Mark C. MeckesU.S. EPA

Office of Research and Development

Senior Research Microbiologist

Chair: Pathogen Equivalency Committee

Northwest Biosolids Management Association

Annual Conference

Chelan, WA

September 19-21, 2010

Understanding Class A and Pathogen Equivalency

• Wastewater sources

• Classifying biosolids and treatment alternatives

• Vector attraction reduction

• Process equivalency

• The Pathogen Equivalency Committee (PEC)

• Web resources: www.epa.gov/nrmrl/pec

• The road to demonstrating equivalency (the process)

• Some of those on the road

• Research

OverviewOverview

SOURCES OF WASTEWATER & ASSOCIATED MICROORGANISMS

Sources of microorganisms

• Contributors to municipal wastewater collection systems. Homes. Commercial establishments. Hospitals. Industries. Storm water.

Human pathogens

• 1415 species of infectious organisms. 538 bacteria and rickettsiae. 217 viruses. 307 fungi. 287 helminths. 66 protozoa.

Source: Taylor, Latham & Woolhouse, 2001

Pathogenic bacteria of concern

AeromonasE

BurkholderiaE

Campylobacter

Clostridium perfringensI

E.coliE Pathogenic

Helicobacter pyloriE

Legionella

Leptospira*

Listeria

Mycobacterium

Neisseria meningitidisE

Pseudomonas

Salmonella

Shigella

StaphylococcusI

StreptococcusI

Vibrio cholerae*

Yersinia enterocolitica

Antibiotic resistant bacteria

• Affect control of bacterial infections.• Caused by:

Prophylactic dosages in medicine. Recurring infections – increased doses. Prophylactic dosages in animal

husbandry. Discharges from manufacturing

processes. Genetic exchanges. Competitive advantage.

Biosolids: Schematic Representation

WastewaterTreated

Discharge

Clarifier Oxidation Clarifier

Solids treatment

Solids treatments:

•Dewater and dispose

•Beneficial reuse

•Energy recovery

•Land application

CURRENT PRODUCTION & MANAGEMENT OF SLUDGE/BIOSOLIDS

• Produce 7 MILLION DMT/Y• 54 % IS LAND APPLIED/BENEFICIALLY USED• 18 % IS SURFACE DISPOSED

Classification of sludge treatmentsFederal Regulations

Federal Register Vol. 58, No. 32 February 19, 1993

Subpart D-Pathogens and Vector Attraction Reduction

•Class B – Some pathogens present. Site restrictions are required.

•Class A – Free of measurable pathogens. No site restrictions required.

•Vector Attraction Reduction is required regardless of Class.

40 CFR 503 Subpart DClass B Alternatives

• Alternative 1 Monitoring of fecal coliform Seven samples of treated sewage sludge collected at the time

of use or disposal. Geometric mean of the samples must be less than 2 million

per gram dry weight.

• Alternative 2 Use of a PSRP process. Aerobic digestion Anaerobic digestion Composting Lime addition Air drying

• Alternative 3 Use of processes equivalent to PSRP

Class B Processing Alternatives

Alternative Percentage of Total Systems

1 – Testing 27

2 – PSRP 71

3 – PSRP Equivalent

2

PSRP PROCESS EMPLOYMENT

AEROBIC DIGESTION

ANAEROBIC DIGESTION

CHEMICAL (LIME)

COMPOSTING

OTHER

• 36 %

• 38 %

• 9 %

• 12 %

• 5 %

Class A vs.Class B

12%

76%

12%

A B ?

CLASS A ApproachCLASS A Approach

1. Thermal Treatment – Batch reactors or plug flow conditions. Time at temperature restrictions based upon solids content.

2. Alkaline Treatment + heat (≥52°)3. Prior Testing for Enteric Virus & Viable Helminth 4. Routine monitoring of each batch of treated

sewage sludge.5. Use one of the Processes to Further Reduce

Pathogens (PFRP) – composting, heat drying.6. Use PFRP Equivalent Process.

Microbiological standards(40 CFR 503)

• Class A:At the time of use or disposal (dry weight) : 1000 fecal coliform/g or <3 salmonellae/4g <1pfu enterovirus/4g <1viable helminth ova/4g Class B: Use of a PSRP or equivalent process or <2 million fecal

coliform/g at the time of use or disposal.

40 CFR 503 Subpart DClass A Alternatives

• Alternative 1 (19 %) Time and temperature. Derived from experience with fluids; all parts of sludge must

meet the requirements for time and temperature. In general these processes are limited to batch reactors or

plug flow rather than continuous flow reactors.

• Alternative 2 (12 %) Alkaline treatment at elevated temperature. The process partially described here is that of N-Viro’s PFRP

equivalent process.

• Alternative 3 (4 %) Monitoring. This is sometimes labeled a “self equivalency.” Demonstration of PFRP equivalency (Alternative 6)

40 CFR 503 Subpart DClass A Alternatives

• Alternative 4 (9 %) AKA: Orphaned sludge rule. Limitations and/or concerns include the cost of analyses. Limited availability of qualified laboratories. Adequate sampling plan. Absence of enteric viruses and helminth ova does not insure

the absence of other pathogenic organisms.

• Alternative 5 (52 %) PFRP Processes. Composting, pasteurization, and heat drying are most

frequently used. Limitations of Add on Processes: (Like irradiation and

pasteurization) – Be aware of vector attraction concerns.

ALTERNATIVE 5: PFRP PROCESSES TO FURTHER REDUCE PATHOGENS

U.S. EPA

PathogenPathogen Equivalency Equivalency CommitteeCommittee

Office of Research &

Development

National Exposure Research Laboratory

National Homeland Security Research Center

National Risk Management Research Laboratory (chair)

Region VIII

Regional Offices

Office of

Water

Office of Science & Technology

Office of Wastewater Management

Center for Disease Control & Prevention

(CDC)National Institute of

Occupational Safety & Health

National Center for Environmental Health

Alternative 6 Alternative 6 ~~ Equivalent processes Equivalent processes

• Created in 1985 to provide technical expertise to permitting authorities on PFRP/PSRP Equivalencies

Microbiology Virology Parasitology Medicine

• 11 members with direct or related expertise and diverse points of view

Environmental engineering Wastewater treatment Industrial hygiene Federal regulations

Requirements for Reducing Vector Attraction

• Vector - Living organisms capable of transmitting a pathogen from one living organism to another.

• Intent: Decrease transport of pathogens• Organisms most likely to serve as vectors

Insects Rodents and other small mammals Birds

Vector Attraction Reduction Options• Reduction in volatile solids (>38%)• Additional anaerobic digestion (<17%)• Additional aerobic digestion (<15%)• Specific Oxygen Uptake Rate ≤ 1.5mg/hr/g• Aerobic process > 40°C• Addition of Alkali pH≥12 2hr, pH≥11.5 22hr• Moisture reduction stabilized solids - 75%• Moisture reduction unstabilized solids – 90%• Subsurface injection• Incorporation within 6 hours• Daily cover (surface disposal sites only)

VAR Usage by POTWs

Method POTW Estimate(based on 4500)

38% VSR 1535

SOUR 669

14 Day @ 40ºC 204

pH 12 – 22hr 448

Inject 588

Incorporate 361 

VECTOR ATTRACTION REDUCTION

• THE CALCULATION OF 38 PERCENT VOLATILE SOLIDS REDUCTION IS NOT APPROPRIATE FOR COMPOST

• THE SOUR TEST SHOULD BE RUN ONLY ON AEROBICALLY DIGESTED LIQUID SLUDGES PROCESSED BETWEEN 10 AND 30 DEGREES; THE SOUR TEST SHOULD BE RUN AT THE TEMPERATURE AT WHICH THE SEWAGE SLUDGE WAS PROCESSED

• THE SOUR TEST IS NOT APPROPRIATE FOR SOLIDS; IT SHOULD NOT BE USED FOR COMPOST OR DRIED SLUDGE PRODUCTS

VECTOR ATTRACTION REDUCTION

• PRODUCTS THAT HAVE BEEN STABILIZED BY ADDING LIME TO RAISE THE pH SHOULD BE DISTRIBUTED AND USED BEFORE pH DROPS BELOW 10.5

• HEAT-DRIED PRODUCTS SHOULD BE STORED UNDER COVER SO THAT MOISTURE IS NOT RE-INTRODUCED

U.S. EPA

PathogenPathogen Equivalency Equivalency CommitteeCommittee

Office of Research &

Development

National Exposure Research Laboratory

National Homeland Security Research Center

National Risk Management Research Laboratory (chair)

Region VIII

Regional Offices

Office of

Water

Office of Science & Technology

Office of Wastewater Management

Center for Disease Control & Prevention

(CDC)National Institute of

Occupational Safety & Health

National Center for Environmental Health

Alternative 6 Alternative 6 ~~ Equivalent processes Equivalent processes

• Created in 1985 to provide technical expertise to permitting authorities on PFRP/PSRP Equivalencies

Microbiology Virology Parasitology Medicine

• 11 members with direct or related expertise and diverse points of view

Environmental engineering Wastewater treatment Industrial hygiene Federal regulations

Website Resourceswww.epa.gov/nrmrl/pec

How to Apply page

Website Resourceswww.epa.gov/nrmrl/pec

Website Resources

• Contact permitting authority first if applicable• A must for site-specific cases

• Specific region targeted

• Permitting authority will make initial contact with PEC

• Contact PEC directly otherwise• General mailbox:

pec@epa.gov

• Treatment plant where testing will occur has already been identified

• Coordinator Locator page

www.epa.gov/nrmrl/pec

QAPP

• QAPP = Quality Assurance Project Plan• Provides framework and details for sampling and analysis

• Ensures the validity of the data

• Now REQUIRED!

• Prior agreement with PEC on QAPP will save time and $

• Head start on application

QAPP

• QAPP page• QAPP guidelines - annotated outline

• Example QAPPs

• A checklist used by the PEC to review

• A list of applicable analytical methods, plus links

• Equivalency Criteria page• Provides QAPP objectives• 4 necessary criteria:

Identify Critical Process Parameters Verify Pathogen Reduction Demonstrate scale-up Provide Appropriate Documentation

(i.e., QAPP)

Website Resources

- Treatment time- Temperature- Chemical dosing- pH- %TS range- etc.

www.epa.gov/nrmrl/pec

QAPP Phase

• QAPP page• QAPP guidelines - annotated outline

• Example QAPPs

• A checklist used by the PEC to review

• A list of applicable analytical methods, plus links

• Equivalency Criteria page• Provides QAPP objectives• 4 necessary criteria:

• Identify Critical Process Parameters• Verify Pathogen Reduction• Demonstrate scale-up• Provide Appropriate Documentation

(i.e., QAPP)

Website Resources

PSRP Equivalency: ≥ 2 log red. FC*; and ≤ 2,000,000 MPN or CFU/g TS FC in treated sludge

PFRP Equivalency: ≥ 3 log red. enteric viruses; ≥ 2 log red. viable helminth (Ascaris) ova; ≥ 3 log red. FC*; and ≤ 1 pfu/4 g TS total enteric viruses; ≤ 3 viable helminth (Ascaris) ova/4 g TS; ≤ 1,000 MPN FC/ g TS or ≤ 3 MPN Salmonella spp./4 g TS

*FC can be replaced by E. coli, Enterococcus, or Salmonella (PFRP only)

- Treatment time- Temperature- Chemical dosing- pH- %TS range- etc.

www.epa.gov/nrmrl/pec

QAPP Phase

• QAPP page• QAPP guidelines - annotated outline

• Example QAPPs

• A checklist used by the PEC to review

• A list of applicable analytical methods, plus links

• Equivalency Criteria page• Provides QAPP objectives• 4 necessary criteria:

Identify Critical Process Parameters Verify Pathogen Reduction Demonstrate scale-up Provide Appropriate Documentation

(i.e., QAPP)

Website Resources

PSRP Equivalency: ≥ 2 log red. FC*; and ≤ 2,000,000 MPN or CFU/g TS FC in treated sludge

PFRP Equivalency: ≥ 3 log red. enteric viruses; ≥ 2 log red. viable helminth (Ascaris) ova; ≥ 3 log red. FC*; and ≤ 1 pfu/4 g TS total enteric viruses; ≤ 3 viable helminth (Ascaris) ova/4 g TS; ≤ 1,000 MPN FC/ g TS or ≤ 3 MPN Salmonella spp./4 g TS

*FC can be replaced by E. coli, Enterococcus, or Salmonella (PFRP only)

Issues with spiking make verification difficult at full-scale.

Lab-scale verification.

Use of surrogates may be necessary.

www.epa.gov/nrmrl/pec

• Application Guidelines

• New Equivalency Application Package Form• Ready-made fill-in

form • summary information

& attachment list• Detailed line-by-line

instructions

Website Resources

How to Apply page

www.epa.gov/nrmrl/pec

Autothermal Thermophilic Aerobic Digestion (ATAD)

• ATAD is a two-stage, autothermal aerobic digestion process. The stages are of equal volume. Treated sludge amounting to 1/3 the volume of a stage is removed every 24 hours from the second stage as product. An equal amount then is taken from the first stage and fed to the second stage. Similarly, an equal amount of untreated sludge is then fed to the first stage. In the 24-hour period between feedings, the sludge in both stages is vigorously agitated and contacted with air. Bio-oxidation takes place and the heat produced increases the temperature. Sludge temperature in the reactors averages between 56 and 57°C for ≥ a 16-hour period, while the overall hydraulic residence time is 6 days.

Alkaline Stabilization

• Manchak process uses quicklime to simultaneously stabilize and pasteurize biosolids.

• Quicklime, or a combination of quicklime and flyash, is mixed with dewatered biosolids at a predetermined rate in a confined space. An instant exothermic reaction is created in the product wherein the pH is raised in excess of 12 after two hours of contact, in addition, the temperature is raised in excess of 70°C for > 30 minutes.

OxyOzonation

• Operation occurs in a batch mode and under the following conditions: sludge temperature of > 20°C sludge solids of < 6% TSS pH during ozonation of 2.5 - 3.1 pH during nitrite contact of 2.6 - 3.5 ORP after ozonation of > 100 mV nitrite dose of ≥ 670 mg (NO2)/1 sludge or 16 g (NO2)/kg sludge

solids, whichever is greater is to be mixed into the ozonated sludge.

• Ozonation takes place in a pressure vessel at 60 psig.

On the road to equivalency

ID 2PAD SYSTEM TWO PHASE

ANAEROBIC DIGESTION

Lyonnaise des Eaux’s Two-Phase Thermo-Meso Feed Sequencing

Anaerobic Digestion Process•Sewage sludge is treated in the absence of air in an acidogenic thermophilic reactor and a mesophilic methanogenic reactor connected in series.•The mean cell residence time shall be at least 2.1 days (± 0.05 d) in the acidogenic thermophilic reactor followed by 10.5 days (± 0.3 d) in the mesophilic methanogenic reactor.•Feeding of each digester shall be intermittent and occurring 4 times per day every 6 hours.•The mesophilic methanogenic reactor shall be fed in priority from the acidogenic thermophilic reactor.•Between two consecutive feedings, temperature inside the acidogenic thermophilic reactor should be between 49°C and 55°C with 55°C maintained during at least 2.8 hours.•Temperature inside the mesophilic methanogenic reactor shall be constant and at least 37°C.

PERFORMANCE OF 2PAD SYSTEM PILOT PLANT

Schwing-BiosetINFLUENCE OF TEMPERATURE, TIME, % AMMONIA,

& PRESSURE ON ASCARIS INACTIVATION

PEC’S RECOMMENDATION OF The BIOSET PROCESS AS A PFRP

• The sludge is held at a temperature of 55PC or greater for a minimum of 25 minutes.

• The solids content of the sludge being treated is in the range of 6% to 35%.

• The ammonia content in the reactor is 1% (10,000 mg/L) on a volume basis.

• The pressure in the reactor is 30 psi.• The amount of lime added is 0.55 to 0.75 lbs. lime to 1 dry

lb. of sludge.• The amount of acid added is 8 to 10 lbs. per dry ton of

sludge.• The pH is greater than 12.

CHARACTERISTICS OF BCR’s NEUTRALIZER PROCESS

DISINFECTION CAPABILITY OF BCR’s NEUTRALIZER PROCESS

Vermicomposting

Vermitech Process formerly Granville, Pennsylvania

The MagnaGro Process

Research

• Validated methods of analysis.

• Indicator organisms relationship to pathogens.

• Holding times, how long is reasonable?

• Transport - air, soil and runoff.

• Survival – natural attenuation factors.

• Wastewater sources

• Classifying biosolids and treatment alternatives

• Vector attraction reduction

• Process equivalency

• The Pathogen Equivalency Committee (PEC)

• Web resources: www.epa.gov/nrmrl/pec

• The road to demonstrating equivalency (the process)

• Some of those on the road

• Research

WHAT WAS DISCUSSED

Questions?meckes.mark@epa.govwww.epa.gov/nrmrl/pec