Enhancing anaerobic digestion of wheat straw through multistage milling

Enhancing anaerobic digestion of wheat straw through multistage milling

Pierpaolo Dell’OmoSabatino La Froscia 

Department of Astronautical, Electric and Energy Engineering, University La Sapienza, Via Eudossiana 18, Rome 00184, Italy

Scienza per Amore Association, Via Monteleone Sabino 9, Rome 00131, Italy

Corresponding Author Email: 
paolo.dellomo@uniroma1.it
Page: 
127-132
|
DOI: 
https://doi.org/10.18280/mmc_c.790310
Received: 
2 May 2018
| |
Accepted: 
8 June 2018
| | Citation

OPEN ACCESS

Abstract: 

The effects of a mechanical pretreatment, carried out by a two stages mill followed by fractionation into two different products, were determined on the biodegradability and methane yield of wheat straw. Straw was chopped in a knife mill to an average length of about 30 mm, and a portion was used as reference material. Pretreatment reduced the size of the processed straw, whose median particle size was 300μm and 1200μm for the fine and the coarse fractions, respectively. Untreated and pretreated materials were anaerobically digested in batch reactors under mesophilic conditions for 28 days. The methane yield of raw material was 167.8 Nm3 tVS-1, whereas the pretreated material reached an average methane yield of 250.6 Nm3 tVS-1, showing a 49.3 % gain on VS basis compared to the feedstock. The finest fraction of the processed material reached a methane production of 264.7 Nm3 tVS-1. The specific electric energy consumption was 66.6 kWh per ton of processed material. The energy efficiency was high, since consumption was only 23.7 % of the gross electric energy gain available after pretreatment. These results proved that the investigated pretreatment could be successfully implemented to improve methane production efficiency in anaerobic digesters.  

Keywords: 

biogas, biomethane, pretreatment, straw

1. Introduction
2. Materials and Methods
3. Results
4. Discussion
5. Conclusions
Acknowledgment

The authors thank Scienza per Amore Association (National Research Register, n. 61097BTH) for having funded this research, Mr. Danilo Speranza and all those who gave their assistance during the field work.

Nomenclature
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