GB2182651A

GB2182651A - Root zone plant for the purification of contaminated water

Info

Publication number: GB2182651A
Application number: GB8622946A
Authority: GB
Inventors: Jorgen Logstrup
Original assignee: Individual
Current assignee: Individual
Priority date: 1985-06-26
Filing date: 1986-09-24
Publication date: 1987-05-20
Also published as: DK290185D0; SE8602818D0; SE8602818L; DK290185A; DK153135C; NO162759C; DK153135B; SE466057B; GB8622946D0; NO862557L; NO862557D0; GB2182651B; NO162759B

Abstract

A root zone plant for the purification of contaminated water comprises a mass 3 of a growth culture medium such as soil planted with marsh plants 4. Contaminated water is supplied to the soil 3 through a shingle 5 at one end of the plant and purified water is discharged at the other end through a further shingle filling 6 and a drain pipe 7. The soil is positioned in an upwardly open movable container 1,2 whereby the plant need only be placed in its position of use once the marsh plants have grown to the required size. <IMAGE>

Description

SPECIFICATION Root zone plant for the purification of contaminated water This invention relates to a root zone plantforthe purification of contaminated water comprising a mass of growth culture medium planted with marsh plants such as common reed (Phragmetis com munis), rush (Schoenoplectus lacustris), and reed mace (Typha), means for supplying contaminated watertothegrowth culture medium and means for discharging the purified water therefrom, During recent years such root zone plants have become widely used for sewage purification.

The water purification obtained by a root zone plant is based on a complicated interaction between the growth culture medium,the root system ofthe marsh plants, and the micro flora ofthe growth culture medium.

The micro flora partly consists of aerobic bacteria and partly of facultative anaerobic and obligate anaerobic bacteria. The capability of the bacteria as far as the degradation of the organic matters supplied by the sewage is concerned is determined by the oxygen supply effected by the intercellular oxygen supply system (aerenchym) ofthe marsh plants conducting air to the root system beneath the water such face.

The growth culture medium also forms part of said interaction by functioning partly as substratum for the root system of the plants and partly as supplier of the different nutritive salts for plants and micro organisms.

A major drawback of the known root zone plants is the considerable time e.g. up to 2 years which elapses from thetime of planting tothetime of complete functioning of the plant. The reason forthis is thatthe plants require considerable time to develop a ramified root system which is a prerequisite for the effectiveness of the system.

This drawback is eliminated by the root zone plant ofthe invention, said plant being characterized in that the growth culture medium is placed in an upwards open mobile container.

Using such a container makes it possible to start the establishmentofa root zone plant at such a timethat the plant is fully functional at the time of delivery. In practice, this may be effected by the planting ofthe desired plants in such a number of containers with growth culture medium which corresponds to the estimated sale 2-3 years ahead.

The container is preferably a plastic tank or a metal or wooden tank e.g. made from water resistant ply- wood, which on the inside is coated with a water proof plasticfilm e.g. of a thickness of 2 mm.The container which is preferably rectangular and e.g. of a length of about 6 m and a width of 2.4 m is preferably filled with a growth culture medium such as soil up to a heightof60-80cm.

At the one end the rectangular container preferably comprises a mass of a particulate, inorganic material such as limestone, marble pieces and shingles, and at the opposite end a second mass of an inorganic material. Adrain pipefordischarging the purified sewage is preferably provided in the second mass.

Instead of providing such atthe ends of the contain er it may comprise open channels which are sepa rated from the growth culture medium by means of water permeable separation walls e.g. in the form of a perforated plasticfilm or a woven textile material.

Large or small containers may be used as needed and the containers may be provided with such cou pling means thatthey can be coupled in parallel.

When delivering a plant ofthe invention the containeror containers are transported to the place of use and are there placed on the soil or in specially shaped, optionally cast, holes in the soil.

A special advantage of the root zone plant of the invention is that it causes no pollution because the risk of leakage of contaminated water and thus pollution ofthe surrounding soil is completely eliminated.

Furthermore, the system may be easily replaced if, for one reason or another, it ceases to function.

Finally, the location ofthe plant can be freely chosen because no considerations as to special soil conditions have to be taken.

For security reasons a railing is preferably attached to the top of the container.

The plant described is particularly suitable for the purification of sewage. However, it should be understood that it may also be used for the purification of other types of contaminated water e.g. water with an undesired high salt content. Thus, it has proved to be suitable for reducing the contents of salts imparting hardness to the water and other salts such as nitrates, phosphates, and heavy metal salts in ground water.

Also water containing undesirably large amounts of organic material can be purified in a plant ofthe invention.

The invention will now be described in detail with reference to the drawing wherein Figure 1 shows a top view of a root zone plant ofthe invention and Figure2 shows a sectional view after the line Il-Il of the root zone plant shown in Figure 1.

In the drawing lisa rectangu lar tank, the inside of which is coated with a water-proof plasticfilm 2. In the tank 1 there is a soil mass 3 which is planted with marsh plants4 (Phragmetis communis). At the right end ofthetank 1 there is a filling 5 of an inorganic material such as shingles and a similar but smaller filling 6 is placed at the left end ofthetank 1. The latter filling 6 is placed over a drain pipe 7.

The plant shown furthermore comprises a railing 8 encircling the top ofthetank 1.

When using the plant of the invention contaminated water e.g. sewage is introduced into the filling 5 from where it penetrates into the soil mass 3 and movestowardsthefilling 6 and the drain pipe7 placed therein.

Duringthepassagethroughthesoil mass 3the sewage is purified to such an extent that it can be passed into natural recipientsthroughthedrain pipe 7 or it may be used as fresh waterwithoutfurther purification.

1. A root zone plant for the purification of con

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. SPECIFICATION Root zone plant for the purification of contaminated water This invention relates to a root zone plantforthe purification of contaminated water comprising a mass of growth culture medium planted with marsh plants such as common reed (Phragmetis com munis), rush (Schoenoplectus lacustris), and reed mace (Typha), means for supplying contaminated watertothegrowth culture medium and means for discharging the purified water therefrom, During recent years such root zone plants have become widely used for sewage purification. The water purification obtained by a root zone plant is based on a complicated interaction between the growth culture medium,the root system ofthe marsh plants, and the micro flora ofthe growth culture medium. The micro flora partly consists of aerobic bacteria and partly of facultative anaerobic and obligate anaerobic bacteria. The capability of the bacteria as far as the degradation of the organic matters supplied by the sewage is concerned is determined by the oxygen supply effected by the intercellular oxygen supply system (aerenchym) ofthe marsh plants conducting air to the root system beneath the water such face. The growth culture medium also forms part of said interaction by functioning partly as substratum for the root system of the plants and partly as supplier of the different nutritive salts for plants and micro organisms. A major drawback of the known root zone plants is the considerable time e.g. up to 2 years which elapses from thetime of planting tothetime of complete functioning of the plant. The reason forthis is thatthe plants require considerable time to develop a ramified root system which is a prerequisite for the effectiveness of the system. This drawback is eliminated by the root zone plant ofthe invention, said plant being characterized in that the growth culture medium is placed in an upwards open mobile container. Using such a container makes it possible to start the establishmentofa root zone plant at such a timethat the plant is fully functional at the time of delivery. In practice, this may be effected by the planting ofthe desired plants in such a number of containers with growth culture medium which corresponds to the estimated sale 2-3 years ahead. The container is preferably a plastic tank or a metal or wooden tank e.g. made from water resistant ply- wood, which on the inside is coated with a water proof plasticfilm e.g. of a thickness of 2 mm.The container which is preferably rectangular and e.g. of a length of about 6 m and a width of 2.4 m is preferably filled with a growth culture medium such as soil up to a heightof60-80cm. At the one end the rectangular container preferably comprises a mass of a particulate, inorganic material such as limestone, marble pieces and shingles, and at the opposite end a second mass of an inorganic material. Adrain pipefordischarging the purified sewage is preferably provided in the second mass. Instead of providing such atthe ends of the contain er it may comprise open channels which are sepa rated from the growth culture medium by means of water permeable separation walls e.g. in the form of a perforated plasticfilm or a woven textile material. Large or small containers may be used as needed and the containers may be provided with such cou pling means thatthey can be coupled in parallel. When delivering a plant ofthe invention the containeror containers are transported to the place of use and are there placed on the soil or in specially shaped, optionally cast, holes in the soil. A special advantage of the root zone plant of the invention is that it causes no pollution because the risk of leakage of contaminated water and thus pollution ofthe surrounding soil is completely eliminated. Furthermore, the system may be easily replaced if, for one reason or another, it ceases to function. Finally, the location ofthe plant can be freely chosen because no considerations as to special soil conditions have to be taken. For security reasons a railing is preferably attached to the top of the container. The plant described is particularly suitable for the purification of sewage. However, it should be understood that it may also be used for the purification of other types of contaminated water e.g. water with an undesired high salt content. Thus, it has proved to be suitable for reducing the contents of salts imparting hardness to the water and other salts such as nitrates, phosphates, and heavy metal salts in ground water. Also water containing undesirably large amounts of organic material can be purified in a plant ofthe invention. The invention will now be described in detail with reference to the drawing wherein Figure 1 shows a top view of a root zone plant ofthe invention and Figure2 shows a sectional view after the line Il-Il of the root zone plant shown in Figure 1. In the drawing lisa rectangu lar tank, the inside of which is coated with a water-proof plasticfilm 2. In the tank 1 there is a soil mass 3 which is planted with marsh plants4 (Phragmetis communis). At the right end ofthetank 1 there is a filling 5 of an inorganic material such as shingles and a similar but smaller filling 6 is placed at the left end ofthetank 1. The latter filling 6 is placed over a drain pipe 7. The plant shown furthermore comprises a railing 8 encircling the top ofthetank 1. When using the plant of the invention contaminated water e.g. sewage is introduced into the filling 5 from where it penetrates into the soil mass 3 and movestowardsthefilling 6 and the drain pipe7 placed therein. Duringthepassagethroughthesoil mass 3the sewage is purified to such an extent that it can be passed into natural recipientsthroughthedrain pipe 7 or it may be used as fresh waterwithoutfurther purification. CLAIMS

1. A root zone plant for the purification of con taminated water comprising a mass (3) of a growth culture medium planted with marsh plants (4), means (5) for supplying contaminated water to the growth culture medium (3), and means (6,7) for discharging purified water therefrom characterized in that the growth culture medium is placed in an upwards open mobile container 2).

2. Arootzoneplantasinclaim 1 characterizedin that the container (1,2) sofa rectangular shape and comprises atthe one end a filling (5) of a particulate, inorganic material for distributing the sewage in the growth culture medium (3) and at the opposite end a second filling (6) of a particulate, inorganic material fordischargingthe purified water.

3. A root zone plant as in claim 2 characterizedin that a drain pipe (7) for discharging purified water is mounted in the second filling (6).

4. A root zone plant as in claim 1 characterized in thatthe container is of a metal or wooden tank (1) the inside of which is coated with a water-proof plastic film (2).

5. A root zone plantforthe purification of contaminated water substantially as specifically herein described with reference to the accompanying drawings.