WO1990001019A1

WO1990001019A1 - Apparatus and process for purification of surface waters

Info

Publication number: WO1990001019A1
Application number: PCT/HU1988/000073
Authority: WO
Inventors: András DOMBI; Vidor Otoltics
Original assignee: Mohacsi Laszlo; Noviki Kisuezemi Innovacios Iroda
Current assignee: Mohacsi Laszlo; Noviki Kisuezemi Innovacios Iroda
Priority date: 1988-07-25
Filing date: 1988-11-15
Publication date: 1990-02-08
Anticipated expiration: 1991-01-25
Also published as: CN1036377A; AU2786889A; HU203063B

Abstract

The water inducted during the process according to the invention is circulated in the tank (1, 2, 3) for at least 30 minutes. The amount of dissolved ozone in the purified water is measured continually, and injection of the ozone is stopped over 0.05 mg/dm3, and started up below 0.01 mg/dm3. While the purified water is constantly circulated, as much water is discharged by withdrawal and/or draining as to have the water in the tank exchanged at least once a day, where 2-16 g ozone on the average is injected into 1 m3 water to be purified. The apparatus contains a refill pump (6), a mechanical filter (9), ozonizers (15) and a water tank (1, 2, 3) as well as pipelines valves (20, 26) and a control system. The pressure side of the circulating pump (24) is connected with the water tank (1, 2, 3), the water outlet valve (26) and the dissolved ozone concentration metering unit (28) provided with a drain pipe (29).

Description

APPARATUS AND PROCESS FOR PURIFICATION OF SURFACE WATERS

The present invention relates to a mobi le apparatus for the purification of surface waters, or for reducing the mechanical and biological pol lution, said apparatus contains refi l l pump, mechanical fi lter, ozonizer and wa¬ ter-tank, as wel l as pipel ines, valves and control system. Furthermore, the invention relates to a process for the purification of surface waters with ozone, when the ozone is injected into the prefi ltered water and the treated water is stored in a tank.

It is wel l-known that waters in the nature contain more or less undesirable dissolved matter and bacteria that might be harmful or infectious. In addition, the purity of the surface and subsurface water sources has been recently deteriorating at a rapid rate under the effect of the intensive industrial and agricultural activities. Thus, as a consequence of the ever increasing mechanical , chemical and biological pol lutions, a large part of the drinking water requires purification. Providing adequately pure dringing water is one of the important problems of our age.

A certain part of the water treatment processes is fi ltering out the mechanical and floating pol lutions with fi lter of different fineness (DE-OS 29 5 317, DE-OS 29 33 499).

Chemical treatments are used for removal of the undesir¬ able chemical components, and at the end of the process the water is disinfected.

The most frequently used method of d i s i n i fect i on is c I or inat i on, since the chlorine decomposes the organic matters in the water. -2 -

A more powerful oxidizing effect can be attained with ozone treatment. Because of the extremely intensi e oxidizing property of the ozone, it is the best and quickest bactericide, the effect of which - contrary to the chlorine - hardly depends on the pH of the water. The ozone destroys or neutral izes the viruses, parazites, even the toxicants. At the same time - again contrary to the chlorine - it does not deteriorate the sensory properties of the water, but considerably improves it by decomposi- tion and transformation of the tase and smell substances or coloured compounds.

Further beneficial property of the ozone is that it decomposes within a short time and produces oxygen, which is one of the most frequent elements in the nature and fundamental substance of the life.

Treatment with ultraviolet ray is also a process used for disinfection (see for instance EP-0 202 820, UK-PS 2 023 980, or FR-PS 83 07 513). Its main drawback is partly the high specific operating and investment cost, and partly its inefficient appl ication in the case of waters containing a large amount of organic matter ab¬ sorbing light to a considerable extent.

Further drawback of the UV-lamps is that they can not generally used for individual water supply, because they operate effectively only in waters of certain degree of pollution, in a narrow quality range of raw water.

Use of the chlorination technology is limited to waters containing high aluminium ion and organic matter, because of its poor effectiveness and formation of chlorinated compounds harmful to the health. Most ly the apparatuses using ozone proved to be fit for individual water supply. The apparatus disclosed in the DE-OS 33 13 723 is recommended for the treatment of drinking waters kept at relatively high temperature and for a long time in pipel ines or water tanks resulting in deterioration of its qual ity and savour. Accordingly, capacity of the apparatus is fairly low: it is suitable only for the supply of a single household and it is bui lt for laying on of minimal amount of ozone.

Mobi le apparatus to produce dringing water from surface waters (DE-OS 32 08 912) is also known. Its drawback is however, that is disregards change in the water qual ity in the course of the treatment, thus the amount of ozone in- put is either insufficient or excessive. The excessive amount of ozone is col lected in the space above the water tank. Nevertheless, ozone content of the withdrawn dringing water cannot be regulated.

The object of the present invention is therefor to provide a process and an apparatus for the purification of differently pol luted waters to dringing water in a manner, that the amount of ozone used in the apparatus depends on the pol lution present in the water, furthermore in which the ozone concentration of the dringing water does not exceed a permissible level , and at the same time the apparatus is protected against any infection and deterioration of the qual ity as a consequence of stagna- t ion,

According to the invention the water to be purified is held minimum 30 minute in the apparatus, the amount of dissolved ozone present in the purified water is continual ly measured, and over 0,05 mg/dm^ the ozone input is stopped, whi le below 0,01 mg/dm^ it is switched on. -h -

Infection of the purified water is prevented by constant circulation of the water, and as much water is discharged by withdrawal and/or draining as to have the total amount of purified water exchanged at least once a day.

In the course of the process even 16 g ozone can be injected into 1 rvr water to be purified, since the amount of dissolved ozone present in the water is constantly checked. For the purification of pol luted tropical waters, general ly 8-13 g/rr ozone is used.

In the mobi le water purifying apparatus according to the invention, the pressure side of a circulating pump l inked with the water tank is connected with the water outlet valve, water tank and ozone concen ration metering unit provided with drain pipe.

The water tank consists of three units provided with separate ozone absorbers, where the first and third units are interconnected with a lower l ine, the first and second units with an upper overflow line, and the circulating pump is joined to the third unit.

The coarse fi lter adjoining the refi l l pump is connceted with the first unit and the pressure side of the pump is provided with a check valve.

Preferably a return tap joint is between the refil l pump and coarse f i I ter .

A backwashing pump is the second tank interconnected with the coarse fi lter through check valve.

An afterfilter after the third unit and a prefilter in the first unit may be arranged in the apparatus, where the prefi lter and afterfi lter are provided with repleceable inset suitably of identical fi ltering capacity.

The third unit may be provided with an ultraviolet lamp and/or a cool ing spiral .

The invention enables to produce drinking water from sur¬ face waters of different qual ity, with the same apparatus. The apparatus is designed for individual water supply, it is easi ly transportable and can be instal led and operated under optional conditions, practical ly without the need of special ist. The apparatus offers the possibi l ity for the efficient purification of highly pol luted waters, since multiple of the customary amount of ozone can be used without danger in the apparatus for individual water supply, considering that the amount of dissolved ozone present in the water can be constantly checked before withdrawal , and injection of the ozone can be regulated accord i ng I y.

The main advantage of the invention is that bacteria or germs cannot propagate in water stored in the apparatus, even without water output over a long time. A definite amount of water is namely continuously discharged from the water tank whi le the water is circulated. That is the amount necessary to exchange the whole content of water in the tank at least once a day.

Further detai ls of the invention wi l l be described by way of example, with reference to the accompanying drawing, in whi ch:

Figure 1 is a l ine diagram of an embodiment of the apparatus according to the invention. Water tank of the apparatus consists of unints 1,2,3 where unit 1 and 2 are interconnected with an upper overflow l ine 4, and units 1 and 3 with a lower pipel ine. The refil l Ipump 6 as part of the apparatus is connected with coarse fi lter 9 through l ine 8 provided with a check valve 7. Line 8 between the check valve 7 and coarse fi lter 9 is provided with backwashing tap joint.

The water passes from the coarse fi lter 9 through pre- fi lter 11 to the water tank 1.

Al l the three units 1,2 and 3 of the water tank are fitted with ozone absorbers 12, 13 and 13 respectively. These are connected with the ozonϊzer.

A lower level indicator 16, upper level indicator 17 and lower level indicator 18 are arranged in the first unit 1, second unit 2 and third unit 3 of the water tank, respect ive I y.

A backwash pump 19 in unit 2 is interconnected with the coarse filter 9 through line 21 provided with'check valve 20.

The third unit 3 contains a cool ing spiral 22, and an ultraviolet lamp 23. The same unit 3 is conected with the circulating pump 24 that passes the purified water through afterfilter 25 to the water outlet valve 26. Likewise, the circulating pump 24 passes the purified water through line 27 to the .ozone concentration meter 28, from where the water flowing through leaves via the drain pipe 29.

The ozone concentration meter 28 and ozonizer 15 are in¬ terconnected with control unit 30. This control unit regulates operation of al l units. When starting the apparatus, the refi l l pump 6 begins to function and pumps pol luted water into the rol uni t 30 keeps the magnetic valve 31 between the coarse fi l ter 5 and the tank closed for one minute, and at the same ime it opens the magnetic valve 32 in the backwashi.ng tap joint 10. Thus the highly pol luted water in l ine 8 passes into the duct 33.

After washing f or 1 minute, the magnetic valve 32 closes, the magnetic valve 31 opens, and the water to be purified passes through coarse fi lter 9 into uni s 1 and 3 of the water tank. At the same time, the control unit starts up the ozonizer 15 and feeds ozone through ozone absorbers 12, 13 and 14 into units 1, 2 and 3 of the water tank.

The water purified on the coarse fi lter 9 from the mechanical and floating pol lutions passes through pre¬ fi lter 11 into units 1 and 3 receiving the pretreated water. The refi l l ing is continued unti l the water fi l ls up the unit 2 through the upper overflow l ine 4 and the level indicator 17 stops the refi l l pump 6 through the control unit 30.

Injection and absorption of the ozone in the water to be purified go on for about 10 minutes. After expiry of the saturation period, the control unit 30 switches on the backwashing pump which backwashes the coarse fi lter 9 with the disinfected water through check valve 20 and l ine 21.

Meanwhi le, first the magnetic valve 32 is closed, and the magnetic val.ve 31 is open for disinfection of the pipe section interconnecting the coarse fi lter 9 with unit 1 of the water tank. Then, by opening the magnetic valve 32 and closing the magnetic valve 31, the disinfected water in unit 2 of the water tank removes the pol lut ion accumulation the coarse fi lter into the duct 33 through magnetic valve 32. This completes disinfection of the coarse filter 9 and the interconnecting pipe sections. Meanwhile the check valve 7 prevents the backwashing water from returning to the vicinity of the point of water intake.

During the refi l ling and backwashing cycles, the cir¬ culating pump 24 functions continual ly and circulates the purified water in the three units of the water tank through afterfilter 25. The inducted and ozone treated water stays in the tank for minimum 30-40 minutes to al low development of the proper disinfecting effect. Part of the circulated water passes through l ine 27 into the ozone concentration meter 28, then from there into duct 33 through drain pipe 29. In this way, the water in the tank will be exchanged in maximum one day, if no water is withdrawn from the apparatus through the outlet valve 26. Thus, stagnation cannot occur in the water tank and besides this, the water is continual ly exchanged.

THe ozone concentration metering unit 28 checks the efficiency of purification and closes the magnetic valve 34 in front of the water outlet valve 26 at a predermined level of ozone concentration (below 0.01 mg/dm^ in the present case) meanwhile continually actuates the ozonizer 15 and feeds ozone through ozone absorbers 12, 14 into the units 1 and 3 of the water tank unti l the predermined upper concentration, (in the present case: 0.05 mg/dm^) appears on the ozone concentration meter 28. At this point, the control unit 30 stops the ozon input. Meanwhi le the control unit 30 opens the magnetic valve 34 when the lower ozone concentration is reached, and actuates .the water outlet valve 26.

As much water is passed through the ozone concentration -9 -

meter 28 as necessary to exchange the water in units 1,2,3 of the tank at a fixed number of cycles, preferab I y -a ^*■* least once a day. This is accompl ished in the given apparatus so that 4 % of the dimensioned water withdrawal passes continual ly through the ozone concentration meter 28, so that at least one refi l l ing - backwashing cycle should take place once a day without water withdrawal, as a consequence of which the water stagnant on the couarse fi lter and interconnecting pipes can be prevented from in- fection. The level indicator 18 arranged in the lower part of unit 3 of the water tank emits warning signal in case of trouble, and it stops the circulating pump 24 and closes the magnetic valve 34 through the control unit 30 to prevent withdrawal of water from the apparatus.

In the presented embodiment an addit ional ultraviolet ray lamp 23 and cool ing spiral 22 where bui lt into the unit 3 of the water tank. The ultraviolet ray lamp 23 can complement the ozone treatment and fruther purify the circulated water in unit 3.

The cool ing spiral is used frjst of al l to main tain the approximate temperature of the dringking water produced by the apparatus even in case of relatively high outside temperature.

The apparatus according to the invention is suitable for the efficient purification of any pol luted surface water with relatively low demand for energy. Size of the apparatus is smal l, its assembly, instal lation and handl ing are simple, its maintenance is practical ly ni l , apart from the fi lter change.

Of course the example described above restricts by no means the scope claimed in the attached claims.

Claims

C L A I M S

1. Process for the purification of surface waters with ozone, wherein ozone is injected into pref ϊ I tered -water , and the treated water is stored in a tank, or conducted to the location of water withdrawal , characterized in that the inducted water is circulated in the tank for at least 30 minutes, the amount of dissolved ozone present in the purified water is continual ly measured and the ozone injection is stopped over 0.05 mg/dm , while ft is started below 0,01 mg/dm , and during the constant circulation of the purified water as much water is discharged by withdrawal and/or draining, as to have the water content of the tank exchanged at least once a day.

2. Process according to claim 1 characterized in that 2-16 g ozone on the average is injected into 1 m^ water to be pur i f i ed.

3. Process according to claim 2 characterized in that 8-13 g/m° ozone on the average is injected into the water.

4. A mobi le apparatus for the purification of surface waters containing refi l l pump, mechanical fi lter, ozonizer and water tank, as wel l as pipel ines, valves and a control system, characterized in that the pressure side of the circulationg pump (24) is connected with the water tank, the water outlet valve (26) and a dissolved ozone concentration metering unit (28) provided with a drain pipe (29).

5. Apparatus according to claim 4 characterized in that the water tank consists of three units (1,2,3) provided with separate ozone absorbers (12,13,14), where the first and third unit (1,3) are interconnected with a lower l ine (5), the first and second unit (1,2) with upper overf low line (4) and the circulating pump (24) is conected with the th i rd un i t (3) .

6. Apparatus according to claim 5 characterized in that backwashing pump (19) is in the second unit (2) inter¬ connected with coarse fi lter (9) through check valve (20) .

7. Apparatus according to claim 6 characterized in that the coarse fi lter (9) joined to the refi l l pump (6) is connected with the first unit (1) of the water tank.

8. Apparatus according to claim 7 characterized in that the pressure side of the refi l l pump (6) is provided with check va I e (7) .

9. Apparatus according to claim 7 or 8 characterized in that backwashing tap joint (10) is between the refi l l pump (6) and coarse fi lter (9).

10. Apparatus according to any of claims 4 to 9, charac¬ terized in that it is provided with after fi lter (28) connected to the third unit (3) of the water tank.

11. Apparatus according to any of claims 4 to 10, charac¬ terized in that a prefi lter (11) is in the first unit (1) of the water tank.

12. Apparatus according to claim 10 or 11 characterized in that the prefi lter (11) and after fi lter (21) are of identical structure.

13. Apparatus according to any of claims 4 to 12, charac- terized in that ul traviolet ray lamp (23) is in the third unit (3) of the water tank.

14. Apparatus according to any of claims 4 to 13, charac¬ terized in that a cool ing spiral (229 is in the third unit (3) of the water tank.