Cement Kiln and Waste to Energy Incineration of Spent MediaCraig Patterson1, Seyed A. Dastgheib2

1U.S. Environmental Protection Agency, Center for Environmental Solutions and Emergency Response

2Illinois State Geological Survey,University of Illinois at Urbana-Champaign

THERMAL TREATMENT OF PFASSTATE OF THE SCIENCE WORKSHOP

Sponsored by U.S. Environmental Protection Agency's (EPA) Office of Research and Development (ORD) and Department of Defense SERDP/ESTCP Programs

Cincinnati, Ohio

February 25, 2020

Project Focus: Incineration of PFAS-laden Ion Exchange Resins with a Lime Sludge Additive

PFAS removal from water by ion exchange resins Management of spent PFAS-laden resins

Rotary kilns (e.g., cement kilns) for solid waste and waste to energy incineration

Incineration of PFAS-laden resin in rotary kilns

HF capture after incineration is needed

Calcium additive can capture fluorine

Lime sludge reuse as a low cost additive for fluorine capture during incineration

Source: Bernard, B., DiPasquale, M.., From Pilot to Full-Scale: A Case Study for the Treatment of PFC’s with Ion Exchange, AWWA ACE, Denver, CO 2019.

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PFAS Removal from Water Ion exchange and activated

carbon adsorption are identified as the most mature and feasible technologies for PFAS removal

Anion exchange resins can be used as a stand-alone treatment or in combination with GAC

Anion exchange resins have shown excellent performance for PFAS removal at relatively low EBCTs when compared to GACSources: 1) I. Ross et al. A review of merging technologies for remediation of PFASs. Remediation 2018, 28, 101-126. 2) Purolitepresentation and case study. F. Boodoo et al. 3

Management of Spent PFAS-Laden Resin

Options for Management of the Spent Resins Regeneration with brine solutions: Not recommended due to the

fate and liability of concentrated PFAS residuals in wastewater Offsite incineration of single use anion exchange resins Waste-to-Energy Incinerators Cement Kiln Incinerators

Source: journal-news.net

Source: Paul Chaplin, The Patriot-News/file

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Case Studies from Resin Manufacturers (Kuraray, Formerly Calgon Carbon)

Spent resin in North Carolina (~70 cubic feet) was sent to a waste-to-energy incinerator in Virginia.

Spent resin in Colorado (~425 cubic feet) was sent to a waste-to-energy incinerator in California.

New resin water treatment installations are planned in Colorado (14.5 MGD) and New Jersey (3 MGD) in 2020. This equates to ~ 2,700 cubic feet and ~540 cubic feet of spent resin that will be incinerated at the end of their service lives at least two years from now.

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Case Studies from Resin Manufacturers(Purolite)

Select cement kilns have incinerated waste resins from Purolite’s production plant in Philadelphia.

Not all cement kilns are set up to dry feed resins or similar media.

Each pound of resin will generate about 12,000 BTUs of energy making resin a useful fuel supplement for the cement kilns.

The temperature at which the cement kilns operate (1400°C-2000°C) allows for full destruction of PFAS compounds.

The recoverable energy is also helpful from a sustainability standpoint.

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Rotary Kiln Incinerators

Rotary kilns are used for various manufacturing, calcination, thermal processing, and incineration applications including GAC reactivation Cement production Waste incineration

Rotary kilns can be operated in co-current or counter-current modes

Source: Gossman. The reuse of petroleum and petrochemical waste in cement kilns. Environmental Progress 1992, 11, (1), 1-6.

Counter-current

Co-current

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Rotary Kiln Incinerators

Rotary kilns can be operated under different operating conditions Gas temperature up to ~2,000 ºC Gas residence times of up to 10 sec Solid residence time of up to 30 min

8Source: D. Gossman. The reuse of petroleum and petrochemical waste in cement kilns. Environmental Progress 1992, 11(1), 1-6.

Rotary Kilns for Municipal or Industrial Waste Incineration

Solid or liquid waste is injected co-currently with fuel on one side Organic waste combustion provides additional heat, lowering the fuel

consumption and energy input A second burner burns the residual organic contaminants in the flue gas Heat is recovered and converted to steam/power Filtration and scrubbing systems clean the flue gas before sending it to the stack

Source: Z. Jegla et al. Secondary combustion chamber with inbuilt heat transfer area – Thermal model for improved waste-to-energy systems modelling, Chemical Engineering Transactions 2010, 21, 859-864.9

Incineration of PFAS-laden Media Ion exchange resins saturated with PFAS compounds can be incinerated in

rotary kilns with gas temperatures of up to ~2,000 ºC PFAS compounds decompose at < 700 ºC and generate different free radicals

and unstable fragments of original PFAS molecules, and finally form stable fluorocarbon compounds such as CF4 and C2F6

Higher temperatures (1,000-1,600 ºC) may be needed to break very stable C-F bonds without a catalyst (e.g., calcium), complete oxidation reactions, and finally form HF that requires post-combustion treatment with a caustic medium such as Ca(OH)2

A conventional cement kiln with post-combustion treatment unit can effectively incinerate PFAS-laden media and capture HF from combustion flue gas

However, there are several research data gaps such as information about optimized temperature and residence time requirements for destruction of various PFAS compoundsSources: Krusic et al. Gas-phase NMR studies of the thermolysis of perfluorooctanoic acid. J. Fluorine Chem. 2005, 126, (11-12), 1510-1516. Watanabe et al. Residual organic fluorinated compounds from thermal treatment of PFOA, PFHxA and PFOS adsorbed onto granular activated carbon (GAC). J. Mater. Cycles Waste Mgt. 2016, 18, 625-630. Wang et al. Effectiveness and Mechanisms of Defluorination of Perfluorinated Alkyl Substances by Calcium Compounds during Waste Thermal Treatment. Environ. Sci. Technol. 2015, 49, (9), 5672-80. Qin et al. Highly Efficient Decomposition of CF4 Gases by Combustion. Conference on Environmental Pollution and Public Health 2010, 126-130. Gossman. The reuse of petroleum and petrochemical waste in cement kilns. Environmental Progress 1992, 11, (1), 1-6. 10

Lime as a Low Cost Additive for Fluorine Capture during PFAS Incineration

Several researchers have reported effective PFAS destruction and capture by using a mixture of PFAS and excess amounts of CaO, CaCO3, or Ca(OH)2

Incineration of a mixture of PFAS-laden media and a calcium sorbent can lower the total energy requirement (by lowering the incineration temperature)

Different free radicals and unstable fragments generated during the decomposition stage of PFAS compounds (at < 700 ºC) react with a calcium additive to form stable calcium fluoride mineral before forming stable organic fluorocarbon compounds (e.g., CF4) that require very high temperature (up to 1,600 ºC) for decomposition

Sources: Wang et al. Effectiveness and Mechanisms of Defluorination of Perfluorinated Alkyl Substances by Calcium Compounds during Waste Thermal Treatment. Environ. Sci. Technol. 2015, 49, (9), 5672-80. Wang et al. Influence of calcium hydroxide on the fate of perfluorooctanesulfonate under thermal conditions. J. Hazard. Mater. 2011, 192, (3), 1067-71. Wang et al. Mineralization behavior of fluorine in perfluorooctanesulfonate (PFOS) during thermal treatment of lime-conditioned sludge. Environ. Sci. Technol. 2013, 47, (6), 2621-7.

Waste 2: Water-softening lime sludge or lime

Water Treatment Plant

Spent Anion ExchangeIncinerator and Energy Recovery System

Waste 1: Spent PFAS-Laden Anion Exchange Resin

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Lime as a Low Cost Additive for Fluorine Capture during PFAS Incineration

Similar to conventional incineration of PFAS-laden materials, there are major research gaps in understanding the temperature and residence time requirements for incineration of PFAS-laden media and calcium additive mixtures

Utilization of low-cost calcium materials such as lime softening sludge as a replace-ment for CaCO3, CaO, or Ca(OH)2 in PFAS incineration has not been explored

Source: Purolite presentation and case study. F. Boodoo et al. https://ebcne.org/wp-content/uploads/2018/06/Presentations-EBC-Connecticut-Program-Contaminants-of-Emerging-Concern-Update-on-PFAS.pdf 12

Water Treatment Plant Lime Softening Sludge

Lime sludge is precipitated calcium carbonate produced during the lime softening process at water treatment plants

Lime sludge is a highly reactive form of calcium carbonate with a BET surface area of up to 12 m2/g, about one order of magnitude higher than the surface area of limestone or reagent CaCO3

In the US, ~ 3.2 million tons of lime sludge is generated per year with an estimated disposal cost of ~$90 million

Generated lime sludge is currently managed by disposal in landfills that may add up to 10% to the overall cost of the water treatment

Beneficial reuse of lime sludge can reduce disposal costs and generate revenue

Source: Utilization of water utility lime sludge for flue gas desulfurization in coal-fired power plants: Part 1. Supply-demand evaluation and life cycle assessment. H. Salih, C. Patterson, J. Li, J. Mock, S.A. Dastgheib. Energy & Fuels 2018, 32, 6627-6633. 13

EPA Disclaimer

The U.S. Environmental Protection Agency, through its Office of Research and Development, funded and managed, or partially funded or collaborated in, the

research describe herein. It has been subjected to the Agency’s peer and administrative review and has been approved for external release. Any opinions expressed in this presentation are those of the author(s) and do not necessarily

reflect the views of the Agency, therefore, no official endorsement should be inferred. Any mention of trade names or commercial products does not

constitute endorsement or recommendation for use.

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Office of Research and DevelopmentNational Risk Management Research Laboratory – Water Supply and Water Resources Division

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Questions?Craig Patterson at EPA, 513-487-2805, patterson.craig@epa.govSeyed A. Dastgheib at UIUC, 217-265-6274, seyed@Illinois.edu

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