A Case Study Comparing Costs of Gas-to-Energy Landfill Gas Collection Systems to NSPS-Compliant Landfill Gas Collection Systems
The New Source Performance Standards (NSPS) and Emissions Guidelines (EG) for municipal solid waste (MSW) landfills, promulgated on March 12, 1996, will require landfill gas (LFG) emissions control at many landfills nationwide. NSPS and EG design, operational, compliance, monitoring, reporting, and recordkeeping requirements are extensive, particularly when compared to LFG collection and control systems designed under migration control or gas-to-energy criteria. Potential costs associated with NSPS/EG compliance can be substantial as well.
This case study considers three currently-operating landfills that have undergone Tier 1 analyses, and are subject to the NSPS based on their design capacities and estimated non-methane organic compound (NMOC) emissions under Tier 1. Each landfill has the option to proceed to Tier 2 analyses, which involves obtaining site-specific NMOC concentrations and performing emissions estimates using these site-specific values, or installing a NSPS-compliant LFG collection and control system. Although each subject landfill has, or will soon have, a gas-to-energy system, there is a significant difference between these systems and NSPS-compliant LFG systems. This case study highlights the potential additional annual costs associated with the implementation of NSPS- compliant LFG system designs and operational practices at each of the three subject landfills.
A summary of the Tier 1 analyses performed at each subject landfill is presented below:
All three of the landfills exceed the NMOC emissions threshold of 50 Mg/yr, and without proceeding to Tier 2 testing, will be required to install and operate LFG emission control systems under the NSPS. Under the current scenario, the LFG emission control systems at these landfills would have to be operated for 70 to 89 years.
Estimated additional annual costs, comparing costs associated with each landfill’s gas-to- energy system design to NSPS-compliant LFG collection and control system designs, are $80,000 for Landfill A, $39,000 for Landfill B, and $34,000 for Landfill C.
These estimated annual costs include additional design costs, additional construction costs, landfill surface monitoring and cover assessment, additional wellhead monitoring, several NSPS reporting requirements, and the system replacement cost associated with the additional LFG collection system components. These estimated annual costs may well be on the low side as they do not include additional system operations and maintenance costs associated with the additional wells, controls, etc. that would be implemented to comply with the NSPS requirements, nor any costs associated with remediation or fines should a site become non-compliant.
Target average NMOC concentrations, based on the Tier 1 estimates, that would result in exemption from further NSPS requirements (with the exception of calculating NMOC emissions annually or every 5 years, and assuming no modifications have been implemented that would increase NMOC emissions), range from 132 parts per million by volume (ppmv) to 412 ppmv.
Recently completed Tier 2 services for a national client at seven landfills have resulted in average, site-specific NMOC concentrations ranging from 104 ppmv to 593 ppmv. The average NMOC concentration from these seven landfills is 293 ppmv. If this average NMOC concentration is representative, and Landfills A through C above are “average”, Landfills B and C would escape NSPS/EG emission control requirements completely. Landfill A is not likely to fully escape NSPS requirements, but the compliance period would be decreased.
As highlighted above, estimated additional costs associated with NSPS compliance for the three landfills that currently, or will, employ gas-to-energy systems ranges from $34,000 to $80,000 per year. As is evident, these costs can be quite substantial, particularly when compared to the estimated costs of performing Tier 2 services at the subject landfills, which range from $3,000 to $16,000. Furthermore, these costs are likely not all-inclusive as they do not include operations and maintenance costs associated with the additional NSPS gas system components, nor do they include the costs that may be incurred if compliance with NSPS requirements becomes a problem.
Technical Bulletins are prepared by SCS Engineers to alert clients to potential issues that can affect their businesses. For more information on how SCS Engineers can assist you with NSPS-related services, call Jim Walsh at (513) 421-5353.