Figure 9: Maryland’s waste sector GHG emissions trends, historical and projected, from 2006 to 2050 based on current and new policies 

The waste sector accounted for 10% of Maryland’s GHG emissions in 2020. This sector includes emissions from landfills, wastewater management, waste combustion, and residential open burning. Maryland can reduce GHG emissions in the waste sector by implementing waste reduction, reuse, and recycling strategies to fundamentally shift the way businesses and residents currently produce, use, and handle products and materials at the end-of-life cycle. Additional emissions reductions can be achieved by minimizing emissions at solid waste management facilities and wastewater treatment plants, and through the evaluation of the beneficial use of methane captured from landfills.

Landfill Methane Regulations (current)

A municipal solid waste (MSW) landfill is a parcel of land that accepts garbage or non-hazardous residential and commercial wastes. As the waste decomposes it produces landfill gas that is composed of several GHGs. The gases produced at landfills include methane - a short-lived but significant GHG with a GWP more than 80 times that of CO2. Landfills are the second largest industrial source of methane emissions in the United States. MDE has concurred with recent research findings which show that MSW landfills in Maryland are the single largest source of the state’s methane emissions and these emissions are approximately four times higher than previously thought.

In 2021, MDE proposed to implement regulatory requirements for owners and operators of new and existing MSW landfills, which include surface emission monitoring, detecting, and repairing landfill gas leaks, recordkeeping and reporting requirements, and installing and operating emission control systems based upon regulatory applicability.

Additional climate change abatement strategies include MDE forming partnerships with state agencies, local jurisdictions, environmental advocacy groups, and the private and public sectors to limit the amount of methane-generating waste that enters landfills through waste diversion. Waste diversion combines both recycling and source reduction activities. These strategies have been effective in reducing methane emissions from landfills and helping to meet Maryland’s climate goals.

MDE has long fostered the use of methane captured from landfills as fuel to generate electricity. Sometimes this is tied to the installation of solar farms at closed landfills, which MDE also supports. The MDE Air and Radiation Administration recently promulgated regulations imposing more strict monitoring and remedial requirements for methane emissions at landfills that will both dramatically reduce these emissions and encourage methane reuse.

Emissions from MSW landfills are characterized and calculated using accepted industry standards along with some measured and reported figures. The methane and CO2 generation rates are modeled using EPA’s Landfill Gas Emissions Model tool “Land GEM”. Additional figures come from the landfill facility reporting to EPA Part 98 GHG reporting and from annual MDE emission certification Reports.

Landfill gas is typically composed of methane, CO2, and other volatile organic compounds. Landfill gas and potential methane production are unique to each landfill. Temperature, waste components, waste cell size, compaction, liners and covers, rainfall intensity, and more are all factors in methane production and the design criteria to capture and reduce methane. Scientists report landfill generation curves with four phases. Methane generation begins as soon as trash is placed but maximizes between 5–20 years, then tapers off over the next decade or two.

MDE used the 2020 GHG Inventory to calculate a range of anticipated emission reductions that will come from minimizing surface leaks and capturing and converting methane to CO2. By applying a range of emission reduction factors to the list of affected sources, MDE estimates a 25-50% reduction in CO2 (CO2 and CO2 equivalent – using a GWP of 28) emissions from the affected landfills subject to MDE’s latest landfill regulations when fully implemented. 

The new requirements and standards for MSW landfills are either equivalent or more stringent than current federal requirements for MSW landfills, such as component leak testing, surface emission monitoring, gas collection and control systems (GCCS), and recordkeeping and reporting schedules. Furthermore, the new requirements and standards for MSW landfills are more stringent than those under Title 26, Subtitle 11, Chapter 19.20 of the Code of Maryland Regulations (COMAR 26.11.19.20) - Control of Landfill Gas Emissions from Municipal Solid Waste Landfills. The new regulations result in decreased methane emissions from MSW landfills in the state and MDE will continue to evaluate the emission reductions and benefits.

Food Residuals Diversion Law (current)

In 2021, the Maryland General Assembly passed House Bill 264/Senate Bill 483 entitled Solid Waste Management – Organics Recycling and Waste Diversion – Food Residuals, which requires "persons" that generate at least two tons of food residuals per week as of November 1, 2023, and one ton of food residuals per week as of November 1, 2024 to separate the food residuals from other solid waste and ensure that the food residuals are diverted from final disposal at landfill or incineration. MDE issued supporting regulations under COMAR 26.04.13 Food Residuals - Organics Recycling and Waste Diversion. The law and regulations follow the traditional food recovery hierarchy: prevent waste before it occurs, provide food for people, animal feed, and/or recycle. The focus is to reduce the amount of GHG emitted from landfills, provide edible food to people at a free or low cost, and improve Maryland's soil and water quality. The law currently does not identify a private residence or restaurant as a "person". MDE will evaluate the benefit of potential expansion of the "persons" definition to include more entities, such as all businesses that generate lower quantities of food residuals than in the current law, and determine if the applicable organics recycler range is a hindrance for diversion.

Sustainable Materials Management (current)

Sustainable materials management (SMM) includes using and managing materials as efficiently and sustainably as possible throughout their entire life cycles. Through source reduction, reuse, and recycling, Maryland can extend existing disposal capacity, reduce the need to construct new or expanded solid waste disposal facilities, conserve natural resources including water and energy, increase the innovative reuse and beneficial use of dredged material, and support a productive economy through the recovery of valuable resources.

Studies have shown that diverting material from disposal to reuse, recycling, and composting results in more jobs and a more sustainable economy. New and emerging materials management technologies provide opportunities to recover more energy, nutrients, and other resources from waste while fostering new businesses in Maryland.

The potential applications for innovative reuse or beneficial use of dredged materials are vast, including transportation, climate change adaptation, publicly-funded site remediation projects, habitat creation, wetland restoration, shoreline stabilization, landscaping, road construction, landfill cover, land reclamation and the manufacture of marketable products such as concrete, bricks, blocks, aggregate, and topsoil. Source reduction, reuse, and recycling reduce GHG emissions relative to disposal and can assist the state in meeting its GHG reduction goals for 2030 and beyond.

In 2021, Maryland’s recycling activities reduced the amount of CO2 equivalent by over 8.3 million tons, on a lifecycle accounting basis. That was with recycling rates below the 2035 goals outlined in the SMM Executive Order 01.01.2017.13.

Table 2. Sustainable Materials Management Targets and Status.

*GHG emissions reductions are calculated using the EPA Waste Reduction Model (WARM), a lifecycle accounting tool that factors in emissions from the entire lifecycle: raw materials extraction, manufacturing or processing, transportation, use, and end‐of‐life management.

While MDE is responsible for implementing the requirements of Executive Order 01.01.2017.13, Maryland Counties perform all recommended recycling and source reduction activities. The Executive Order defines the SMM policy for the state. MDE provided Waste Reduction and Resource Recovery Plan Goals and Metrics Recommendations in April of 2019. The voluntary statewide metrics and goal recommendations support the Maryland Recycling Act by defining specific material recycling goals for each county.

Through the combined efforts of Maryland’s local governments, businesses, and residents, the state has made significant progress in recycling over the past 23 years, more than doubling the recycling rate from 19% in 1992 to 43% in 2015. A recent plateau in the recycling rate and the evolving composition of the waste stream suggest that an updated and more holistic materials management approach is needed to ensure continuous improvement.

Maryland has undertaken key initiatives to strengthen recycling programs, including the establishment of clearer permitting pathways for composting facilities; adoption of more aggressive county and state government recycling rates; coordination of a statewide waste sort study; enhancement of electronics recycling education and outreach; and provision of recycling opportunities at apartments, condominiums, and special events. MDE recognizes the value of partnerships in achieving statewide recycling and source reduction goals, including cooperative efforts of waste generators, state agencies, local governments, the waste industry, the recycling industry, environmental groups, boards of education, and other interested parties.

MDE continues to consult with relevant stakeholders to assess and improve the state’s methodology for tracking waste generation, recycling, and source reduction in Maryland. MDE has pursued numerous partnerships to work towards the recycling and source reduction goals established in the SMM Executive Order 01.01.2017.13 and the recommendations made in April 2019.

As MDE works to develop markets for recyclables in Maryland, key partnerships with other Maryland agencies include:

• MDE and the Maryland Department of Commerce work in cooperation with local and economic development agencies to identify local markets for recycled materials and provide siting, permitting, and technical assistance for innovative recycling and resource recovery businesses.

• MDE and the Maryland Department of Agriculture (MDA) work to support research and demonstration of innovative technologies for recovering nutrient resources in a manner protective of water quality.

• MDE and MEA work to research and promote methods of recovering energy from waste, including anaerobic digestion.

• MDE and the Maryland Port Administration work to develop technical screening criteria and guidance to support innovative reuse and beneficial uses of dredged material removed from the Port of Baltimore’s shipping channels and other state-funded dredging projects. State agencies shall consider innovative reuse and beneficial uses of dredged material when economically feasible and in conformance with all appropriate environmental standards.

State Incentives for Waste Sector Decarbonization (current, modified)

The state supports waste diversion programs in several ways. One example includes the School Waste Reduction and Composting Program, which awards grants to schools to reduce food waste and establish composting programs. Additionally, the Maryland Water Infrastructure Financing Administration (MWIFA) provides low-interest rate loans under the two Revolving Loan Fund Programs and grants under the State Bay Restoration Fund Program for water quality point source projects and non-point source pollution control projects, drinking water system upgrade projects, and septic system upgrade projects using best available technology to achieve nitrogen removal on onsite sewage disposal systems. Between FY21 and FY23, the Bay Restoration Fund provided $45 million in revenues for 2,567 Best Available Technology (BAT) installations and 497 connections to public sewer. 

The Energy-Water Infrastructure Program (EWIP) was established during the 2016 legislative session through MCCBL 2016, funded through a PSC order that provided $40 million in funding for programs that reduce GHG emissions and conserve energy. Between FY17 and FY20, MDE budgeted and awarded $40 million in grants to water and wastewater systems throughout the state of Maryland for alternative energy generation and upgrading to more energy-efficient equipment. EWIP provided funds for the planning, design, and construction of projects that benefited both the environmental and economic interests of the state. This dual-pronged program provided reliable and resilient infrastructure for communities throughout Maryland by implementing energy efficiencies, and reducing emissions and operating costs at water and wastewater treatment facilities. While EWIP was discontinued due to the lack of ongoing funding, it helped in planting the seeds and jump-starting the concept of energy-water infrastructure throughout the state of Maryland.  The projects under this concept are eligible for and continue to be funded under MDE's Revolving Loan Fund Programs, which provide low-interest loans and principal forgiveness (grant). One such project is the WSSC Piscataway Bio-Energy Project, for which MDE has provided $168M in Revolving Loan Funds to date. 

With new funding, the state will support additional decarbonization activities in Maryland’s waste sector. Priority investments include landfill and wastewater treatment plant methane capture projects. 

Impact of Waste Sector Policies

The new policies are modeled to reduce waste sector GHG emissions by 18.1 MMTCO2e between now and 2050. The societal benefit of this level of emissions reduction is estimated to be $600 million. Figure 9 illustrates the change in GHG emissions from this sector based on historical and modeled trends.​​​​​​