JPS6362604B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for treating surplus water from a water surface landfill using dredged mud, waste, land sediment, and the like. Conventional methods for treating surplus water include direct injection of coagulant into muddy drainage pipes, shower addition method, coagulation sedimentation tank installation method, and sand filtration tank installation method. There have been cases where it was not possible to respond to changes in the quality of leftover water in the landfill, or where the cost of the leftover water treatment facility and construction costs were not appropriate from the economics of the overall reclamation work because it was necessary to use it only at the final stage of construction. many. Generally speaking, the quality of surplus water in water surface reclamation is less than 100 ppm (suspended solids (SS)) when the construction is slow reclamation, and is on the order of 10 ³ to ^{10 4} ppm because reclaimed particles resurface only at the final stage of construction. Become. If the construction is rapid reclamation, the state at the end of construction in the case of slow reclamation will appear earlier. On the other hand, the standard for drainage of surplus water from a landfill to the surrounding water area is often based on a suspended solids (SS) of 20 to 150 ppm or less, depending on the level of impact on the environment of the surrounding water area. The above-mentioned wastewater quality and wastewater standards are compared to determine the reduction rate of suspended solids by the wastewater treatment method. The combination method of installation method and sand filtration tank installation method has the function of reducing the amount of suspended solids more than necessary in accordance with the drainage standards, and some devices cannot cope with the high concentration of leftover water quality at the end of construction. This will result in non-conformity and economic waste. The present invention solves the above-mentioned technical and economical problems, and aims to remove the amount of suspended solids to the minimum value necessary for the wastewater standard value.
This is a stage filtration method for filtration of waste water from a landfill. The contents of the present invention will be explained below with reference to the drawings. Figure 1 shows the planar shape of a reclaimed land for explaining the method of filtration of surplus water of the present invention, and shows a mixed water of dredged mud and waste (such as rice hulls) into a reclaimed land 2 surrounded by a reclaimed seawall 1. It is made to flow in from the mud removal pipe 3. Near the inflow point, an exposed portion 4 of dredged mud, waste, etc. is formed above the water surface. In other parts of the landfill, dredged mud, waste, etc. are deposited below the surface of the spill water, and the surplus water bypasses the tip of the diversion embankment 5 in the landfill, and the pretreatment filtration device 6 of the present invention and adsorption By passing through the filter 7, the amount of suspended solids is reduced and the quality of the water becomes below the drainage standard value, and the water passes through the spillway 8 and flows out from the spillway pipe 9 into the surrounding water area. FIG. 2 shows the installed cross-sectional configuration of the pretreatment filtration device 6 and adsorption filter body 7 of the present invention. The pretreatment filtration device is composed of a filter plate 10 and a filter plate holding column 11 having a guide groove in which the filter plate can be attached and removed in the vertical direction. The filter body is constructed by stacking up coarse filter media 12 placed in a net bag or the like, and storing this in a fence plate 14 having a gap provided on the coarse filter media side of the filter plate holding column and the coarse filter media holding column 13. do. The upper beam 15 is a connecting beam between the filter plate holding column and the coarse filter medium holding column. Below the spill water 16 there is a sediment layer 17 of dredged mud and waste particles, and the surface layer of sediment is rising as the construction progresses. Due to the rise in the surface of the deposited layer, the filter plate 10 will be in a dead state at the end of construction. On the native ground 18 within the reclaimed land, there are a foundation embankment 19 for the adsorption filter and a bank foundation 20. FIG. 3 shows a cross section of a filter plate of the pretreatment filtration device of the present invention, in which filter sand 22 is sandwiched and housed in a sandwich-like structure between water-permeable sheets or water-permeable mats 23 in a filter frame 21. Filter frame reinforcement material 24
This prevents the permeable pine from swelling outward. FIG. 4 is a front view of the filter plate shown in FIG. 3 above. In the present invention, a two-stage filtration method using a pretreatment filtration device and an adsorption filter body is used as described above so that surplus water can rapidly pass through a limited cross section of the filter medium. The filter plates of the device are replaced one after another, and the coarse filter medium of the adsorption filter reduces the quality of leftover water to below the wastewater standard value through its adsorption action. In general, the permeability coefficient of a filter medium has the values shown in Table 1 below.

[Table] From Table 1, the filter sand of the pretreatment filtration device of the present invention is coarse sand, the permeability coefficient k = 0.35 cm/sec, the water level difference before and after the filter plate h = 10 cm, and the water flow distance of the filter sand l = 5 cm. Then, to find the relationship between the filter sand water flow area A and the water flow rate Q, we get: Q=k・h・A/l=0.35×10×A÷5=0.77Acm ² /sec……25.2Am ³ /Hr・m ^{2 The} above value is A=
Requires a water flow cross-sectional area of ^200m2 , and in general land reclamation work, the total water flow height of the filter plate of the pretreatment filtration device is 2
m, and a total water flow width of about 100 m can be applied.
Therefore, as the filter medium of the adsorption filter body, use a coarse filter medium of the size of small gravel or more as shown in Table 1. In an example of a waste water quality reduction test using the method of the present invention, the amount of suspended solids (SS) = 50 ppm (average) of the waste water was reduced to approximately half, 25 ppm (average), by the pretreatment filtration device.
Therefore, in the adsorption filter body, it is reduced by approximately 1/5,
(SS) = 20ppm (average) and was released into general water bodies. The water level maintenance of the adsorption filter made of coarse filter media is determined by the elevation setting of the spillway. FIG. 5 shows an example in which the pretreatment filtration device and the adsorption filter of the present invention are installed separately, and the pretreatment filtration device 6 is installed vertically using retaining stakes 25.
The adsorption filter body 7 is installed in a chevron shape on the outside, which simplifies the work when it is necessary to replace the coarse filter medium during long-term construction. In addition, at the end of the construction work, the filter plate of the pretreatment filtration device will be removed.
A shower of flocculant is added at this point to reduce the amount of suspended solids in the surplus water, and the adsorption filter is buried from below by the sedimentary mud that flows down. As explained above, the method for filtration of landfill surplus water of the present invention is capable of removing a large amount of clogged filter media or using backwashing equipment, unlike conventional filtration equipment, by sequentially replacing the filter plates of the pretreatment filtration device. does not require. Adsorption filters are designed solely for adsorption, which is different from conventional filtration devices, and by setting the altitude of the pretreatment filter, adsorption filter, and spillway outlet, the amount of wastewater is reduced relative to the wastewater standard value. The purpose is to reduce the amount of suspended solids in water to the required limit, and is not intended to obtain excessively clear water.

[Brief explanation of drawings]

FIG. 1 shows the planar shape of a reclaimed land for explaining the surplus water filtration treatment method of the present invention. In the figure, 1 is a reclaimed land revetment, 2 is a reclaimed land, 3 is a sludge pipe, and 4 is a water surface of accumulated mud. In the upper exposed portion, 5 is a diversion embankment, 6 is a pre-treatment filtration device, 7 is an adsorption filter, 8 is a spillway, and 9 is a spillway pipe. Figure 2 shows the installed cross section of the pre-treatment filtration device and the adsorption filter, in which 1 is the landfill revetment, 8 is the spillway, 9 is the spillway pipe, 10 is the filter plate, and 11 is the filter plate holder. Column, 12 is coarse filter medium, 13 is coarse filter medium holding column, 14 is fence plate, 15 is upper beam, 16 is surplus water, 1
7 is a precipitated sedimentary layer, 18 is a conventional ground, 19 is a foundation embankment for an adsorption filter, and 20 is a seawall foundation. FIG. 3 shows a cross section of the filter plate of the pretreatment filtration device, in which 21 is a filter frame, 22 is filter sand, 23 is a water-permeable mat, and 24 is a filter frame reinforcing material. FIG. 4 shows a front view of the filter plate of the pretreatment filtration device, in which 21 is a filter frame, 23 is a water-permeable mat, and 24 is a filter plate.
is the filter frame reinforcement material. Figure 5 shows a cross-section of the applied installation of the pre-treatment filtration device and the adsorption filter, in which 1 is a reclaimed land revetment, 8 is a spillway, 9 is a spillway pipe, 10 is a filter plate, and 11 is a filter plate. 12 is a coarse filter material, 16 is leftover water, 17 is a precipitated mud layer, 18 is the reclaimed land's native ground, 19 is the foundation embankment of the adsorption filter, 20 is the bank foundation, and 25 is the retaining pile.

Claims (1)

[Scope of Claims] 1. Pretreatment in which a filter plate is installed inside the landfill of a landfill spillway, which is made by sandwiching filter sand in the guide groove of a filter plate holding column in a sandwich-like manner with permeable mats and placing it in a filter frame. A filtration device is provided, an adsorption filter made of a coarse filter material is provided behind the filtration device, and the remaining water is passed through the pretreatment filtration device and the adsorption filtration device, thereby reducing the amount of suspended solids in the remaining water. A method for filtration of wastewater from a landfill. 2. The landfill surplus according to claim 1, characterized in that the filter plate of the pretreatment filtration device is detachably attached to the filter plate holding column, and clogged filter plates are replaced one after another. Water filtration treatment method. 3. The amount of water permeable through the adsorption filter using the coarse filter medium is made larger than the amount of water permeated through the filter plate of the pre-treatment filtration device,
3. A method for filtering wastewater from a landfill according to claim 1 or 2, characterized in that the water level of the spillway is maintained.