entec Services - Proven Technology - Anaerobic Digestion - Types of Anaerobic Digestion Systems

entec biogas offers five different anaerobic digester systems: CSTR, BIMA, MBS, UASB, and Anaerobic Digestion Filter System.

CSTR- Digester System
The entec biogas-CSTR-Digester is a sealed vertical, cylindrical digester. The mixing of its contents is provided by a centered vertical low-speed agitator which is characterized by its high circulation rate. Thus the digester content is perfectly mixed.

At the same time, the low rotation speed guarantees gentle treatment of the anaerobic microorganisms and due to continuous mixing provides optimal substrate transport for the bacteriological degradation of the organic substances into biogas.

The entec biogas-CSTR-Digester is suitable for the treatment of high solid material, such as bio waste and sludge, as well as for scum developing material. Sediments can be removed easily during operation. It is especially suitable for large scale biogas plants because of construction sizes of up to 1.585 million gallons (6,000 m³).

This digester type has already been applied for the treatment of all kinds of degradable organic wastewater or sludge and waste, such as manure, renewable primary products, municipal bio waste, restaurant and market waste, food industry waste, slaughterhouse waste, sewage sludge.

BIMA- Digester System

The entec biogas-BIMA-Digester System (Biogas-Induced-Mixing-Arrangement) is the “Original” among the self-mixing hydraulic digester systems. It was developed in 1979 and has been continuously improved ever since. It doesn’t require any mechanical equipment such as agitator, circulation pumps or gas injection for mixing the digester contents.

The 2-chamber system uses the produced biogas to create a level difference in the chambers and in this way builds up a mixing pressure of up to 500 mbar. The turbulent mixing occurs against the biogas production in intervals of 4-10 times a day. The system is extremely low-maintenance and has lower operational costs than conventional systems.

More than 40 BIMA-Digesters are in operation worldwide for a variety of applications; some of them already since the beginning of the 80’s. Ideal applications of this system are high solid sludge and waste, such as in the sewage sludge treatment, treatment of organic solid wastewater, manure, organic household and industrial waste, etc.

MBS-Digester System

The flat construction of the entec biogas-MBS-Digester makes it perfectly suited for low-cost applications at small and mid-scale biogas plants. Depending on the operation purpose, high-speed agitators or incline shaft agitators are used for mixing its contents.

This digester type can be used as a main or post-digester and can be sealed with a firm cover or a double-membrane serving as the gasholder. It can be applied for biogas production for all degradable organic wastewater, sludge and solid waste.

UASB-Digester System

The waste water in the UASB-Digester flows through a sludge bed of anaerobic bacteria which shows a high biomass density by its pellet structure. These bacteria degrade the organic pollutants via multiple intermediate levels and convert them into biogas.

This high-performance sledge-bed digester is suitable for highly polluted, low-solid, and organic loaded waste water, such as in the food industry, yeast industry, breweries, distilleries, etc.

Anaerobic Digestion Filter- Digester System

The entec biogas-Anaerobic Filter System is a high performance digester loaded with filling material and is used for the treatment of wastewater without suspended solids.

The special filling material forms a huge surface in the digester which allows the construction of smaller volume tanks. The wastewater passes the affixed anaerobic bacteria which are formed on the filling material. The waste water is biologically cleaned at the same time.

Ideal application for this system can be found in the pharmaceutical, food industries and dairies, distilleries, breweries, etc.