PRODUCTS

WE WORK ON THESE TOPICS:

 - Phytoremidiation (der dækker plantebaserede systemer)

 - Rootzone treatment / Constructed Wettland

 - Evapotranspiration

 - Mineralisation

 - Soil remediation

 - Air remediation / BioVentic / Indoor Climate

 - Greening / Green Wall

 - Composting / BioFertilizer

 - Natural Ventilation / Geotemperating

 - Symbiosis

 - Urban Planning / Ecohouse

BACKGROUND FOR THE ROOTZONE FILTER

The root zone method was developed in the 1950’s and the following years based on the fact that certain soil types have a high adsorption capacity to phosphorous.

The root zone/filter plant is a biological filter, where the biological treatment of waste water takes place in a soil volume, which is penetrated by roots. The root network is to be composed by suitable plant species, it is even beneficial if the optimum varieties of these species are selected. This structure implies that the waste water flows horizontally through the soil mass. However, also vertical flows are a part of the process.

 During the waste water flow, the nutrient elements - phosphorous and nitrogen - are bound to the soil colloids respectively released to the atmosphere through nitrification and denitrification. The turnover of the organic substances occurs with assistance from a diverse, aerobic and anaerobic, microbial activity in the soil

 The aerobic activity is supplied with oxygen from the plant roots as well as via the surface of the system. Thus aerobic activity is concentrated near the plant roots, while anaerobic activity prevails in some distance from the roots. This mosaic of aerobic and anaerobic pockets provides optimum conditions for a wide range of active microbial organisms. Aerobic as well as anaerobic groups of organisms are required for the required down-break of the waste water constituents and may be compared with the anaerobic and aerobic steps in a biological waste water treatment system.

 In biological treatment plants, the two processes are normally separated. In the root zone/filter system, the above mosaic structure permits all processes to occur in the same soil volume. Soil with a plant cover is known for a very high biological activity. This activity is further enhanced by maintaining a large surface and pore volume within the soil structure. Wetland plant species, in particular reed (Phragmites Australis/Communis L.) stimulates a high pore volume and in-depth supply of oxygen. When the plant stand is fully developed, the pore volume constitutes 42% of the total volume in the upper 60 cm of the soil. The microbial activity is at the below approximate range:

 The micro organisms in the soil are likewise characterised by having a diverse composition. In a root zone/filter bed, more than 5,000 species of bacteria are commonly found as compared to 200-300 in the biological treatment plants.

 Through various research institutions, TransForm of 1994 Ltd. / Danish Root Zone has recorded the turnover of more than 6,000 different compounds in root zone/filter plants.

 The principle in the root zone method is to activate the microbial processes that actively stimulate the down-break of the toxic compounds in a specific waste water situation.

  In root zone plants, the water transport activates aerobic as well as anaerobic processes. This has the effect that large amounts of organic matter is metabolized in a short period of time. This produces metabolites such as organic acids, lactates etc. These compounds assists in mobilising iron and aluminium, which bind phosphate. Down-break of slow - metabolizing carbon compounds are likewise stimulated.

The anaerobic metabolic processes are commonly causing development of odorous gases. These gases, however, are absorbed by soil clay particles and colloids, which have high sorptivity and thus hinders bad odours from being released to the atmosphere.

 The plant roots creates a horizontal net of pores, which further are connected by star shaped, horizontal root net structures. This net of pores is conserved and in conjunction with clayous soil types they provide the hydraulic capacity of the system. Additionally, the evapo-transpiration during the growth season reduces the amount of effluent. The polluting compounds are being concentrated, and the processes are further activated. In a fully developed stand of Phragmites, the evapo-transpiration lies within the range of 3-8 times pan-evaporation.

 Not only a biological turnover takes place in the root zone/filter plant. The on-going reactions in conventional waste water treatment plants may also take place in the root zone/filter plant. However, the required compounds have to be in place for the reactions to occur.

 The first pilot plants were established during the sixties, and the first full scale plants were established in Israel in 1968 and in Germany in 1974. During the last centuries, experience with the root zone method has been obtained world wide and with all sorts of waste water and sludge.

 Through experience and research, the plant design has been improved. This has led to higher hydraulic efficiency and better dosing of the waste water and regulation of the water level, which checks the risk of surface flow in the system.