title: Processing anaerobic sludge for extended storage as anaerobic digester inoculum.
abstract: Thermophilic anaerobic sludge was processed to reduce the volume and moisture content in order to reduce costs for storing and transporting the sludge as microbial inoculum for anaerobic digester startup. The moisture content of the sludge was reduced from 98.7% to 82.0% via centrifugation and further to 71.5% via vacuum evaporation. The processed sludge was stored for 2 and 4 months and compared with the fresh sludge for the biogas and methane production using food waste and non-fat dry milk as substrates. It was found that fresh unprocessed sludge had the highest methane yield and the yields of both unprocessed and processed sludges decreased during storage by 1-34%, however processed sludges seemed to regain some activity after 4 months of storage as compared to samples stored for only 2 months. Maximum methane production rates obtained from modified Gompertz model application also increased between the 2-month and 4-month processed samples.
authors.affiliation: College of Agronomy and Biotechnology, China Agricultural University, Beijing 100193, China; Department of Biological and Agricultural Engineering, University of California, Davis, CA 95616, United States.
authors.forename: Jiajia
authors.initials: J
authors.lastname: Li
authors.affiliation: Department of Biological and Agricultural Engineering, University of California, Davis, CA 95616, United States.
authors.forename: Steven M
authors.initials: SM
authors.lastname: Zicari
authors.affiliation: College of Agronomy and Biotechnology, China Agricultural University, Beijing 100193, China.
authors.forename: Zongjun
authors.initials: Z
authors.lastname: Cui
authors.affiliation: Department of Biological and Agricultural Engineering, University of California, Davis, CA 95616, United States. Electronic address: rhzhang@ucdavis.edu.
authors.forename: Ruihong
authors.initials: R
authors.lastname: Zhang
mesh_terms: D001421:Bacteria, Anaerobic / Q000378:metabolism / Q000502:physiology*; D002498:Centrifugation; D003890:Desiccation / Q000379:methods*; D005735:Garbage; D008697:Methane / Q000096:biosynthesis*; D012722:Sewage / Q000737:chemistry / Q000382:microbiology*; D013048:Specimen Handling / Q000379:methods*; D013997:Time Factors; D014618:Vacuum; D014867:Water / Q000032:analysis
chemical_list: D012722:Sewage; D014867:Water; D008697:Methane
keywords: Anaerobic sludge; Biogas production; Concentrated sludge; Methanogenic activity; Storage time