JPH02229505A - Filter - Google Patents

Abstract

PURPOSE:To prevent the clogging of the filter by placing the beds of activated carbon having different grain diameters in a basket with the bottom netted in layers. CONSTITUTION:A filter medium-packed bed is provided at the inter-mediate region of the filter main body, and the filter medium-packed bed consists of the lower fine activated carbon bed 2A, and the fine activated carbon lower bed 3A' on the bed 2A and the coarse activated carbon upper bed 4B encased in the basket 38. The fine activated carbon bed 2 is held by a support 36 protruding into the filter main body 1. A screen 41 is laid at the bottom of the basket 38 by a bolt 40, and the activated carbons 3 and 4 in the basket 38 are separated from the lower fine activated carbon bed 2. By this method, the time unitl the filter is exchanged due to clogging is prolonged.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a filtration device. [Prior Art] As a conventional packed bed type filtration device, a sand filtration device installed at the lower stage of a coagulation sedimentation tank in a water treatment plant is well known, and this sand filtration device is used for regeneration. It is also known that a packed layer can be formed from two phases with different average particle sizes. In this case, particles with a larger particle size are filled above the sand filter layer, and the upper filled layer with a larger average particle size is filled with deeper layers. We aim to extend the regeneration cycle by causing filtration. Regeneration is performed by flowing water from the bottom of the packed layer upwards in the opposite direction to the water flow, loosening the packed layer and draining suspended solids out of the system. Therefore, for the large particles placed on the top of the sand filter layer, materials with a specific gravity smaller than sand (for example, anthracite) are used.
This prevents large particles from coming to the bottom of the packed layer at the end of reverse regeneration. [Problem to be solved by the invention] However, when the above sand filtration method is regenerated, 1
2) The amount of waste liquid generated during regeneration is large compared to the amount of liquid to be treated, which is inefficient. 3)
There are problems such as the time required for regeneration cannot be ignored, and 4) lumps of suspended matter in the surface layer that cannot be thoroughly loosened during regeneration may remain in the packed layer. This problem is even more pronounced in the case of difficult-to-filter waste liquids that have a high concentration of suspended solids and contain organic substances, which easily clog the packed layer, especially in small-scale filtration where the amount of waste liquid to be treated is not large. become. Other filtration methods include bricoat filtration, reverse osmosis,
Although there are ultrafiltration methods, etc., the same problems as 1), 2), and 3) associated with regeneration operations in the sand filtration method, ie, problems with regeneration equipment, regeneration efficiency, and regeneration time, remain. The present invention examines the possibility of changing the adoption of the regenerative operation method that has the above-mentioned problems to a non-regenerative operation method, and also aims to minimize the disadvantages associated with adopting the non-regenerative operation method. This is a topic. Therefore, the present invention does not require regeneration equipment, it takes a long time to replace the packed layer as it progresses, and it is easy to replace the clogged packed layer and manage the amount of replacement. This paper relates to a filtration device that uses a non-regenerative operation method that minimizes the amount of waste, especially a filtration device that is suitable for small-scale filtration of difficult-to-filter waste liquids that have a high concentration of suspended solids and contain organic matter. Furthermore, the aim is to obtain a filtration device suitable for filtering waste liquid containing heavy metal ions, etc., which is a system with strict standards for treated water quality. (Means for Solving the Problems) The above object is to provide activated carbon having an average particle size equal to or similar to the particle size of the activated carbon of the filled layer (A) on the activated carbon filled layer (A) with a small average particle size. A filled layer (A゜) and an activated carbon filled layer (B) having an average particle size larger than that of the activated carbon in the filled layer (A) were placed in a basket with a rope attached to the bottom. It has been found that this can be achieved by a filtration device characterized by the following.In the present invention, activated carbon is used as the filtration layer, and on top of the activated carbon packed layer (A) with a small average particle size, The activated carbon packed layer (B) is filled so that it can handle both surface filtration and deep filtration, and the operating time until clogging progresses and replacement is extended compared to the packed layer (A) alone. At the same time, activated carbon is easy to dispose of by incineration, so it is suitable for non-regeneration methods.In addition, among the activated carbon filled layers, the upper part of the activated carbon layer (A゛) with a small average particle size and the upper part of the activated carbon layer with a large average particle size By storing the activated carbon layer (B) in a basket with a rope attached to the bottom, it is easy to replace the activated carbon layer that has become clogged and to manage the amount of replacement. Because it is only activated carbon,
The amount of waste generated is very small and it is economically effective. Therefore, the filtration of the present invention is particularly suitable for filtering difficult-to-filter waste liquids that have a high degree of suspended matter TFI and contain organic substances. The particle size of activated carbon used in each layer is not particularly limited;
When suspended solids with a particle size of 10 μm or more in the water to be treated account for 50% (by weight) or more of the total suspended solids, the average particle size of (B)> the average particle size of (A) or (A゜) While satisfying (A
) or (A') is preferably 20 mesh or more, and (B) is preferably 30 mesh or less. Particle size 10
When suspended solids smaller than μm account for more than 50% (by weight) of all suspended solids, especially when particles smaller than 1 μm cannot be ignored,
The particle sizes of (A), (A'), and (B) are relatively reduced to about 1/1.
Although it is necessary to reduce the particle size to near 0, the impact of the increase in differential pressure is very large, and it is not economically advisable to use it unless it is used at a low concentration of several pp or less. (A) Assuming that (A″) is a different particle size, operationally (A), (
It is complicated to manage three activated carbons, A゜) and (B). Therefore, (A) and (A°) are usually the same particle size. The suspended solids do not penetrate to (A), (B), (A"
), it is better to have a smaller difference in particle size between (A) and (A゛). It is preferable that the average particle size of (A) and (B) be at most the average value or less. In a two-phase filtration system consisting of a lower layer with small particle size and an upper layer with large particle size, it is the suspended solids in the surface layer of the packed layer that contribute most to the resistance of the filtration layer due to clogging.
If this can be completely removed from the system, the permeability of the packed layer can be restored. Visually, it can be seen that deep filtration tends to proceed to some extent from the surface layer, and it is preferable from the viewpoint of stable operation to increase suspended solid removal efficiency and to remove this portion at the same time.

In addition, looking at the boundary between the lower layer with small particle size and the upper layer with large particle size, it seems that the progress of deep filtration stops at the boundary in the large particle size part of suspended solids, and the packed layer is replaced after clogging progresses. By limiting this to only the upper part of the packed layer with small particle size (A゛) and the filled layer part with large particle size (B),
Exchange can be performed including the boundary area mentioned above, which further increases suspended solids removal efficiency and enables more stable operation.
In the present invention, the replacement parts (A' and B) are stored in advance in a basket, thereby achieving efficient, safe and easy replacement. Furthermore, if the structure is such that the basket can be lifted, a clogged filling layer can be replaced at a location other than the filtration device itself. In addition, when replacing the basket by lifting it by hand, which makes it easier to remove only the suspended solids in the surface layer, the size of the basket mesh should be the same as the size of the activated carbon in the lower packed layer (A°) with small particle size inside the basket. In comparison, it is preferable to use stainless steel or the like so that it is the same or lower and can withstand the weight of the filling layer. The thickness of the upper activated carbon layer (B) with large particles varies depending on the particle size of the activated carbon and the particle size of the target suspended solids. In the long run, the lower part of the filled layer (A) will gradually become clogged, so at that time the entire amount will need to be replaced. Furthermore, in cases where treated water quality standards are strict, such as in the treatment of laundry wastewater at nuclear power plants, the upper part (B) and/or lower part (A) and (A') of the packed layer are activated carbon that adsorbs heavy metal ions. It is preferable to use a material that has a chemical substance attached to it that has high properties. For example, in the case of a nuclear power plant, Co-6
0 has a long half-life and causes an increase in the radioactivity concentration of laundry wastewater. However, for example, those impregnated with oxin as the chemical substance mentioned above are effective in removing heavy metals such as cobalt, copper, manganese, and zinc. There is a fruit. As a product, for example, K-MMC
(manufactured by Johoku Kagaku Kogyo ■, 24-42 mesh).
[Example] The example shown in the drawings will be described in detail below. Fig. 1 is a diagram schematically showing the filtration device and its piping state, and Fig. 2 shows the main body of the filtration device. In the filtration device l,
Above it, an inflow pipe 1l having a treated water source valve 12 for introducing treated water into the filtration device passes through the treated water population A, and a treated water outlet for discharging the filtered treated water. An outflow pipe l3 with a valve l4 is installed via the treated water outlet B. Further, above the filtration device, a pipe 15 for introducing washing water into the filtration device and a pipe 17 for introducing compressed air into the filtration device further supply compressed air into the filtration device via a washing water population H and an air population G, respectively. Vent valve 2 to release
2, and a pressure gauge 24 for measuring the pressure inside the filtration device are provided through the mounting port E, respectively. In addition, a wash water source valve 16 is installed in the wash water introduction pipe l5.
The air introduction pipe 17 is provided with an air flow control valve 18, a check valve 19, a pressure reducing valve 20, and an air valve 21 in this order from the filtration device side. In addition, there is an intermediate drain D on the side of the filtration device.
An intermediate drain valve 28 and a peephole 2a are provided through which the water level and filtration layer can be visually observed during draining (
If the basket is made of transparent acrylic resin or the like, the filtration layer inside the basket can be seen visually), and furthermore, a blow valve 30 is provided below the filtration device via a drain hole F. A filter material (activated carbon) filled layer is provided in the middle region of the filter main body 1, and this filter material filled layer is housed in a fine activated carbon layer 2 (A) below and a basket 38 above it. It consists of a fine activated carbon lower layer 3 (A") and a coarse activated carbon upper layer 4 (B). The fine activated carbon layer 2 is held on a support 36 that projects inward of the filter body l. Details are shown in FIG. So, at the bottom of the basket 38,
A screen 41 is stretched by bolts 40, and the activated carbon layers 3 and 4 in the basket 38 are separated from the fine activated carbon N2 located below. The basket 38 is provided with a grip portion 39 on the upper side, and has a structure that allows the filter device to be removed upwardly from the filter main body l by opening the M34 of the filter device. It is preferable to have a hole in the basket above the level of the activated carbon that is filled in the basket so that when water is drained using air, it is possible to confirm through the peephole that the water has drained to the vicinity of the filled part of the basket. A body flange 33 is formed at the top of the filter body 1, and a lid 34 corresponding to the outer diameter of the body flange 33 is attached to the lid 34 so that it can be opened and closed by a hinge 35. As described above, the lid 34 is provided with a vent C for venting the air inside the filtration device body, and the lid 34 can be tightened as appropriate with bolts or the like at the body flange 33, for example. ．． In this activated carbon filtration device, the fine activated carbon layer 2 has a particle size of 24 to 42 mesh and a layer thickness of about 9 cm, and the fine activated carbon N3 in the basket has a particle size of 24 to 42 mesh and a thickness of about 1 cm.
m+, the coarse activated carbon layer 4 was set to have a particle size of 8 to 30 mesh and a layer thickness of approximately 20 mm. In addition, this activated carbon filtration device is assumed to have a processing capacity of 1 to 4 rrf/h (LV (value obtained by dividing the flow rate (rrf/h) by the cross-sectional area of the filtration device (a)) and 5 to 20 + * 8). L■ is almost the same as the value of rapid filtration in sand filtration equipment at water treatment plants. However, depending on the concentration of suspended solids and the particle size of activated carbon, the processing amount is not limited to the above amount. Hereinafter, the treatment operation of water to be treated using the filtration device of the present invention will be explained based on Fig. 1. The water to be treated flows through the inflow pipe 11
The filtered treated water is introduced into the main body of the filtration device through the outlet A, and is discharged from the outflow pipe 13 through the outlet B.
The progress of clogging of the filter medium can be confirmed by the pressure gauge 24, and when the water flow progresses and the indicated value of the pressure gauge 24 increases and reaches a predetermined value, the treated water source valve 12 and the treated water outlet valve l4
Close and stop water flow. Open the outlet valve 14, then open the air flow control valve l8 little by little, and when the water has drained to the top of the activated carbon layer as seen through the peephole 26! Close the control valve 18 and then close the exit valve 14. The reason why water is removed using pressurized air is because the resistance of the filtration layer is large, and it takes a very long time to remove water from the activated carbon filtration device using the head. Next, open the vent valve 22 little by little to release the pressure. Open the lid 34 and replace some of the activated carbon (the one in the basket 38) with a new one. Close the lid 34, open the wash water source valve l6 little by little, and fill the activated carbon filtration device W1 with water. After confirming that the water is full, open the cleaning water source valve 16, followed by the vent valve 22.
Close. After completing the above operations, open the water source valve l2 to be treated.
Then, open the treated water outlet valve l4 and restart water flow. experiment l
．． Below, we will confirm that in packed layer filtration using activated carbon, filling the upper layer of the packed layer with particles with a larger particle size than the lower layer can advance deep filtration and extend the service life. Inner diameter 1. Prepare two 95c Tsuru acrylic columns, put a 40 mesh polyethylene net on the bottom, and add activated carbon (manufactured by Nimura Chemical Industry ■, CW830B) with a particle size distribution of 8 to 30 mesh, 24 to 42 mesh. Activated carbon (manufactured by Nimura Chemical Industry ■ 11c4) with a particle size distribution of
2) was filled to a depth of 10 cm each, and the simulated liquid was filtered using a birch whose water level was approximately 15 cm from the top of the filled layer. The simulated solution was a 500pp aqueous solution containing Jinson Baby Powder manufactured by Jinson & Gilinson ■, and as a result of microscopic observation, it was confirmed that it had a particle size distribution of 10 to 150μ. The results are shown in Figure 4. The horizontal axis represents the filtration time, and the vertical axis represents the total filtration amount. The greater the slope of the line, the greater the filtration flow rate and the lower the filtration resistance. O mark indicates simulated liquid 5 on activated carbon with coarse particle size of 8 to 30 mesh.
The results show that the slope is steep and constant until 1i is filtered, and it is assumed that the baby powder is partially captured in the packed layer in a form similar to deep filtration. The Δ mark is the result of passing the filtrate passed through the above-mentioned coarse activated carbon (filtered in the 0 mark test) through 24 to 42 Messier activated carbon, and the slope is constant during 12 filtrations, and the O mark and It is presumed that it is trapped in the packed layer in a similar manner to deep filtration. By the way, the filtrate marked with Δ is visually transparent, indicating that most of the baby powder has been removed.
The result is that the filtration flow rate is the same as the Δ mark until 17 minutes after the start of filtration, but after that, the filtration flow rate is 1/3 of the Δ mark.
It can be seen that it has fallen to From the above facts, it is possible to suppress filtration resistance and extend the operating time until the activated carbon is replaced by filling activated carbon N with a larger average particle size on top of the activated carbon packed layer and passing water through it. Recognize. Experiment 2. This paper shows the progress of surface filtration and deep filtration in double activated carbon layers and their effects on filtration resistance. As in Experiment 1, the inner diameter was 1. Attach a 40 mesh polyethylene net to the bottom of a 95c-acrylic power ram,
10 cm of activated carbon with a particle size distribution of 24 to 42 mesh, similar to that used in Experiment 1, was filled, and 8 cm
Fill 20 cs+ of activated carbon with a particle size distribution of ~30 mesh. The simulated liquid was baby powder with the same specifications as in Experiment 1, and the concentration was 12,500 pp-. The experiment was conducted by intermittently flowing the simulated liquid from the top of the column to maintain the water level approximately 15 cm from the top of the 8-30 mesh packed layer (20°C). The results are shown in Figure 5. In Figure 5, the O mark indicates the case where only pure water is flowed into the column. The Δ mark is a test in which a simulated liquid was added, but the amount of permeated water is not different from that of pure water for about 3 minutes after the start of filtration. However, after that, the resistance of the packed layer increases rapidly and the amount of permeated water decreases. 2.5 hours after filtration, an additional 1.5 cm of baby powder layer was deposited on top of the packed layer, and the resistance of the surface filtration layer became almost dominant. In this state, temporarily stop filtration,
The person holding the column held the outlet with his hand and shook the column to force part of the powder layer into the packed layer. Even so, 50% of the baby powder layer remained on the surface layer (A in the figure).
．． 2.5 hours after the start of filtration, the amount of permeated water recovered, but not significantly. Three hours after the start of filtration, the amount of permeated water returned to the state immediately after the start of filtration when it was completely removed to the surface baby powder layer (B in the figure). This shows that surface filtration increases the resistance of the packed layer more than deep filtration, and that completely removing the surface layer is important from the perspective of restoring the amount of permeated water. (Effect of the invention) By using the filtration device according to the present invention, the activated carbon packed layer (B) with larger particle size is filled on top of the activated carbon filled layer (A and A'') with smaller particle size, and surface filtration and deep layer filtration are performed. Compared to using a fine-grained activated carbon layer alone, the operation time until clogging progresses and replacement is extended.In addition, activated carbon is used for regeneration operation, and water flow If clogging of the packed layer progresses, the amount of waste generated can be reduced by stopping the water flow and replacing only the activated carbon layer with large particle size (B) and a part of the activated carbon layer with small particle size (A). Since it is activated carbon, it is easy to incinerate.The layer to be replaced with S is stored in a basket with a net on the bottom, so it is not only easy to replace, but also easy to dispose of by incineration.
It also makes it easier to manage the number of replacements. If the basket can be lifted, replacement will be easier. Furthermore, by using activated carbon in which the activated carbon layer (A), (A゛) and/or (B) is impregnated with a chemical substance that has high adsorption properties for heavy metal ions, it can be used in systems with strict treatment water quality standards such as nuclear power plants. I can handle it well.

[Brief explanation of the drawing]

Fig. 1 is a diagram schematically showing the filtration device and its piping state, Fig. 2 shows the filtration device main body, and Fig. 3 is a detailed view of the basket portion in the filtration device main body. 4th ti! Q is a graph showing the time change in the total filtration amount based on Experiment 1, and FIG. 5 is a graph showing the time change in the total filtration amount of the double activated carbon layer based on Experiment 2. ■Filtration device 2 3 Fine activated carbon layer (A゜) 4 Coarse activated carbon (B) 1112 Water source valve to be treated 13 14 Treated water outlet valve 15 16 Washing water source valve 17 l8 Air flow tirui valve 19 20 Pressure reducing valve 2l 22 Drop valve 24 26 Peephole 28 30 Blow valve 31 32 Bottom FX33 34 Lid 35 36 Support 37 38 Basket 39 40 Bolt 4l A Water population to be treated B C Vent D E Pressure gauge installation port F Fine activated carbon layer (A) To be treated Water inflow pipe Treated water outflow pipe Cleaning water inlet pipe Air inlet pipe Check valve Air source valve Pressure gauge Intermediate drain valve Trunk flange Hinge Leg handle Screen Treated water outlet Intermediate drain Drain Lo Air inlet Cleaning water inlet Figure

Claims (1)

[Claims] 1. On the activated carbon filled layer (A) with a small average particle size, an activated carbon filled layer (A') having an average particle size equivalent to or similar to the activated carbon particle size of the filled layer (A). ) and an activated carbon filled layer (B) having an average particle size larger than that of the activated carbon in the filled layer (A), which is housed in a basket with a net on the bottom. Filtration device. 2. The filtration device according to claim 1, wherein activated carbon impregnated with a chemical substance having high adsorption properties for heavy metal ions is used in at least one of the activated carbon filled layers (A), (A'), and (B).