GB1586630A

GB1586630A - Process and apparatus for removing iron and manganese frompumped well water

Info

Publication number: GB1586630A
Application number: GB1235278A
Authority: GB
Original assignee: Individual
Current assignee: Individual
Priority date: 1977-03-31
Filing date: 1978-03-30
Publication date: 1981-03-25
Also published as: FR2385850A1; NL7801147A; BE865602A; DE2714261A1; DE2714261C2; FR2385850B3

Description

(54) PROCESS AND APPARATUS FOR REMOVING IRON AND MANGANESE FROM PUMPED WELL WATER (71) I, STEFAN ELMER of Brockstrasse 8, 4835 Rietberg 1, Germany, a German citizen do hereby declare the invention, for which I pray that a patent be granted to me, and the method by which it is to be performed, to be particularly described in and by the following statement: This invention relates to a method of pumping water with simultaneous iron removal and manganese removal, and to a water supply installation for carrying out the method.

In many cases, well water is unsuitable for drinking and for various other purposes because of a considerable content of iron and manganese. For these reasons special steps must be taken in order to remove these undesirable impurities from the water. Generally, special filter plant is used for this purpose, requiring continuous supervision and servicing.

However, a system of iron and manganese removal is known, which is effected in the ground before pumping of the underground water. This method is based on the experience that oxidation procedures reduce the solubility of the iron and manganese compounds. In this way iron and manganese removal is achieved in several stages: by the oxidation of the iron4l-compounds to iron-III-compounds and the manganese-II- compounds to higher manganese compounds, there is flocculation of the iron and manganese compounds, which may be filtered off.

This conversion of the iron4l and manganese-II-compounds into higher-value compounds by oxidation can be effected in the ground, if sufficient atmospheric oxygen is present.

The known method of iron and manganese removal makes use of these factors, the underground water being artificially enriched with oxygen-containing water. For this purpose at least two removal wells are provided, there being associated with each several enrichment wells a few metres distant. In order to enrich the ground water with oxygen, the water pumped from the first well is saturated with oxygen in an oxygenator, is depressurised in a degasification container, and is returned through a second well and the associated enrichment wells into the ground water. After a stationary period, the water may be pumped out of this second well. The water from the second well is now used for oxygen enrichment and introduction into the first well and the procedure is repeated, several times. After running in of both wells, both wells provide water free of iron or manganese. However, the ground water must be repeatedly enriched with oxygencontaining water at certain time intervals, alternately, and in a repeated fashion, over both wells.

The known method however has the great disadvantage that the installation costs, due to the necessary number of enrichment wells, to the oxygenator and to the degasification tank, is not only expensive, but is also costly in terms of space requirements.

An object of the invention is to provide a method of pumping water with simultaneous iron and manganese removal, and also a watersupply system which obviate or mitigate the above disadvantages.

According to the present invention there is provided a method for pumping water with simultaneous removal of manganese and iron, wherein two spaced-apart pump wells are supplied at regular time-intervals alternately with oxygen-enriched water, water being removed during this period from the well not being supplied.

It has proved appropriate to effect the supplying of oxygen-enriched water during times when water requirements are at their lowest.

According to a particularly preferred feature of the invention, about 10% of the amount of water consumed is enriched with oxygen and returned to the pump well ready for enrichment at any moment, and, after the enrichment phase, a stationary phase is provided, during which no water is pumped from the well previously enriched with atmospheric oxygen.

Further according to the present invention there is provided a water supply installation comprising two spaced-apart pump wells each connected via a double valve and a first pressure pipe to a pressure vessel, and connected via a respective well valve to a common suction pipe via a pump, and a second pressure pipe to said pressure vessel, a breather valve in the pump or in the second pressure pipe being connected to the external air via a fresh air valve.

An advantageous factor is that the system is a sealed system, which is at a pressure adapted to the requirements of the consumer points connected thereto. It has proved suitable to provide the pressure vessel with a floatcontrolled evacuation device. According to a further preferred feature, the valves are automatically controlled by a timing circuit. A recommended advantageous improvement is to combine the controllable valves with the timing circuit into one constructive unit.

Embodiments of the invention will now be described by way of example, with reference to the accompanying drawings in which: Fig. 1 is a diagrammatic representation of one embodiment of the installation; and Fig. 2 is a circuit diagram for the electrical control of the installation of Fig. 1: Referring to the drawings, two wells 1 and 2 (Fig. 1) are connected via respective well pipes 3 and 4 to respective well valves 5 and 6 and a double valve 7, said valves being servocontrolled. Both well valves 5 and 6 connect the well pipes 3 and 4 selectively via a pump suction pipe 8, a pump 9 and a pump pressure pipe 10 to a pressure vessel 11. The double valve 7 enables connection of the well pipe 3 via a valve 7a or well pipe 4 via a valve 7b to a pressure pipe 12 for enrichment water coming from the pressure vessel 11. Provided in the double valve 7 in a pressure pipe 12 is a special filter 13, and in the pipeline, a manuallyactivated closure slide valve 14. Should an automatic metering device 15 be required, for example for adding chlorine or similar material, this should be located between the closure slide valve 14 and the pressure valve 11. A pressure regulator 16, likewise connected to the pressure pipe 12, controls switching on and off of a drive motor 17 for the pump 9. A breather valve 18 inserted in the pump 9 is connected via an air pipe 20 to a magnet valve 21. The pressure vessel 11 has an evacuator 23 controlled by a float 22, said evacuator 23 initiating dry evacuation of the pressure vessel 11 as soon as the water level in said vessel has reached a fixed minimum height.

The water supply installation is controlled at a regularly-repeated cycle by a timing circuit 24. This timing circuit, along with magnet valves, slide valve relays and switches, is housed in a control box 25, which offers the advantage that, for assembly of the water-supply system, the prefabricated control box 25 need only be connected to a few pipelines and the powersupply cables, if an already-existing watersupply system is to be converted to the method according to the invention, on condition that a second well is available or has been constructed.

The electrical system (Fig. 2) is operated by activation of a key contact Tl, whereby a contactor C is energised, switching on the installation with its contacts C1 to C3, this being indicated by signal lamps L1 to L3. The relay C is self-cancelling by means of its contact C4. The installation is switched off by activation of key circuit-breaker T2, the maintenance circuit for the contactor C being thereby interrupted, so that it drops, and interrupts the power supply by opening contacts C1 to C3.

Contacts pl to p3 of the pressure regulator 16 are located in the power-supply to the drive motor 17 of the pump 9. When the contactor C is energised, a conductor 27 is connected to the T phase of the three-phase current circuit, and powers a motor 28 of the time clock and all the relays and magnet valves. The time clock of the timing circuit 24 has two adjustable time switches S1 and S4. Switch S4 is located in the circuit of the Eltaco relay 26, whose contact 1 is connected to a relay Tri, and whose contact 2 is connected to a relay R2. In series with switch S4 there is a further switch 51, whose other contact is connected to the magnet valve 21 of the air pipe 20 (Fig. 1), of the breather valve 18 of the pump 9. In series with the switch Sl there are also, in parallel with one another, the series circuits of a contact rl2 of relay Tri, with the second valve 7b and the con tact r22 with the first valve 7a of the double valve 7. The first well valve 5 is connected by a contact rl 1 of relay 1 to the voltage cable 27, and the second well valve 6 is connected via contact r21 of relay 2 to said voltage cable 27.

Before the water-supply installation can pro vide water free of iron and manganese, the ground areas of both wells must be prepared, i.e. they must be supplied with oxygen-contain ing water. This is effected in such a way that firstly water is pumped out of the first well and brought into contact with the air via breather valve 18. The water absorbs up to about 8% of oxygen from the air, depending on the pressure obtaining in the system, as the system is opera ted as a sealed system. The pressure in the sys tem depends on the requirements for consump tion, e.g. in the single-family houses of the bungalow type, a lower pressure is required than in houses with several storeys. Medial values for the pressure lie between 2 and 6 bars.

The water enriched with atmospheric oxygen is immediately fed to the second well. The amount of water to be enriched at any time de pends on the size of the system and the ground conditions. After a stationary pause of a few hours, water is pumped out of the second well and, enriched with atmospheric oxygen, is passed back again to the first well. This proce dure is repeated several times in order to pre pare the installation, until the pumped water has the required degreee of freedom from iron and manganese. The system may then be con verted to the normal method of operation, which is executed as follows: The so-called enrichment phase is located at a time of day when generally the smallest amount of water is removed; this will normally be at night.

In the present case, a time from midnight to 1 a.m. is selected. The enrichment phase must be followed by a stationary phase i.e. no water is removed from the well to which oxygenenriched water has just been passed for a period of e.g. three hours. In the present case a period of 1 a.m. to 4 a.m. has been selected. These time-intervals of 1 hour and 3 hours respectively depend on the amount of water to be pumped daily, and on the ground conditions.

With the time selected, a regularly-repeated two-day cycle results: Day 1: midnight to 1 am.: pumping from first well, supplying of second well with oxygenenriched water; 1 a.m. to 4 a.m.: stationary phase for second well, pumping of consumer water from first well; 4 a.m. to midnight: pumping of consumer water from first and second wells; Day 2: midnight to 1 am.: pumping from second well, supply of first well with oxygenenriched water; 1 a.m. to 4 a.m.: stationary phase for first well, pumping of consumer water from second well; 4 a.m. to midnight: pumping of consumer water from second and first well; Day 3: as Day 1; Day 4: as Day 2, etc.

Changeover from day 1 to day 2 etc. is effected via the switch S4 of the time clock (4-hour) (Fig. 2), which activates the Eltaco relay 26, whose switch over contact E energises either relay R1 or relay R2. The spacing contact r1 1 of relay Rl controls the first well valve 5 (Fig.

1), the spacing contact r21 of relay R2 controls the second well valve 6, i.e. in the stationary condition of relays R1 and R2, both well valves 5 and 6 are energised or open. This switching enables either relay R1 or R2 during the closed period of switching S4 (4 hours) depending on the position of switch over contact E of the Eltaco relay 26, to be energised and thus either the second well valve 6 is energised (open) or the first well valve 5 is energised (open). This further ensures that during the remaining period, when switch S4 is open, the relays R1 and R2 are not energised, the spacing contacts ri 1 and r21 are closed, and this the well valves 5 and 6 are energised, i.e. open. In the times outwith the enrichment phase (switches S4 and S1 closed) and the stationary phase (switch S4 closed, switch S1 open), water is thus pumped out of the wells.

Assuming that at midnight the relay R2 (Day 1, Day 3 etc) is energised by the switch S4 of the Eltaco relay 26 by means of its switchover contact e, the spacer contact R21 cuts off current to the second well valve 6, thus closing it, while the first well valve 5 is energised via the closed spacer contact rl 1 of relay R1, and is thus open. Simultaneously with switch S4, switch S1 is also closed, and the second valve 7b of the double valve 7 is opened by the closed contact r22 of the relay R2. By means of the pressure contained in pressure vessel 11, water is delivered from pressure vessel 11 (Fig. 1) via pressure pipe 12, valve 7b and the second well pipe 4, into the second well 2. The pressure regulator 16 will respond immediately thereafter and switch on the pump 9, which will deliver water into the pressure vessel 11 out of the first well 1 via the first well pipe 3, the first well valve 5, the pump suction pipe 8 and the pump pressure pipe 10. Simultaneously with closure of switchs S4 and S1, the magnet valve 21 for the airpipe 20 has been opened, so that external air is sucked through the breather valve 18 into the water delivered by pump 9. Thus the water is enriched with oxygen, and is delivered into the second well in the way described above.

After an hour, switch S1 opens, and the second valve 7b and magnet valve 21 for the airpipe are closed. The pump 9 shortly thereafter is likewise switched off by the pressure regulator 16, when the vessel pressure has reached a prescribed value. The magnet valve 21 in the airpipe leading to the breather valve 18 closes off the air supply, and second valve 7b closes off the further supply of water into second well 2.

After a further three hours (stationary phase for the second well), the switch S4 opens and removes current from relay R2, causing spacer contact r2 1 to close, energising and opening the first well valve. Thus during the remaining period of the day, both well valves 5 and 6 are open and ready to deliver water. At midnight of the following day, when switches S1 and S4 close again, the Eltaco relay 26 switches over its switchover contact E and energises relay R1.

The spacer contact ri 1 of relay Rl opens and removes current from the first well valve 5, thus closing it, while the second well valve 6 is energised and thus open via the closed spacer contact r21. Water will now be delivered from the second well, enriched with oxygen and passed again to the first well. At 1 a.m., the enrichment phase is terminated and the stationary phase initiated by opening of switch S1. After a further three hours switch S4 opens, and water removal can again be undertaken from both wells. This described cycle is repeated every two days. It is emphasised that the cycle described and the time-intervals selected (two days, 1 and 4 hours) are only as an example.

The cycle and the time-intervals to be selected depend on local ground conditions, and on the amounts of water to be pumped.

The method according to the invention and the water-supply installation are characterised in that, apart from the two wells, no additional enrichment well, degasification tank or costly oxygenator is required. Instead of the oxygenator, only the breather valve already available in piston pumps, or an injector with built-in breather valve in the case of centrifugal pumps, is required. Particularly notable in comparison to prior art is the fact that the installation according to the invention is a sealed system with known advantages (e.g. tropical operation).

WHAT WE CLAIM IS: 1. A method for pumping water with simultaneous removal of manganese and iron, wherein two spaced-apart pump wells are supplied at regular time-intervals alternately with oxygenenriched water, water being removed during this period from the well not being supplied.

2. A method as claimed in Claim 1, wherein the supply with oxygen-enriched water is carried out at times of minimum water demand.

3. A method as claimed in either Claim 1 or 2, wherein about 10% of the consumed amount of water, enriched with atmospheric oxygen, is passed back into the pump well available at any time for enrichment, and that, after the enrichment phase, a stationary phase is provided, during which no water is pumped from the well previously supplied with oxygenenriched water.

4. A water supply installation comprising two spaced-apart pump wells each connected via a double valve and a first pressure pipe to a pressure vessel, and connected via a respective well valve to a common suction pipe via a pump and a second pressure pipe to said pressure vessel, a breather valve in the pump or in the second pressure pipe being connected to the external air via a fresh air valve.

5. A water supply installation as claimed in Claim 4, wherein the installation is a sealed system, under a pressure adapted to the requirements ofthe consumer point connected thereto.

6. A water supply installation as claimed in either Claim 4 or 5, wherein the pressure vessel is provided with a float-operated evacuation device.

7. A water supply installation as claimed in any one of Claims 4 to 6, wherein the valves are automatically controlled via a timing circuit.

8. A water supply installation as claimed in any one of Claims 4 to 7, wherein the valves are unified into one constructive unit with the timing circuit.

9. A method for pumping water with simultaneous moving of manganese and iron substantially as hereinbefore described with reference to the accompanying drawings.

10. A water supply installation substantially as hereinbefore described with reference to the acccompanying drawings.

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

Claims

**WARNING** start of CLMS field may overlap end of DESC **. according to the invention is a sealed system with known advantages (e.g. tropical operation). WHAT WE CLAIM IS:

1. A method for pumping water with simultaneous removal of manganese and iron, wherein two spaced-apart pump wells are supplied at regular time-intervals alternately with oxygenenriched water, water being removed during this period from the well not being supplied.