ABSTRACT
Sludge or biosolids are the two most common terms for the organic substances removed from wastewater during treatment. Due to its complicated structure and slow biodegradability, the generation of biogas from various wastewater sludge is currently limited. Due to the economic liabilities associated with the treatment and disposal of the sludge, along with the gradual shift in attention towards alternative sources of energy, the researchers have proposed many augmentations for enhancing the biogas yield during the anaerobic sludge digestions process. Studies have shown that the application of some pre-treatments techniques could be deployed to accelerate the hydrolysis of sludge, resulting in improved biogas yield, sludge quality, and solids removal after digestion. This article discusses the various pre-treatment procedures, focusing on current advancements. The various methods and their implications on sludge characteristics and anaerobic digestion are discussed in detail. Additionally, the potential hurdles and concerns regarding the feasibility and implementation of the pre-treatment techniques on a larger scale are also discussed.
