Pilot Plant Investigation of Thermophilic-Mesophilic Digestion for a Full-Scale Retrofit

Bucher, Bob; Newman, Gary; Moore, R. N.; Lepistö, Raghida; Stensel, H. David; Ferguson, John F.

doi:10.2175/193864701784992903

Cited by 2 publications

(2 citation statements)

References 2 publications

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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.…”

Section: Discussionmentioning

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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Section: Discussionmentioning

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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“…Vik and Olsen (1997) found that, after conversion of single‐stage mesophilic full‐scale digesters to a TPAD system, the VSR efficiency increased by 21.8% (from 63.3 to 77.1%). Bucher (2003) and Bucher et al (2001) , using a pilot TPAD system operated at a total SRT of 16 days compared with a full‐scale mesophilic digester averaging a 26‐day SRT for the same time period, found that the average VSR efficiency was higher by 4.5 percentage points for the TPAD system, at 68.3% compared with 63.8% for the full‐scale mesophilic digester. Oles et al (1997) , through laboratory and pilot work, showed that a TPAD system degraded municipal organic solids better than a single‐stage mesophilic process (60% compared with 48% VSR).…”

Section: Introductionmentioning

confidence: 99%

Performance and Stability of Two‐Stage Anaerobic Digestion

Zahller¹,

Bucher²,

Ferguson³

et al. 2007

Water Environment Research

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The stability, capacity, and solids destruction efficiency of single versus two-stage anaerobic digestion was studied in bench-scale reactors using combined waste activated and primary sludge. Laboratory staged mesophilic digesters showed an improved volatile solids and volatile suspended solids destruction efficiency over a single-stage system (at the same total solids retention time [SRT]) of approximately 3.2 and 5.8 percentage points, respectively. To quantify stability and capacity, a new digester monitoring method was introduced that measured the digester maximum acetate utilization capacity, V max,ac , and was used to investigate the potential for digester instability at different transient loadings. The ratio of the V max,ac value to the estimated acetate production rate for a given digester loading was termed the acetate capacity number (ACN). Values greater than 1.0 indicate excess acetate utilization capacity. The first stage of the laboratory two-stage mesophilic system (10-day SRT for each stage) had an ACN number of 1.3 compared with a value of 1.8 for the single-stage 20-day SRT digester. Thus, while a staged mesophilic system can improve solids destruction efficiency, it demonstrates a lower capacity for metabolizing highly variable loads. Water Environ. Res., 79, 488 (2007).

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Pilot Plant Investigation of Thermophilic-Mesophilic Digestion for a Full-Scale Retrofit

Cited by 2 publications

References 2 publications

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

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

Performance and Stability of Two‐Stage Anaerobic Digestion

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