bio scrubbers and biotrickling filters

Likusta bio scrubbers

Two-stage process for odour removal and waste-gas purification

Bio scrubbers are used for biological treatment of waste and exhaust gases. The adsorption of organic emission components and of hydrogen sulphide and ammonia are the main application areas. For these purposes, a physical gas scrubber is combined with a biological aeration unit.

First, the raw gas is brought into contact with a scrubbing solution in the absorber. In a second step, the pollutants that have been converted in the scrubbing solution are decomposed into carbon dioxide and water by microorganisms in a regeneration reactor. This reactor corresponds to the aeration tank in waste-water treatment. The nutrients required for bacterial growth as well as acids and alkalis are dosed in to achieve the optimum pH value.

Upstream gas scrubbers prevent aggressive harmful substances in the waste gas from damaging the microorganisms used for treatment.

Biotrickling filters for hydrogen sulphide removal
Bio scrubber for ammonia removal Likusta biotrickling filter
Bio scrubber for ammonia removal

Application areas: Adsorption of organic emission components

Likusta bio scrubbers can be used at air pollutant concentrations of more than 100 mg/m3 – depending on the water solubility of the pollutants.

We have experience with the scrubbing of the following groups of substances

  • Phenols
  • Sulphur compounds
  • Carboxylic acids and carboxylic acid esters
  • Aldehydes
  • Alcohols

Our systems are used by our international customers from a wide range of industries including:

  • Waste-water treatment plants
  • Composting plants
  • Food and feed industries
  • Animal rendering plants
  • Foundries
  • Painting facilities

The application areas for bio scrubbers as well as the specific technical requirements are described in the following VDI guidelines:       

  • VDI 3478 Sheet 1 Biological waste-gas scrubbing - Bio scrubbers                
  • VDI 3897 Emission control - Soil vapour extraction and groundwater stripping systems


Likusta bio scrubbers are always part of a bespoke solution

Absorbers can in principle be designed single- or multi-staged. Decisive for the design is a phase boundary area which is as large as possible in order to ensure the longest possible residence time of the air pollutants with the biological carrier material.

For easily degradable substances, a regeneration reactor can be dispensed with, provided that a sufficiently large absorber sump is installed.

Sedimentation tanks are provided with active ventilation if required.

The individual scrubbing components must be able to withstand the chemical stress. Likusta mainly uses high-quality plastics such as PP or HDPE, but also stainless steel tanks and pipes.



R&I Biotricklingfilter


Likusta biotrickling filters

Biotrickling filters from Likusta for odour removal and waste-gas treatment

Likusta biotrickling filters (also known as bio trickle-bed reactors or bio trickle bodies) use microorganisms for waste-gas treatment in order to remove emission components from odorous and pollutant-contaminated waste-gas streams.

Inert substrates for microorganisms

In biotrickling filters, inert substrates are used instead of the biological substrates in conventional biofilter methods, on which the microorganisms are settled. They are capable of biochemically oxidising organic and inorganic gaseous compounds under aerobic conditions and converting them into low-molecular-weight, non-harmful compounds which are no longer perceptible, such as carbon dioxide and water.

Moisture and the necessary nutrients are supplied to the bio trickle body via sprinkling. In contrast to conventional biofilter methods, the substrates are inert, i.e. they are not decomposed in the oxidation of waste products. Likusta biotrickling filters are suitable for treating both solvent- and odour-laden waste gas with concentrations of up to 1,000 mg/m³.

Biotrickling filter for VOC (Volantile Organic Carbon) elimination
Activated carbon filter downstream of biotrickling filter
Activated carbon filter downstream of biotrickling filter

Bespoke solutions through a variety of possible combinations

Hydrogen sulphide can be successfully be reduced using Likusta biotrickling bed reactors - as specified in the technical instructions for air treatment (TA-Luft).

Likusta biotrickling bed reactors can also be used as a combination with additional waste-gas treatment systems such as activated carbon filters, chemical scrubbers or with downstream biofilter systems.

Some possible fields of application are

  • Waste-water treatment plants
  • Composting plants
  • Food and feed industries
  • Painting facilities
  • Textile industry

By working together with universities, universities of applied sciences and research centres, Likusta has the latest scientific findings available.

When designing Likusta biotrickling filters, all special requirements of the VDI guideline are taken into account (VDI 3478 Sheet 2: 2008-04 Biological waste-gas treatment; Biotrickling bed reactors).


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