title: Destroying lignocellulosic matters for enhancing methane production from excess sludge.
abstract: A lot of lignocellulosic matters are usually present in excess sludge, which are hardly degraded in anaerobic digestion (AD) and thus remains mostly in digested sludge. This is a reason why the conversion rate of sludge organics into energy (CH4) is often low. Obviously, the hydrolysis of AD cannot destruct the structure of lignocellulosic matters. Structural destruction of lignocellulosic matters has to be performed in AD. In this study, pretreatments with the same principles as cell disintegration of sludge were applied to destruct lignocellulosic matters so that these materials could be converted to CH4 via AD. Acid, alkali, thermal treatment and ultrasonic were used in the experiments to observe the destructed/degraded efficiency of lignocellulosic matters. Thermal treatment was found to be the most effective pretreatment. Under optimized conditions (T = 150 °C and t = 30  min), pretreated sludge had a degraded rate of 52.6% in AD, due to easy destruction and/or degradation of hemicelluloses and celluloses in pretreatment. The sludge pretreated by thermal treatment could enhance the CH4 yield (mL CH4 g(-1) VSS) by 53.6% compared to raw sludge. Economically, the thermal treatment can balance the input energy with the produced energy (steam and electricity).
authors.affiliation: a Beijing Climate Change Research and Education Center , Beijing University of Civil Engineering and Architecture , Beijing 100044 , China.
authors.forename: Xiaodi
authors.initials: X
authors.lastname: Hao
authors.affiliation: a Beijing Climate Change Research and Education Center , Beijing University of Civil Engineering and Architecture , Beijing 100044 , China.
authors.forename: Yuansheng
authors.initials: Y
authors.lastname: Hu
authors.affiliation: a Beijing Climate Change Research and Education Center , Beijing University of Civil Engineering and Architecture , Beijing 100044 , China.
authors.forename: Daqi
authors.initials: D
authors.lastname: Cao
mesh_terms: D000143:Acids / Q000737:chemistry; D000468:Alkalies / Q000737:chemistry; D006358:Hot Temperature; D008031:Lignin / Q000737:chemistry*; D008697:Methane / Q000737:chemistry*; D012722:Sewage / Q000737:chemistry*; D000069453:Ultrasonic Waves; D014865:Waste Disposal, Fluid / Q000379:methods*
chemical_list: D000143:Acids; D000468:Alkalies; D012722:Sewage; C036909:lignocellulose; D008031:Lignin; D008697:Methane
keywords: Anaerobic digestion (AD); excess sludge; lignocellulosic matters; methane (CH4); pretreatment