FI78443B - IMPORTANT BEHANDLING AV VATTEN. - Google Patents

Description

1 78443

Water treatment device.- Anordning för behandling av vatten.

The present invention relates to an apparatus for treating water, in particular for removing iron and manganese from water, in pairs of flowable vertical filter chambers in series or in a row, the latter chamber of the former pair being in flow communication with the first chamber of the next pair.

The development of the present water treatment plant has been aimed in particular at the removal of groundwater iron and manganese in small units, which is one of the problem areas of water treatment.

Iron and manganese are very common constituents in groundwater. When groundwater comes into contact with air, for example when water is taken out of its natural environment, these substances are easily oxidized to a solid form. This causes considerable inconvenience, e.g. due to the precipitate formed.

In natural waters, iron and manganese exist as various compounds, sometimes bound to humus, for example, whereby their separation (by precipitation) varies. Sometimes simple aeration and filtration are enough to remove iron in particular, and sometimes much more efficient processes are required. Removing manganese is generally more difficult than iron. In general, the quality range of groundwater is considerably wide, which means that their treatment needs and possibilities vary considerably. In addition to iron and magnesium, water treatment problems can be caused by e.g. nitrogen compounds in reduced form (NH4 and NO2 ions), harmful gases dissolved in water (methane, sulfur, hydrogen, radon), low pH and high CO2 content (corrosive properties to metal pipelines) and oxygen-free.

2 78443

Known, usually prefabricated, small water treatment devices, the operating principle of which starts from simple aeration and filtration to chemical treatment of water, cover aspects of water treatment, but there are considerable shortcomings. My most effective11a methods achieve good results but at a considerable cost. Another problem is the demanding maintenance of the equipment and the short service intervals. Especially in the presence of high iron concentrations (> 10 mg Fe / l), the formation of a precipitate is abundant and the cleaning equipment quickly becomes clogged. All cleaning devices on the market are based on pressure systems, which are limited by e.g. with a view to removing harmful gases. It is difficult to find a device that meets all the cleaning requirements.

Groundwater treatment plants alone are required to perform very well in the removal of iron and manganese, taking into account different water qualities. This is usually achieved at a reasonable cost only by biological treatment methods already applied in water utilities. Such plants most commonly comprise above-ground aeration stairs and crushed stone filters as a pre-treatment unit and as a main treatment unit a slow filter made of sand paints, which may be an artificial pool or a suction pool flowing into the groundwater zone. Such space-consuming structures cannot be used for small-scale water treatment, which can be placed in commercial premises if necessary. In addition, it would also be beneficial for water utilities for winter use if the ratio of the total area yield of the plant could be reduced from the current one.

In known so-called in slow filtration plants or the like, this ratio is usually such that an area of 1-2 m2 or more is required per cubic meter of water produced.

The object of the invention has been to develop a device which is particularly suitable for small-scale water treatment. Its functional requirement has been, above all, the efficient removal of iron and manganese from all water qualities and under all treatment conditions, but also the achievement of a result in other treatment needs mentioned above. The device has also been required to function well in terms of maintenance and to have a simple structure that even allows self-construction.

The objects of the invention are achieved by a device characterized in that the chambers of each pair of chambers are in flow communication at their lower part and that at least one of the water-filled pairs is provided with a surface filter layer partially above the water surface, the filter layer can extend to the bottom of the chamber. the flow connection between successive pairs of chambers takes place as an overflow, whereby aeration of water takes place at the same time.

Other features of the invention will become apparent from claims 2-6 below.

The treatment device consists of a filter chamber purchase in which water slowly flows in the vertical direction. The chambers operate in pairs so that in each pair, after aeration, the water flows down and again up through the biologically active filter into the filter, after which it is aerated before moving to the next pair of chambers. The number of chamber pairs can be selected arbitrarily according to the needs (water treatment difficulty). This starting point is particularly important in the application areas of large water utilities, because, as mentioned above, the need for treatment varies greatly and can be studied in advance.

Small units can most practically be built directly as a unit with several pairs of chambers, whereby the necessary cleaning safety is achieved.

The chamber filter unit can be used either alone or connected to a separate small-scale post-filter, e.g. a sand filter, which in difficult water quality conditions improves cleaning reliability and prolongs the service interval.

The functionality of the device construction is based on e.g. to the next.

- oxidation takes place throughout the process as water flows from one pair of chambers to another. Adequate oxygen supply is a prerequisite for biological activity - the filter materials in the chamber are biologically active either naturally or, if necessary, by iron-manganese bacteria plantations - the device is dimensioned so that there is sufficient water residence, eg at least two hours, to achieve the cleaning process itself. that the slow flow rate of water - the filters are located at the upper end of the chambers, partly above the water surface, thus achieving the best oxygen uptake conditions and the possibility of different biological zones - provides a cleaning process. - due to the slow flow of water and the location of the filters, most of the precipitate is sedimented to the bottom of the chambers, thus avoiding the filter too fast clogging 5 78443 - the device design allows the use of different filter materials and even combinations of them in one chamber. Coarse filter materials can be used successfully in iron removal, which is the most common problem, while finer materials are suitable for removing some other components.

- In addition to the removal of iron and manganese, other benefits are achieved in the treatment. Due to efficient oxidation, the water entering the network is well aerated. Its phosphorus and carbon dioxide content decreases and the pH increases, whereby the corrosive properties of the water in the metal pipelines are reduced or completely eliminated. Any reduced nitrogen compounds are oxidized to the more harmless nitrate form. water KMn04 consumption decreases. Harmful gases dissolved in water are removed - the service interval of the equipment has been up to six months at its longest, generally months of operation are achieved.

The invention will be described in more detail with reference to the accompanying drawings, of which

Fig. 1 shows an apparatus embodiment according to the invention, Fig. 2 shows another apparatus embodiment in which three filter chamber units are also arranged in succession, Figs. 3 and 4 show an embodiment in which three filter-chamber pairs are arranged in succession in a circumference, also provided with body structures.

Fig. 78443 Fig. 5 shows the device structure according to Fig. 4 mounted on a storage hose, Fig. 6 shows the structures of the filter basket, Figs. 7 and 8 show the test results obtained with the devices, and Figs.

The device according to Figure 1 consists of three pairs of filter chambers arranged in a row. Each pair consists of a front chamber 2 and a rear chamber 3 in the flow direction, at the lower part of which the chambers are in flow communication with each other. The filter chamber pairs 1 are dimensioned so that their water surface decreases step by step from the first chamber · »pair to the following.

The upper parts of the chamber have a filter layer 4 which can be placed at least in part above the water surface. In the flow direction of the water to be treated coming from the supply pipe 6, the first chamber 2 of the first pair of chambers is, in the case shown in Fig. 1, filled to the bottom with limestone pieces. The liquid flows through this lime-filled chamber where the pH of the water is raised. In the first chamber 2 the water flows slowly downwards and in the lower part of the chamber flows to the next chamber 3 while changing its flow direction. At the top of the chamber 2 there is a filter layer 4 which may consist of a suitable filter medium such as free-floating light gravel, sand, styrofoam granules or the like. Preferably, these filter media are arranged at the top of the chamber 4 on suitable body structures or support frames (19), exemplified from above and from the side in Figure 6. The bottom view of Figure 6 shows a filter basin (20) filled with filter media, or 78443 - substances and may be different from those used in the chamber. From the filter basin (20), water can flow through the outlets into the filter medium of the support frame (19).

Figure 1 shows three pairs of vertical filter chambers in succession, through which the water to be treated slowly flows downwards in the anterior chambers 2 and upwards in the latter chambers 3. From each pair a latter chamber 3 again as shown above in the lower part of the chamber. In this way, by changing the number of vertical filter matching pairs, the total power of the device can be changed and adjusted as needed. The liquid treated from this vertical filter unit is discharged via a pipe 7 and can advantageously be directed to a post-filter, e.g. a sand filter 8 known per se, where any additional impurities are removed. The water purified from the post-filter is led along the pipes 12 for either use or storage.

Figure 2 shows a treatment plant according to Figure 1 in which the water to be treated from the food-water well 10 is led along pipes 6 by means of a pump 20 to a treatment plant having a structure corresponding to that shown in Figure 1. The first chamber 2 is filled with limestone 5.

In the case shown, the first chamber 2 of the second pair of chambers is not provided with any filter material at all. The first chamber 2 of the last pair of chambers is again filled with limestone 5.

The liquid thus purified is passed through an outlet pipe 7 to a sand filter 8 from which it is further led along a pipe 12 for use or storage.

Figures 3 and 4 show an embodiment in which the bypass filter-chamber pairs are arranged in succession to form a circumference. With such a β 78443 solution, a very small and compact overall structure is achieved, and the application also has combination filters.

The embodiment illustrated in Figure 3, which shows a cross-section along the line IV-IV in Figure 4, corresponds in principle to the device of Figure 1, but the chambers are sector-like in cross-section. When joined together, a circular whole with an opening in the middle is obtained. The water to be treated is led along the supply pipe 6 to a first sector-like treatment chamber 2, at the top of which there is a frame for the filter medium (see Fig. 6). As the liquid flows upwards in chamber 3 and fills it, it flows to the next pair of vertical filter chambers through the overflow threshold 11, at the same time the liquid aerates and flows through the biologically active filter down into chamber 2 and up again in chamber 3 through the filter and overflow threshold 11 to the next pair of filters. The number of chamber pairs 1 can be arbitrarily selected according to the needs. In addition, the power of the device can be simply increased or decreased afterwards as needed. Small units can most practically be built directly as units with several pairs of chambers, whereby the required cleaning reliability is achieved. The chamber filter unit can be used either alone or a separate after-filter, e.g. a sand filter 8, can be connected to it, which in difficult water quality conditions improves cleaning reliability and reduces maintenance intervals.

Figure 5 shows a cleaning device according to the invention placed in a storage well, in which case the cleaning device unit, with its vertical filter chamber units, corresponds to the structure of Figure 4.

This device as a whole is placed in a storage well 17, into which the water purified by the device from the supply pipe 12 is drained into the well and the water 15 stored there is held at a certain height by means of a surface regulator 11f. Raw water and sediment can be removed from the cleaning device by means of an outlet pipe 13. In the experiments performed, the average yield of the test plants was 2 m3 / cl, in the test plant according to Figure 2 40 m3 / d. The experiments were performed using three pairs of chambers placed in succession, each measuring 40 x 80 x 60 cm (vm. Vertical) and having a volume of 200 liters. In the middle of the chambers was an open partition at the lower end. The chambers were arranged in steps so that the water fell, aerating from one box to another.

The filter materials used were mainly light gravel packed in mesh frames. These were initially immersed close to the water surface, later the development evolved so that part of the filter was above the water surface, which was most easily achieved by using free-floating light gravel. As other filter materials, styrox granules and sand on a mesh substrate were tested. Limestone was placed in the basket at the beginning of the set of chambers (or also filling the first chamber) to raise the pH of the water.

The hydraulic surface load of these filters was 0.5 m / h.

After the chambers was a 100 x 100 x 30 cm sand filter box with a hydraulic surface load of 0.08 m / h.

One test facility (No. 5, Figure 5) was built as a fixed "box" of three pairs of chambers. Its size was 2.8 x 1 x 1.1 m, volume 2.6 m3 and the hydraulic surface load of the filters was 3.6 m / h. Lightweight gravel packs placed in the latter half of the borehole pairs and limestone in the first half were used as filter materials. The last was a Heikka filter with a surface area of 6.3 m ^ built into the well rings. Their hydraulic surface load was 0.27 m / h.

Figures 7 and 8 show the result of the water purification of the experimental equipment at the end of the experiment. Figures 9 and 10 also show the cleaning result representative of both device sizes over the entire test period (Pe, Mn).

On the basis of these and other individual observations not presented here, the following can be concluded.

1) A good or at least satisfactory cleaning result was achieved in all test facilities. 2) The full efficiency of the operation of the equipment is achieved due to variations in raw water quality in different units at different times. In the case of iron, purification can begin at full capacity within a week; in difficult water quality conditions (binding to humus, etc.) it can take more than a month. Manganese in the case of start-up is always slow, months and even more than half a year. Here, the presence of iron and Magna nibacteria has been found to be very significant (the study of biofunctions was an extensive part of the work).

3) Iron may be removed mainly at the beginning of the unit; under difficult conditions, the purification process develops from chamber to chamber throughout the unit for a residence time.

4) Manganese removal is most efficient with a sand filter.

The equipment is suitable for both small and large plants, in large units (> 100 mVd) the most advantageous application is the installation of successive pairs of chambers. Dimensioning is based on raw water quality. In smaller water utilities (<100 mVd), either the former can be applied or 11 fixed units can be built like site 5. 784 4 3

The treatment plants required for the use of one household can use a fixed cleaning device comprising several pairs of chambers, which can be prefabricated or, in a simple form, also self-built.

The cost of the device remains lower than similar factory-made ones, despite the fact that the non-pressurized system requires more tank space and double pumping.

The cleaning device design can be selected based on needs. In easy-to-treat waters, an end-of-life sand filter is needed; in difficult-to-treat waters, it ensures a cleaning result. The sand filter can also be placed as part of the filters 4 in the chamber 2, 3, whereby, for example, the biological function necessary for the removal of manganese is already achieved here.

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Claims (6)

Apparatus for treating water, specifically for removing iron and manganese from water with vertical filter chamber chamber (1) standing in flowing relationship one after another in a row or in a ring, wherein a precursor The later chamber (3) of the star chamber is in flow communication with a first pair's first chamber (2), characterized in that vane chamber pair (1) chambers start 1 flow connection with its lower part and that of the water-filled chamber pairs ( 2, 3) at least one chamber is provided with a surface filter layer (4) located above the water surface, that in the at least one filter chamber pair (1) the first chamber (2) the filter layer (5) can reach the bottom of the chamber until the flow connection between successive combs (1, 2) occur as an overflow, with simultaneous aeration of the water. 2. Device according to claim 1, characterized in that the water surface drops gradually from the first filter-chamber pair to the following. Device according to claim 1 or 2, characterized in that the material of the filter layer (4) is light gravel. gravel, sand or styrox granules. Device according to any of the preceding claims, characterized in that at least one filter chamber pair (1) later (3) chamber is connected to one known per se. after filter (8), e.g. a sand filter. Device according to any of the preceding claims, characterized in that the filter consists of a perforated support frame (19) placed in the chamber into which the filter material is inserted. in