Alleviating the environmental and economic challenges of rice farming in Thailand

Rice cultivation accounts for 20% of land use in Thailand. Every year this generates 42 million tonnes of rice straw, 70% of which is burnt in the fields following harvest. Burning rice straw releases climate-harming greenhouses gases, causes air and water pollution, and decreases soil fertility.

Nearly half of Thai farming households have annual incomes below the national poverty line. This is partly due to a reliance on expensive imported fossil fertilisers.

Researchers from Queen’s University Belfast are examining how the environmental and economic challenges of rice farming in Thailand could be alleviated. Anaerobic digestion (AD) – the process by which microorganisms break down organic matter without oxygen – could hold part of the answer. The process produces biogas, a clean and renewable fuel, as well as environmentally friendly fertiliser.

By using the anaerobic digestion process, the harmful impacts of burning rice straw could be prevented, expensive and environmentally damaging fossil fertilisers could be replaced, and sustainable clean-burning indigenous energy could be provided. All of this would benefit farming communities as well as the wider population. In Thailand, a specific issue with the burning of rice straw has been production of dangerous forms of haze, which constitute a public health hazard.

Reactor Structure

With these concerns in mind, a UK-Thai collaboration has been working on a project designed to transform the uptake of anaerobic digestion of rice straw in Thailand. From the Queen’s University side, this research has included the provision of technical insights into AD, whilst also examining social-economic challenges and opportunities associated with its upscaling. The latter has included stakeholder engagement on context specific experiences, drawing on literature from case studies across Europe, as well as first-hand interviews with stakeholders in Northern Ireland – the region now has the most anaerobic digesters per capita in the UK.

An overall goal of the project was to support a move towards sustainable biogas recovery from rice straw residues in developing countries.

The project achieved the following aims:

  • Collaboration and knowledge-sharing across engineering, science, and economic geography to provide a rounded approach to the problem of rice straw utilisation
  • Pre-treatment and co-digestion options were investigated to improve biogas yields from rice straw
  • A pilot-scale rice straw anaerobic digestion facility was built and is regularly used for demonstrations and open days
  • Research findings were communicated to stakeholders in the Thai rice sector from government, industry and academia

The major output of the project involved construction of a pilot anaerobic digestion plant in Thailand to test ways of improving biogas output by, for example, pre-treating the rice straw feedstock with fungi before putting it into the digester. The pilot plant consisted of a 3 m3 cylindrical-shaped reactor holding up to 300 kg of feedstock for anaerobic digestion in batches.

The pilot plant was supported by environmental and socio-economic analysis. Cross-disciplinary working was identified as vital in delivering the objectives and providing valuable insights on what works and what doesn’t in the anaerobic digestion sector. The environmental analysis focused on greenhouse gas emissions and found that the anaerobic of rice straw brings substantial benefits compared to both in-field burning and combustion for electricity. Fieldwork in the form of interview data and desk-based research was especially important for gathering insight.

The pilot plant is regularly used for demonstrations and open days, which are attended by students, public workers, local industry, and local rice farmers. In addition, the rice straw workshop held in December 2021 disseminated the research findings to stakeholders in academic, business and government.

The main messages communicated during the workshop were that

  • the burning of rice straw after harvesting is still the main practice by farmers
  • large-scale power generation using rice straw as fuel has the potential to enhance rice straw utilization, but is problematic since its availability depends on crop cycles
  • anaerobic digestion of rice straw with other co-substrates such as food wastes presents a sustainable way to reduce field burning and provide renewable energy generation.

“This project represented an ideal opportunity for knowledge sharing between different departments at Queen’s – in particular Management and the School of Mechanical and Aerospace Engineering – and King Mongkut’s University in Thailand.  Northern Ireland has recent experience of a rapid expansion in AD, and we are thrilled insights from this transition could be used to support our partners in Thailand.” Dr Hastings, Queen’s University Belfast, Management School.

The application of learnings and experience from the anaerobic digestion industry in Northern Ireland and elsewhere, which are relatively well-established industries, was important for informing recommendations for the industry in Thailand.

Academics at QUB acknowledged the importance of conducting research which aligns with UN Sustainable Development Goals (SGGs) which are a strategic priority of the University. Commenting on this aspect of the project, Dr Beatrice Smyth and Dr Thomas Hastings identified a strong alignment with SDG goals including Climate Action (SDG 13) and Affordable and Clean Energy (SDG 7).

“Cross-disciplinary working was of real help in communicating insights into both technical and socio-economic factors which underpin the successful transition to AD. Working internationally during the time of Covid-19 has been challenging, but we are pleased to have helped further the sustainable development of Thailand’s rural economy by finding better solutions for rice straw.” Dr Smyth, Queen's University Belfast.

Sustainable biogas recovery from rice straw residues in developing countries 

Project Leads: Dr Beatrice Smyth, Queen’s University Belfast, UK, and Dr Nipon Pisutpaisal, King Mongkut’s University of Technology North Bangkok (KMUTNB), Thailand.

Key Partners: Dr Vanatpornratt Sawasdee, Valaya Alongkorn Rajabhat University Under The Royal Patronage (VRU), Thailand, Dr Thomas Hastings, Queen’s University Belfast.

Postdoctoral Researchers: Dr Neha Mehta, Queen’s University Belfast, Dr Saowaluck Haosagul, King Mongkut’s University of Technology North Bangkok, Thailand.

 

This project was a GCRF project funded through Department for the Economy of Northern Ireland (DfENI). DfENI is one of four UK national funding bodies that received GCRF funding from BEIS as part of the UK’s dual funding structure for research.  Learn more – www.newton-gcrf.org/gcrf/

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