Waste Treatment and Disposal (U.S.) — NAICS 56221

A rollup investor's primer for a general audience — relevant to both public-market and private investors. This is the North American Industry Classification System (NAICS) 2022 five-digit industry 56221, "Waste Treatment and Disposal," which sits inside subsector 562 (Waste Management and Remediation Services) within sector 56 (Administrative and Support and Waste Management and Remediation Services). It bundles four child industries. This primer synthesizes their separately written profiles plus our federal ground-truth statistics for the combined level; its distinctive value is the contrast across the four children — which is biggest, which is growing, who owns each, and how the economics differ. Plain language; acronyms defined on first use; figures cited; forward-looking statements marked as judgments.

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1. Overview

This is the disposal endpoint of the American waste economy — the permitted facilities where waste actually gets treated, buried, or burned, as opposed to the trucks that collect it or the sort-plants that recycle it. Four distinct businesses live here: hazardous-waste treatment and disposal, ordinary trash landfills, waste-to-energy incinerators, and a residual "everything else" bucket dominated by composting and liquid-waste treatment.[1]

What ties them together is a single economic shape. Each sells scarce, permitted disposal capacity priced per ton, earns high margins on every extra ton put through a mostly-fixed-cost asset, and is protected by regulation that both manufactures the demand (the law forbids dumping waste elsewhere) and blocks new competition (almost no new disposal sites get permitted). These are infrastructure-like, cash-generative, recession-resistant businesses — waste keeps arriving in booms and busts alike.

What separates them is almost everything else: relative size, growth direction, how concentrated they are, and — the point most useful to an investor — who owns them and how you can buy in. One child is a public-equity story led by a near-pure-play stock; another is the profit core of the big listed waste majors; a third has no U.S.-listed pure-play at all and lives in infrastructure funds; the fourth is a fragmented field of private and municipal operators. This primer leads with that contrast, then treats the level as a whole.

Two ways in, at the level. Public-market investors reach this industry mainly through a handful of diversified waste companies (Waste Management, Republic Services, Waste Connections, GFL, Casella) that straddle several of the children, plus the hazardous-waste specialist Clean Harbors and the French major Veolia. Private investors reach it through infrastructure funds, private equity (PE), private credit, direct facility ownership, and — because so many sites are government-owned — municipal bonds. A large slice of the real activity sits outside the tradable market entirely: municipal landfills and incinerators, captive on-site industrial treatment, and federal (defense/energy) cleanup programs.

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2. What's inside — the four children, and how they differ

The level's ~$24.8 billion of receipts and ~62,600 workers split very unevenly across the four child industries. The table below is the heart of this primer.

Read the shares together. Landfill is the biggest by revenue (~half the level) but hazardous is the biggest by headcount (~48%) — because landfilling is capital-heavy and thinly staffed while hazardous work is skilled, licensed, and labor-intensive. Incineration is a rounding error by employment (~4%) despite very expensive plants. And the two children that are growing — hazardous and organics — are the smaller half of the level, while the two mature-or-declining children (landfill, incineration) hold ~56% of the revenue between them. In one line: the cash is in landfill, the growth is in hazardous and organics, and the decline is in incineration.

Concentration differs even more sharply than size (see §8). The combined level looks only mildly concentrated, but that average hides four very different sub-markets — from a near-monopolized incineration niche to a genuinely fragmented composting field.

A note on scope. These four are the treat-and-dispose core. The trucks that collect waste (562111/562112), the recycling sort-plants (562920), remediation/site-cleanup crews (562910), and sewage treatment (221320) are separate NAICS codes — even though a single big company often does all of them and books revenue across many codes. That cross-coding is why no listed company maps cleanly to this level (see §4, §9).

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3. How big it is

Federal ground-truth figures for NAICS 56221 (our supplied statistics). Note the mixed vintages: the Economic Census (receipts, firms, concentration) is 2022; County Business Patterns (CBP; establishments, employment, payroll) is 2023.

The children add up — a useful cross-check. Sum the four child industries and you land almost exactly on the level: receipts $9.0B + $12.3B + $1.5B + $2.0B ≈ $24.8B;[5][6][7][8] establishments 994 + 1,559 + 64 + 709 = 3,326 (an exact match); employees 29,880 + 23,871 + 2,390 + 6,458 = 62,599 (exact); payroll $2.70B + $1.65B + $0.25B + $0.49B ≈ $5.09B.[5][6][7][8] The one figure that does not simply add is the firm count — the four children list 1,658 firms combined but the level reports 1,630, because a company that operates in more than one child (say, a major running both landfills and hazardous facilities) is counted once at the level but in each child it touches.

A few reads on scale. Average pay works out to roughly $81,000 per employee ($5.09B ÷ 62,599)[3] — skilled, licensed, technical work, not minimum-wage labor. Receipts run about $15 million per firm and $7.4 million per establishment[2][3] — capital-heavy sites, not storefronts. And the SBA's "small business" line sits at $47 million in receipts for every child in this level[4] — unusually high, because a single permitted disposal facility is expensive to run.

Undercount and scoping caveats (important, and larger here than for any single child).

• CBP is an employer-based series and the Economic Census generally excludes government-owned establishments.[3] This level is unusually governmental at the disposal endpoint: a large share of the ~1,200 active municipal-solid-waste landfills, many waste-to-energy plants (publicly owned, privately operated), and thousands of municipal yard-waste composting sites sit mostly outside the ~$24.8B receipts figure.[6][7][8]
• The figure also excludes captive on-site treatment (refineries, chemical plants, and mills that treat their own hazardous waste) and federal (Departments of Defense and Energy) hazardous and radioactive programs, which are large but budget-funded rather than commercial revenue.[5]
• Because the big integrated operators book much of their money under adjacent codes (collection, remediation, recycling, field services), any single-NAICS figure understates the total economics flowing around waste disposal.
• Our federal file contains no national tonnage, capacity, utilization, average tipping fee, margin, or growth figure for this level; none is invented here. Where physical scale appears below, it is flagged as coming from other public data, not from these statistics.

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4. The investable universe — where value concentrates across the children

There is no public company that maps cleanly to NAICS 56221. The listed names are diversified operators; each child's exposure is a segment inside a broader business. Tickers are identifiers, not recommendations; revenue figures are approximate and total-company.

The listed operators (and which children they cover)

Where the public-market value actually concentrates: in landfill (the profit core inside WM/RSG/WCN/GFL/CWST) and in hazardous (Clean Harbors as the near-pure-play, Veolia as the international alternative). Incineration and organics have no listed pure-play — public exposure is indirect at best.

The private and municipal owners (the rest of the level)

• Hazardous: PE and infrastructure platforms — Arcwood/Heritage (EQT), Tradebe, Triumvirate (Berkshire Partners, ~$1.8B) — plus captive industrial capacity and federal (defense/energy) contractors.[5]
• Incineration: two infrastructure-owned platforms run most private WTE — Reworld (formerly Covanta; EQT, with sovereign fund GIC a ~25% minority) and WIN Waste Innovations (Macquarie) — atop a base of municipal/county authorities that own many plants and hire those firms to operate them.[7]
• Landfill & organics: family-owned regionals (Rumpke), employee-owned operators (Recology), PE/infra platforms (Lakeshore Recycling Systems/Macquarie; Valicor/Pritzker; Liquid Environmental Solutions/Goldman Sachs), independent organics recyclers (Denali), and RNG developers (Vanguard Renewables/BlackRock, Divert, Generate, Anaergia) — alongside a very large tail of government-owned landfills and composting sites.[6][8]

Bottom line for a public-market investor: you are almost always buying a diversified waste company — most cleanly a landfill-led major, or Clean Harbors for hazardous. For direct exposure to incineration or organics, and for most of the assets across all four children, you go private (infrastructure/PE funds, direct facility ownership, project finance, private credit) or lend through municipal bonds tied to a specific public site. Ownership changes frequently, so any roster goes stale fast.

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5. How the money works

Across all four children the model rhymes: volume × price × utilization, protected by permits, offset by long-tail liabilities. Owners here make money the way toll roads and quarries do — scarce permitted capacity, priced per ton, run as full as possible.

• Gate / tipping fees are the core revenue. Customers pay per ton to drop waste at a landfill, feed an incinerator, or deliver organics/liquids for treatment; hazardous adds charges for characterization, lab profiling, packaging, and treatment. Contracts are recurring and sticky. Reported per-ton fees vary widely by child and geography — roughly $45–80/ton at landfills, an estimated $80–100/ton at WTE plants, $30–60/ton at organics sites, and far higher for hazardous streams — but our federal file contains no tipping-fee figure, so treat those as external estimates.[5][6][7][8]
• Utilization is the master metric. These are high-fixed-cost assets, so every ton above breakeven is nearly pure margin; operators watch throughput the way a hotel watches occupancy. There is no industry-wide utilization figure in the federal data; single-company disclosures (e.g., Clean Harbors' incineration utilization) are the only public gauges.[5]
• The permit is the moat, and airspace/capacity is the asset. A hazardous landfill or WTE plant sells a finite, permitted volume; almost no new sites get approved, so scarce capacity carries pricing power. The whole game is pushing price per ton up on a fixed, hard-to-replicate asset.
• A secondary energy/credit line runs through three of the four children. Landfills capture methane and upgrade it to renewable natural gas (RNG); WTE plants sell electricity and recovered metals; anaerobic digesters make RNG from food waste. All monetize environmental credits — federal Renewable Identification Numbers (RINs), California's Low Carbon Fuel Standard (LCFS) credits, and the federal 45Z clean-fuel production tax credit — which can be worth more than the physical energy. It is high-margin, fast-growing, and policy-dependent.[6][7][8]
• Vertical integration is the landfill majors' edge. A company that both collects and disposes "internalizes" its own trucks' waste into its own site, capturing collection and disposal margin on the same ton.[6]
• The offset: closure and long-tail liability. Landfills must fund site closure plus ~30 years of post-closure monitoring; hazardous operators carry cleanup and financial-assurance obligations; all face potential remediation. Earnings before interest, taxes, depreciation, and amortization (EBITDA) looks rich, but these accrued liabilities are the counterweight.

Cost drivers across the level: labor, fuel, energy, chemicals/reagents, transport, maintenance, insurance, testing/compliance, financial assurance, ash and residual disposal, and closure obligations. Gauges that matter: tons by stream, realized price per ton, utilization and downtime, remaining permitted airspace/capacity, permit status and compliance record, credit exposure, and free cash flow after maintenance and compliance capital spending.

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6. What drives demand

• Regulatory necessity — the baseline. Generators must move waste through a documented, compliant, permitted chain; they cannot legally dump it elsewhere. Regulation is, in effect, this industry's sales force.[5][6]
• Economic activity. Waste generation tracks population, households, consumption, GDP, construction, and industrial output. Municipal trash is defensive and steady; construction-and-demolition (C&D), industrial, and hazardous volumes are more cyclical and swing with the building and manufacturing cycle.[5][6]
• Reshoring and industrial policy. New U.S. factories (semiconductors, batteries, chemicals) generate fresh hazardous and industrial waste streams — a structural tailwind that lands mostly in child 562211.[5]
• PFAS — the shared wild card. In 2024 the Environmental Protection Agency (EPA) designated two "forever chemicals," PFOA and PFOS (per- and polyfluoroalkyl substances, or PFAS), as hazardous substances under Superfund law. It cuts both ways across the level: a multi-year demand driver for hazardous treatment/incineration and disposal, but a liability and cost overhang for landfills (leachate) and organics (compost/biosolids).[5][6][8]
• Diversion mandates reallocate tons within the level. Recycling, composting, and state organics/food-waste bans (California's SB 1383 and peers) pull tonnage away from landfills and incinerators and toward child 562219 — a structural headwind for two children and a tailwind for another.[6][8]
• Energy and credit markets increasingly drive the secondary revenue line — RNG demand plus the prices of RINs, LCFS credits, and the 45Z subsidy.[6][7][8]
• Remediation and emergency events. Site cleanups, spills, fires, and derailments create steady-to-episodic, often high-margin, disposal demand — concentrated in hazardous.[5]

Forward-looking judgment: continued industrial investment, PFAS cleanup, and diversion mandates support demand for the specialized and organics children, while waste minimization, substitution, and recycling could trim volumes in particular streams — an investment judgment, not a federal forecast.

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7. Regulation

Regulation is both the demand engine and the barrier to entry — the defining feature of the whole level. The framework splits by whether waste is hazardous.

• Resource Conservation and Recovery Act (RCRA, 1976). Governs waste "cradle to grave." Subtitle C covers hazardous waste: any facility that treats, stores, or disposes of it is a treatment, storage, and disposal facility (TSDF) and needs a federal or authorized-state permit (child 562211).[5] Subtitle D sets the floor for nonhazardous landfills — liners, leachate collection, groundwater monitoring, closure/post-closure — and delegates permitting to the states (children 562212 and 562219).[6][8]
• Land Disposal Restrictions (LDR). Many hazardous wastes must be treated to a standard before land disposal — a rule that directly manufactures demand for treatment and incineration services.[5]
• CERCLA / Superfund (1980), and the 2024 PFAS designation. The Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA) assigns cleanup liability — often strict and joint-and-several — to owners, operators, generators, and transporters. The PFOA/PFOS designation both expands hazardous cleanup work and creates a new liability overhang for nonhazardous sites.[5][6]
• Clean Air Act (CAA). Sets emission limits on incinerators — maximum achievable control technology (MACT) standards and New Source Performance Standards (NSPS); EPA's Large Municipal Waste Combustor rule was finalized in 2026, adding pollution-control capex for the aging WTE fleet — and requires gas collection systems on large landfills.[6][7]
• Clean Water Act, TSCA. Wastewater/stormwater discharge permits apply across the level; the Toxic Substances Control Act (TSCA) governs PCBs and asbestos in the hazardous child.[5][8]
• State permitting and NIMBY. States issue most permits and often go stricter than federal rules; "not in my backyard" (NIMBY) opposition and community/environmental-justice challenges are the main practical barrier to building new capacity in every child. That difficulty is a curse for entrants and a gift to whoever already owns permitted capacity.[5][6][7]

The upshot: a strong permit portfolio creates scarcity value, while a release, enforcement action, permit loss, or community challenge can destroy it.

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8. Consolidation and competitive dynamics

The level looks only mildly concentrated — but that average is misleading. The combined HHI is 537 and CR4 is 38.5%,[2] technically "unconcentrated." But that blends four very different sub-markets, and it stays low mainly because different giants lead different children — the landfill majors (WM, RSG) dominate one, Clean Harbors dominates hazardous incineration, Reworld and WIN Waste dominate WTE — so no single firm rules the combined code. Look inside and concentration ranges enormously:

And even these understate reality, because waste disposal is a local business — transport cost, permitted streams, and community acceptance limit practical alternatives, so a single landfill or incinerator often behaves as a local near-monopoly regardless of the national ratio.

Because you cannot easily permit new capacity, the way to grow is to buy it. M&A (mergers and acquisitions) is the growth engine across all four children, and the past few years have been a consolidation wave:

• Hazardous: Republic bought US Ecology ($2.2B, 2022); J.F. Lehman took Heritage-Crystal Clean private (~$1.2B, 2023); EQT took Heritage Environmental (now Arcwood); WM bought Stericycle ($7.2B, 2024); Berkshire Partners backed Triumvirate (~$1.8B, 2025); Veolia bought Clean Earth (~$3.0B, 2026).[5]
• Incineration: Covanta → EQT (2021) → rebranded Reworld → GIC minority (2024); Wheelabrator → Macquarie → WIN Waste.[7]
• Landfill & organics: the public majors spent nearly $11 billion on acquisitions in 2024 alone, rolling up haulers, disposal sites, and organics platforms.[6][8]

The buyer pool is a short list of well-capitalized public strategics, infrastructure PE, and sovereign wealth funds. Antitrust reviewers (the Department of Justice, the Federal Trade Commission, and states) scrutinize deals that combine collection and disposal in the same local market, often forcing divestitures.[6] Expect the trend to continue: scarce permitted assets command premium prices.

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9. Risks

• PFAS regulatory uncertainty — the shared swing factor. The hazardous-growth thesis leans on PFAS/CERCLA rules that face litigation and shifting politics; the same rules threaten large, hard-to-quantify leachate and liability costs for landfills and organics. A rollback dents the biggest growth story; an expansion raises costs for two children.[5][6][8]
• Cyclicality. Base compliance and municipal waste are resilient, but C&D, industrial, hazardous, remediation, and emergency volumes track the economy; a manufacturing or construction downturn pulls tonnage — and pricing — down.[5][6]
• Environmental incidents and long-tail liability. Fires, releases, contamination, and transport accidents can force shutdowns and produce fines, cleanup costs, litigation, and permit loss — concentrated in a few high-value assets — while closure/post-closure obligations run for decades.[5][6]
• Permitting cuts both ways. The same difficulty that protects incumbents caps their ability to expand and can strand airspace when an expansion is denied (one major booked a multi-hundred-million-dollar landfill impairment in 2024).[6]
• Subsidy dependence. The fast-growing RNG/energy line rests on RINs, LCFS, and 45Z credits — all subject to volatile prices and policy change.[6][7][8]
• Cost inflation. Labor, fuel, energy, insurance, chemicals, and compliance spending can rise faster than customer pricing.
• Structural decline in one child. WTE incineration is a mature, slowly shrinking segment facing tighter emission rules, community opposition, and cheap landfill competition in most of the country.[7]
• Measurement / misclassification risk. No listed company maps to this NAICS level; diversified "environmental services" segments blend collection, remediation, recycling, and multiple disposal codes, so reported company revenue is not the same as 56221 revenue. Leveraged PE ownership adds refinancing and integration risk.[5][8]

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10. How to invest, and the outlook

Public-market routes. There is no clean way to buy the whole level, so match the vehicle to the child:

• Landfill (the cash core): the integrated majors — WM, RSG, WCN, GFL, CWST — where landfilling is the highest-margin slice inside a broad collection business. Historically premium-valued compounders with recurring, inflation-protected cash flows; WM and RSG are steady dividend growers.[6]
• Hazardous (the growth pure-play): Clean Harbors (CLH) for the cleanest listed exposure; Veolia (VEOEY) as the international alternative; Perma-Fix (PESI) for a small nuclear/mixed-waste niche.[5]
• The energy/organics theme: OPAL and MNTK (RNG developers) — smaller, more volatile, more subsidy-sensitive.[6]
• Incineration and most of organics: essentially no direct listed access — exposure is indirect through the diversified majors or the listed platform managers (EQT AB, Macquarie).[7][8]

When sizing any of these, track the operating gauges — tons and realized price per ton, utilization and downtime, remaining permitted airspace/capacity, closure and environmental liabilities, credit exposure, and free cash flow — and reserve valuation-multiple work (enterprise value to EBITDA, free-cash-flow yield, net leverage) for your own diligence.

Private-market routes. This is where most of the level actually lives — direct facility ownership, infrastructure and PE funds, project finance, private credit, and municipal bonds (a fixed-income way in, since so many landfills, WTE plants, and composting sites are government-owned). Underwrite the quality of permits and waste streams, not just the number of sites: permit duration and expansion potential; remaining airspace/capacity and closure obligations; utilization and downtime by asset; customer and contract concentration; realized price and cost pass-through; environmental liabilities, insurance, and financial assurance; community opposition and haul distance; feedstock security and contamination (for organics); and acquisition integration and leverage. Federal (defense/energy) cleanup work is accessible only through the contractor channel, not as a tradable asset.

Outlook (forward-looking judgment). Taken as a whole, NAICS 56221 is a durable, cash-generative, regulation-driven disposal-infrastructure complex — but its four children are heading in different directions, and that mix is the investment story:

• Landfill stays the steady cash engine — flat-to-modest volumes, mid-single-digit pricing, scarcity value in airspace, with RNG as the clearest upside and PFAS the clearest downside.
• Hazardous is the most attractive growth option — capacity-tight, price-firm, with PFAS remediation and reshoring as multi-year tailwinds, provided the regulation holds.
• Organics offers real structural growth off a small base, driven by diversion mandates, but is fragmented, capital-intensive, and policy-sensitive.
• Incineration is the mature, slowly declining piece — value comes from consolidation, uptime, and disciplined recapitalization, not growth.

Consolidation should continue across all four, with scarce permitted assets commanding premium prices. The central question at this level is not "how much waste exists?" but "which owner controls the best permitted capacity — in the fastest-growing children — at the lowest all-in regulatory and environmental risk?"

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Sources

1. U.S. Census Bureau, 2022 NAICS — 56221 Waste Treatment and Disposal (industry definition and child codes 562211/562212/562213/562219). https://www.census.gov/naics/
2. U.S. Census Bureau, 2022 Economic Census — Concentration of Largest Firms, NAICS 56221 (receipts ~$24.76B; 1,630 firms; CR4 38.5% / CR8 54.5% / CR20 71.0% / CR50 80.5%; HHI 537). https://www.census.gov/programs-surveys/economic-census.html
3. U.S. Census Bureau, County Business Patterns: 2023, NAICS 56221 (3,326 establishments; 62,599 employees; ~$5.087B annual payroll; ~$1.253B Q1 payroll); CBP methodology (employer-only coverage; excludes most government employees). https://www.census.gov/programs-surveys/cbp.html
4. U.S. Small Business Administration, Table of Small Business Size Standards, 2023 (NAICS 562211/562212/562213/562219 threshold = $47.0M avg. annual receipts). https://www.sba.gov/document/support-table-size-standards
5. Child primer — Hazardous Waste Treatment and Disposal (NAICS 562211): Economic Census 2022 (~$9.01B receipts; 321 firms; CR4 51.3%; HHI 925), CBP 2023 (994 establishments; 29,880 employees; ~$2.70B payroll), Clean Harbors Form 10-K, Veolia/Clean Earth, Republic Services/US Ecology, WM/Stericycle, Perma-Fix, EQT/Arcwood, Triumvirate/Berkshire, EPA RCRA/CERCLA/PFAS/LDR/TSCA. (Full source list in the 562211 primer.)
6. Child primer — Solid Waste Landfill (NAICS 562212): Economic Census 2022 ($12.273B receipts; 812 firms; CR4 62.2%; HHI suppressed), CBP 2023 (1,559 establishments; 23,871 employees; ~$1.65B payroll), WM/RSG/WCN/GFL/CWST Form 10-K, EREF tipping-fee surveys, EPA landfill/RCRA Subtitle D/CAA landfill-gas rules, EPA LMOP, Waste Dive M&A coverage, OPAL/MNTK. (Full source list in the 562212 primer.)
7. Child primer — Solid Waste Combustors and Incinerators (NAICS 562213): Economic Census 2022 (~$1.48B receipts; 39 firms; CR4 86.7%; HHI suppressed), CBP 2023 (64 establishments; 2,390 employees; ~$253M payroll), EIA waste-to-energy data (~57 plants), EQT/Reworld/GIC, Macquarie/WIN Waste, EPA Large MWC rule (2026), Clean Harbors. (Full source list in the 562213 primer.)
8. Child primer — Other Nonhazardous Waste Treatment and Disposal (NAICS 562219): Economic Census 2022 (~$1.99B receipts; 486 firms; CR4 28.4%; HHI 303.9), CBP 2023 (709 establishments; 6,458 employees; ~$489M payroll), EPA food/organics data, California SB 1383, BioCycle composting surveys, RIN/RNG economics, Denali/Vanguard/Divert/Generate/Anaergia, LRS/Valicor/Liquid Environmental Solutions. (Full source list in the 562219 primer.)
9. WM (Waste Management, Inc.), Form 10-K and Stericycle acquisition coverage (~$22B+ revenue; ~253 solid-waste landfills; RNG program; $7.2B Stericycle deal, 2024). https://www.sec.gov/cgi-bin/browse-edgar?action=getcompany&CIK=0000823768&type=10-K
10. Republic Services, Inc., Form 10-K (~$16B revenue; ~207 active landfills; Environmental Solutions/hazardous segment ~11% of revenue; ~25 organics facilities). https://www.sec.gov/cgi-bin/browse-edgar?action=getcompany&CIK=0001060391&type=10-K