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Enzymatic hydrolysis of cellulosic municipal wastewater treatment process residuals as feedstocks for the recovery of simple sugars

Champagne, Pascale, Li, Caijian
Bioresource technology 2009 v.100 no.23 pp. 5700-5706
wastewater treatment, enzymatic hydrolysis, cellulose, lignocellulose, raw materials, biomass, renewable energy sources, reducing sugars, ethanol production, municipal solid waste, biosolids, acid treatment, alkali treatment, activated sludge
This study examined the hydrolysis of lignocellulose extracted from municipal wastewater treatment process residuals for the purpose of investigating low-cost feedstocks for ethanol production, while providing an alternative solid waste management strategy. Primary and thickened waste activated sludges and anaerobically digested biosolids underwent various pre-treatments to enhance subsequent enzymatic hydrolysis. Half of the pre-treated samples were dried and grinded, while the other half were used as is (wet). The wet primary sludge yielded the highest reducing sugar conversions. When wet primary sludge without pre-treatment was hydrolyzed at 40°C and an enzyme loading of 800U/g substrate, 31.1±2.7% was converted to reducing sugars in 24h. This increased to 54.2±4.0% when HCl and KOH pre-treatments were applied. FTIR analyses were used to examine differences in the sludge compositions. These indicated that the cellulose content in the primary sludge was higher than that of the thickened waste activated sludge and biosolids, which was consistent with the higher reducing sugar yields observed in the primary sludge.