Express Drainage Solutions Kenya Ltd can Design, Supply and Install Root Zone Waste Water Treatment facilities. It consists of planted filter-beds containing gravel, sand and soil. The RZ-WAT system utilizes nature’s way of biologically processing domestic & industrial effluents-it uses anaerobic processes or anaerobiosis. This effective technology which is also a variant of Decentralised Wastewater Treatment Systems (DEWATS) was developed in 1970s in Germany and has been successfully implemented in different countries mainly in Europe and America. This why we have called it the Minor DEWAT to differentiate it from the Major DEWAT which is adapted to producing viable amounts of biogas.

The root zone wastewater treatment system which Express Drainage Solutions Kenya Ltd can undertake makes use of biological and physical-treatment processes to remove pollutants from wastewater. Due to its natural process, there is no need to add any input such as chemicals, mechanical pumps or external energy. This reduces both the maintenance and energy costs.

To accomplish this, the root zone wastewater treatment undertakes the following steps:

  • Pre-treatment done in a Settler – a device that separates the liquid from the solid
  • First treatment takes place in Anaerobic Baffled Reactor – a device with several identical chambers through which the effluent moves from top to bottom.
  • Second treatment happens in an Anaerobic Filter – a device filled with a filter material (cinder), through which the effluent moves from top to bottom.
  • Third treatment takes place in a Planted Gravel Filter – a structure filled with gravel material and planted with water-resistant reed plants, which provide oxygen to the passing effluent.

The type of RZ-WAT Express Drainage Solutions Kenya Ltd design, supply and install is illustrated by the diagrams below;


The Root Zone Waste Water Treatment system takes into account the natural slope of the ground, so that water flows from one device to another without any external energy input such as motor pump. The root zone waste water spot is illustrated by the diagram below;

Root Zone Waste Water Spot

Root Zone Waste Water Spot

Once the reed plants create an established stand, usually after the first growing season, the reed bed requires little or no maintenance. The plant foliage will soon blend naturally into the landscape, ever changing with the seasons and creating a pleasing sight as well!

Garden Chambers, 2nd Flr. Off Jeevangee Gardens, Mokhtar daddah Street

+254 727 160738

+254 738 627632

P.O.BOX 8620-00200, Nairobi, Kenya