Recent Advances and Perspectives of Nanotechnology in Anaerobic Digestion: A New Paradigm towards Sludge Biodegradability

Anaerobic digestion (AD) is the strategy of producing environmentally sustainable bioenergy from waste-activated sludge (WAS), but its efficiency was hindered by low biodegradability. Hence, the usage of nanomaterials was found to be essential in enhancing the degradability of sludge due to its nanostructure with specific physiochemical properties. The application of nanomaterials in sludge digestion was thoroughly reviewed. This review focused on the impact of nanomaterials such as metallic nanoparticles, metal oxide nanoparticles, carbon-based nanomaterials, and nanocomposite materials in AD enhancement, along with the pros and cons. Most of the studies detailed that the addition of an adequate dosage of nanomaterial has a good effect on microbial activity. The environmental and economic impact of the AD enhancement process is also detailed, but there are still many existing challenges when it comes to designing an efficient, cost-effective AD digester. Hence, proper investigation is highly necessary to assess the potency of utilizing the nanomaterials in enhancing AD under various conditions.