Biofilters (water) are developed to collect and purify storm- and wastewater and represent a promising system for storm water treatment. Bacteria and microorganisms are located on a filter medium (biofilm), which often consists of sand or granular activated carbon. The biofilm degrades nutrients and contaminations in the wastewater (influent) that is piped through the filter material. As mentioned above, the term “filter” is misleading. Biofilters separates/removes nutrients and organic carbons from wastewater/storm water through biodegradation. As a result biofiltration improves the quality of wastewater (reduction of nutrients, metals, sediments) and storm water and at the same time harvests storm water and stores it for a certain period.

Performance

Evapotranspiration none none
Shading none none
Reflection (Albedo) none
Water Conveyance 1
Water Infiltration 2
Water Retention 1
Water Storage 2
Water Reuse 1
Water Filtering 2
Water Bio-remediation 2
Deposition none
Bio-filtration none
Habitat Provision 1
Connectivity none
Beauty / Appearance 1
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 degrades/removes/ nutrients and contaminations and biological substances.
Technical & Design Parameters: 
- Biofilter as demonstration for bioretention system - Biofilter situated at the car park in Clayton Campus - processed storm water per annum: 1.000.000 litres - removal: nitrogen, phosphorus, 90% of heavy metals - water storage in ornamental pond - reuse of water runoff after treatment - Improves the removal of difficult pollutants such as Nitrate - Uses shredded newspaper (a synthetic waste material), as it is an effective source of carbon for denitrification - Shredded newspaper is mixed with coarse sand to create a new layer under the soil media, which is kept continuously saturated with water, to maintain an anaerobic condition - Can be integrated to any bioretention facility
Conditions for Implementation: 
Space for construction needed, flat terrain
Benefits & Limitations: 
Benefits: - water purification - improving quantity of storm- and wastewater - storm water regulation/management - quality of live (reduction of odours) - habitat for wildlife (limited service)

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