title: Full-scale class A biosolids production by two-stage continuous-batch thermophilic anaerobic digestion at the hyperion treatment plant, Los Angeles, California.
abstract: The City of Los Angeles Hyperion Treatment Plant (HTP) (California) converted its anaerobic digesters to thermophilic operation to produce Class A biosolids. Phase IV tests demonstrated compliance of a two-stage, continuous-batch process with Alternative 1 of U.S. Environmental Protection Agency 40 CFR Part 503 (U.S. EPA, 1993), which defines the time-temperature requirement for batch treatment (T > or = 56.3 degrees C at 16-h holding). Fecal coliforms, Salmonella sp., viable helminth ova, and enteric viruses were not detected in biosolids in the postdigestion train, including the truck-loading facility and the farm for land application as the last points of plant control where compliance is to be demonstrated. The same results were achieved during Phase V tests, after lowering the second-stage holding temperature to 52.6 degrees C to reduce the elevated methyl mercaptan production that was observed during Phase IV. Hence, the Phase V process complied with Alternative 3 of 40 CFR Part 503. Currently, HTP operates its digesters under the same conditions as tested in Phase V. In 2003, monthly monitoring of the biosolids at the truck-loading facility and the farm for land application demonstrated consistent compliance with Alternative 3.
authors.affiliation: City of Los Angeles Hyperion Treatment Plant, California, USA. Rezairanpo@aol.com
authors.forename: Reza
authors.initials: R
authors.lastname: Iranpour
authors.forename: Huub H J
authors.initials: HH
authors.lastname: Cox
authors.forename: Steve
authors.initials: S
authors.lastname: Fan
authors.forename: Varouj
authors.initials: V
authors.lastname: Abkian
authors.forename: Traci
authors.initials: T
authors.lastname: Minamide
authors.forename: Ray J
authors.initials: RJ
authors.lastname: Kearney
authors.forename: Roger T
authors.initials: RT
authors.lastname: Haug
mesh_terms: D000693:Anaerobiosis; D019149:Bioreactors / Q000382:microbiology / Q000469:parasitology / Q000821:virology; D005243:Feces / Q000382:microbiology / Q000469:parasitology / Q000821:virology; D015141:Los Angeles; D012722:Sewage / Q000382:microbiology / Q000469:parasitology / Q000821:virology; D013696:Temperature; D014865:Waste Disposal, Fluid / Q000379:methods*; D018505:Waste Management / Q000379:methods* / Q000592:standards*
chemical_list: D012722:Sewage