This list of Pennsylvania companies includes environmental services providers, utilities, and some firms in professional services and mining. Most are large, established organizations, with several founded in the early to mid-20th century. Examples include Asplundh Tree Expert, specializing in line clearance, and SUEZ - Water Technologies & Solutions, which offers water treatment and process optimization.
Other notable companies are Harsco Corporation, a global provider of waste management and recycling services, and Aqua, which delivers water and wastewater services. Many of these companies have headquarters in the greater Philadelphia area, including Philadelphia, Willow Grove, Trevose, and King of Prussia.
| # | Company | Employees | |||
|---|---|---|---|---|---|
| 1 |
Asplundh Tree Expert, LLCasplundh.com
A company specializing in safe and efficient line clearance services for utilities, as well as vegetation management for various industries |
5,645 | |||
| 2 |
SUEZ - Water Technologies & Solutionswatertechnologies.com
Providing innovative solutions for industries, including water treatment and process optimization, to help businesses thrive and overcome challenges |
4,538 | |||
| 3 |
Harsco Corporationenviri.com
Global provider of environmental waste management, recycling, onsite material processing, and rail infrastructure services across multiple industries and countries. |
3,553 | |||
| 4 |
Aquaaquawater.com
Providing water and wastewater services to over 3 million people across multiple U.S. states with a focus on safety and integrity. |
3,174 | |||
| 5 |
Eurofins Environment Testing (USA)eurofinsus.com
Provides comprehensive environmental testing services across the US, including air, water, soil, hazardous waste, and indoor air quality analysis for various sectors. |
1,966 | |||
| 6 |
Envirienviri.com
The company provides essential waste management solutions for hazardous and non-hazardous waste, contaminated soil, and recycling services for steel and metals industries worldwide |
1,900 | |||
| 7 |
Clean Earthcleanearthinc.com
Leading provider of environmental and regulated waste management services, offering tailored solutions for recycling, repurposing, and safely disposing of difficult wastes Promotes sustainability |
1,701 | |||
| 8 |
Inframarkinframark.com
Specializing in water infrastructure management, operations, and support services, we tailor solutions for clients to achieve performance, safety, compliance, and reliability |
1,527 | |||
| 9 |
Weston Solutions, Inc.westonsolutions.com
A national environmental and infrastructure services firm providing excellence in remediation, compliance, water management, infrastructure improvements, and more for various clients |
1,459 | |||
| 10 |
Aquatechaquatech.com
Global leader in water technology, specializing in desalination, water reuse, and zero liquid discharge solutions to reduce water and carbon footprint worldwide |
1,270 | |||
| 11 |
TMS International LLCtmsinternational.com
A global leader in providing on-site steel mill services, focused on safety, innovation, environmental protection, and creating value for customers through expertise and unrivaled service |
1,146 | |||
| 12 |
Harsco Metals & Mineralsharsco-environmental.com
Harsco Metals & Minerals is now Harsco Environmental, focusing on sustainable solutions for waste management and resource recovery Visit their LinkedIn page |
1,020 | |||
| 13 |
Liberty Tire Recycling, LLClibertytire.com
Reclaims over four billion pounds of scrap tires annually, transforming waste into sustainable products through a network of North American processing facilities. |
927 | |||
| 14 |
Philadelphia Water Departmentwater.phila.gov
This company provides integrated water, wastewater, and stormwater services to the City of Philadelphia's 15 million residents, focusing on high-quality water supply and watershed management |
863 | |||
| 15 |
Calgon Carbon Corporationcalgoncarbon.com
Activated carbon products for water, air, and environmental purification across more than 700 applications, leveraging over 80 years expertise. |
783 | |||
| 16 |
RoadRunnerroadrunnerwm.com
Innovative waste and recycling company offering tech-enhanced services to streamline operations, drive cost savings, and increase landfill diversion for zero waste goals |
693 | |||
| 17 |
GE Water & Process Technologiesgewater.com
A leader in developing water and process solutions for various industries, focusing on efficiency, profitability, and environmental sustainability |
576 | |||
Want more companies than this list?This page shows the largest ones only. Connect to Tamtam to see every company that matches, filter by size, industry or growth, and reach their decision-makers. | |||||
| 18 |
Veolia | Water Tech North Americaveoliawatertech.com
Global experts in water technology delivering sustainable water treatment and process solutions ensuring efficiency, resilience, and environmental protection for businesses and communities. |
547 | |||
| 19 |
H&K Group, Inc.hkgroup.com
Family-owned group, heavy civil construction, materials supplier, land development, transportation, water management, demolition, emergency response, building materials, ready-mix concrete, precast concrete, and landscape materials. |
540 | |||
| 20 |
Phoenix Globalphoenixglobal.com
Specializes in slag handling, metal recovery, and scrap handling services for steel mills, enhancing operational efficiency and resource management. |
536 | |||
| 21 |
Microbac Laboratories, Inc.microbac.com
Testing company partnering with businesses to ensure quality, safety, and performance of products and operations through a network of laboratories Delivery of timely and reliable data |
479 | |||
| 22 |
Quench USA, Inc.quench.culligan.com
Providing water-as-a-service solutions with point-of-use machines offering various water options to keep employees, customers, and guests happy and hydrated |
465 | |||
| 23 |
ALL4all4inc.com
Environmental, health, and safety consulting firm offering tailored services to help clients turn environmental management into a company asset for competitive advantage |
414 | |||
| 24 |
City of Bethlehembethlehem-pa.gov
A university providing academic programs, degrees, and opportunities for personal and professional growth to students seeking higher education |
321 | |||
| 25 |
Keystone Clearwater Solutionskeystoneclear.com
A provider of engineered solutions for safe and efficient water transfer, management, and environmental services for various industries with innovative technology and 24/7 emergency response |
319 | |||
| 26 |
Ecovyst, Inc.ecovyst.com
A catalyst and services company with a focus on supporting ecological health, providing specialty sulfuric acid, and developing technologies for cleaner fuels and waste reduction |
235 | |||
| 27 |
Pittsburgh Waterpgh2o.com
The company is a large authority providing water, sewer, and stormwater services to 465,000 consumers in Pittsburgh and surrounding areas |
208 | |||
| 28 |
Newterranewterra.com
Experts in designing, engineering, manufacturing, and servicing environmental water and wastewater treatment solutions globally to renew ecosystems with reliability and value |
207 | |||
| 29 |
Green Home Solutionsgreenhomesolutions.com
Green Home Solutions offers plant-based mold removal, probiotic air cleaning, hospital grade disinfection, odor elimination, duct cleaning, and crawlspace encapsulation services |
186 | |||
| 30 |
Chester Engineers, Incchesterengineers.com
An engineering services firm providing energy, water, and wastewater solutions to public and industrial clients nationwide and globally since 1910 |
84 | |||
| 31 |
Well Service Group (a Newpark Company)newpark.com
A diversified service provider to energy, construction, water treatment, and industrial markets offering containment services, rig mats, facility construction, and more |
58 | |||
| 32 |
Shelton Associates, Inc.sheltonassoc.com
A leader in water treatment solutions, specializing in advanced systems for industrial applications with a focus on innovation, expertise, and customized solutions |
36 | |||
| 33 |
Klenzoid, Inc.www2.klenzoidinc.com
A full-service water treatment organization dedicated to assisting partners in maintaining safe and efficient water systems |
27 | |||
| 34 |
Keystone Technology Managementkeystonetm.com
IT asset management provider offering investment recovery programs, certified for data security, environmental standards, and worker safety, serving clients worldwide |
17 | |||
| 35 |
Chemtech International Incchemtech-us.com
Global solutions provider for manufacturing needs in various industries, with emphasis on sustainability Specializing in wastewater testing, pharmaceutical manufacturing, gas valves, and spill containment |
3 | |||
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How this list is built
Every company on this list has a Tamtam company profile. The industry is the one the company gives on LinkedIn; categories such as SaaS or fintech are classified by Tamtam's AI from the company's website and LinkedIn page; and the headquarters city must match the company's own address. Companies are ranked by the number of employees on LinkedIn, and the list is refreshed every night. Classifications can be wrong, so treat the list as a starting point rather than an official ranking. Last updated Nov 12, 2026.
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The same list elsewhere in United States
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