Transforming the way wastewater solids are processed and managed.

Transforming the way wastewater solids are processed and managed

Thermal Hydrolysis Pretreatment for Digestion Intensification

Fewer resources. Better results

Wastewater treatment plants (WWTP) are continually processing water to remove pollutants and return treated effluent back into the water cycle. As plants continue to work within constrained footprints, operate more sustainably, and increase capacity to meet forecasted demands, it’s imperative we research and confirm more efficient and effective treatment technologies.

The costs of sludge management typically account for 30% or more of a WWTP capital costs and upwards of 50% of the operational costs[1]. However, improved sludge management has the potential to generate revenue, reduce costs and improve sustainable operations. Brown and Caldwell has been partnering with WWTPs to research and apply data-driven solutions including series thermophilic digestion (1990’s), temperature phased anaerobic digestion (2000’s) and thermal hydrolysis (2014)to reduce sludge mass, stabilize solids, and produce clean marketable biosolids products. With this experience as our foundation, we introduced and applied the very first use of thermal hydrolysis technology in North America, and the largest such facility in the world at DC Water.

Thermal hydrolysis intensifies the digestion process by applying high temperature and pressure ahead of a mesophilic digestion process. This pretreatment step nearly doubles the loading capacity of the digestion process when compared to conventional digestion processes. When the entire sludge stream is treated, it produces a high-quality Class A biosolids product with soil-like properties that stacks well, is low in odor, and is low in water at 30 percent cake solids. Methane from the digestion process can be recovered and converted into usable electric power and recoverable heat.

Chris Muller, PhD, PE

Chris Muller, PhD, PE

Expert, Environmental Engineering

Boston, MA

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Camilla Kuo-Dahab, BSCE, PhD

Camilla Kuo-Dahab, BSCE, PhD

Senior Staff, Environmental Engineering

Boston, MA

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Are your existing digesters limited on capacity, or are you site constrained for tank construction?

The use of heat and pressure to enhance sludge digestion and stabilization is transforming the way biosolids are processed and managed. This innovation can maximize existing tanks and takes up a smaller footprint than conventional digestion. Temperature intensified digestion produces a low-odor, pathogen-free and nutrient-rich Class A biosolids product, it can be energy neutral as the process produces heat and steam, and it provides a significant reduction in greenhouse gas emissions.

Are your existing digesters limited on capacity, or are you site constrained for tank construction?

The use of heat and pressure to enhance sludge digestion and stabilization is transforming the way biosolids are processed and managed. This innovation can maximize existing tanks and takes up a smaller footprint than conventional digestion. Temperature intensified digestion produces a low-odor, pathogen-free and nutrient-rich Class A biosolids product, it can be energy neutral as the process produces heat and steam, and it provides a significant reduction in greenhouse gas emissions.

Implementation

Brown and Caldwell is implementing this innovation to meet our clients’ wastewater and biosolid digestion goals.

 

DC Water, District of Columbia

The first installation of CAMBI thermal hydrolysis system in the U.S. and the largest in the world, generating clean, renewable energy from wastewater.

 

Hampton Roads Sanitation District, Virginia

The first thermohydrolysis system integrated with co-digestion to increase solids at the production plant in a reliable, cost effective and energy efficient way with a potential marketable byproduct.

 

Washington Suburban Sanitary

Commission, Maryland
Established a pilot test to validate variability in performance, it’s envisioned the new technology and processing plant will reduce operating costs by more than $3 million per year and reduce greenhouse gases by 15%.

Implementation

Brown and Caldwell is implementing this innovation to meet our clients’ wastewater and biosolid digestion goals.

DC Water, District of Columbia
The first installation of CAMBI thermal hydrolysis system in the U.S. and the largest in the world, generating clean, renewable energy from wastewater.

Hampton Roads Sanitation District, Virginia
The first thermohydrolysis system integrated with co-digestion to increase solids at the production plant in a reliable, cost effective and energy efficient way with a potential marketable byproduct.

Washington Suburban Sanitary Commission, Maryland
Established a pilot test to validate variability in performance, it’s envisioned the new technology and processing plant will reduce operating costs by more than $3 million per year and reduce greenhouse gases by 15%.

Related Awards

  • 2016

    U. S. Water Alliance, U.S. Water Prize, New Class A Biosolids and Energy Facility at Blue Plains Advanced Wastewater Treatment Plant

  • 2012

    American Academy of Environmental Engineers and Scientists, Excellence in Engineering Grand Award, New Class A Biosolids and Energy Facility at Blue Plains Advanced Wastewater Treatment Plant

  • 2012

    International Water Association, Global Honour Award in Planning, New Class A Biosolids and Energy Facility at Blue Plains Advanced Wastewater Treatment Plant