Using support materials to alleviate NaCl inhibition in anaerobic digestion
Managing the increasing volume of organic waste, especially food waste, has become an escalating challenge. Anaerobic digestion (AD) has emerged as a preferred solution for food waste management because it not only reduces waste volume but also generates biogas serving as clean energy. However, the presence of high salinity in food waste, primarily sodium chloride, poses significant obstacles to AD. This high salinity can damage anaerobic microorganisms and lead to process instability. Attempts to mitigate this issue by introducing osmoprotectants or utilizing halophilic microorganisms have limitations such as being non-resistant, high cost, and time-consuming. An alternative and cost-effective strategy is using support materials to enhance the AD process. Nevertheless, there is limited information regarding the effectiveness of support materials in alleviating high salinity inhibition. To bridge this knowledge gap, we conducted a comprehensive study aimed at evaluating the ability of various commonly used support materials to mitigate the inhibitory effects of NaCl in anaerobic digestion. A set of lab-scale continuous stirred tank reactors (CSTRs) was set up tailored for this purpose. Over an extended period of monitoring and sampling, we explored the effects of different support materials from aspects of degradation performance, microbial community dynamics, and metabolite dynamics with the help of statistical methods.