Anaerobic Reactor/ Anaerobic Digester

EEI has designed and manufactured Anaerobic Digester for the treatment of sewage sludge and other organic wastes. The effluent is used as a fertilizer.

Anaerobic Digesters can be used for agricultural, industrial, and wastewater treatment facilities. They are also utilized in industrial and agricultural operations that produce significant organic waste. Municipal Solid Waste (MSW) is used to produce gas from natural decomposition of organic material in the waste, which is used as an energy source.

Anaerobic digestion is to produce combustible biogas which can be burned to provide energy for a whole range of uses. Biogas systems or Anaerobic Reactors/ Anaerobic Digester produce biogas from a variety of wastes and are hygienic and ecologically sound Wastewater Treatment Plants (WWTPs).

The use of Anaerobic Digesters to produce renewable energy could reduce fossil fuel dependency and the cost, particularly in the food & beverage industry.

During the process of anaerobic digestion, methane-rich biogas is produced which can be used in combined heat and power (CHP) plants to produce electricity and heat. Methane is not released to the atmosphere and the environment is protected.

Digesters have an additional advantage of energy production and effluent of high nutrient content. Effluent can be used directly for fertilizer application and irrigation.

Biofertilizer (or Bio-fertilizer) from the anaerobic digestion process is produced which has more advantages like

  • Biofertilizers increase the nitrogen and phosphorus available to plants more naturally than other fertilizers.
  • Biofertilizers do not pollute the soil or the environment
  • Production of the Biofertilizer is another source of income
  • Biofertilizers improves fertility to the soil and make it biologically alive.
  • Biofertilizers increases yield

Types of Anaerobic Digesters

Digesters can be broadly grouped based on the need to process liquid or solid waste.

Liquid Waste Digester

Covered Lagoon Digester, sludge blanket type digesters are used with wastes discharged into water and where the solid is less than 2%. The decomposition of waste in water creates a naturally anaerobic environment. These digesters can produce stable, reduced odor, nutrient rich effluent for application on fields and crops to produce biogas for farm energy use. Heat recovery from the biogas can be used to heat chicken farms and dairy farms. Covered Lagoons Digesters are best for hot climates and produce sufficient quantity, quality, and consistency of gas use in an engine generator.

Slurry Waste Digester

Complete Mix Digesters work best with slurry manure or wastes that are semi-liquid when the waste’s solids composition is less than 10 percent.  The wastes are deposited in a heated tank and periodically mixed.

The design of a complete mix digester displaces the volume of the Incoming liquid, and an equal amount of liquid flows out, also allows for removal of bottom grit. This complete mixing process prevents the formation of a floating layer of oils and fats from accumulating at the top of the digester contents. Biogas that is produced remains in the tank until use or flaring.

Semi-solid Waste Digester

Plug flow digesters are used for solid manure or waste when the waste’s composition of solids is 11 percent or greater. The flow pattern in plug flow digesters is simple and without back-mixing wastes are deposited in a long, heated tank that is typically situated in-ground concrete, concrete block or lined rectangular tank. The digester can be covered by a fixed rigid top, floating cover, or flexible inflatable top to collect and direct biogas to the Biogas utilization system. Biogas remains in the tank until use or flaring.


There are three or four different styles of digesters but all share three components.

First, there is an input of manure and other waste products.

The second component is the digester itself and,

The third component is the facility to remove the residual material.

Digestion process

Digestion, or decomposition, occurs in three stages.  In the first process enzyme secreting bacteria converted into higher volatile fatty acids.

In the second process bacteria convert these fatty acids into hydrogen (H2), Carbon dioxide (CO2), and acetic acid.

In the final process bacteria called methanogens to use hydrogen (H2), Carbon dioxide (CO2), and acetate to produce biogas which is methane rich


Each of these three components may vary in size, technology, and cost. Choice of style depends on the size of the user, and some technologies are more cost-effective with larger operations.


Anaerobic digestion is the solution for the waste problems of food and beverages manufacturing companies.

Anaerobic Reactors/ Digesters are the best Waste Management Plan for Food & Beverages Manufacturing Companies, Hotels, Large Apartment Complex and have both financial and environmental long term benefits. with the following details for techno- commercial offer
Quantity of water to be treated along with analysis- COD, BOD, oxygen present, PH value.