Journal of Environmental Biology

Effect of increase in organic loading of fermented rice noodles wastewater on biogas production in anaerobic biogas bag

S. Laowansiri¹ and P. Phothilangka²*     

¹Energy and Environment for Sustainable Development Research and Training Center, Faculty of Environment and Resource Studies,

Mahasarakham University, Kantarawichai, Mahasarakham-44150, Thailand

²Department of Environmental Science and Technology, Faculty of Science, Lampang Rajabhat University, Mueang, Lampang-52100, Thailand

Received: 06 May 2025                   Revised: 29 August 2025                   Accepted: 30 September 2025

*Corresponding Author Email : phimphaka@g.lpru.ac.th                    *ORCiD: https://orcid.org/0000-0002-9053-1141

Abstract

Aim: To investigate the effect of increase of organic loading of fermented rice noodles wastewater effect on the production of biogas and organic treatment efficiency using a low-cost anaerobic biogas bag system.

Methodology: The anaerobic biogas bag was setup for treating fermented rice noodles wastewater. The anaerobic biogas bag was filled with 20 l d^-1 wastewater feeding as batch mode system and the pH was adjusted to 7.00 with NaOH and H₂SO₄. The loadings of reactor was 7.5 g COD m^-3 d^-1 for 15 days, later (the first phase) increased to 2.5, and 17.5 g COD m^-3 d^-1 at every 15 days interval was considered as 2nd and 3rd phase, respectively. The effects of loading rates on biogas yield and its compositions were investigated.

Results: With 17.5 g COD m^-3 d^-1, COD loading rate, with the fermented noodles were digested 77.7% removal of COD within 45 days, later stable anaerobic digestion was maintained after 30 days. At that point, a high biogas production (0.65±0.01 m³ biogas d^-1) with methane production rate of 0.400±0.01 m3 CH4 d^-1 was achieved.

Interpretation: Wastewater with high COD loading rate (17.5 g COD m^-3 d^-1) such a rice noodles wastewater, can be treated with anaerobic biogas bag. This system provides high treatment efficiency and produces biogas as an alternative source of energy.

Key words: Anaerobic treatment, Biogas bag, Fermented rice noodles wastewater

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