Extraction and Characterization of Extracellular Polymeric Substances (EPS) from Waste Sludge of Pulp and Paper Mill

Abstract

Secondary sludge (SS) and mixed sludge (MS) from a Canadian paper mill were characterized, and investigated for extracellular polymeric substances (EPS) to explore the potential opportunity for value added utilization of waste paper sludge as wood adhesive. After basic characterization which showed the availability of significant amount of organic matter, further study of wood adhesive extenders were carried out through extraction of EPS by using 4000g  centrifugation, a physical control method,  and a chemical extraction  technique involving formaldehyde and sodium hydroxide reagents. Gravimetric analysis showed the chemical extraction technique as being efficient method by yielding up to 5 times more EPS compared to physical control method. SS sludge, as anticipated, contained significantly high amount of EPS compared to MS. Fourier transform infrared spectrometry (FTIR) studies on extracted EPS confirmed the presence of key functional groups related to potential adhesions like protein, glucose, lignin, and carbohydrates. The polymeric nature of EPS was further diagnosed through calorimetric studies