Synagro’s History

Synagro is North America’s leader in the safe, reliable, environmentally responsible recycling of biosolids.

Our company began with a small group of passionate environmentalists responsibly partnering with our customers to find recycling and beneficial use for biosolids to comply with new clean water regulations.  Along the way, we combined Bio Gro’s portfolio of land application, thermal dryers and composting facilities with Synagro’s experience in land application, thermal reduction and rail movement of biosolids.  This combination yielded the only company of its kind, constantly striving to provide more environmentally sound solutions for our customers and the communities we serve and in which we live.

Timeline Key:

Legislative and Regulatory

Bio Gro

Synagro (Pre-Acquisition)

Synagro (Combined Entities)


Born in the wake of elevated concern about environmental pollution, the U.S Environmental Protection Agency (EPA) is established on December 2, 1970 to consolidate in one agency a variety of federal research, monitoring, standard-setting and enforcement activities to ensure environmental protection.


The Clean Water Act passes, removing biosolids from water treatment plant discharges, dramatically increasing the production of biosolids.​


Bio Gro is founded to help municipalities find biosolids solutions driven by the passage of The Clean Water Act.


Synagro is founded in Houston, Texas.


Congress enacts the Ocean Dumping Ban Act, including prohibition of at-sea disposal of industrial and medical wastes. The U.S. EPA phases out at-sea dumping of sewage sludge.


Bio Gro has become the leading provider of beneficial use biosolids management services in North America, recycling more than 5 million wet tons of biosolids and other organic by-products annually for over 275 generators across the U.S. and Canada.


Bio Gro joins the Waste Management family as a division of Wheelabrator Water Technologies, Inc. linking Bio Gro’s large land application and biosolids services strength with Wheelabrator’s excellence in in-vessel composting.


Wheelabrator purchases Enviro-Gro Inc., a Baltimore-based company that is a leader in thermal drying technologies for biosolids.  The combined entities became the only biosolids management company with a national footprint and industry-leading expertise in biosolids services, composting and thermal drying.


Bio Gro’s biosolids experts work in partnership with the U.S. EPA to craft the landmark Federal “503” regulations, ensuring the environmentally conscious and safe disposal and recycling of biosolids nationwide.​


The Standards for the Use or Disposal of Sewage Sludge (40 CFR 503) becomes effective.


Synagro rapidly expands its biosolids management business with the purchase of Rehbein, Inc., giving Synagro a strategic presence in the Midwest, and the biosolids operations of Whiteford Environmental Services, a Maryland-based biosolids services company.


​Synagro acquires Bio Gro from Wheelabrator, creating a clear industry leader in U.S. and Canada biosolids management and recycling.


Synagro acquires NETCO, adding three biosolids incinerators to Synagro’s portfolio of facilities.


Synagro adds Environmental Protection & Improvement Company, Inc. (EPIC) to the portfolio.  EPIC’s fleet of approximately 150 high-capacity railcars and 1,300 containers are used to transport biosolids by rail for disposal or land application for beneficial reuse. ​


HYPEX, a world-class centrifuge repair and maintenance facility, is added to Synagro.


Synagro is purchased by EQT, mainland-Europe’s largest private equity firm, beginning a period of significant investment in Synagro’s infrastructure.


The acquisition of the large Nursery Products Composting facility bolsters Synagro’s leading position in West Coast composting.


Synagro enters Canada, winning the contract to design, build, own and operate a new thermal drying facility in Hamilton, Ontario. Later wins in operating the Windsor, Ontario dryer (2018) and leading the design, build, ownership and operation of a world-class biosolids drying facility in Victoria, British Columbia, to become operational in 2021 affirms Synagro’s leadership in the Canadian biosolids market.


Synagro experiences a period of aggressive organic growth, and adds to its extensive portfolio with two acquisitions.  Adding Old Line Environmental, Inc. bolsters Synagro’s biosolids management footprint in the Mid-Atlantic, and brings more than a dozen employees, each with more than 20 years of biosolids experience.


Synagro acquires Pace Dewatering Systems, an Edmonton, Alberta, Canada supplier of centrifuge technology, expanding its position as North America’s largest and most capable biosolids management company. The acquisition adds 13 centrifuges, a centrifuge-repair unit, and personnel with more than 30 years of biosolids dewatering experience.


Synagro is purchased by West Street Infrastructure Partners III, an infrastructure investment fund managed by Goldman Sachs Merchant Banking division.


Synagro acquires LimeCorp, LTD, an Ohio-based a premier provider of lime-residual management and land-application services for industrial and municipal customers, expanding its lime-residual management and land-application services, and also broadening its client base in the region.


Synagro acquires Liberty Composting, Inc., a California-based premier provider of organics and biosolids composting services adding more than 40 industrial and municipal customers.


Synagro acquires Burch Hydro, Inc., a Ohio-based premier provider of biosolids and lime-residuals management and land-application services specializing in digester cleaning and dewatering services adding 20-plus municipal customers.


Synagro acquires New England Fertilizer Company (NEFCO), a Massachusetts-based, privately held company with customized client solutions and proven biosolids management technologies.


Synagro publishes its inaugural Sustainability Report outlining the Company’s goals for sustainable growth and highlights its achievements across three main pillars – a Greener World, Passionate People and Transparent Integrity.