Application of carbon-based amendments derived from plant residues or treated animal byproducts
Use this practice to accomplish one or more of the following purposes:
As PFAS continues to be banned from products across North America and around the world, many organizations are asking “what should be done with our legacy PFAS products and wastes”?
This is the next chapter in GHD’s ongoing review of waste management considerations for PFAS impacted media. Previous insights have discussed the regulatory, technical, and industry uncertainties regarding PFAS waste classification, treatment, storage and disposal facility (TSDF) acceptance, and waste treatment technologies.
PFAS are common in commercial products and are used widely throughout industry, however there are few demonstrated technologies available to destroy PFAS in waste materials. This is a growing concern for generators of PFAS waste, regulators, waste receivers, and the public.
CHAR has demonstrated PFAS elimination from three biosolids samples using its high temperature pyrolysis technology; PFAS compounds were eliminated from the solids at >99% after pyrolysis at 700 °C. Further studies will be conducted at CHAR’s larger-scale HTP demonstration unit at temperatures up to 800 °C to illustrate the value of a full-scale project in eliminating PFAS from waste feedstocks and creating value-ad
This paper provides an overview of pyrolysis and gasification technologies, characteristics of the char product, air emission considerations, and potential fate of PFAS and other pollutants through the systems. Results from a survey of viable suppliers illustrate differences in commercially available options. Additional research is required to validate performance over the long-term operation and confirm contaminant fate, which will help determine whether resurging interest in pyrolysis and gasification warrants widespread adoption.
Concentrations of per- and poly-fluoroalkyl substances (PFAS) present in wastewater treatment biosolids are a growing concern. Pyrolysis is a thermal treatment technology for biosolids that can produce a useful biochar product with reduced levels of PFAS and other contaminants. In August 2020, a limited-scope study investigated target PFAS removal of a commercial pyrolysis system processing biosolid with the analysis of 41 target PFAS compounds in biosolids and biochar performed by two independent laboratories. The concentrations of 21 detected target compounds in the input biosolids ranged between approximately 2 µg/kg and 85 µg/kg. No PFAS compounds were detected in the biochar…
An overview of regulations, treatment & challenges surrounding PFAS in biosolids.
In recent years, per- and polyfluoroalkyl substances (PFAS) have become a topic of public concern, particularly when discovered in drinking water supplies. PFAS are a family of more than 3,000 man-made chemicals that have been manufactured and used since the 1940s. This large class of fluorosurfactants have unique chemical and physical properties, which make them extremely persistent, as well as mobile, in the environment.
In Spring 2020, the EPA established the PFAS Innovative Treatment Team (PITT). The PITT was a multi-disciplinary research team that worked full-time for 6-months on applying their scientific efforts and expertise to a single problem: disposal and/or destruction of PFAS-contaminated media and waste. While the PITT formally concluded in Fall 2020, the research efforts initiated under the PITT continue.
As part of the PITT’s efforts, EPA researchers considered whether existing destruction technologies could be applied to PFAS-contaminated media and waste. This series of Research Briefs provides an overview of four technologies that were identified by the PITT as promising technologies for destroying PFAS and the research underway by the EPA’s Office of Research and Development to further explore these technologies. Because research is still needed to evaluate these technologies for PFAS destruction, this Research Brief should not be considered an endorsement or recommendation to use this technology to destroy PFAS.
This study focuses on the conversion of biosolids to biochar and its further use in adsorbing per- and polyfluoroalkyl substances (PFASs) from contaminated water. In particular, this study aims to (a) investigate the performance of a semi-pilot fluidised bed pyrolysis unit in converting biosolids into biochar, (b) examine the ability of the pyrolysis–combustion integrated process to destruct PFASs present in biosolids and (c) study the application of biosolids derived biochar for removing PFASs from contaminated water.
Incineration (thermal oxidation) is one of the three options for managing wastewater solids and other organic residuals. Water resource recovery facilities (WRRFs) in southern New England and some cities in Quebec rely on incineration for disposal of wastewater solids….Pyrolysis and gasification are other forms of thermal conversion where solids are burned with little or no oxygen. In recent years, considerable research and development has advanced the possibility of cost-effective gasification of wastewater solids (sewage sludge). As of January 2020, a WRRF in Tennessee has several years of successful experience in gasifying all their wastewater solids in a mixture dominated by wood waste. One or two gasification or pyrolysis systems for just biosolids have been starting up recently.
The overall objective of the Plan is the formulation, adoption, and implementation of a program to meet the County’s solid waste management requirements for at least a ten year period. The Plan is designed to respond to state-established goals for solid waste management tailored to the needs of the County. A major goal in formulating the Plan was the adoption of cost effective solutions for solid waste management using reliable, proven technologies that are environmentally sound, while allowing flexibility for future technological changes.
Pyrolysis is a thermochemical decomposition process that can be used to generate pyrolysis gas (py-gas), bio-oil, and biochar as well as energy from biomass. Biomass from agricultural waste and other plant-based materials has been the predominant pyrolysis research focus. Water resource recovery facilities also produce biomass, referred to as wastewater solids, that could be a viable pyrolysis feedstock. Water resource recovery facilities are central collection and production sites for wastewater solids. While the utilization of biochar from a variety of biomass types has been extensively studied, the utilization of wastewater biochars has not been reviewed in detail. This review compares the characteristics of wastewater biochars to more conventional biochars and reviews specific applications of wastewater biochar…
This report is an update to the Division of Materials Management 2011 edition of “Biosolids Management in New York State.” It provides the most current information available concerning biosolids management practices in New York State. Biosolids was previously called sewage sludge. 6 NYCRR Part 360 regulations define biosolids as: the accumulated semi-solids or solids resulting from treatment of wastewaters from publicly or privately owned or operated sewage treatment plants. Biosolids does not include grit or screenings, or ash generated from the incineration of biosolids.
The need to dispose of human-generated waste streams is growing in line with the expansion of urban population centers. This is particularly true for the byproducts of wastewater treatment. According to the US EPA, there are over 7 million dry tons of biosolids (stabilized sewage sludge) produced per year in the US. In 2004, 49% of biosolids were beneficially used—primarily for agricultural land application—with most of the remainder either landfilled or incinerated (NEBRA 2007). Because biosolids have a high nutrient content, land application as a fertilizer substitute is an appealing management strategy. Yet concerns around nutrient run-off and contamination of waterways have led to tighter environmental controls making land application increasingly tenuous. Promising alternate management strategies exist but are in early stages of development. Pyrolysis and gasification—a continuum of thermochemical conversion processes—have been shown to minimize harmful air emissions, while producing energy and biochar, a carbon-rich solid material with beneficial soil health properties. This white paper briefly explores experiences of pyrolysis and gasification of biosolids as a waste management strategy, and research into biosolids biochar (BSB) as a soil amendment.
Purpose Biochars are a by-product of the biofuel processing of lignocellulosic and manure feedstocks. Because biochars contain an assemblage of organic and inorganic compounds, they can be used as an amendment for C sequestration and soil quality improvement. However, not all biochars are viable soil amendments; this is because their physical and chemical properties vary due to feedstock elemental composition, biofuel processing, and particle size differences. Biochar could deliver a more effective service as a soil amendment if its chemistry was designed ex ante with characteristics that target specific soil quality issues. In this study, we demonstrate how biochars can be designed with relevant properties as successful soil amendments through feedstock selection, pyrolysis conditions, and particle size choices.
Background Biochar’s role as a carbon sequestration agent, while simultaneously providing soil fertility improvements when used as an amendment, has been receiving significant attention across all sectors of society, ranging from academia, industry, government, as well as the general public. This has lead to some exaggeration and possible confusion regarding biochar’s actual effectiveness as a soil amendment. One sparsely explored area where biochar appears to have real potential for significant impact is the soil nitrogen cycle. Scope Taghizadeh-Toosi et al. (this issue) examined ammonia sorption on biochar as a means of providing a nitrogen-enriched soil amendment. The longevity of the trapped ammonia was particularly remarkable; it was sequestered in a stable form for at least 12 days under laboratory air flow. Furthermore, the authors observed increased 15N uptake by plants grown in soil amended with the 15N-enriched biochar, indicating that the 15N was not irreversibly bound, but, was plant-available.