Enhanced Thermal Hydrolysis of Sewage Sludge by Introducing Tannic Acid (TA)

Thermal hydrolysis is becoming a crucial approach to enhance the level of sewage sludge resource utilization. Introducing additives became the dominant way to improve thermal hydrolysis efficiency for sewage sludge, because elevating temperatures increased system energy consumption. Traditional additives like strong acids (e.g. vitriol) may lead to high overall operating costs for sludge thermal hydrolysis. This study proposed a new strategy to improve significantly the thermal hydrolysis efficiency of sewage sludge by adding a new additive of tannic acid (TA). It was observed that TA facilitated the dissolution of organic matter during the thermal hydrolysis process of sewage sludge and promoted the conversion proportion of macromolecular organic matter into smaller molecular forms. The highest organic matter content (142