Landfill gas (LFG) fired leachate evaporation is a novel technology attracting the attention of landfill owners because it can offer an operational win-win. The technology uses a readily available resource at landfills, LFG, to remove liquid from landfill leachate via evaporation, thus abating this environmental liability onsite, often at a lower cost than conventional leachate treatment options. In addition, combusting LFG to evaporate leachate converts methane, a highly potent greenhouse gas, to carbon dioxide, which reduces overall greenhouse gas emissions.
Landfill owners seeking to implement LFG-fired leachate evaporation must undergo the necessary air permitting and follow applicable emissions regulations. In this regard, air permitting and regulatory requirements for the combustion-related component of LFG-fired evaporation are similar to those applicable to conventional LFG flares. However, in addition, there are permitting considerations for evaporation-related emissions too. As this is uncharted territory for regulators, it is important to work closely with your agency to ensure you or your consultant is properly addressing these technology-specific requirements.
Read Landfill Leachate, Just ‘Evaporate’ the Problem …or Permitting Issues for Using Landfill Gas to Reduce Leachate Volume by David Greene, PE, SCS Engineers. Published by em, the Magazine for Environmental Managers, A&WMA, issue June 2019.
About the Author: David Greene is a project manager at SCS Engineers with a multiplicity of solid waste related environmental engineering experience, including air permitting, landfill gas, financial analysis, due diligence efforts, regulatory development and analysis, compliance planning, greenhouse gas monitoring, emission inventory including emission factor development, SPCC and SWPPP development. Mr. Greene also consults internationally in Southeast Asia focusing on the areas of planning and implementing training and evaluating the feasibility of LFG energy and renewable energy projects at solid waste disposal sites. He is a Professional Engineer in North and South Carolina.
Managing landfill leachate and wastewater treatment is increasingly challenging and costly for landfill owners and operators. In some cases, publicly owned treatment works (POTWs) are required to impose limitations on liquids received at their facilities, resulting in increased charges, or the POTW could refuse to permit or process the leachate wastewater altogether. These developments are due in part to more stringent discharge requirements and the shift to newer disinfection technology that has limited the POTW’s ability to accept higher strength wastewaters. As a result, many facilities and landfill operators are facing higher costs and fewer options for disposal.
Another factor that affects landfills is the fact that the composition of leachate in landfills differs depending on the degree of leachate stabilization and a seasonal increase in quantity as well as on the influence of more frequent and higher intensity storms due to changing climatic conditions.
The single most influential factor on the volume of landfill leachate is precipitation. The most influential factor regarding leachate quality is that leachate typically contains high concentrations of organic compounds, ammonia and other forms of nitrogen, metals, and dissolved solids. Ammonia concentrations in the leachate, from many landfills, are increasing every year as shown in the graph below. Compounding the high strength concentrations of constituents found in landfill leachate are the emerging contaminants of concern including per and poly-fluoroalkyl substances (PFAS) that are now a significant concern with the U.S. EPA and many state environmental agencies.
Top 5 Questions and Answers When Selecting the Right Leachate Treatment Option for Your Landfill
Without considering leachate recirculation and a host of other factors, this blog provides answers to frequently asked questions regarding the analysis of treatment options for landfill leachate.
ONE: What is an example of a typical work scope of a leachate treatment options analysis?
TWO: What information is necessary to begin assessing the on-site treatment options of leachate?
THREE: What constituents should I expect to have analyzed to assess the options for leachate wastewater treatment?
FOUR: What are some of the issues taken into account regarding treating ammonia-N in leachate/wastewater?
FIVE: What are some examples of the options for how to effectively treat ammonia-N in leachate on-site?
We hope you find our SCS Advice from the Field blogs helpful. For more information, we recommend these articles and resources:
In February of this year, New Hanover County, North Carolina volunteered to be the first landfill to participate in North Carolina Department of Environmental Quality’s (NCDEQ) new landfill leachate sampling protocol. The County volunteered for the study to test their new leachate treatment system designed by SCS Engineers, PC, (SCS).
The NCDEQ’s sampling results released this month show the landfill’s reverse osmosis (RO) system is effectively filtering out Per- and Polyfluorinated substances (PFAS) before discharging treated water into the Northeast Cape Fear River. The lab certified results are available on the NCDEQ website.
After learning about landfill leachate as a possible source of PFAS, New Hanover County’s Board of Commissioners and landfill management looked at the NCDEQ sampling protocol as an opportunity to be proactive in evaluating the existence of PFAS in leachate and in the treatability for removal of the PFAS. The outcome would also be valuable information for other landfill owner/operators in North Carolina and the US.
PFAS are compounds formerly used by manufacturers and still exist in many commercial household products. For landfills, these substances can leach out of the waste mass and into the landfill leachate. PFAS concentrations in the parts per trillion are thought to be problematic for human health and the environment. The testing processes allow for detection at these low concentrations.
The County’s reverse osmosis (RO) treatment system designed by SCS treats the leachate and recirculates the RO reject water back into the landfill. While NCDEQ’s results show PFA compounds in the raw leachate, no detectable levels of the thirty-three PFAS tested for were found in the treated leachate. This confirmed that the system works effectively to protect human health and the environment. New Hanover County continues working with NCDEQ’s landfill sampling plan.
“The technology is available to provide treatment of the leachate and other wastewaters to protect water resources,” stated Robert Gardner, Senior Vice President at SCS. “We’re supporting New Hanover County and other landfill operations across the nation to find the appropriate treatment system for their landfill.”
To learn more about treatment options and best management practices contact SCS Engineers or visit us at Waste Expo for this 90-minute session on managing landfill leachate.
The partnership expands the availability of complex wastewater treatments for landfill leachate and industrial effluents.
SCS Engineers (SCS), and WEHRLE Umwelt GmbH (WEHRLE), today announced the availability of integrated services between the two firms to streamline the design-build of leachate treatment facilities in the United States.
SCS’s depth of experience with the engineering, construction, operations, monitoring, and management of U.S. landfills, as well as industrial wastewater treatment systems, and WEHRLE’s depth of experience designing landfill leachate and industrial wastewater treatment plants around the world creates opportunities for both firms to bring more sustainable solutions to their clients.
In the last several years, U.S. landfill owners and operators are increasingly under pressure to meet more strident water quality demands while keeping their rates low. Selecting the most effective method of treatment at a sustainable cost requires advanced landfill engineering expertise, waste management expertise, and excellent knowledge of which proven wastewater treatment technologies will perform best depending on the type and location of the landfill, the leachate composition, and the volume of leachate generated, among other considerations.
“The SCS Engineers and WEHRLE Umwelt teaming agreement brings a world of talent and technologies to our U.S. clients, improving our support to the private and municipal solid waste industries, with the responsibility of generating cleaner wastewater,” said Samuel Cooke, an SCS vice president, and the firm’s national liquids management director.
“As global technology leader for the treatment of complex wastewaters, WEHRLE has built up an excellent reputation in over 40 countries worldwide with more than 250 installations. Detailed customized consultation upfront the projects is important to us – especially since we are dealing with multiple technologies that require explanation and competence. SCS with its technological knowledge and background of U.S. waste industries is for us the perfect match to bring best long-term economical solutions to demanding customers.” said Frank Natau, WEHRLE’s Senior Expert for treatment of leachate and waste-derived effluents.