be about the substrate of

biogas plants

• No influence on the study objective : itself free of promoters / inhibitors

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Realization by:

• Acetate( acetic acid directly for the methane-producing microorganisms available

• Corn starch: Substrate for hydrolyzing and acid-forming microorganisms

• Corn silage: practical substrate complex

• Synthetic substrate complex: Mixture of cellulose, starch, glucose, urea and phosphate buffer in a

fixed composition

• Equipment and methods

First results and perspective

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Degratation kinetics various substrates

Fermenter probe: agr. BGA, free manure

Seed sludge ratio: 0,15 (MS, starch) or 0,022 (ES)

Development of the test procedure

For the experimental procedure the fermentor to be is researching taken from a sample of

a possible active area (sampling adapter, if any, circulatingg, ggf. overflow to digestate storage…)

• Realisation and prozess

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Initial weight per fermentation vessel (500 ml volumen) : 200 … 400 g fermenter probe bzw. 15

g oDM, ggf. dilution (with VE-water)

In addition to BLANK (only Fermenter content) a control experiment (with standard

substrate) and any attempts at treatment applied.(n=3)

Recording intervall 30 min. ; once a day homogenization of contents of the fermentation

vessel using magnetic stirrer.

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Development of the test procedure

Validation run Jan. 2010

Mixture: per 400ml digested sludge and 2,5g cellulose, microcrystalline

Development of the test procedure

Test period : 5 bis 10 d

Analysis and interpretation of data

17.12.2010 10UNIVERSITÄT ROSTOCK | AGRAR- UND UMWELTWISSENSCHAFTLICHE FAKULTÄT

Presentation of results: Gas volume s (in l(N)/kgoDM ) to the theoretical maximum Gas

production potential of the standard substrate (calculated by BUSWELL)

Representation is a time-curve.

For comparison of different fermentation samples, the first criterion to be used as a time t50,

which is required to achieve 50% of the theoretical biogas yield. Quantify the performance

degradation using mathematical models is provided as the project continues.

Development of the test procedure

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Degradation kinetics synth. Substrate

Comparison of different fermenter samples

First results and perspective

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0,00

0,10

0,20

0,30

0,40

0,50

0,60

0,70

0,80

0,90

1,00

0,0 0,5 1,0 1,5 2,0 2,5 3,0 3,5 4,0 4,5 5,0 5,5

rela

tive

r B

iog

aser

trag

(B

ezu

g:

Bu

swel

l-E

rtra

g S

ynsu

b)

Zeit in d

Vergleich der Abbaukinetik unterschiedlicher Fermenterproben

optimaler Substratumsatz

leicht verzögerter Substratumsatz

verzögerter Substratumsatz

stark gehemmter Substratumsatz

Comparison of the kinetics of different fermenter samples

First results and perspective

Example: Substrate conversion and trace elements supply

17.12.2010 13UNIVERSITÄT ROSTOCK | AGRAR- UND UMWELTWISSENSCHAFTLICHE FAKULTÄT

Probe Cu Ni Zn Fe Bor Co Mn Mo Se W

1 129,13 9,99 342,68 5688,0 21,51 1,95 733,83 3,65 0,46 2,24

2 213,43 7,80 166,97 2371,0 28,42 1,63 248,23 4,33 0,55 0,91

3 184,55 6,01 686,83 1006,0 41,91 2,03 327,30 4,38 1,12 3,87

4 18,00 3,70 127,30 1504,5 13,30 0,40 285,90 2,10 0,58 0,70

mg/kgTM

The fermenter sample Nr. 4 (strongly

inhibited substrate degradation) shows in

almost all trace elements examined, the

lowest concentrations.

Trace element deficiency?

(Color table: Comparison of the four shown

in the diagram fermenter samples.)

First results and perspective

Evaluation of effects of fermentation aids

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comparative experimental trace element addition

First results and perspective

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Evaluation of effects of fermentation aids

Ca. 7 %

higher yield

Comparative experimental enzyme addition

Residual gas form a fermenter sample with / without enzyme addition

First results and perspective

17.12.2010 16UNIVERSITÄT ROSTOCK | AGRAR- UND UMWELTWISSENSCHAFTLICHE FAKULTÄT

Assessing the effect of inhibitors

Objective of the experiment:

• Evaluate the impact of massive fungal infection on the

kinetics of fermentation of corn silage

Preparation:

• Corn silage was stored in air influence, to clear fungi

can be seen (image)

• In the activity test comparison with the original material

without fungi

• Smear on special fungi-agar, morphological

investigation is still pending

Silage with fungal infection after air stress (top)

Smear on fungi-agar (left)

0

100

200

300

400

500

600

700

0,0 0,5 1,0 1,5 2,0 2,5 3,0 3,5 4,0 4,5 5,0 5,5 6,0 6,5 7,0

Bio

gas

in l(

N)/

kgo

TS

Time in d

Corn silage with / without fungal infection: specific biogas yield and kinetics

Maissilage

Maissilage mit Pilzbefall

synth. Standardsubstrat

First results and perspective

17.12.2010 17UNIVERSITÄT ROSTOCK | AGRAR- UND UMWELTWISSENSCHAFTLICHE FAKULTÄT

g/kg FM

Silage

normal

Silage nach

Luftstress/ Pilz

Milchsäure 16,18 0,69

Essigsäure 6,13 0,27

Propionsäure 0,09 0,15

Buttersäure 0,00 0,00

I-Valeriansäure 0,00 0,17

Äthanol 2,95 0,04

Propanol 0,17 0,12

Butandiol 0,20 0,05

Propandiol 0,20 0,00

oTM(k) in % FM 36,60 32,00

First results and perspective

In the current research project is to test the activity developed

and used for detailed investigations of the supply of NaWaRo-

biogas digesters with trace elements.

As part of the project, a screening system based on the activity

tests carried out and completed with studies on the supply of the

fermenter biology with essential trace elements.

Current research projects

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Project partners and promotion

The IGF-project 16 103 BG Research Association Association for the Promotion of Energy and Environmental

Technology-TEU, Bliersheimer Straße 60, 47229 Duisburg was the AIF under the program to promote industrial

research and development (IGF) of the Federal Ministry of Economics and Technology based on a decision of the

German Bundestag encouraged.

17.12.2010 19UNIVERSITÄT ROSTOCK

Fraunhofer Institut für Umwelt- Sicherheits-

und Energietechnik UMSICHT, Oberhausen

HAWK Fachhochschule Göttingen

Fakultät Ressourcenmanagement,

Fachgebiet NEUTec

Universität Rostock

Agrar- und Umweltwissenschaftliche Fakultät

Institut für Umweltingenieurwesen

Lehrstuhl Abfall- und Stoffstromwirtschaft

Vielen Dank für Ihre Aufmerksamkeit !

Nils Engler1, Ute Merrettig-Bruns3, Adam Feher4 , Thomas Fritz2 , Michael Nelles1

1Universität Rostock, Agrar- und Umweltwissenschaftliche Fakultät, Lehrstuhl für Abfall- und

Stoffstromwirtschaft2IS Forschungsgesellschaft mbH, Pinneberg3Fraunhofer Institut für Umwelt- Sicherheits- und Energietechnik UMSICHT, Oberhausen4HAWK Fachhochschule Göttingen, Fakultät Ressourcenmanagement, Fachgebiet NEUTec

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