Cambi Group AS

CAMBI B2 “packaged unit” thermal hydrolysis plant, including steam explosion disintegration


Source: Cambi Group AS

Cambi, the world’s leading company within Thermal Hydrolysis (THP) pre-treatment of sewage sludge before digestion, will present the following new development at this year’s IFAT in Munich, 7 – 11 May:

  • The new Cambi B2 THP for medium sized WWTPs starting at 50,000 p.e.  or 1,500 t DS (dry solids)/year up to 6,600 t DS (240,000 p.e.) . The Cambi B2 will enable your plant to supply up to 50% more Biogas, halve the disposal costs and double the digestion capacity. It is a “plug & play” concept for smooth integration into the existing plant.

Cambi’s unique Thermal hydrolysis process with high pressure disintegration (“steam explosion”) enables enhanced VS  reduction with more biogas, faster anaerobic digestion rates , better dewatering and high capacities of all Cambi models: B2, B6 and B12 THP. Please find attached brochure giving capacities of each model.

In addition Cambi has prepared the following IFAT program for you:

  1. Tour to the Cambi THP plant at Amperverband in Geiselbullach on 7 May. A bus will leave at 1 pm from entrance North.  Please let us know if and when you can attend this tour, by contacting:
  2. Prof. Horn will speak on Monday 7 May at 11 a.m. about the Wastewater Treatment Plant of the Future.
  3. Prof. Dichtl will speak on Tuesday 8 May at 10 a.m. about disintegration of sludge prior to anaerobic digestion.

Various Cambi experts will be present during IFAT and would be happy to exchange facts, experiences and opinions with you. We look forward to meeting you at our booth A2-402 in Hall 2.

The new Cambi Thermal Pressure Hydrolysis (THP) Compact B2 packaged unit:

The compact B2 THP comes as a packaged unit, installed with all pipework on a skid/frame, is equipped with all electrical and pneumatic connections, and tested prior to delivery. This allows shorter delivery, installation and integration. In summary Cambi B2 is:

  • A fully integrated skid mounted THP system
  • Based on Cambi standard design and specifications
  • Supplied as a standard “plug & play” unit.
  • Installed with a small footprint (40 foot container size building)
  • Delivered and installed in a short time period.
  • Integrated into existing plants with minimum disruption.
  • Offered with Cambi after sale support program.

A further introduction and status on Cambi can be found in the next pages:

From IFAT web page:

Thermal hydrolysis Sludge Treatment: Medium to large-scale application

The Norwegian company Cambi AS has developed and installed worldwide its unique “steam explosion” thermal hydrolysis process (THP), a technology for the treatment of wastewater treatment plant (WWTP) sludge prior to anaerobic digestion. Cambi THP optimizes biogas production and has many other benefits, which are described below, along with a look at some real-life experiences at medium and large-scale facilities.


  • Established in 1989. Offices in Norway, Denmark, UK, and USA
  • Global industry leader in our segment (advanced biogas production from sludge and biowaste) with 26 plants worldwide (530,000 metric tons DS/y) and 5 plants under design/construction
  • Treatment capacity for sludge and biowaste equivalent to 26 million people and 768,000 metric tons of DS (dry solids)/year
  • Production capacity of 1,900 GWh thermal energy (biogas) and 760 GWh electrical energy, when using gas engine cogeneration.
  • Green energy production replaces760,000 tons of fossile CO2 emissions. Avoidance of methane emissions from landfills, less transport, etc. comes in addition (about 2.5 mill tons CO2 equivalents)
  • Cambi THP is an eco-friendly “Paradigm-shifting Technology”, dramatically improving design and operations of biogas plants worldwide.

The use of the thermal hydrolysis process in sludge treatment for WWTPs presents some major advantages in terms of energy, public health and environmental protection. Medium-sized plants can be converted, with the import of sludge from other nearby plants, into strategic sludge treatment centers.  Here biogas production from anaerobic digestion is maximized using existing capacity, generating a pasteurized sludge with high dry solids content. The generation of electricity from renewable sources, produced from biogas, allows the energy costs of the WWTP plant itself to be reduced and the WWTP may even have surplus energy production.

Thermal hydrolysis “Steam Explosion” process

The thermal hydrolysis process (THP) patented by Cambi AS is a pre-treatment of sludge combined with anaerobic digestion. Cambi THP works by dissolving and disintegrating sludge using pressure and temperature. Primary, biological or mixed sludge is pre-dewatered and introduced into a reactor where the direct application of saturated steam hydrolyzes and changes its internal structure. This reduces sludge viscosity and increases its biodegradability and shortens hydraulic retention time. The thermal hydrolysis increases the production of biogas in digestion, reduces the volume needed for digestion, increases the dryness of the final dewatering of digested sludge, eliminates odors, and provides pasteurized final sludge Class A, a valuable and natural fertilizer.

The thermal hydrolysis is part of a wastewater treatment plant as a pre-treatment prior to digestion

The Cambi thermal hydrolysis process disintegrates the cellular structure of the bacteria in bio-sludge by solubilizing exopolymers (proteins protecting the bacteria), producing an easily digestible product. This is done by means of a temperature of 165 degrees for 20 minutes, at 6 bar, followed by a sudden drop in pressure, resulting in so-called “steam explosion”, unique among all thermal hydrolysis technologies available in the market. The steam explosion tears cells and fibers apart, further improving the disintegration effect.

The Cambi hydrolysis system allows maximum disintegration of the cells and it enhances the production of biogas in the subsequent anaerobic digestion and allows high loads in digesters. In the Cambi plant at Thames Water’s Chertsey WWTP (London, UK) our process operators have tuned the plant to the exceptional capacities of up to 7 kg VS m3/day and retention times as low as 10-12 days.

The use of Cambi thermal hydrolysis achieves the following:

  • Generates more energy (higher biogas production).
  • Reduces the final amount of sludge. It improves sludge dewatering up to 40% DS.
  • Ensures sludge pasteurization, i.e. a pathogen-free sludge
  • Produces a stabilized an compost-like product, with 70% decrease in odour .
  • Increases the speed and capacity of digestion (less digestion volume).
  • Reduces carbon footprint.

A medium-scale sludge treatment center: The case of Lindum (Norway).

Cambi hydrolysis system for medium capacities (15-40 dry tonnes per day) is based on 6 m3 reactors. The system is modular, permitting its expansion up to 3 reactors. For lower sludge productions, Cambi has developed an even more compact plant (see press release, IFAT). The whole system of hydrolysis is closed without leakage of odor and energy loss.

Drammen (Norway) has recently installed a medium-scale sludge treatment center for dewatered sludge from 9 municipalities (18,500 wet t/year), fats from the food industry (3,000 t/year), sludge from septic tanks (7,000 t/year) and other biological substrates (2,000 t/year). The project’s main objective was to generate biogas and produce a safe product. Investment, operation and maintenance costs were also considered. The use of the 2 reactor Cambi B6 hydrolysis system in Lindum allows the generation of 16 GWh/year of biogas and 12,000 t/year of dewatered biosolids product used as fertilizer. This plant shows that it is possible to develop sludge treatment centers on a medium scale where you can optimize the energy efficiency of equipment by importing sludge from outside the WWTP.

Large-scale thermal hydrolysis: The case of DC Water (Washington DC, USA)

The District of Columbia Water and Sewer Authority (DC Water) in its Blue Plains plant treats a sewage flow of 370 MGD (15 m3/s), the largest wastewater treatment plant with advanced treatment in the U.S. DC Water will be the first to build a thermal hydrolysis plant in North America. This thermal hydrolysis plant will be the largest in the world and will be built by Cambi AS in Washington DC, with start-up in 2014. The plant will treat up to 450 t DS sludge/day, and 149,000 t DS sludge/year. Only four digesters, each with a 14,400 m3 capacity, will be built. The biogas will go to a cogeneration facility which will cover the entire steam needs of the THP process itself and generate 13 MWe of power with initial savings of USD 20 million/year from the energy produced, the reduction of the amount of biosolids to agriculture, and by avoiding the use of lime. The carbon footprint will be reduced by about 60,000 t CO2/year. The final dewatered biosolids quantity will be reduced from 500,000 t/year to 200,000 t/year, with safe application to agriculture as a pathogen-free product with no odor problems. The project demonstrates the effectiveness of feeding the digesters at a digester load of more than 4 kg VS/m3, twice that of conventional digestion, with low retention time in the digesters. The Cambi THP consists of 4 lines of equal capacity.

Comparative hydrolysis parameters vs. conventional digestion

The advantages of applying thermal hydrolysis are summarized in the table below, which compares conventional digestion values with thermal hydrolysis and digestion for mixed sludge.


From 1996 to the present, Cambi thermal hydrolysis units installed and under design/construction worldwide have a capacity of 768,000 t DS/year, to serve a population equivalent of more than 26 million. It is a fully proven technology for small to large scale anaerobic digestion plants.

With the Cambi thermal hydrolysis process you can:

  • Improve the energy efficiency of the WWTP. More biogas = more power.
  • Reduce the final volume of dewatered sludge.
  • Ensure an agriculture output of the final pasteurized sludge, with low odor, and without pathogen regrowth risk.
  • Eliminate or reduce the need for subsequent thermal drying or incineration.
  • More than double the capacity of anaerobic digesters.
  • Have a smaller carbon footprint.
  • Have an installation that is reliable and robust with high availability and automation.

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