WO1990010597A1

WO1990010597A1 - Water purifying means

Info

Publication number: WO1990010597A1
Application number: PCT/FI1990/000059
Authority: WO
Inventors: Viljo JÄRVENPÄÄ; Arto Latvala
Original assignee: Wiser Oy
Current assignee: Wiser Oy
Priority date: 1989-03-06
Filing date: 1990-03-06
Publication date: 1990-09-20
Anticipated expiration: 1991-09-06
Also published as: EP0427804A1; FI891064A7; FI89703C; FI891064A0; FI89703B

Abstract

The present invention concerns a means for treating liquid, in particular waste water, comprising a body (1, 1a) consisting of a cylindrical and a conical part, a primary flow part (I) and a clarification part (6). The primary mixing (I) part of the treatment means is composed of a cylindrical inner cell (2) and a conical part (2a) immediately adjacent thereto, which have been so disposed that between the body (1, 1a) and the primary flow part (I) is left an annular gap in which passes a sludge flow (k), that inside the inner cell (2) is disposed a treatment tuber (3) wherein is disposed a flow generator (17) for guiding a supply (a) from the treatment tube (3) further as a flow (c) from the inner cell (2) to become a flow (e) to the clarification part (6), and a flow (1) to the discharge (7) of the conical part (6a) disposed around the inner cell (2), and, if needed, of lamellae cones (6b, 6c, 6d,...) for clarifying the flow (e) to become a downward flow (k) and a flow (f) to a pure liquid outlet (5), that in the treatment means is disposed a secondary flow part (II) external to the body (1, 1a), which guides the discharge flows (k, 1) into a divider (10) in which a partial flow (h) is removed and the remaining flow (k+1-h) is returned to circulation.

Description

1 Water purifying means

5 The present invention concerns a means for treating liquid, in par¬ ticular waste water, comprising a body consisting of a cylindrical and a conical part, a primary mixing part, and a clarification part.

Waste water purification is the more important measure, the more the -|Q society becomes technical. Along with technical development, waste water residues are increased. As the standard of living rises also water consumption increases. For an average person living in town, over 150 liters of residual water are calculated to be produced in twenty-four hours. In great cities located in highly developed 15 countries the waste water production is calculated to be even 250 liter per 24 hrs. Industry in itself can be a great water consumer, that is, great masses of waste water are produced. The waste water may contain fats, organic releases, phosphorus, oxygen and metal com¬ pounds, etc. Essential in a great many of said organic releases is 20 the property that they consume their biological oxygen, that is, they reduce the amount of oxygen dissolved in water, whereby the ecosystem of the water courses becomes disturbed. Therefore, one of the most important tasks in treating waste water is to eliminate the organic components consuming biological oxygen from the water.

25

Several of such methods are known in the art. Oxidation methods by which air is conducted into the water have been developed long since. Endeavours have been made to provide designs and apparatus for dis¬ solving oxygen efficiently. Unfortunately, a drawback in many of 30 them is their high energy consumption in proportion to the amount of dissolved oxygen.

Essential in a biological purification installation is not only to provide oxygen into water, but to make the active sludge to be dis- 35 tributed as uniformly as possible in the entire water mass, that is, to cause the bacteria activity to take place as uniformly as possible in the entire water mass, that is, the sludge and oxygen content of 1 the water to become as uniform as possible. Such design has been aimed at in biological purification installations in that compressed air is conducted from the bottom of a water basin into the whole basin with the aid of fine orifices or dispersers, in order to make ς the air bubbles as small as possible. Gas dissolution in liquid is, in fact, directly proportional to the contact surface area and gas pressure. The deeper under the water the air can be supplied into the water the better the oxygen access is using the same bubble size. Therefore, endeavours are made to provide as small air bubbles

-|Q as possible and to cause them to go as deep into the water as possible while trying to make as uniform circulation and suspension situation in the water space being treated as possible. Hereby, the bacterial activity is good, whereby the solid matters, in particular organic wastes, become decomposed off, phosphorus is oxidated into indis-

^■|5 soluble form and the outflowing water contains oxygen.

The treated water still contains solid matter particles which should be removed from the water before it is let or conducted into common water courses. For this purpose, the latter end of the waste water

20 purification installation is provided with a so-called clarification part in which, utilizing appropriate flocculants, that is preci¬ pitating agents, the precipitate is made to settle to the bottom of the clarification unit, wherefrom it is later removed using appro¬ priate pumps or removing devices, precipitated and possibly dried.

25 The size of such water purification installations becomes rather massive. It is obvious that also the water masses treated therein are great. The capacity of a clarification basin is calculated roughly according to the surface area of the clarification basin so that one (1) square meter (m²) in the clarification basin corresponds to

30 about one (1) cubic meter's (πr) hourly capacity. In small units the supply price becomes quite high if a respective treatment with basins is desired. For such situations no respective activities are avail¬ able.

35 It is this drawback which is the object of the present invention to be solved utilizing the present invention. The substantial functions of the invention are all placed into one and same apparatus: air 1 supply into water in as finely divided form as possible and provision of under-water homogenizing, suspendizing in the primary circuit, and returning from the secondary circulation the required, that is desired, amount through a lamellae clarification out of the apparatus.

5 Furthermore, with the means of the invention the separation of oil and fats is provided from the water, and possibly, removal of float¬ ing components from the treatment means in the form of overflow, that is, as foam through a separate outlet. The size of the appar- atus is small compared with its capacity, and its clarification -JO capacity is high compared with the floor surface area required by the means.

The means of the invention is mainly characterized in that the primary mixing part of the treatment means consists of a cylindrical inner

-(5 cell and a conical part immediately adjacent thereto, which have been so disposed that between the body and the primary mixing part is left an annular gap in which passes a sludge flow, that inside the inner cell is disposed a treatment tube wherein is disposed a flow generator for guiding a supply flow from the treatment tube

20 further as a flow from the inner cell to become a flow into the clarification part, and a flow to the discharge of the conical part, that the clarification part of the treatment means is composed of a conical part disposed around the inner cell, and, if needed, of lamellae cones for clarifying the flow to become a downflow and a

25 flow to a pure liquid outlet, that in the treatment means is disposed a secondary flow part external to the body, which guides the discharge flows into a divider in which a partial flow is removed and the re¬ maining flow is returned to circulation.

30 A means of the invention is described, referring to the accompanying Fig. 1, which in no way confines the invention exclusively to this embodiment.

The waste water purifying means is composed of an outer shell 1 and 35 ^a conical part la. Thereinside is located an inner cell 2 nearly corresponding in configuration, and a respective conical part 2a. Between said conical parts la and 2a is left an annular gap in which 1 a sludge flow k passes to a discharge part 8 located in the lower end of the concial part la. Inside the inner cell 2 is located a concentrical treatment tube 3, its top edge being close to the top edge of the inner cell 2. Both top edges are lower than the liquid surface in the cells, the VH2O surface, which is more than the distance -ΔK, being located between the top edge of the treatment tube 3 and the lower edge of a concentrical central tube 16. Said dis¬ tance ΔK is so defined that the liquid flow rate in the annular aperture ΔK drawn in by a rotor wheel 17 located in the treatment

-|0 tube 3 is set to the moderate limits known in themselves in the art, so as not to cause unnecessary pressure losses. In the present em¬ bodiment, the lower end of the central tube also extends below the liquid surface VH2O. The top edge of the inner cell 2 is above the lower end of the conical funnel 6a. Feeding enters the purification

-|5 cell as a flow a through the cover of the cell 1 to the central tube 16. The flow is substantially smaller than the liquid flow taken in by the rotor wheel 17, therefore the flow mass a is guided into suction into the rotor 17 together with the flow d entering through the annular aperture ΔK. The rotor wheel 17 has been so

20 constructed, supported by a hollow shaft and a belt drive 12, and bearings 13, that the rotation movement causes, because of the mount¬ ing angles of the blades of the rotor wheel 17, a suction resembling cavitation so that air is drawn along the hollow shaft into the rotor wheel 17. Here the air is mixed with the liquid/water drawn in

25 by the rotor to become very finely divided bubbles which are dis¬ charged in the flow c through the lower end of the treatment tube 3. The quantity of the air drawn into the rotor 17 can be regulated by means of a regulator 14. The flow c turns into a mainly upward flow ascending in the primary flow part I between the pipe section 3 and

30 the inner cell 2. From the flow c only a small, and the heaviest amount (sand, gravel or heavy sediment) is divided as a flow 1 through an aperture 7 located in the funnel part 2a. The flow 1 joins the flow k, and in the present embodiment they are drawn together from the housing 8 through a pump 9 to become a flow passing in the

35 secondary flow part II into a divider 10 from where part of the flow in the secondary flow part II is conducted out to form a flow h. Rest of the flow in the secondary flow part II is returned into cir- 1 culation in the centre pipe 16 together with the supply a. Majority of the flow c circulated into the central tube 16 together with the supply a. From the flow passing in the primary flow part I dis¬ charges an amount of liquid which descends through the annular gap 5 between the funnel aperture 6a and the inner cell 2, in which part of the flow e continues its passage directly downwards to become a flow k, this concerning in particular heavier components and precipi¬ tate. Rest of the flow e turns through the lamella cones 6b,6c,6d, or other interspaces to the outlet 5, which is provided with apertures

-|Q on the wall of the cell 1, and outside and below which apertures a trough 4 passes provided with an outlet 4a, in which the flow f corresponds to the difference between the flows a and h. The outer edges of the lamellae cones 6b to 6d, etc. leave between the walls of the cell 1 an opportunity for a flow for the clarifying liquid to

■| flow into the outlet 5. Sludge descends into the lamellae cones 6b to 6d etc., that is, the lamellae cones serve as so-called lamella clarifying means. The settled precipitate f lls further and becomes a flow k. In this manner, the outflowing liquid flow f is clarified and without any solid matter.

20

In the primary flow part I the flow is provided with air, whereby it attempts to rise upwards and carries therewith potential oil and fats, and part of the sludge, at least light and floating solid matter which rise on the liquid surface, forming together with solid

25 matter a foam and oil surface thereon. The thickness of said layer H has been selected as the limit in the present context, when exceeding the height of which the flow g starts tpo remove foam. From the cell is thus received as separate discharges the following: oil and floating solid matter in the form of the flow g, heavy

30 precipitate and solid matter in the form of the flow h, and the purified water/liquid in the form of the flow f.

The topmost conical part 6a of the conical lamella part extends to the outer edge of the cell 1, and therefore, the foam is not allowed 35 to be mixed with the outgoing liquid flow.

With the design of the invention, probably with the biological waste 1 water purification cell, for instance waste water can be purified, whereby, using an approriate bacterial stock, the organic solid matter can be removed by circulating sufficiently in oxidating circumstances and sufficiently long, whereby the primary flow part I c attends to the internal circulation and the secondary flow part II returns the desired part of the sludge already discharged to the treatment. Thus, even high solid matter contents-may be obtained in sludge contents. The capacity of the conical lamella clarifying means included in the apparatus can with ease be provided to be

-\ Q adequate, owing to the design of the means. The conical lamella clarifying means differs advantageously from a lamella clarifying means known in the art in that therein the flow rate of the through- flowing liquid reduces in the square of the diameter increase. In conventional lamella clarifying means the through flow rate remains

-J5 constant throughout the entire settling cell.

With the means considerable saving in costs is obtained compared with designs in which traditional waste water treatment apparatus must be built. In such designs, it is possible to execute with the 20 cell of the invention even the most difficult waste water problems.

The design of the invention is not merely the presently disclosed embodiment. The same embodiment concerning primary and secondary flow parts can be implemented also with several placements. Such a

25 modification can be obtained from the design e.g. from the discharge aperture of the heavy precipitate flow 1 to become a separate dis¬ charge (not shown) . Hereby, potential sand, gravel or heavy precipi¬ tate will not unnecessarily wear the pump 9 and the rotor wheel/flow generator 17 because also different flow generators are available

3 than a rotor wheel. In this case, the number of outlets is increased. Thus, air/oxygen may also be conducted in another fashion into the tube 3 than using the rotor wheel 17.

Potential chemicals may most appropriately be fed into the flow a, 35 but they may also be added into the central tube 16.

The design of the invention is also appropriate for treating raw water, for instance for removing iron and manganes, as well as for humus removal. Thus, it is not exclusively, neither specifically, restricted to waste water treatment. It is equally well appropriate for foaming all appropriate liquids, gas treatment/oxidation, and mixing chemicals, as well as for homogenizing liquids.

Claims

1. A means for treating liquid, in particular waste water, comprising a body (1,1a) consisting of a cylindrical and a conical part, a 5 primary flow part (I) and a clarification part (6) , characterized in that the primary flow part (I) of the treatment means is composed of a cylindrical inner cell (2) and a conical part (2a) immediately adjacent thereto, which have been so disposed that between the body (1,1a) and the primary mixing part (I) is left an annular gap in

^■(0 which passes a sludge flow (3), that inside the inner cell (2) is disposed a treatment tube (3) wherein is disposed a flow generator (17) for guiding a supply (a) from the treatment tube (3) further as a flow (c) from the inner cell (2) to become a flow (e) to the clarification part (6) , and a flow (1) to the discharge (7) of the

-|5 conical part (2a), that the clarification part (6) of the treatment means is composed of a conical part (6a) disposed around the inner cell (2), and, if needed, of lamellae cones (6b,6c,6d, ... ) for clarifying the flow (e) to become a downward flow (k) and a flow (f) to a pure liquid outlet (5) , that in the treatment means is disposed

20 a- secondary flow part (II) external to the body (1,1a), which guides the discharge flows (k,l) into a divider (10) in which a partial flow (h) is removed and the remaining flow (k+l-h) is returned to circulation.

25 2. Means according to claim 1, characterized in that the top edges of the inner cell (2) and the treatment tube (3) disposed therein are susbtantially on the same level below the liquid surface.

3. Means according to claim 1 or 2, characterized in that the inner 30 cell (2) and the treatment tube (3) are substantially concentrical.

4. Means according to any one of claims 1 to 3, characterized in that the lower edge of the conical part (6a) disposed around the inner cell (2) is below the upper edge of the inner cell (2) .

35

5. Means according to any one of claims 1 to 4, characterized in that the flow generator (17) is a rotor wheel (17) located in the treatment tube (3) , which is so disposed that the rotary movement of the rotor wheel causes, because of the setting angles of its blades, a suction generating cavitation so that air is drawn in along the hollow shaft of the rotor into the rotor wheel (17) .

6. Means according to any one of claims 1 to 5, characterized in that the proportion of the flow in the secondary flow part (II) is adjustable.

7. Means according to any one of claims 1 to 6, characterized in that the proportion of the flow in the discharge flow (h) of the secondary flow part (II) is adjustable.

8. Means according to any one of claims 1 to 7, characterized in that the flow (1) of heavy sediment is disposed to constitute a separate outflow (7) .

9. Means according to any one of claims 1 to 8, characterized in that from the treatment means can be received a separate outflow for pure water, a foam/oil/fat flow (g) , a sludge flow (h) , and an outflow (1) for heavy precipitate.