Song, Donald

Mr. Song has twenty-five years of experience in civil/environmental engineering planning, design, and construction, focused on municipal and...

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About Song, Donald

Mr. Song has twenty-five years of experience in civil/environmental engineering planning, design, and construction, focused on municipal and industrial wastewater treatment plants, pump stations, and sewer systems. His most recent experience focuses on biosolids management.

Song, Donald

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Description: Commercial-Scale Pyrolysis Demonstration for PFAS Destruction, Syngas Recovery, and...

Commercial-Scale Pyrolysis Demonstration for PFAS Destruction, Syngas Recovery, and Biochar Production at the Synagro Drying Facility, City of Baltimore Back River WWTP

Abstract

Introduction A commercial-scale short-term demonstration of biosolids pyrolysis will be conducted at the Synagro Drying Facility at the City of Baltimore Back River WWTP i, Maryland. The pyrolysis process is designed and supplied by CHAR Technologies, of Toronto, CA. This project aligns with current environmental priorities, particularly the need for PFAS (per- and polyfluoroalkyl substances) mitigation in waste streams. The proposed objectives for this temporary pyrolysis demonstration unit will be: a. Verify the PFAS (synthetic, per- and polyfluoroalkyl substances) characteristics of the biosolids, the Syngas and the Biochar confirming the anticipated PFAS destruction in the pyrolysis process. b. Demonstrate the viability of converting biosolids pellets into valuable by-products: syngas for potential energy recovery and biochar for agricultural or environmental applications.. c. Verify the performance of the pyrolysis process on biosolids continuously for at least six months. d. Verify the resultant Syngas characteristics, and the opportunities and requirements for reusing within the dryer system or upgrading to renewable energy. e. Verify the resultant Biochar characteristics, and suitability for its use as a soil amendment. This six-month demonstration, scheduled from January 2025 to July 2025, aims to provide valuable insights into the operational sustainability and environmental benefits of pyrolysis in biosolids management. Process Description The Pyrolysis Demonstration Unit from Char Technologies uses a pyrolysis process to thermally decompose biosolids pellets in the absence of oxygen; the absence of oxygen prevents incineration from occurring. This pyrolysis process occurs within a rotary kiln chamber with an external burner that after starting-up with propane, burns the Syngas generated during the pyrolysis process. The Char Technologies pyrolysis demonstration unit will process over 8 tons per day of dried biosolids pellets and is projected to produce approximately 143 standard cubic feet per minute of high heating value Syngas containing dust, steam, hydrogen, carbon monoxide, carbon dioxide and methane. The Pyrolysis Demonstration Unit includes Syngas scrubbers that convert the Syngas for internal use in the pyrolysis unit. The excess Syngas that is not used in the pyrolysis process will be combusted, in a thermal oxidizer unit before being discharged at the Demonstration Unit Stack. An isometric of the facility being constructed is presented in Figure 1. A photo of the pyrolysis kiln is provided in Figure 2. A process flow diagram is presented in Figure 3. Sampling and Analytical Methodology Comprehensive sampling and analysis will be performed throughout the six-month demonstration period, with multiple data points collected from key stages of the process. These sampling points are presented in red in Figure 3. Parameters measured include: - Feedstock and Biochar: Elemental and proximate analysis, metals, nutrients, PFAS - Wastewater Analysis: BOD/COD, nutrients, pH - Raw pyrogas, clean syngas, and exhaust gas analysis: hydrocarbons and VOCs, particulates and metals, acid gas, NOx and Sox, PFAS US EPA Method 1633 will be followed to test for all PFAS compounds. Sampling will be conducted at regular intervals to capture variability in process performance. Quality assurance measures, including duplicate and blank samples, will be implemented for data validation. The test methods used for analysis are outlined in Table 1. Results and Discussion We expect to have interim analytical results available by April 2025 for presentation at RBC. Primary discussion will include fate and transformation of PFAS compounds, but will also discuss biochar characteristics, syngas quality and lessons learned in operating and maintaining the pyrolysis unit.

This paper was presented at the WEF Residuals & Biosolids and Innovations in Treatment Technology Joint Conference, May 6-9, 2025.

SpeakerSong, Donald

Presentation time

11:05:00

11:25:00

Session time

08:30:00

11:45:00

SessionSome Like It Hot - Diving into Incineration, Pyrolysis, and Gasification

Session number13

Session locationBaltimore Convention Center, Baltimore, Maryland, USA

TopicAdvanced Thermal Conversion, Biochar, Energy and Carbon Neutrality, Energy Conservation/Management, Energy recovery, Gasification, Greenhouse Gases, incineration, Intensification, Knowledge Transfer, PFAS, PFAS/Emerging Contaminants, pyrolysis, Regulatory Requirements, Thermal Processes

Author(s)

Song, Donald, Hasan, Mahmudul

Author(s)D. Song1, M. Hasan2

Author affiliation(s)Synagro, 1Baltimore City Department of Public Works, 2

SourceProceedings of the Water Environment Federation

Document typeConference Paper

PublisherWater Environment Federation

Print publication date May 2025

DOI10.2175/193864718825159780

Volume / Issue

Content sourceResiduals and Biosolids Conference

Word count23

PFAS Assessment of a Rotary Drum Dryer

Abstract

Introduction Biosolids drying is gaining interest as a volume reduction strategy in regions where biosolids management outlets are becoming increasingly constrained due to concerns over per- and polyfluoroalkyl substances (PFAS). However, no studies as of yet have been conducted on the fate of PFAS through a thermal dryer system. Synagro partnered with Brown and Caldwell to conduct a PFAS mass balance through a centrifuge dewatering and rotary drum dryer facility to evaluate the fate of PFAS through the system and assess potential points of PFAS transfer to the environment. Methodology A three-day PFAS sampling event was conducted the week of April 17, 2023. Process samples were taken at all inputs and outputs to the system with composite sampling over a four hour period each day. An overview of the dewatering and dryer system and PFAS sampling points is provided in Figure 1. The dewatering and dryer system was operated at roughly 2,300 dry pounds of total solids per hour for the duration of the test. Gas-phase sampling was conducted by a commercial stack sampler using an OTM-45 PFAS sampling train at the stack and prior to the regenerative thermal oxidizer emissions (RTO) control device. In addition, a fourth run was conducted on the final day of the week when the dryer was down, but the scrubber was kept in operation to evaluate if PFAS were released from cooling water in the scrubber. The PFAS data was received in October 2023 and are currently being evaluated using the data quality analysis plan developed under the Brown and Caldwell lead Water Research Foundation Tailored Collaboration program project (WRF 5111). Results and Discussion PFAS sampling data is under review and will be available for detailed comparison by 2024 WEF RBC. An initial review of preliminary findings is provided in Tables 1, 2 and 3 attached with the following findings below. - Individual PFAS were transferred from biosolids to the gas phase at a transfer rate of 50% to 92% through the dryer. - No widespread trend of PFAS accumulation in the scrubber water was observed. Individual PFAS showed a modest increase from 10% to 20%. - Eighteen individual PFAS were detected in the gas phase from the dryer, prior to treatment in the RTO, - HFPO-DA and trace amounts of three PFAS were detected in the emissions from the RTO. Field QC and prior study findings indicate HFPO-DA detection may be due to contamination/interference, more work is required to verify. - More work required to refine liquid sludge analysis and develop system-wide PFAS mass balance. Conclusions This study is the first to present data demonstrating PFAS transfer from solids phase to the process air during thermal drying of biosolids. The data suggests the thermal oxidizer is capable of providing effective PFAS destruction or removal from the gas phase. More analysis will be conducted to present PFAS partitioning through the dewatering system and evaluate the aggregate PFAS mass balance through the dewatering and drying process.

This paper was presented at the WEF Residuals and Biosolids Conference, June 18-21, 2024.

Presentation time

10:45:00

11:15:00

Session time

10:45:00

11:45:00

SessionDryer

Session number15

Session locationOklahoma City Convention Center, Oklahoma City, Oklahoma

TopicDrying, PFAS

Author(s)

Ross, John

Author(s)J. Ross1, A. Seidel1, L. Winchell1, M. Wells2, D. Song 3,

Author affiliation(s)Brown and Caldwell 1; Brown and Caldwell 1; Brown and Caldwell 1; EnviroChem Services 2; Synagro Technologies, Inc.3;

SourceProceedings of the Water Environment Federation

Document typeConference Paper

PublisherWater Environment Federation

Print publication date Jun 2024

DOI10.2175/193864718825159466

Volume / Issue

Content sourceResiduals and Biosolids Conference

Word count8

Base text size -

Song, Donald

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