Effect of feeding strategies on the start-up of anaerobic digestion of fish waste

As the effect of global warming, increasing number of dead fish causes mariculture production a considerable amount of economic loss. Anaerobic digestion (AD) is the most plausible treatment for dead fish waste (FW), as other organic waste treatments warrant severe environmental problems. However, ammonia generated from protein degradations of FW leads to challenging start-up. Hence, this study aimed to investigate a proper start-up strategy for FW AD. The systems were operated in repeated-batch with three different increases in FW concentration. The results showed that sigmoid and exponential strategies outperformed stepwise strategy, indicated by 86.51% and 70.72% higher cumulative methane productions at the last three cycles of experiment. Volatile fatty acids accumulation was also observed in the stepwise feeding, reaching 21.07 g-COD/L at the end of experiment. Real-time quantitative polymerase chain reaction revealed that Proteiniphilum had important role in FW degradation. Acetoclastic and hydrogenotrophic methanogens were responsible for higher methane production in exponential and sigmoid feedings. The result of this study is beneficial for managing the start-up of FW, thus guaranteeing economic benefit of AD.

Automated summary

Due to global warming, the increasing number of dead fish has caused significant economic losses in mariculture production. Anaerobic digestion (AD) is the most suitable method for treating dead fish waste (FW) as other organic waste treatments can lead to environmental issues. However, the ammonia generated from the protein degradation of FW poses challenges for start-up. This study investigated a proper start-up strategy for FW AD.