Renewable bio-hydrogen production technologies from lignocellulosic waste and sewage sludge co-fermentation

Introduction

Huge amounts of rice straw are burned annually in the rice fields situated close to Albufera Natural Park (Spain), meaning massive emissions of greenhouse gases (GHGs) and particulate matter that affects the quality of life of surrounding populations with an important environmental impact. In Albufera, 5-6 tonnes of straw are produced annually in each of the 14,700-hectare cultivated. The management of this bio-waste poses a high impact on the economy of the farmers when other techniques different from burning or burying are used. This situation is repeated yearly in other regions of Europe that are main producers of lignocellulosic crops like rice or wheat.

Rice Production in Spain

Albufera park accounts for around 20% of the rice straw nationwide, with Spain being the second country of rice production in the EU. Other countries at the EU level in rice production include:

1. Italy
2. Greece

Meanwhile, countries such as Germany and France are producers of other lignocellulosic residues.

LIFE REPTES Project Overview

LIFE REPTES' new circular model will allow the valorisation of the rice straw, together with sewage sludge, by the production of renewable gas biofuels (biohydrogen and biogas) thanks to the implementation of a combination of technologies.

Core Technology

The most innovative and core technology of the project is the dark fermentation process (DFP) to produce biohydrogen. The technical and economic success of the model is backed by an innovative methodology for pre-treating the rice straw prior to DFP.

Demonstration of Potential

Furthermore, the project will demonstrate the potential of the fermented streams as co-substrate when used in anaerobic digestion in wastewater treatment plants (WWTPs), boosting the biogas yield by 10-43%. This will be demonstrated in Pinedo WWTP, the biggest one in the Valencia Region.

Expected Outcomes

LIFE REPTES will allow not only improving the welfare of the citizens in surrounding areas of lignocellulosic extensive cultivations, thus avoiding GHG emissions and promoting biowaste valorisation, but also creating a new profitable and bioenergy-efficient business model.