Biofilters (air) are facilities to control and purify biological waste gas. They are developed to reduce and eliminate biogenic odours and represent a relatively simple technical installation. The application of biofilters is diverse, including for example agriculture, sewage treatment plants, biogas plants, and composting plants. The term “filter” is misleading in terms of their service: Biofilters (air) does not separate solid particles from gas or water but separate gaseous/dissolved substances through biodegradation. Bacteria and microorganisms are located on a filter medium (breeding ground) that absorbs odours of the air stream (e.g. peat, tree bark, and root wood fibre). The microorganisms on the filter degrade the absorbed, biological substances (biological oxidation) and thus purifies the exhaust air passing the filter material. Biofilters exist in different sizes and structural shapes (often in a box).

Basic information

Type: 
Retrofitting + Creation

Performance

Evapotranspiration none none
Shading none none
Reflection (Albedo) none
Water Conveyance none
Water Infiltration none
Water Retention none
Water Storage none
Water Reuse none
Water Filtering none
Water Bio-remediation none
Deposition 2
Bio-filtration 2
Habitat Provision none
Connectivity none
Beauty / Appearance none
Usability / Functionality none
Social Interaction none
Role of Nature / Mode of Action: 
Biodegradation is a natural process e.g. in soils. This natural degradation is used for different processes for example in anaerobic digestion (biogas production). Microorganisms and bacteria de degrade/remove/ nutrients contaminations, and biological substances.
Technical & Design Parameters: 
- different sizes  flexible modules (expandable) - different shapes  container/box as common construction - low maintenance - easy handling: easy exchange and disposal of filter material - domestic filter materials - ecological process FUCHS-Biofilter (series: BAC): Air purification (example (FUCHS enprotec GmbH n.d.) - different applications - small to medium exhaust air stream (200 to 2.400 m³/h) - integrated facility to pre-damp the air flow (conditioning of exhaust air) - containers made from polyethylene (resistant) - filter covering for protection - natural filter material: bark compost (neutral pH value; balanced moisture  optimal conditions for microorganisms, high degradation rate of organic air impurities)
Conditions for Implementation: 
- optimal conditions ensure microbiological activity and reduction of odorous and harmful substances FUCHS-Biofilter (series: BAC): Air purification (example (FUCHS enprotec GmbH n.d.) physical and chemical conditions: - Moisture content of filter material (40 % - 60 %) - low pressure loss - high buffering capacity - high biodiversity - (optimal) temperature - (optimal) pH value - (optimal) nutrient supply
Benefits & Limitations: 
Benefits: - air purification - reduced odour nuisance (increase quality of life) Potential limitations/disservices: - limited habitat provision for wildlife

This project has received funding from the European Union’s Horizon 2020 research and innovation programme under Grant Agreement No. 730052 Topic: SCC-2-2016-2017: Smart Cities and Communities Nature based solutions