CAMBI AS

About Us

Cambi AS provides profitable and advanced waste and sludge biogas systems, which are focused on maximizing energy production and minimizing final product mass. Cambi biogas plants operate at twice the normal organic loading and are very compact. The resulting biosolids product is pathogen-free and may be used to make high-grade compost or soil improver. Cambi has delivered twelve plants in Norway, Denmark, Belgium, Australia, Poland, Ireland and the United Kingdom, licensed one to Japan and has five more plants in various stages of construction in Norway, Germany and the United Kingdom.

The Cambi Thermal Hydrolysis Process (THP)

Cambi’s patented Thermal Hydrolysis Process (THP) treats municipal and industrial wastewater treatment sludge and bio-waste prior to anaerobic digestion. The THP consists of high temperature steam treatment of raw materials with the purpose of dissolving solid organic matter into an easily digestible feed for biogas production by anaerobic digestion.

Cambi THP provides maximum flexibility in terms of use of the end product (digestate) – a pasteurized biosolid – which can be applied to land directly, composted or dried. The thermal hydrolysis process is highly energy-efficient with low operating costs. It also eliminates odour problems associated with the heating of sludge.

The main advantages of Cambi THP over conventional anaerobic digestion are:

• Significantly increased biogas production
• The biogas can be used to produce green electricity in turbines/engines, where exhaust heat is used to provide all or most of the steam needed in the THP process
• Higher digestion rate and high dry solids digestion (10–12% DS feed) give 2–3 times improved digester capacity, reducing investment in digesters
• Significantly easier and more robust operation of the anaerobic digestion process, with elimination of foam-causing filamentous bacteria
• Up to 100 percent improved dewaterability and organic matter reduction, which result in energy savings and less materials handling
• Total disinfection and stabilization of the end product (133–180° C for 30 minutes)
• Compact THP reactor design makes it well suited for both new installations and retrofits at existing sludge/biowaste treatment plants
• Standard modular reactors are combined to cover all size plants

R&D

• Digestion of organic residues from bioethanol production
• Lignocellulose pre-treatment for bio-ethanol production
• Continuous thermal hydrolysis

Turbo-Charged Digestion of Biodegradable Sludge & Wastes

Cambi’s THP process was developed for all types of wastewater treatment sludge and is particularly effective in treating biological (WAS) sludge, which normally is very difficult to digest and dewater. The THP process can also treat a wide variety of biological wastes, including categories 2 and 3 animal by-products. Cambi delivered one plant for biodegradable municipal waste in 2002 and has signed a contract for another one, to be completed in 2008, both in Norway.

Export Markets

Cambi is represented in the following markets:

• Australia
• Belgium
• Denmark
• France
• Germany
• Hungary
• Ireland
• Italy
• Japan
• Korea
• Poland
• Spain
• Switzerland
• United Kingdom
• United States

Thermal Hydrolysis Sludge Pre-Treatment

Cambi’s Thermal Hydrolysis Process (THP) is a proven and reliable technology that has been used around the world since 1995 in existing and “green field” projects to reduce both disposal quantities and the cost of building and operating digesters.

Cambi THP is a high-pressure steam pre-treatment for anaerobic digestion of municipal and industrial sludge and bio-waste. Applying THP technology results in doubled digester loading, increased biogas production, and a pathogen-free and stabilized biosolids product with increased cake dewaterability. This saves both transport and energy costs, whether applying the end product directly in agriculture or drying it for fertilizer or bio-fuel.

The THP is highly energy-efficient with low operating costs. It also eliminates odour problems associated with the treatment of organic materials. The end product (digestate) – a pathogen free and pasteurized biosolids can be applied to land directly, composted or dried.

Cambi THP plants can be combined with cogeneration plants, which produce green electricity and provide hot steam for the Thermal Hydrolysis Process. However, the biogas can also be cleaned to be used as vehicle fuel or as a replacement of natural gas.

Cambi’s scope of delivery varies from the core THP to complete turnkey digestion plants. We also offer plant operations & maintenance. The THP plants normally handles sludge from wastewater treatment plants for populations upwards from 150,000, or from approximately 5,000 dry metric tons/year of sludge.

Cambi’s THP enhanced sludge treatment maximises both flexibility and profitability.

What is Thermal Hydrolysis, and What Does It Do?

• Disintegrates cell structure and organic materials and dissolves naturally occurring cell polymers (exopolymeric substances - EPS), a form of protein, into an easily digestible feed for anaerobic digestion
• The resulting less viscous (more fluid) sludge allows doubling of digester dry solids (DS) loading with stable operations
• Increases sludge and bio-waste biodegradability and therefore yields more biogas
• Better dewatering - up to 40% total dry solids - by releasing water bound in EPS (EPS binds 4 - 5 g water / g EPS). This gives less biosolids after digestion and dewatering
• Produces an efficient and pathogen-free fertilizer: Treating the material at 165°C for 20 minutes meets all known standards and requirements for sterilization, including the EU Animal By Products Regulation (ABPR, 1774/2002/EC) category II & III materials

Why Cambi Thermal Hydrolysis?

Enhanced biogas production:

- 50-65% of the organic matter (Volatile Solids – VS) in sludge converted to biogas
- High quality biogas, rich in methane, low in H2S
- Ideal for green electricity, as renewable vehicle fuel, or substitute for natural gas

Improved dewaterability after digestion by 50% - 100%

- Dewatering up to 40% DS (dry solids)
- Less material handling/transport
- Significant mass reduction
– Less water evaporation for sludge drying
- Digested and dewatered Cambi cake stockpiles and composts easily without any additional structural material

Pasteurization and stabilization of final biosolids product /cake

- Thermal treatment at 165°C for 20-30 minutes before digestion eliminates all pathogens
- No regrowth or reactivation of bacteria
- Increased stabilization of cake after digestion due to high organic matter conversion.

The digested sludge has no negative odour

- Odour nuisances prevented due to the closed process cycle

Highly energy-efficient and reliable process

- Maximum reuse of steam in thermally insulated vessels
- Maximum dry-solids feed (16-17% DS) to the Thermal Hydrolysis Process
- Thermal energy use is thus comparable or even less than other methods of pasteurization
- Direct steam injection avoids clogging and unexpected shut downs of heat exchangers

Lower retention time and higher dry-solids content in digesters

- Reduced viscosity from thermal hydrolysis (making the sludge more fluid)
- Digesters can be fed with a sludge concentration of 8-12% dry solids (DS), twice that of a conventional digester.
- Increased speed of digestion
- Together these factors increase digester capacity 2-3 times, with loading rates up to 6kg/m3/day of organic matter

Robust anaerobic digestion process

- Ideal feed for anaerobic digestion; consistent and free of unwanted micro-organisms
- Elimination of foam-causing filamentous bacteria
- High alkaline buffering capacity
- High active biomass concentration

Compact design makes THP easy to retrofit to existing sludge treatment plants

Existing digester assets can be used to treat sludge or other bio-wastes from a wider region without further investment

- Existing digester systems can be fed at more than double conventional rates, thus increasing the capacity of existing plants or minimising capital expenditure for new digesters

Sludge Treatment Technology

In Cambi’s patented hydrolysis plant, sludge is cooked under high pressure and temperature (133-200°C). The organic components in the sludge dissolve in water in the same way as when you boil meat, fish, etc. Cell structures in the sludge breaks open under the temperature and pressure used. Energy rich compounds from the cells are then dissolved. In addition the sludge becomes fully sterilized so that the final product is disinfected. The hydrolysed sludge has a much lower viscosity and allows high solids operations in stirred reactors type digesters. The heat treatment makes the final digestate much easier to dewater.

The following benefits can be achieved:

• More biogas production
• Biosolids mass reduction (less solids and less water in final product)
• Enhanced digester capacity due to much higher solids loading rates
• Stable digester operations
• A safe product that is easy to store and has little odour
• A very compact and flexible plant

The thermal hydrolysis plant can easily be integrated into existing and new sludge treatment plants. Each plant is optimized to achieve the lowest possible processing costs.

More Biogas Production

The hydrolysis process creates large amounts of dissolved organic compounds including organic acids, which are effectively broken down into biogas in a digester. Compared to conventional processes for activated sludge, there is up to a 100% increase in the amount of biogas produced. As much as 55-60% of the organic material is converted to biogas. This increase in energy production is significantly larger than the energy consumption needed in the hydrolysis process, so the process provides a considerable energy surplus. The biogas can be burned in a combined heat and power installation in order to produce as much electricity as possible. The excess heat from this installation is almost sufficient to supply the hydrolysis with required heat energy.

Biosolids Mass Reduction

The dewatering properties after the hydrolysis process are up to 100% improved. A dry solids content of sludge over 30% for digestate can be achieved without problems. This gives a considerable reduction in the mass and there is often no need for drying the sludge before it is transported, dispersed or burned. If drying is still necessary, both investment requirement and energy cost will be significantly reduced.

Higher Digester Loading

Due to pre dewatering and viscosity change in the hydrolysis the digester can be loaded with a sludge concentration of 8-12% dry solids (DS). The speed of digestion is also considerably increased. Together these factors improve the digester capacity 2-3 times. Even with this higher loading, customers find that the digesters operate with good stability.

Reduced Wastewater Treatment Costs

Treatment of biological sludge is no longer a problem when using Cambi thermal hydrolysis. The wastewater treatment process can therefore be technically and economically optimized to achieve the required wastewater treatment. No compromise needs to be made to reduce the production of biological sludge.

Recycling Resources

In addition to a high biogas production, the process opens for further use of resources.

• Hydrolyzed undigested sludge can be used as internal carbon source in the wastewater treatment plant due to the dissolved organic carbon compounds from the hydrolysis
• Low volume of reject water in the reject from final dewatering after digestion combined with high concentrations allow a separate treatment and recycling of nutrients
• The dewatered sludge cake is pathogen free and very stable, easy to store in stacks/piles and causes no odour problem. It also composts directly into a brown "soil like" biosolid. Growth tests have proven very good fertilizing value

Removing Hazardous Substances

Legislation and consumer requirements are closing in and restricting use of sludge on agriculture. The Cambi thermal hydrolysis includes and opens for solutions to this problem:

Pathogens, such as intestinal bacteria and spores are effectively eliminated through the sterilization process

The hydrolysis process allows for the use of oxidizing techniques for breaking down environmentally hazardous organic substances both as part of the wastewater treatment or directly on the sludge

Compact and Flexible Plant

The amount of sludge is reduced throughout the entire process and the concentration of solids is very high, beginning with around 15% before hydrolysis. The plant is therefore compact compared to conventional solutions. The plant is designed as a modular system according to the customer's requirements. This means that the plant can be adapted to different needs and it is also possible to change the process at a later time. A step-by-step construction can be planned considering later expansions to meet future government requirements or needs for increased capacity and/or functions.

Cambi’s thermal hydrolysis process is well suited for most existing sludge treatment plants. For example, building a hydrolysis plant can double to triple the capacity of an existing digester. The process has been used as a retrofit or in green field projects because of the good economy Cambi has on the overall digestion process.