Structural and functional properties of organic matters in extracellular polymeric substances (EPS) and dissolved organic matters (DOM) after heat pretreatment with waste sludge

The effects of heat pretreatment on waste sludge hydrolysis were investigated in this study. Heat pretreatment was conducted at 65 °C, 80 °C, 100 °C and 121 °C for 5 min, 10 min, 15 min, 20 min, 25 min and 30 min. Not only analyzed the changes of SCOD (Soluble chemical oxygen demand), carbohydrate and protein, but also evaluated the structural and functional properties of organics in extracellular polymeric substances (EPS) and dissolved organic matters (DOM) by using three-dimensional excitation-emission matrix (3D-EEM) fluorescence spectroscopy with fluorescence regional integration (FRI) analysis. The SCOD in DOM increased with pretreated temperatures. The optimal heat hydrolysis temperature and time were selected by further studying the biodegradable and non-biodegradable components. After treated at 80 °C for 25 min, the fluorescence intensity and percent fluorescence response (Pi,n) of easily biodegradable soluble microbial by-product substance were higher than others, and little non-biodegradable fulvic acid-like substance was accumulated.