title: Parameters affecting the stability of the digestate from a two-stage anaerobic process treating the organic fraction of municipal solid waste.
abstract: This paper focused on the factors affecting the respiration rate of the digestate taken from a continuous anaerobic two-stage process treating the organic fraction of municipal solid waste (OFMSW). The process involved a hydrolytic reactor (HR) that produced a leachate fed to a submerged anaerobic membrane bioreactor (SAMBR). It was found that a volatile solids (VS) removal in the range 40-75% and an operating temperature in the HR between 21 and 35 °C resulted in digestates with similar respiration rates, with all digestates requiring 17 days of aeration before satisfying the British Standard Institution stability threshold of 16 mg CO(2) g VS(-1) day(-1). Sanitization of the digestate at 65 °C for 7 days allowed a mature digestate to be obtained. At 4 g VS L(-1) d(-1) and Solid Retention Times (SRT) greater than 70 days, all the digestates emitted CO(2) at a rate lower than 25 mg CO(2) g VS(-1) d(-1) after 3 days of aeration, while at SRT lower than 20 days all the digestates displayed a respiration rate greater than 25 mg CO(2) g VS(-1) d(-1). The compliance criteria for Class I digestate set by the European Commission (EC) and British Standard Institution (BSI) could not be met because of nickel and chromium contamination, which was probably due to attrition of the stainless steel stirrer in the HR.
authors.affiliation: Department of Chemical Engineering, Imperial College of Science and Technology and Medicine, Prince Consort Road, London SW7 2AZ, UK. a.trzcinski05@ic.ac.uk
authors.forename: Antoine P
authors.initials: AP
authors.lastname: Trzcinski
authors.forename: David C
authors.initials: DC
authors.lastname: Stuckey
mesh_terms: D000693:Anaerobiosis; D001673:Biodegradation, Environmental; D019149:Bioreactors; D002244:Carbon / Q000378:metabolism; D002245:Carbon Dioxide / Q000378:metabolism; D002947:Cities; D009930:Organic Chemicals / Q000378:metabolism*; D012037:Refuse Disposal / Q000379:methods*; D012722:Sewage / Q000737:chemistry / Q000382:microbiology*; D013696:Temperature; D013997:Time Factors; D006113:United Kingdom; D014835:Volatilization
chemical_list: D009930:Organic Chemicals; D012722:Sewage; D002245:Carbon Dioxide; D002244:Carbon