Additives as a Support Structure for Specific Biochemical Activity Boosts in Anaerobic Digestion: A Review

Abstract

Anaerobic digestion is an attractive technology for resource management of organic waste and stubble. The state of biochemical reactions and activities in anaerobic digestion determines the process stability. Biochemical activities, such as syntrophic, metabolic, catalytic, and enzymatic activities, regulate the anaerobic efficiency for improved methane yield. Inhibitors, such as access to volatile fatty acids, ammonia, sulfur, and heavy metals, may slow down the anaerobic digestion and may cause reactor failure. However, additives for various biochemical activities may help to diminish the effect of inhibitors as well as improve process stability for enhanced methane yield. This manuscript presents an overview of various additives for enhancing the biochemical activities. The overview consists of the application of (a) conductive material for improving syntrophic activity, (b) trace metals for metabolic activities, (c) nanoparticles for improving catalytic activity, metabolism, and symbiosis during AD, (d) biological additives for enzymatic action, and (e) application of zeolite for introducing cation exchange properties in anaerobic digestion. Also, a comparison of various additives as per biochemical activity has also been performed for a deeper insight into the application of additives in anaerobic digestion.

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

“…This results in the accumulation of volatile fatty acids (VFA) [6,7]. To overcome these two issues, remedial processes such as pretreatment [8], co-digestion [9], the addition of additives [10], etc., are highly preferred. Researchers detected an increase in the amount of NPs usage in biodegradable waste as a result of increased use of certain additives in key industries.…”

Application of Metallic Additives in Anaerobic Digestion for Improving the Metabolic Activity

“…Organic matter activities, for instance syntrophy, metabolism, catalyst, and enzymes, control the efficiency of the anaerobic process for enhanced methane production. Anaerobic inhibitors, for instance high VFAs, sulphur, and ammonia may hinder the system, resulting in digester failure [7]. Nonetheless, additives for activities may assist in reducing the impact of anaerobic inhibitors and also enhance stability of the process for improved methane and biogas productions.…”

Novel Insight on the Impact of Enzymatic Addition on Organic Loading Rate in Anaerobic Digestion

“…The range of enzymes, enzyme combinations and their optimal working parameters (e.g. pH, temperature, salinity) are vast depending on the enzyme and conditions used in the process [9]. Furthermore, enzymes have been used in two ways: as pretreatment, or in bioaugmentation added directly to the anaerobic digester.…”