PFAS in Biosolids

Mohammad M. Abu-Orf, Ph.D.

Vice President

Residuals and Biosolids Practice Leader

February 4th, 2020

Biosolids beneficial use has had its challenges!

Odors

Persistent public opposition

Land application errors

…and now PFAS

Biosolids beneficial use

recycles valuable nutrients

to the environment &

improve soil health

Agenda

• What are PFAS chemicals

• PFAS in the engineered water cycle

• Regulatory outlook for PFAS

• Solutions to address PFAS

challenges in biosolids

• Source control

• Volume reduction

• Advanced thermal processes

• What to do?

What are PFAS chemicals and

how did we get here?

Per-Polyfluoroalkyl substances (PFAS)

• Family of manmade

fluorinated chains (>4,000

chemicals)

• Perfluoroalkyl substances

• All H atoms attached to carbon

atoms are replaced by F atoms

• Short chain and long chain PFAS

• Polyfluoroalkyl substances

• H replaced by F on at least one C

atoms

• Some can degrade to PFAA

Terminal degradation

products (biotic and abiotic)

of precursor chemicalsSource: ITRC Factsheet, Naming Conventions and Physical and Chemical Properties of Per- and Polyfluoroalkyl Substances (PFAS)

PFAS discovery and manufacturing history

https://pfas-1.itrcweb.org/wp-content/uploads/2017/11/pfas_fact_sheet_history_and_use__11_13_17.pdfSource: ITRC Factsheet, History and Use of Per- and Polyfluoroalkyl Substances (PFAS)

PFAS is a national issue

https://www.ewg.org/interactive-maps/2019_pfas_contamination/map/

https://www.ewg.org/interactive-maps/2019_pfas_contamination/map/

Reasons for concern

• PFAS are ubiquitous and persistent

in the environment

• Humans are often exposed to PFAS

through food, dust, consumer products,

clothing, and water

• Half life in humans is several years

(slow elimination)

• Exposure is cumulative

• Longer-chain molecules bioaccumulate

more than shorter chain molecules

• Phase-out of PFOS and PFOA

• Manufacturers simply switch to shorter

chain PFAS

• Short-chain PFAS are MORE

CHALLENGING to treat

Health Effects

Animal laboratory studies:

• Reproductive and developmental, liver

and kidney, and immunological effects

• Tumors

Humans: in our blood for half a century!

• Consistent findings: increased cholesterol

levels among exposed populations

• limited findings related to:

• Infant birth weights

• Effects on the immune system

• Cancer (for PFOA)

• Thyroid hormone disruption (for PFOS)

PFAS in the engineered

water cycle

Fate and transport of PFAS within

the engineered water cycle

• Detected in drinking water

sources across the nation

• Detected in biosolids

• Detected in WRRFs effluents

Sources of PFAS to WWRFs

Domestic: mainly from consumer products

• 2006 survey in the USA documented that municipal wastewater,

with minimal industry input, can range from 60 to 220 ng/L PFAS

• Septic systems are expected to have slightly higher concentrations

Industrial: typical below

Emissions of perfluorinated alkylated substances (PFAS) from point sources-identification of relevant branches;

M. Clara, C. Scheffknecht, S. Scharf, S. Weiss, and O. Gans; Water Science & Technology; 2008, 51.8

Reasons for concern: water resources

recovery facilities (WRRFs)

• WRRFs don’t produce PFAS

• Precursors discharged to

WRRFs and degradation cause

• PFAS increase across biological

processes and

• PFAS increase effluent

concentrations

• PFAS found in effluents and

residuals in plants not receiving

industrial discharges

• Removal of PFAS is mainly due

to sorption to solids/residuals

• >6 carbon chains adsorb to solids

and removed in residuals Coggan et. al., Heliyon, 2019

Reasons for concern: land application (50% of residuals produced in the USA are land applied)

• PFAS are concentrated in residuals

• Common stabilization technologies, digestion, thermal

hydrolysis pretreatment, composting, drying do NOT remove

PFAS

• Highest concentrations found in residuals with direct industrial

input

• Land application “spreads” PFAS across the environment

• Detected in groundwater near land application of biosolids

• Found in residuals and soils (not impacted by industrial input)

after land application

Regularity outlook for PFAS

National Perspective

• In 2016, the EPA established a lifetime health advisory level of

70 parts per trillion (ppt) for individual or combined

concentrations of PFOA and PFOS in drinking water

• In February of 2019, the EPA released a PFAS Action Plan:

• Statement committing the agency toward developing a maximum

contaminant limit (MCL) for PFAS compounds for drinking water

• As of Feb 2020, EPA currently has not established national primary

drinking water regulations for PFOA and PFOS

• Biosolids is far behind:

• 503 Regulations don’t address emerging contaminants

• No approved EPA standard methods for measurement

No consistent regulatory approach

22 States have or are considering specific guidance or regulations related to PFAS in Drinking Water and/or Groundwater (Beyond EPA HAs)

State of Maine imposed a moratorium on

biosolids land application – March 22, 2019

• Testing of PFAS (PFOA, PFOS and PFBS) required for all

biosolids to be land applied

• Initial sampling and testing completed by May 7, 2019

Screening Concentrations for PFAS in Biosolids (Maine)

PFOA 0.0025 mg/kg

PFOS 0.0052 mg/kg

PFBS 1.9 mg/kg

Other New England and northeast states may consider restriction on biosolids land application

Solutions to address PFAS

challenges in biosolids

• Source control

• Volume/mass reduction

(does not destroy PFAS)

• Anaerobic digestion

• Thermal drying

• Incineration

• Advanced thermal

treatment (destroys PFAS)

• Drying/pyrolysis

• Drying/gasification

• Super critical water oxidation

• Hydrothermal liquefaction

Treating PFAS Chemical – Difficult to Treat!

• Terminal PFAAs are extremely

stable compounds

• Strong C-F bond, and carbon

shielding

• Thermal destruction require

temperatures > 1,000◦C

(~1,850◦F)

• Sewage sludge incinerators

(SSI) range between 1,450◦F

to 1,600◦F

• Chemical hydrolysis,

oxidation and reduction is

challenging due to the

fluorine effect!

Perfluorooctanoic Acid (PFOA)

Source reduction: Michigan DEQ success

Source reduction efforts have resulted in substantial drop in

PFOS concentrations being discharged at the WWTPs

https://www.michigan.gov/pfasresponse/0,9038,7-365-88059_91299---,00.html

Volume reduction (wet tons)

• Does not remove PFAS, but concentrate it

• Reduce amount to be disposed of if PFAS is an

issue (hauling and tipping fees)

• Anaerobic digestion: ~ 35%

• Thermal drying w/o digestion: ~78%

• Thermal drying w/digestion: ~86%

• Incineration: reduces mass to ~96%

Advanced thermal treatment

Pyrolysis/gasification systems reaching

commercial scale

Parameter Combustion Gasification Pyrolysis

Temperature (°F) 1,650-2,000 1,100-1,800 390-1,100

O2 Supplied> Stoichiometric

(Excess Air)

< Stoichiometric

(Limited Air)None

By-ProductsFlue Gas (CO2,

H2O) and Ash

Syngas (CO, H2)

and Ash

Pyrolysis Gas, Oils,

Tars and Char

Biodry/pyrolysis (Bioforcetech Corp)

Silicon Valley Clean Water, CA: 20 wtpd (since 2017)Courtesy: Bioforcetech Corporation

Dry biosolids

PFOA = 89.1 ng/g

PFOS = 26.3 ng/g

Biochar

Non Detect

ND

Thermal drying/gasification (Ecoremedy, LLC)

Morrisville, PA. 70 wtpd,

30 from Morrisville. In

commissioning, 4Q 2019

Courtesy: Ecoremedy,

LLC

No testing on

PFAS, but similar

results expected

as Bioforcetech

TBD

Thermal drying/gasification

(Aries Clean Energy)

• Linden Roselle Sewerage

Authority, NJ

• 430 wtpd : largest gasification

facility globally

• Groundbreaking Oct 17, 2019

• Expected to start ~ end 2021-

2022

Courtesy: Aries Clean Energy

Thermal drying/energy recovery system

(Kruger, Veolia)

No testing on

PFAS, but similar

results expected

as Bioforcetech

TBD

• Buffalo, MN: 20 wtpd, since 2009!

• Largest facility is 50 MGD Pomorzany WWTP in Poland, Europe

High temperature and

pressure treatment

Super Critical Waste Oxidation (374Water)

Duke University

Testing on 3 different

sludges shows non-detect

for PFOS and >99.8% PFAS

removal!

What to do?

• Stay updated and informed, things are changing fast

• Keep an eye on regulations, federal and local

• May want to test PFAS in residuals and effluent, but

be prepared to communicate

• If an issue:

• Start the planning process: diversify outlets

• May want to identify sources, best option if feasible

• Look to update management plans

• There are options out there that can mitigate

Thank you for the privilege of your time!

Mohammad Abu-Orf, PhD

mabuorf@hazenandsawyer.com

Cell: (856) 332-4030

Email if you like reference sources for any of

the facts mentioned in this presentation