RHIZOTECHNIKI is a company with world class expertise in natural wastewater treatment and sludge humification (humus production). RHIZOTECHNIKI offers sustainable wastewater management solutions for the simple domestic household to the most effective and advanced treatment for municipalities and industrial plants (producing the heaviest pollutants such as heavy metals, toxic organic materials, etc.) RHIZOTECHNIKI implements the Kickuth`s `ROOT ZONE METHOD`, a German natural wastewater treatment method with sustainable operation. This method is innovative vis a vis other natural methods because of its use of adapted soil -instead of different inert materials or earths- and special strains of reeds (Phragmites australis).

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Business Type:
Service provider
Industry Type:
Water Treatment
Market Focus:
Internationally (various countries)

Only by natural methods, using soil as a bio-reactor, with a self-regulating operation can sustainable solutions for wastewater purification be guaranteed. These methods provide high purification efficiency without any sludge production, without the need for external energy input, resulting in minimal operational costs.

Unlike compact technical systems, RHIZOTECHNIKI provides sustainability and environment protection along with security for public health in wastewater management. (The results of technical systems are harmful for the public health. They are more than obvious in environmental and health scandals worldwide because of the no exit consequences of compact technical systems. Their following negative characteristics are lack of sustainability, high external energy budget, and continuously growing operational costs.)

Only the soil treatment of impurities guarantees their decomposition and therefore environmental and public health protection.

Soil is the biggest and most effective reactor of nature.

RHIZOTECHNIKI is a company specializing in wastewater treatment using the ROOT-ZONE METHOD.
It has the exclusive rights to the ROOT-ZONE METHOD for Southeastern Europe with its headquarters in Athens and affiliated offices in France and Germany. The ROOT-ZONE METHOD is a natural technology that cleans every type of wastewater from communal to highly toxic industrial effluent. Only through the combination of the biochemical activity of soil interacting with the aeration and hydraulic efficiency of special strains of reeds can such a vast range of pollutants be effectively dealt with, exceeding existing norms. RIZOTECHNIKI has been operating in Greece since 1995.

Dr. Theodora SERETAKI, Founder & Director of RHIZOTECHNIKI is a biologist & environmental engineer, member of VDI, the GERMAN ASSOCIATION OF ENGINEERS. She trained at Athens University, Greece and the Ecochemistry Institute, of Kassel University, Germany. She holds a doctorate in ecological management of wastewater systems by natural methods and has 30 years of experience in research and development of the KICKUTH's ROOT ZONE METHOD. She is a consultant in ecological environmental management and a leading expert on ecological management of algae in natural water bodies.

Professor Dr. Reinhold KICKUTH, soil scientist and inventor of the ROOT ZONE METHOD, Professor Emirate at the Goettingen and Kassel Universities, has installed ROOT ZONE plants all over the world.

Dr. Theodora SERETAKI, has worked with Prof. Dr. R. KICKUTH since 1983. Since 1998 she co-developed new root zone systems especially in the treatment of nitrogen and industrial sludge. She has adapted the design of installations to incorporate humification of solids (pre-treatment) with biological wastewater treatment.

All treatment steps in only one installation providing economy of costs, energy and space

The Root Zone Method harnesses the natural chain reactions of the soil systems. This makes it possible for all wastewater treatment steps to be completed in only one installation. All treatment levels proceed in a Root Zone Bed, whilst conventional systems need different lagoons for each treatment step.


Mechanical Treatment (Pre-treatment)

  • Sedimentation, Drying, Disinfection and Humification of solid remains and sludge

Biological Treatment (Secondary Treatment)

  • Decomposition of organic and toxic matter from the wastewater (e.g. poly-chlorinated hydrocarbons, paints, phenols)
  • Assimilation of biological sludge

Advanced Treatment  (Tertiary Treatment)

  • Simultaneous Nitrification and Denitrification of Ammonia compounds
  • Elimination of phosphorus compounds
  • Incorporation of heavy metals into the soil systems
  • Assimilation of biological sludge

Effluent Disinfection (Elimination of pathogenic micro-organisms)

  • 99,9 % elimination of Coli-bacteria, Salmonella and Viruses

Sludge Humification

  • Dewatering, Decomposition of organic matter, Disinfection and Humification of solid remains and sludge

Advantages Of Sustainable Operation With The Root Zone Method

Two very important advantages vis a vis the conventional methods

  • Operates without any external energy input
  • Produces no sludge during the biological treatment

Additional advantages

  • Advanced treatment is always included as an integral part of the Root Zone Process
  • Self-regulating operation lasting up to 100 years without requiring any machinery
  • Low maintenance and regulation
  • Stability in effectiveness
  • Balancing fluctuations in the pollutants' concentration
  • Tolerance in hydraulic loads' fluctuations
  • Flexibility in installation's capacity from a small household to a large city
  • Durability of up to 100 years
  • Low operational costs
  • Adaptability. Reed beds can be installed in limited or difficult terrain
  • In harmony with the landscape
  • Sludge treatment (humification) without incineration, dumping or costly reprocessing

The results of technical systems are harmful for the public health. They are more than obvious in environmental and health scandals worldwide because of the no exit consequences of compact technical systems. Their following negative characteristics are lack of sustainability, high external energy budget, and continuously growing operational costs.

RHIZOTECHNIKI builds installations that protect the Environment and Public Health through actions that are inherent in the process itself:

Natural CO2 Capture and Storage:

Root Zone installations for a capacity of 2000 P.E., diminish CO2 emissions by 86 tons per year and produce 19 tons per year of carbon matter in the form of Humus stored in the soil. N.B. Conventional methods only produce CO2.

Disinfection of pathogen micro-organisms:

Pathogenic bacteria such as E. coli, Salmonella and viruses are eliminated by the roots exudates. This makes chlorination of effluents superfluous.

From the ecological and public health perspective Chlorination is considered to be very problematic in water and wastewater management. Chlorine creates more problems than it solves.

N.B. A conventional method using Chlorine creates toxic substances at the end of the so-called 'cleaning' process. This in turn pollutes natural water resources. Chlore with its free electron is a very aggressive reacting chemical element which combined with organic impurities creates toxic substances.

100 % efficiency without effluent

In summer, when the water quantities are greatly reduced, high concentrations of pollutants emerge. In this very sensitive period of the year, Root Zone installations do not release any effluent thereby saving natural water from pollutants. The reeds can evaporate up to 3,0 m3/d liquid per m2 resulting in total evaporation.

N.B. Conventional systems release all their so-called cleaned effluents into the natural water bodies.

Equilibrium of thermal pollution

The reeds' mean annual evapo-transpiration can reach 1,600 mm/m2 per year. This natural process creates a cooling effect in the immediate surroundings.

Legacy of biosphere reserves

The world's first Root Zone installation, in Othfresen, Germany, has been in operation since 1974. It comprises 10 % of a natural 25 ha wetland and continues to serving a population of 4,500 P.E. at maximum efficiency. Since 1997, has been recognized by the E .U. as protected reserve. Since it not only cleans sewage and wastewater, it also serves as an ecological refuge for rare and protected species.