We humans create
significant amounts of solid waste and hazardous waste. That waste stream has
varied through time and continues to vary as technology and materials use
change. We deal with solid waste in three main ways: sanitary landfills, incineration,
and reuse/recycling. Hazardous waste may be disposed of in special landfills or
may be injected into wastewater disposal wells. Landfills also emit methane that
may be captured, used, processed into renewable natural gas, and sold. They
also produce CO2 and toxic gases. Landfills also produce toxic leachate that
can enter groundwater aquifers. There has long been a debate about whether
recycling or landfilling is better for the environment, but it is also clear
that both will continue at robust levels.
Solid waste is
classified into three types: 1) Municipal solid waste, 2) Special waste, and 3) Hazardous
waste. Municipal solid waste is basically residential and commercial trash. Special
waste may be of seven types: 1) Medical waste, 2) Construction debris, 3)
Asbestos, 4) Mining waste, 5) Agricultural waste, 6) Radioactive waste, and 7)
sewage sludge. Medical waste is dangerous to workers and the public because it contains
infectious agents. Healthcare workers have the highest exposure potential. Needles
and other ‘sharps’ are a major avenue of exposure. Transmission of Hepatitis B
and C and HIV are major concerns. Construction debris may be disposed of in special
construction materials landfills or in municipal solid waste landfills. Like
construction debris, asbestos is regulated separately. It has specific disposal
requirements to minimize airborne asbestos fibers that cause lung disease. Mining
waste volumes exceed the volume of all other solid wastes combined. Mining wastes
can be sources of acid mine drainage and heavy metals. Agricultural waste has
become more concentrated in industrial-scale farming localities.
Hazardous
waste is waste that has the potential to harm human health and ecosystem health.
The U.S. EPA Resource Conservation & Recovery Act (RCRA) has specific classifications of hazardous waste. Hazardous waste is defined in two ways. First is a listing of
about 500 types of industrial waste, often from specific processes. The way it
is defined is through EPA criteria for specific properties of the waste such as
ignitability, corrosiveness, reactivity, and toxicity. Exclusions from hazardous waste designation are given to oilfield wastewater and hazardous household
chemicals.
Waste Stream Reduction: Mainly Recycling
Waste
management strategies include waste stream reduction. Recycling and
substitution of materials and changing consumer habits are common ways to
reduce the waste stream. Recycling and circular economies can be developed for
industrial and municipal waste.
Certain types
of waste can be challenging. Used tires can be landfilled but often float
upward and cause problems. Tires stored in open dumps can breed mosquitoes and
tire fires once ignited are difficult to extinguish. The ash can leak toxins which
can be carried into surface water and groundwater. Therefore, tire recycling is
desirable. Counties and solid waste districts often handle tire recycling opportunities
for residents and businesses. Unfortunately, tire recycling, like most forms of
recycling, is often uneconomic or marginally economic. However, since waste
reduction is a clear public good, recycling programs should continue, funded by
both private and public sources.
Sanitary Landfills, Industrial, and Hazardous Waste
Landfills
Sanitary
landfills replaced the open dumps of the past that were known for pest vectors,
noxious odors, and easily mobile contaminant potential. Landfill site selection
involves groundwater, surface water, and soil evaluation. Topography is also a
consideration. Then grading can begin. Erosion and sediment control is then
established. An under-barrier is installed to keep leachate water from
percolating down into groundwater aquifers. Landfill leachate can be quite concentrated
and toxic. Leachate collection and treatment systems are installed. Monitoring
wells may be drilled to determine if leachate has entered groundwater. Leachate
monitoring wells are drilled adjacent to cells close to the cell depth and
groundwater monitoring wells are drilled deeper into aquifers. Landfills work
by setting up waste cells. The waste is received, compacted, and covered with
soil frequently, usually daily. Industrial or hazardous waste landfills are
similar but much more heavily regulated. Often these waste streams are specific
and have specific preparation, treatment, and/or packaging requirements before
they are buried.
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Waste Incineration and Waste-to-Energy
Most forms of
waste have been incinerated. Many facilities capture energy for use. These are
waste-to-energy plants. Incineration reduces the amount of waste being
processed. Completeness of combustion is a consideration at incinerators. This is ensured by the three T’s: 1) Time – how long the waste and its combustion gases
are in the burn chamber, 2) Temperature – amount of energy needed to break
molecular bonds and complete the combustion reaction, and 3) Turbulence –
agitation of solids and combustible by-products that leads to more complete
oxidation. Oxygen is added as combustion air. There are different incinerator designs
that often use multiple chambers for primary and secondary combustion.
Emissions from
incinerators can be quite toxic. Now they are more strictly regulated, requiring pollution abatement equipment such as electrostatic precipitators,
venturi scrubbers, and baghouses to capture fine particulate matter. Wet or caustic
scrubbers control acid gas. Activated carbon filtration systems began to be
installed around 20 years ago. These minimize products of incomplete combustion
(PICs) like polyacrylic hydrocarbons (PAHs) and dioxins. Heavy metals such as
mercury, cadmium, lead, and chromium are more difficult and expensive to abate.
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Deep Well Injection
Some waste,
usually oil & gas brines, but also hazardous waste and radioactive waste
may be injected into deep wells into saline reservoirs. EPA has a specific
classification and specific construction and content requirements for these
wells. There are different classes for different kinds of waste.
Other Waste Treatment Technologies
Research into
waste treatment is always ongoing. Treatments such as “supercritical water
oxidation, molten metals and molten salt oxidation, glass melt and
vitrification processes, and waste-specific biological treatment systems and
composting.” Thermal desorption is used for old industrial waste.
Health Concerns from Solid and Hazardous Waste
The textbook Environmental
Health: From Global to Local, edited by Howard Frumkin (2005), of which part
of this post is a summary, gives five specific health concerns of solid and
hazardous wastes:
1.
Risks of infectious disease from poorly
managed solid waste
2.
Contamination of drinking water by
biological and chemical wastes
3.
Formation of air pollutants in landfills
4.
Emission of air pollutants from
incinerators
5.
Contamination of food by waste chemicals
that escape into the environment
Old open dumps had dangerous levels of dangerous pests
and without liners, they leaked leachate into groundwater. Modern sanitary
landfills have largely improved those issues. Chemical reactions occur in
landfills. As microbes decompose garbage and organic waste, organic acids are
produced, making metals in the waste stream more soluble. Dangerous
contaminants like volatile organic compounds (VOCs), industrial solvents, and petroleum
distillates are often found in landfills. Of course, the methane and CO2 released
from landfills contribute to climate change. The air emissions from landfills
are roughly just less than 50% methane and just less than 50% CO2 with small
amounts of other gases.
The book, from 2005, notes that 10% of hazardous waste is shipped across international borders. This must also be monitored and regulated. The Basel Convention regarding the transport of hazardous waste was ratified in May 2005 but not by the U.S. They stated that it needed to be approved by Congress in the Resource Conservation and Recovery Act would have to be updated. The issue is of concern because many countries do not have adequate training and capabilities to process hazardous waste. Lead-acid battery recycling facilities are one example of a dangerous facility due to airborne lead dust pollution that has devastated children in Africa, Mexico, and other places.
Sometimes health
concerns can come from poorly managed solid waste facilities. Municipal recycling
facilities (MRFs) are susceptible to fires that can emit toxic smoke. Landfills
could have unforeseen erosion and sedimentation issues or leachate migration
issues. Natural disasters can generate significant amounts of solid waste such
as when houses and buildings are damaged. Both destruction and construction
debris are generated from the initial cleanup phase through the rebuilding
phase as shown below.
Global Waste Management Data and Trends
The World Bank
provides some useful global information and data on solid waste management. In
2018 they estimated that about 90% of global solid waste is either burned or disposed
of in open landfills. Open landfills and e-waste are concerning for a number of
reasons, and I plan to do a separate post about that issue. Developed wealthy
countries have better waste management systems than developing countries. Waste
management is thus a capability enabled by wealth as well as the recognition of
the importance of public health. The graphs below show some of the global waste
management data and forecasts.
EPA Rules on Solid and Hazardous Waste: RCRA, CERCLA,
EPCRA, TRI
RCRA
The Resource Conservation
and Recovery Act (RCRA) gives the EPA regulatory authority over solid and
hazardous waste from when it is generated to post-disposal monitoring. RCRA is
Congressionally mandated. The EPA provides guidance in the form of “explicit,
legally enforceable requirements for waste management.” RCRA has been amended
several times with required approval by the U.S. president. It was originally passed
in 1976 with amendments added in 1984, 1992, and 1996. Subtitle D deals with
non-hazardous solid waste and regulatory authority for managing it is given to
the states under EPA guidance. Subtitle C deals with hazardous waste. The EPA
may defer to states to regulate hazardous waste if the state is deemed capable.
“Subtitle C regulations set criteria for hazardous waste
generators, transporters, and treatment, storage and disposal facilities. This
includes permitting requirements, enforcement and corrective action or cleanup.”
RCRA has been amended and updated many times and continues
to evolve. The Coal Combustion Residuals (CCR) rules were finalized in 2015,
for example. The amendments are shown below.
RCRA requires
groundwater monitoring around landfills. Monitoring wells are drilled into
aquifers near the landfill and the water is tested regularly. Soil vapor probes
or shallow boreholes may be drilled to test for the presence of leachate outside
the landfill boundaries. If leachate is found to be present, then corrective
actions must ensue. The ability to pay for closure and post-closure of
landfills must also be demonstrated by the owners. According to EPA:
“In order to predict whether any particular waste is
likely to leach chemicals into ground water at dangerous levels, EPA designed a
lab procedure to estimate the leaching potential of waste when disposed in a
municipal solid waste landfill. This labprocedure is known as the Toxicity
Characteristic Leaching Procedure (TCLP).”
“The TCLP
requires a generator to create a liquid leachate from its hazardous waste
samples. This leachate would be similar to the leachate generated by a landfill
containing a mixture of household and industrial wastes. Once this leachate is
created via the TCLP, the waste generator must determine whether it contains
any of 40 different toxic chemicals in amounts above the specified regulatory levels
(see Figure III-7). These regulatory levels are based on ground water modeling
studies and toxicity data that calculate the limit above which these common
toxic compounds and elements will threaten human health and the environment by contaminating
drinking water.”
Since wastes are often mixed with other waste, there is also a mixture rule that requires any amount of hazardous waste mixed with any amount of non-hazardous waste to be designated as hazardous waste. There is also the derived-from rule which covers hazardous waste residues often derived from the initial treatment of hazardous waste. These rules are described below.
RCRA also covers hazardous waste
recycling, recordkeeping, and reporting requirements. EPA’s RCRA Orientation
Manual is a useful resource for assessing RCRA compliance. Hazardous waste
transport, storage, and treatment all have RCRA requirements. Preventive
measures such as drip pads, secondary containment for tanks, leachate leak
detection, and spill response plans are required. There are specific rules for
surface impoundments, such as those that hold coal combustion residuals, or
coal ash slurry ponds. There are also air emission rules for landfills and
other waste facilities. The table below shows different technologies that may
treat hazardous waste. The second table shows the regulatory status of secondary materials
Land disposal and combustion are two ways hazardous wastes
are managed. Each has specific requirements that vary depending on the type and
composition of the waste. Permitting hazardous waste storage, treatment, and
disposal facilities has specific requirements and protocol as shown below.
Corrective
actions, or remediation, of hazardous wastes is also covered under RCRA. According
to EPA:
“Remedy implementation typically involves detailed remedy
design, remedy construction, remedy operation and maintenance, and remedy completion.
In the corrective action program, this step is often referred to as Corrective
Measures Implementation (CMI)”
Compliance monitoring
through periodic inspections and data collection and analysis are the methods
of RCRA enforcement. Below are shown the different categories of enforcement
inspections such as routine RCRA inspections, groundwater monitoring, and O&M
inspections for monitoring wells.
CERCLA
The Comprehensive
Environmental Response, Compensation, and Liability Act (CERCLA), commonly
known as Superfund, was enacted by Congress in 1980. CERCLA is sometimes
referred to as the hazardous waste cleanup program. While RCRA covers hazardous
waste generation, storage, treatment, and disposal, its final remediation is
covered under CERCLA. According to the EPA:
“This law created a tax on the chemical and petroleum
industries and provided broad Federal authority to respond directly to releases
or threatened releases of hazardous substances that may endanger public health
or the environment. Over five years, $1.6 billion was collected and the tax
went to a trust fund for cleaning up abandoned or uncontrolled hazardous waste
sites.”
CERCLA “established prohibitions and requirements
concerning closed and abandoned hazardous waste sites; provided for liability
of persons responsible for releases of hazardous waste at these sites; and established
a trust fund to provide for cleanup when no responsible party could be
identified.”
Two kinds of remedial action were distinguished based on priority:
short-term removals and long-term remedial response actions. CERCLA
had some amendments added in 1986. The National Contingency Plan (NCP) is a
part of CERCLA that requires planning for hazardous waste releases. CERCLA requires
site investigations to determine the best remediation technology to utilize. According
to the EPA:
“CERCLA authorizes cleanup responses whenever there is a
release, or a substantial threat of a release, of a hazardous substance, a
pollutant, or a contaminant, that presents an imminent and substantial danger
to human health or the environment.”
EPCRA and TRI
The Emergency
Planning and Community Right-to-Know Act (EPCRA) was passed by Congress in 1986
to deal with hazardous waste releases into the environment. It requires
planning for the accidental release of toxic materials, or contaminants. It
requires identifying where hazardous substances are generated, transported, and
disposed of and assessing potential risks to public health in the event of a release.
Community emergency response plans are developed.
EPCRA requires
that certain industrial facilities annually report estimates of quantities and
types of hazardous waste stored onsite, treated onsite, and released to the
environment. EPA uses this data to maintain its Toxic Release Inventory (TRI).
Waste Management Financing and Oversight: Budgets,
Cost-Recovery, and Solid Waste Districts
Waste management
at the municipal level is funded by trash removal customers and by state,
county, and local governments. EPA puts the minimum solid waste management costs
in low-income countries for collection, transportation, and disposal in
sanitary landfills at $35 per ton (2014). Adding advanced approaches like waste
treatment and recycling the costs can be $50-100 per ton or more. For cities,
solid waste management often makes up 4% to 20% of the municipal funds. Local
governments provide about half of the required investments for waste services, with
the rest typically provided through national government subsidies and the
private sector. Capex and Opex are the two main cost requirements. Capital is
required to build landfills, to buy and maintain trucks, and to buy dumpsters
and bins. Labor, fuel, and equipment maintenance costs are an important
consideration. Operational costs can be challenging and often make up 70% or
more of solid waste operating budgets. Typical costs are shown below.
Costs for incinerators and anaerobic digestors are given
below. It can be seen that incinerators are roughly comparable to landfilling
costs. “Construction and operation of anaerobic digestion and incineration
systems require a large budget and high management and technical capacity.”
The World Bank writes:
“Waste management investment costs and operational costs
are typically financed differently. Given the high costs associated with
infrastructure and equipment investments, capital expenditures are typically
supported by subsidies or donations from the national government or
international donors, or through partnerships with private companies. About
half of investments in waste services globally are made by local governments,
with 20 percent subsidized by national governments, and 10–25 percent from the
private sector, depending on the service provided.”
In high-income countries, there is better solid waste
management and continuous improvement. Leachate collection systems, biogas
capture and use, and functional recycling supply chains are common. Captured
biogas may be processed into renewable natural gas.
In the U.S. many states have solid waste districts, usually at the county level or a district may encompass multiple counties. These districts are tasked with planning and management of solid waste. They collect data, develop plans, have regular meetings, produce reports, and assess fees guided by the state.
Public Participation, Input, and Opposition
As noted, the
permitting process provides for a public comment period when a facility is
undergoing the permit process. Public hearings are also a part of that process.
The public participation part of permitting is shown below.
Public opposition
can spring up when there are health concerns from the public or when new waste
is added to an existing waste facility. A recent case is where a special hazardous
waste landfill in Michigan was approved to accept low-level radioactive waste
from atomic bomb byproducts from the 1940s Manhattan Project. It is the same
landfill that accepted most of the dug-up waste from the East Palestine train
derailment. Many local residents are opposed to radioactive waste being delivered.
I think they are generally misinformed since adequately disposed of low-level radioactive
waste is unlikely to cause any problems.
Reducing So-Called Climate Pollution
EPA also helps to
fund so-called climate pollution mitigation. Although I don’t like the term climate
pollution since greenhouse gases are not like other pollutants, the mitigation path
is often similar to other air pollution mitigation. Capturing methane from
landfills is one feature. Landfills also produce CO2 which may be captured as
well but I don’t believe any landfills capture and store CO2 since it is a
smaller part of the waste stream than in combustion. Capturing the methane for
use and to mitigate greenhouse gases is important. A lesser step is flaring
methane since burning methane produces less global warming potential than
venting it. EPA’s Climate Pollution Reductions Grant Program has access to a $4.2
billion fund set aside for climate pollution mitigation. This includes methane
capture and utilization at landfills, organics recycling, clean collection
fleets, food waste reduction, processing, and composting. Facilities may apply
for the grants but may not be selected. So-called low-hanging fruit like
methane capture and leak detection and repair (LDAR) is prioritized since it
can have the biggest emissions reduction effects at the lowest cost. Oil and
gas facilities, landfills, and natural sources of methane are targeted.
References:
Environmental
Health: From Global to Local. Chapter Nineteen. Solid and Hazardous Waste. Sven
Rodenbeck, Kenneth Orloff, Harvey Rogers, and Henry Falk. Howard Frumkin,
editor. Wiley & Sons. 2005.
How
agencies in 6 states plan to spend millions from EPA climate pollution grants.
Jake Wallace. Waste Dive. August 8, 2024. How
agencies in 6 states plan to spend millions from EPA climate pollution grants |
Waste Dive
Trends
in Solid Waste Management. The World Bank. 2024. Trends
in Solid Waste Management (worldbank.org)
What a
Waste: An Updated Look into the Future of Solid Waste Management. World Bank
Group. September 20, 2018. What
a Waste: An Updated Look into the Future of Solid Waste Management
(worldbank.org)
What a
Waste 2.0: A Global Snapshot of Solid Waste Management to 2050. Silpa Kaza,
Lisa Yao, Perinaz Bhada-Tata, and Frank Van Woerden. With Kremena Ionkova, John
Morton, Renan Alberto Poveda, Maria Sarraf, Fuad Malkawi, A.S. Harinath, Farouk
Banna, Gyongshim An, Haruka Imoto, and Daniel Levine. World Bank Group 2018. 9781464813290.pdf
Resource
Conservation and Recovery Act (RCRA) Laws and Regulations. U.S. EPA. 2024. Resource Conservation and Recovery Act (RCRA)
Laws and Regulations | US EPA
Resource
Conservation and Recovery Act (RCRA) Laws and Regulations. Final Denial of
Non-Hazardous Secondary Materials Rulemaking Petition. October 18, 2023. Final
Denial of Non-Hazardous Secondary Materials Rulemaking Petition | US EPA
Resource
Conservation and Recovery Act: Critical Mission & the Path Forward. U.S.
EPA. June 2014. RCRA's
Critical Mission and the Path Forward
RCRA
Orientation Manual 2014. U.S. EPA. RCRA
Orientation Manual: Table of Contents and Foreword (epa.gov)
Small
town erupts as landfill will process radioactive waste. Alyssa Guzman. Daily Mail.
August 20, 2024. Small
town erupts as landfill will process radioactive waste (msn.com)
Solid
Waste Management Planning. Ohio EPA. Solid
Waste Management Planning | Ohio Environmental Protection Agency
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