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

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