Recent Advances in Biosolids Stabilization: Case Histories

Arant, Steve; Fries, Kim; Jolly, Martin

doi:10.2175/193864703784292737

Cited by 1 publication

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“…One possible option to reduce odor emissions is to use a process in which the thermophilic stage is followed by a mesophilic stage, such as temperature phased anaerobic digestion (TPAD) ( Schafer et al, 2003 ). Although volatile solids and pathogen destruction by TPAD has been well‐documented in laboratory‐ and pilot‐scale tests (e.g., Bucher et al, 2001 ; Reusser and Zelinka, 2001 ; Sandino et al, 2002 ; Santha et al, 2003 ), and several plants have implemented TPAD on a full scale ( Arant et al, 2003 ; Schafer et al, 2003 ; Wilson and Dichtl, 1998 ), the effect of polishing by a mesophilic stage on reducing odor emissions has not been well‐established. We opted for reducing the digester temperature in Phase V to the lower end of the thermophilic range, to maintain disinfecting conditions, while reducing odor emissions.…”

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confidence: 99%

Full‐Scale Class A Biosolids Production by Two‐Stage Continuous‐Batch Thermophilic Anaerobic Digestion at the Hyperion Treatment Plant, Los Angeles, California

Iranpour

Cox²,

Fan³

et al. 2006

Water Environment Research

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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 ≥ 56.3°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°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.

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