Biological wastewater treatment

  • On the pictures below an example is shown of water recycling in a production unit, where annual ly +/-18 million liters of water are purified through a biological wetland.
  • The type of reed that is used is Prachmytes Australis reed for brackish water.
  • This environmentally friendly system can be used in many applications.
  • Such applications are also used for :
    - purification of domestic wastewater
    - wastewater in the agricultural industry from the potato, vegetable and fruit processing,etc....
Reed used for the water treatment
  • Reed, Phragmites Australis has rhizomes on the roots with a network of hollow, underground stems, which can go very deep. These rhizomes serve as a substrate for the bacteria to get rid of water pollution.The bacteria need  oxygen.Via air stems (a kind of hollow tubes which are connected to the hollow rhizomes), the underground plant parts are feeded with oxygen. This process of oxygenation, works the whole year round . It must also be carefully mowed. If the stems are fillling up with water or slip, the reed can be heavely and long-term damaged. It is only allowed to mow the reed if it has heavely suffered from drought. A newly constructed wetland with reed grows slowly. The young canes invest first in the rhizome and root growth and then in air stems
Other types of suitable  wetland plants for water treatment are:
            - Scripus Lacustris - Matt Rush
          - Glyceria Maxima
          - Typha Latifolia - BroadLeaf Cattail
          - Iris Pseudoacorus - Yellow Iris
 Read is the best choice. when planting several types, it often happens that reed eventually takes over.

Environmentally friendly

Of all small-scale systems ,reed is the most natural. They do not require  intensive care or high energy (only one pump which works occasionally). There are only a few mechanical devices needed. With the necessary creativity,a good reed field can be integrated in the garden.In such a reedbed the most work is done by the bacteria.In addition, the effect of the soil must be added: formation of poorly soluble salts; Phosphates are converted in insoluble iron and calcium .Nitrogen compounds are converted by bacteria in harmless nitrogen gas. The presence of plants also means an additional asset. They take nutrients (phosphorus and nitrogen) out of the polluted water. The operation during the winter months will not deteriorate significantly. Compared with conventional water treatment plants, reed fields have the great advantage that no sludge should be removed.
  • Different types of reed fields: 
1.When flow-wetlands are used, wastewater flows horizontally across the field. There is no infiltration of the soil. This system has a much lower return than percolation fields and give off an unpleasant smell.
2.In percolation fields,the wastewater percolates vertically through the field. The purified water is collected through drains and removed. The yield is 4 to 5 times higher compared with flow-wetlands.
3.In Root zone treatment , the water flows horizontally through the root zone of the reed bed. The inlet and outlet zone of the reed bed are filled with gravel. The risk of clogging at the beginning of the field is very high.Therefore this type of constructed wetlands is not the best choice.