Degradation performance and microbial population shifts in an anaerobic digester treating thermally pretreated biosolids
During the construction of an anaerobic plant to process 110 000 wet tons of secondary sludge per year at the site of a Canadian municipality,parallel experimentation took place at lab-scale to validate the design and the operation conditions planned for the full-scale installation.Preliminary tests in bottles confirmed that a thermal hydrolysis pretreatment (55℃,24-48 hours) increased the biodegradability of the sludge by up to 40%.The lab-scale hydrolyser and anaerobic digester (6L) were assembled and processed secondary sludge from the plant in continuous at an HRT of 20 days and at 37℃ during 6 months.The process suffered performance loss on two occasions although digester recovery was successful with partial re-inoculation and strict pH control (< 7.3).Both bacterial and archaeal populations were monitored all along the process through a metagenomics approach.While only limited variations were observed in the archaeal population,major shifts occurred in the bacterial population,with significant differences observed between the various phases of the process (initial,problematic and optimal).Once steady-state conditions were obtained,the sludge was successfully degraded with an average of 56% volatile solids (VS) removal at an organic loading rate of 1.8 gVS/L.d following a one day and 19 days retention time in the hydrolyser and digester,respectively.The methane production stabilized at 279 L STP/kg VS added.Monitoring the microbial population allowed identifying microorganisms possibly directly linked to the optimal performance of the digester,with notably a putative important role of the bacterial phyla Cloacimonetes and Tenericutes in the recovery and stability of the system.Validation at smaller scale helped reducing the risks of implementing an innovative design at full-scale.
Anaerobic digestion sludge wastewater treatment plant thermal hydrolysis metagenomics microbial population Cloacimonetes,Tenericutes
Jean-Claude Frigon Guillaume Bruant Caroline Roy Marie-Josée Lévesque Serge R.Guiot
Bioengineering Group, Energy, Mining and Environment, National Research Council Canada, Montreal, Canada, H4P 2R2
国际会议
The 15th IWA World Conference on Anaerobic Digestion( 第15届IWA世界厌氧大会)
北京
英文
332-335
2017-10-17（万方平台首次上网日期，不代表论文的发表时间）