Single-stage Sequencing Batch Process for Producing Class A Biosolids from AD Effluent at Terminal Island Treatment Plant

2006 ◽  
Vol 1 (4) ◽  
Author(s):  
Huub H.J. Cox ◽  
Steve Fan ◽  
Reza Iranpour
Keyword(s):  
Fecal Coliform ◽  
Treatment Plant ◽  
Batch Process ◽  
Single Stage ◽  
Fecal Coliforms ◽  
Class A ◽  
Truck Loading ◽  
Train Operation ◽  
Plant Control ◽  
Class A Biosolids

Terminal Island Treatment Plant converted its digesters to thermophilic operation with the objective to comply with the U.S. EPA Part 503 Biosolids Rule requirements for Class A biosolids. The following processes were tested: a) single-stage continuous; b) two-stage continuous; c) single-stage sequencing batch. Salmonella sp. were always non-detect in digester outflows (<3 MPN/4 g dry wt), whereas fecal coliform densities were usually below the Class A limit of 1000 MPN/g dry wt. However, the recurrence of fecal coliforms in post-digestion caused non-compliance with the Class A limit at the truck loading facility as the last point of plant control for compliance. After several design modifications of the post-digestion train, operation of the digesters as sequencing batch digesters according to the time-temperature requirement of Alternative 1 of the Part 503 Biosolids Rule achieved compliance for both Salmonella sp. and fecal coliforms at the last point of plant control (truck loading facility).

Removal of fecal coliforms by thermophilic anaerobic digestion processes

2002 ◽  
Vol 46 (10) ◽  
pp. 147-152 ◽  
Author(s):  
C. De Leén ◽  
D. Jenkins
Keyword(s):  
Anaerobic Digestion ◽  
Treatment Plant ◽  
Operating Conditions ◽  
Single Stage ◽  
Fecal Coliforms ◽  
Two Stage ◽  
Class A ◽  
One Stage ◽  
Combustible Gas ◽  
Screening Study

Recent U.S. EPA regulations (40 CFR Section 503) specify maximum concentrations of pathogens and metals for Class A wastewater treatment plant sludges. The most common sludge process is mesophilic (35¡C) digestion which stabilizes the solids, produces a combustible gas but does not create an effluent that meets the 503 Class A pathogen requirements. This investigation was conducted to determine whether anaerobic digestion processes incorporating a thermophilic stage could achieve 503 Class A pathogen levels. The research reported here was a bench-scale screening study meant to identify the most promising process alternatives for further investigation. Fecal Coliform (FC) concentrations were used to assess disinfection efficiency. Digesters were 30 L capacity fed semi-continuously in draw-fill mode. Digester startup was rapid to produce true thermophiles. Temperature staging and pH were assessed in 3 sets of experiments: Set 1 were one stage (“acid phase”), Set 2 were one stage (“acid + methane phases”) and Set 3 were two stage (“acid phase” then “methanogenic phase”). Feed was a 1:1 mixture of Thickened Waste Activated Sludge and Primary Sludge. The following anaerobic digestion configurations and operating parameters allowed the production of digested sludge with a mean FC concentration statistically less than 103 (the regulatory value for Class A sludge): thermophilic single stage acid phase at 52 and 62°C; thermophilic single stage acid + methane phase at 48°C, 52°C and 62°C; two-stage mesophilic acid phase followed by mesophilic methane phase; two stage mesophilic acid phase followed by thermophilic methane phase at 48°C, 52°C and 62°C. If the maximum digested FC concentration must be below 103 MPN/g TS then the following digester configurations and operating conditions will be compliant: two stage mesophilic acid phase followed by thermophilic methane phase at 52°C and 62°C.

Solving fecal coliform growth/reactivation in biosolids during full-scale post-digestion processes

2005 ◽  
Vol 52 (1-2) ◽  
pp. 283-288 ◽  
Author(s):  
R. Iranpour ◽  
R. Palacios ◽  
H.H.J. Cox ◽  
V. Abkian
Keyword(s):  
Los Angeles ◽  
Fecal Coliform ◽  
Treatment Plant ◽  
Pilot Scale ◽  
Full Scale ◽  
Fecal Coliforms ◽  
Anaerobic Digesters ◽  
Plant Conversion ◽  
Thermophilic Anaerobic Digestion ◽  
The City

Fecal coliform recurrence has been observed at the City of Los Angeles Hyperion Treatment Plant during pilot-scale experiments with a designated thermophilic battery of six anaerobic digesters, while other digesters were still at a mesophilic temperature. Several lab and full-scale experiments indicated the following possible causes of the growth/reactivation of fecal coliforms in post-digestion: a) contamination of thermophilically digested biosolids with mesophilically digested biosolids; b) a large drop in the biosolids temperature between the centrifuges and silos, which could have allowed the reactivation and/or growth of fecal coliforms. These were resolved by the full plant conversion to thermophilic anaerobic digestion and design modifications of the post-digestion train.

Thermophilic-Anaerobic Digestion to Produce Class A Biosolids: Initial Full-Scale Studies at Hyperion Treatment Plant

2006 ◽  
Vol 78 (2) ◽  
pp. 170-180 ◽  
Author(s):  
R. Iranpour ◽  
H.H.J. Cox ◽  
S. Oh ◽  
S. Fan ◽  
R.J. Kearney ◽  
...  
Keyword(s):  
Anaerobic Digestion ◽  
Treatment Plant ◽  
Full Scale ◽  
Class A ◽  
Thermophilic Anaerobic Digestion ◽  
Class A Biosolids

Reactivation and/or growth of fecal coliform bacteria during centrifugal dewatering of anaerobically digested biosolids

2004 ◽  
Vol 50 (9) ◽  
pp. 115-120 ◽  
Author(s):  
Y.N. Qi ◽  
S. Gillow ◽  
D.S. Herson ◽  
S.K. Dentel
Keyword(s):  
Fecal Coliform ◽  
Treatment Plant ◽  
Land Application ◽  
Fecal Coliforms ◽  
Coliform Bacteria ◽  
Human Pathogens ◽  
Indicator Organisms ◽  
Treatment Facility ◽  
Fecal Coliform Bacteria ◽  
Media Type

Fecal coliform bacteria are used as indicator organisms for the presence of pathogens. In sludges, it has often been assumed that the counts of fecal coliforms after digestion (where the sludges may also be called biosolids) are representative of the counts when the sludge is disposed or recycled, such as by land application. The possibility has been raised, however, that dewatering processes can lead to increased counts of fecal coliforms and, by inference, human pathogens. This paper presents data from previous studies of this possibility; the results were inconsistent but showed observable increases in fecal coliforms at one treatment plant. Additional studies were then performed at another treatment facility, which showed statistically significant increases in fecal coliform counts after dewatering and two days of aging. The increases exceeded two orders of magnitude and included two centrifuge types and two biosolids types. Artifacts of media type and enumeration method have been excluded, and shearing of the material by commercial blender did not produce the same effects.

Significance of indicator bacteria changes in an urban stream

1995 ◽  
Vol 31 (5-6) ◽  
pp. 243-246 ◽  
Author(s):  
Ernst M. Davis ◽  
M. Truett Garrett ◽  
Terri D. Skinner
Keyword(s):  
Fecal Coliform ◽  
Municipal Wastewater ◽  
Treatment Plant ◽  
High Flow ◽  
Fecal Coliforms ◽  
Urban Stream ◽  
Municipal Wastewater Treatment ◽  
Bacterial Populations ◽  
Sewerage System ◽  
Tidal Reach

An urban coastal stream, above tidal reach, and three municipal wastewater treatment plant effluents were analyzed for fecal coliforms, fecal streptococci and enterococci to determine the effect of dechlorination on those bacterial populations. Analyses were conducted during low and high flow periods from stormwater inflow. Improvement in bacterial water quality was found, principally due to municipality efforts to correct illicit connections and other sewerage system problems. Fecal coliform genera were identified and quantified. Regrowth of dechlorinated effluent bacteria was minimal.

REGROWTH OF FECAL COLIFORMS IN CLASS A BIOSOLIDS

2004 ◽  
Vol 2004 (1) ◽  
pp. 138-143
Author(s):  
Domènec Jolis ◽  
Matina Marneri ◽  
GuoJi Huang ◽  
Bonnie M. Jones
Keyword(s):  
Fecal Coliforms ◽  
Class A ◽  
Class A Biosolids

Increasing microbial activity in thermophilic anaerobic digestion of physicochemical sludge

2006 ◽  
Vol 54 (2) ◽  
pp. 245-251
Author(s):  
A. Tinajero ◽  
A. Noyola
Keyword(s):  
Biogas Production ◽  
Treatment Plant ◽  
Primary Treatment ◽  
Fecal Coliforms ◽  
Salmonella Spp ◽  
Digested Sludge ◽  
Class A ◽  
Effect Of Additives ◽  
Thermophilic Anaerobic Digestion ◽  
Chemically Enhanced Primary Treatment

Two thermophilic lab-scale reactors of 5 L were operated on a daily fed basis. Digester T1 received raw sludge (control) and digester T2 was fed with raw sludge plus metallic micronutrients and a bacilli additive. Raw sludge was obtained from a municipal chemically enhanced primary treatment plant. The effect of additives was clear on methane production, since on day 50, digester T2 produced 900 ml more methane than T1, an increase of 64%. On day 80, T2 reached twice the production of biogas of T1. Volatile solid removal (% VSR) in T2 increased to 29%; while T1 achieved only 15%. Acetic acid concentration in T2 diminished to 100 mg/L, which related to the higher biogas production. Based on the Mexican biosolids standard, the digested sludge reached Class A biosolids, in both digesters: fecal coliforms were reduced to less than 1000 MPN/gTS; Salmonella spp was totally eliminated and helminth egg counts were lower than one viable egg per gram of total solids.

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