WO1998023540A1

WO1998023540A1 - Miniature waste-water treatment system for cleaning of waste-water from one or more households and the like

Info

Publication number: WO1998023540A1
Application number: PCT/DK1997/000542
Authority: WO
Inventors: Jørgen Marcus FERDINAND
Original assignee: Ferdinand Joergen Marcus
Priority date: 1996-11-26
Filing date: 1997-11-26
Publication date: 1998-06-04
Also published as: AU5048998A; EP0946429A1; DK9600416U4

Abstract

Miniature waste-water treatment system (100) for biological cleaning of waste-water from one or more households, institutions, recreation centres, business premises and the like, and for up to approx. 50 person equivalents (PE), said treatment comprising aeration and biological filtration of the waste-water, nitrification and chemical precipitation of phosphor. According to the invention, the miniature waste-water treatment system (100) is characterized in that the system (100) comprises a container (1) with a solid filter element (13) and a post-clarification zone (21), the system (100) has elements (15, 16, 17) to lead air in counterflow in relation to the waste-water, a pump (9) controlled by a level switch is provided in a pump well mounted on the side of the container (1), a time-controlled pump (33) is arranged to dose waste-water to a precipitation chemical (18), and the system (100) has elements (27, 28, 29, 30) to lead sludge which, by the aeration and chemical precipitation is deposited in the bottom of the container (1), to a sedimentation tank (200) which is placed upstream from the system (100).

Description

MINIATURE WASTE WATER TREATMENT SYSTEM FOR CLEANING OF WASTE WATER FROM ONE OR MORE HOUSEHOLDS AND THE LIKE

Field of the invention

The present invention concerns a miniature waste-water treatment system for the biological cleaning of waste-water from one or more households, institutions, recreation centres, business premises and the like and up to approx. 50 person equivalents (PE), said cleaning comprising aeration and biological filtration of the waste-water, nitrification and chemical precipitation of phosphor.

The known technique

Biological cleaning with submerged, solid aerobic filters and the chemical precipitation of phosphor with metal salts has for many years been the technique used in larger plants for the cleaning of waste-water.

The technique most known for the cleaning of waste-water is the use of cascade filters, which up until 30 to 40 years ago was the method most used.

Related to submerged, solid aerobic filters are fluid aerobic filters, so-called fluid beds, which are described in DK utility model publication no. 95 00039 U3.

Fluid aerobic filters have seldom been used for the clea- ning of waste-water, and the construction of the system for the latter-known technique as the function thereof differs considerably from the cleaning system according to the present invention.

In DK utility model publication no. 95 00039 U3, the biological cleaning of the waste-water is achieved in a bio- logical part by oxydation of a bacteria mass on a support medium of quartz sand, in that the bacteria mass and the quartz mass are held suspended in the biological part by means of air.

The precipitation of phosphor is effected by the introduction of FeCI„, which with a flow-controlled dosing pump is added in a subsequent clarification part - a so-called post-precipitation.

Precipitated sludge is pumped with a plunger pump to a sedimentation tank situated upstream.

The system is built up as a rectangular container which is normally constructed on-site, whereby the system is not suitable for mass production.

The known system has a number of disadvantages, of which the following can be mentioned:

- the filter mass must constantly be held in movement, which requires energy,

- the filter membrane for the support medium has a rela- tively poor precipitation characteristic, the reason being that it is subject to comminution by being held in movement,

- the decomposition of heavier organic materials and the nitrification of nitrogen occurs relatively poorly, the reason being that the air is led co-currently in relation to the waste-water, and

- the precipitation means is added in the post-clarifica- tion part, which requires continuous operational regulation. The object of the invention

It is the object of the present invention to provide a system of the kind disclosed in the introduction which, under the greatly varying load conditions which arise at single households and smaller sources of waste-water, is suitable for:

- the considerable reduction of the energy required for cleaning,

- reducing the discharge of suspended material,

- ensuring a stable cleaning effect for air-consuming, or- ganic material,

- the nitrification of nitrogen by recirculation in order to achieve a considerable reduction of total nitrogen,

- the considerable reduction of discharged phosphor,

- the minimization of operational supervision, and

- effecting the functions in a unit which is suitable for prefabrication.

This object is achieved with a miniature system which according to the invention is characteristic in that:

- the system comprises a container with solid filter element and a post-clarification zone,

- the system has elements for leading the air countercur- rently in relation to the waste-water, - a pump which is controlled by a level switch is provided in a pump well mounted on the side of the container,

- time-controlled pump is arranged to dose waste-water to a precipitation chemical, and

- the system has elements for leading sludge, which by aeration and chemical precipitation is precipitated in the container, to a sedimentation tank which is placed ups- tream from the the system.

The miniature waste-water treatment system according to the invention is thus a solid-filter system, where energy does not have to be used to hold the filter mass in movement, where the worn-out filter membrane on the filter has a relatively good precipitation characteristic because it is not subject to comminution by being held in movement, and where it is not necessary to effect any feed-back of active bio-mass and support medium from a post-clarification part.

Moreover, the miniature system according to the invention has the advantage that the filter has counterflow between waste-water and air, which results in a more positive decomposition of heavier organic materials and a more re- liable nitrification of nitrogen.

Furthermore, the miniature system according to the invention has an advantage from the point of view of security, in that a solid precipitation medium is used in a simul- taneous precipitation in the biological part. The miniature cleaning system according to the invention does not require any constant working regulation and is therefore more simple in operation.

The associated claims disclose advantageous embodiments of the present invention. The drawing

The miniature waste-water treatment system according to the invention will now be described in more detail with refe- rence to the drawing, where

fig. 1 shows vertical section through a miniature waste- water treatment system according to the invention,

fig- 2 shows a plan view of the miniature waste-water treatment system according to fig. 1,

fig. 3 shows a plan view of the dosing equipment in the system according to fig. 1, and

fig. 4 shows a vertical section through the dosing equipment according to fig. 3.

Example of a preferred embodiment

In figs. 1 and 2 a miniature waste-water treatment system according to the invention is indicated with the reference number 100. The system 100 is buried down in the earth 7 in a known manner and is connected to a sedimentation tank 200. The sedimentation tank 200 can be a new tank which is established together with the system 100, or it can be an existing tank which has been buried down in the earth at an earlier time.

The sedimentation tank 200 is divided, for example, into two chambers by means of an internal wall, but is preferably a tank 200 with two internal walls 201 and 202 in the formation of three chambers, which provides a better clarification of the waste-water in the tank 200 than that which can be achieved with only two chambers. There are also two shafts 203 and 204 which provide the possibility of periodic emptying of the precipitated sludge from the tank

200. The sedimentation tank is thus of a commonly-known

3 kind, and has a suitable volume, for example at least 2m at 5 person equivalents ( PE ) .

The miniature system 100 according to the invention is built up as a unit in a cylindrical container 1 with a bottom 2 and a cover or lid 3. The bottom 2 comprises a fundament 4 with a strong flange 5 which has a greater diameter than the container 1 in order to safeguard the system 100 against buoyancy when it is empty.

The container 1 is placed in the earth 7 in a suitable pit, in the bottom of which there is provided a levelling layer 8 in the form of gravel.

Since the system 100 is intended for mounting in an existing network, where the positioning of the sewage pipes is given, it is expedient to raise the waste-water up to the system 100. For this purpose the system 100 is provided with a feed pump 9.

The feed pump 9 is placed in a pump well 10 which is mounted on the side side of the container 1. The feed pump 9 is controlled by a level switch which is activated when waste- water is led to the pump well 10 through a sewage pipe 11, which extends from the household through the sedimentation tank 200. The pump well 10 can be provided with an emergency spillway which leads the waste-water around the con- tainer 1 if, for some reason or another, there is a failure in the power supply.

When the feed pump 9 is activated, waste-water is pumped from the bottom of the pump well 10 up through a first ri- ser-pipe 12 to a biological part 13, which is explained in more detail in the following. The biological part 13 is housed in a vessel 14 which is disposed centrally in the container 1, said biological part 13 consisting of a block of plates which form a large surface inside the vessel 14. An air pump 15 is provided above the vessel 14, this being arranged to pump air through a hose 16 down to a hose diffusor 17 lowermost in the bottom of the vessel 14. The air can thus rise inside the vessel 14.

A riser-pipe 33 in the form of a so-called mammoth pump leads to a precipitation block 18 which is placed above the vessel 14. The precipitation block 18 consists of suitable salts in solid form. The dosing is effected by moistening the block with waste-water when the mammoth-pump 33, which is time controlled, lifts water from the bio-zone up to the precipitation block 18.

Together with the dissolved salts, the waste-water sinks down through the biological part 13, and the waste-water is aerated in counter-flow by its meeting with the air which rises up through the plates in the vessel 14, while at the same time that phosphor is precipitated and is deposited as sludge in the bottom of the container 1. The aeration gives rise to a biological conversion of the organic material which exists in the waste-water.

The aerated waste-water leaves the vessel 14 through a lower outlet 19 and, as indicated by the arrows 20, rises upwards in the space 21 between the outside surface of the vessel 14 and the inside surface of the container 1.

The aerated waste-water enters an annular pipe 22 which is disposed in the space 21 around the uppermost part of the vessel 14. A second riser-pipe 23 leads from the annular pipe 22 up to an outlet 24, which via a further sewage pipe 25 leads to a recipient for the cleaned waste-water. Be- cause of the vertical distance from the annular pipe 22 to the outlet 24, the level of waste-water in the container 1 is held constant.

The space 21 which surrounds the vessel 14 with the biological part 13 forms a post-clarification tank of the type which is called a "Dortmund tank" . This type is known and distinguishes itself by its good hydraulic characteristics. The waste-water is led in centrally from the outlet 19 in the bottom of the biological part 13, and rises upwards to the annular pipe 22 which is disposed at a short distance from the surface of the waste-water - a so-called submerged outlet.

The lowermost part of the container 1 consists of a truncated cone 26, the smallest diameter of which is disposed at the bottom 2 in the container 1 , and the wall of which slopes for example at an angle of 60° in relation to the horizontal. The precipitated sludge will therefore be con- centrated in the truncated cone 26, thus making it easier to collect. A third riser-pipe 27, which is also in the form of a mammoth-pump, is provided for the collection of the precipitated sludge, and the inlet 28 of the riser-pipe 27 is positioned lowermost in the truncated cone 26. The third riser-pipe 27 extends upwards through the space 21 between the outside wall of the vessel 14 and the inside wall of the container 1, and continues over into a return pipe 29 which is disposed at a higher level than the level of the discharge 24, so that waste-water can not be led back to the sedimentation tank 200 via the return pipe 29.

The return pipe 29 continues to a sewage pipe 30 which, upstream from the sedimentation tank 200, is connected to the sewage pipe 11 which leads from the household. With the third riser-pipe or mammoth-pump 27, the precipitated sludge can be sucked up from the bottom of the truncated cone 26 and conveyed through the riser-pipe 27, the return pipe 29 and the sewage pipe 30 to the sedimentation tank 200.

The third riser-pipe or mammoth-pump 27, which serves to pump the sludge away from the truncated cone 26, functions with periodic control by a clock and is driven by the same compressor 15 as that which supplies air to the vessel 14 and the biological part 13. Together with the sludge, a considerable amount of water containing nitrate is pumped back to the sedimentation tank 200, so that nitrate-containing waste-water can be given a renewed cleaning by being fed through the system 100 during continuous operation of the system.

The chemical which forms the precipitation block 18 is aluminium salts in solid form. The dosing is effected by the block 18 of aluminium salts being moistened automatically at predetermined intervals with waste-water from the riser- pipe or mammoth-pump 33, which like the sludge pump 27 is driven by the above-mentioned compressor 15 which supplies the vessel 14 and the biological part 13 with air. The dissolved aluminium salts are hereby added to the biological part 13, so that phosphor is precipitated and deposited as sludge.

The precipitation block 18 is placed in a vessel 31 at the top of the container 1. The vessel 31 has a dividing wall 32 which can control and/or delimit the precipitation block 18, and the riser-pipe or mammoth-pump 33 is disposed in the bottom of the vessel 31 which extends down in the biological part 13 in the vessel 14. An outlet 34 is provided in the side of the vessel 31.

The electrical connections, control elements and other mechanical means for the operation of the miniature waste- water treatment system 100 are arranged in a technique tray 35 uppermost in the container 1, hereby providing easy accessibility for inspection and maintenance of the miniature system.

Cleaning effect

Bl_r NH₃+ H₄-N total content N SS

(mg/1) (mg/1) (mg/1) (mg/1)

Expected in outflow: 3-5 0.5-1 >50% red. <2 5-10

Typical municipal demand: <15 <2-4 none <2 <20

Dimensions

5 PE 12 PE

Measurements: 01.4x2.25m (dxh) 01.6x2.6m (dxh)

Weight: 185 kg. 275 kg.

Power consumption: 230V - 44W 230V - 66W

30 PE 50 PE Measurements: 02.3x3.4m (dxh) 02.3x3.8m (dxh)

Weight: 650 kg. 750 kg.

Power consumption: 230V - 220W 230V - 230W

Claims

C A I M S

1. Miniature waste-water treatment system ( 100 ) for biological cleaning of waste-water from one or more households, institutions, recreation centres, business premises and the like, and up to approx. 50 person equivalents ( PE ) , said treatment comprising aeration and biological filtration of the waste-water, nitrification and chemical precipitation of phosphor, c h a r a c t e r i z e d in that

- the system (100) comprises a container (1) with a solid filter element (13) and a post-clarification zone (21),

- the system (100) has elements (15,16,17) to lead air in counterflow in relation to the waste-water,

- a pump ( 9 ) controlled by a level switch is provided in a pump well (10) mounted on the side of the container (1),

- a time-controlled pump (33) is arranged to dose waste- water to a precipitation chemical (18), and

- the system (100) has elements (27,28,29,30) to lead sludge which, by the aeration and chemical precipitation is deposited in the bottom of the container (1), to a sedimentation tank ( 200 ) which is placed upstream from the system ( 100 ) .

2. Miniature waste-water treatment system ( 100 ) according to claim 1, c h a r a c t e r i z e d in that the container ( 1 ) is circular cylindrical with a bottom ( 2 ) and a cover (3), that the solid filter element (13) is disposed in a vessel (14) arranged centrally in the container (1), that the post-clarification zone (21) consists of the space between the outside wall of the vessel (14) and the inside wall of the container ( 1 ) , and that both the container ( 1 ) and the vessel (14) taper conically towards the bottom (2).

3. Miniature waste-water treatment system (100) according to claims 1-2, c h a r a c t e r i z e d in that the elements for leading air in counterflow in relation to the waste-water comprise an air pump (15) uppermost in the container (1), and connected to said air pump (15) a hose (16) which opens out in a diffusor (17) placed lowermost in the vessel (14).

4. Miniature waste-water treatment system ( 100 ) according to claims 1-3, c h a r a c t e r i z e d in that the pump (9) which is controlled by a level switch is placed in a pump well (10) mounted on the side of the container (1), and that the pump ( 9 ) is mounted downstream from the sedimentation tank (200), which on its side is placed downstream from the source of waste-water.

5. Miniature waste-water treatment system ( 100 ) according to claims 1-4, c h a r a c t e r i z e d in that the cleaned waste-water is led away through an annular pipe (22) which is disposed around the vessel (14) in the uppermost part of the space (21), said pipe (22) leading via a riser-pipe (23) up to an outlet (24) which is connected to a sewage pipe (25) which leads the cleaned waste-water to a recipient.

6. Miniature waste-water treatment system (100) according to claims 1-5, c h a r a c t e r i z e d in that the precipitation chemical ( 18 ) is a solid block which is disposed in a vessel (31) with a dividing wall (32), a riser-pipe (33) which extends from the vessel (14), and a waste-water outlet (34) provided in the side.

7. Miniature waste-water treatment system (100) according to claims 1-6, c h a r a c t e r i z e d in that the electrical connections, control elements and other mechanical means for the operation of the miniature waste-water treatment system ( 100 ) are arranged in a technique tray (35) placed uppermost in the container (1).

AMENDED CLAIMS

[received by the International Bureau on 23 April 1998 (23.04.98); original claims 1-7 replaced by amended claims 1-6 (3 pages)]

1. Miniature waste-water treatment system ( 100 ) for biological cleaning of waste-water from one or more households, institutions, recreation centres, business premises and the like, and up to approx. 50 person equivalents ( PE ) , said treatment comprising aeration and biological filtration of the waste-water, nitrification and chemical precipitation of phosphor, in which

- the system ( 100 ) comprises a container ( 1 ) with a solid filter element (13) and a post-clarification zone (21),

- a pump ( 9 ) controlled by a level switch is provided in a pump well ( 10 ) mounted on the side of the container ( 1 ) ,

- a time-controlled pump ( 33 ) is arranged to dose waste- water to a precipitation chemical (18), and

- the system (100) has elements (27,28,29,30) to lead sludge which, by the aeration and chemical precipitation is deposited in the bottom of the container (1), to a sedimentation tank (200) which is placed upstream from the system (100).

c h a r a c t e r i z e d in that the container ( 1 ) is circular cylindrical with a bottom ( 2 ) and a cover ( 3 ) , that the solid filter element ( 13 ) is disposed in a vessel (14) arranged centrally in the container (1), that the post-clarification zone (21) consists of the space between the outside wall of the vessel (14) and the inside wall of the container (1), and that both the container (1) and the vessel ( 14 ) taper conically towards the bottom ( 2 ) .

2. Miniature waste-water treatment system ( 100 ) according to claim 1, c h a r a c t e r i z e d in that the elements for leading air in counterflow in relation to the waste-water comprise an air pump (15) uppermost in the container (1), and connected to said air pump (15) a hose (16) which opens out in a diffusor (17) placed lowermost in the vessel ( 14) .

3. Miniature waste-water treatment system ( 100 ) according to claims 1-2, c h a r a c t e r i z e d in that the pump

(9) which is controlled by a level switch is placed in a pump well (10) mounted on the side of the container (1), and that the pump (9) is mounted downstream from the sedimentation tank (200), which on its side is placed downstream from the source of waste-water.

4. Miniature waste-water treatment system (100) according to claims 1-3, c h a r a c t e r i z e d in that the cleaned waste-water is led away through an annular pipe (22) which is disposed around the vessel (14) in the uppermost part of the space (21), said pipe (22) leading via a riser-pipe (23) up to an outlet (24) which is connected to a sewage pipe (25) which leads the cleaned waste-water to a recipient.

5. Miniature waste-water treatment system ( 100 ) according to claims 1-4, c h a r a c t e r i z e d in that the precipitation chemical (18) is a solid block which is disposed in a vessel (31) with a dividing wall (32), a riser-pipe (33) which extends from the vessel (14), and a waste-water outlet (34) provided in the side.

6. Miniature waste-water treatment system (100) according to claims 1-5, c h a r a c t e r i z e d in that the electrical connections, control elements and other mechanical means for the operation of the miniature waste- water treatment system (100) are arranged in a technique tray (35) placed uppermost in the container (1).