RU2275457C2 - Flood-plain sludge pond for industrial waste - Google Patents

Abstract

FIELD: hydraulic structures, particularly to store industrial waste in flood-plains.

SUBSTANCE: sludge pond comprises ground basin defined by enclosing structure, trench arranged at sludge pone base between the enclosing structure and river, protective dam located between trench and river. Ridge of protective dam extends over maximal predicted level of water in river. Impervious protective dam member closes water-permeable layer at base thereof and is connected with aquiclude at dam depth. Trench bottom is below everyday water level in river. Trench interior communicates with water recycling system of industrial plant by water supply system. The sludge pond may be provided with drain arranged in waste and spaced from base. The drain extends along enclosing structure and is provided with vertical spaced apart water conduits. Upper end of each water conduit is hydraulically communicated with drain, lower one is communicated with water permeable base layer. Protective dam ridge height is selected from V_e≥V_d, where V_e is volume of emergency ground basin defined by protective dam, V_d is calculated volume of liquefied waste discharge from sludge pond in river direction. Drain may be formed as drainage band provided with drainage pipe. Impervious layer is created at drain base.

EFFECT: increased reliability of waste storage and decreased risk of underground water pollution.

4 cl, 3 dwg

Description

The invention relates to the field of hydraulic engineering and can be used in the storage of enterprise waste in floodplains, in particular to the waterproofing protection of a river or reservoir from drains, for example, from ash and slag dumps, both newly created and in operation.

Known floodplain waste dump of the enterprise, including the earth tank formed by the enclosing structure, and a trench located at the base of the hydraulic dump between the enclosing structure and the river [1]. In such a floodplain dump, contaminated wastewater that has penetrated into the base is mixed with pure pressure head groundwater of natural origin (hereinafter: natural water) and with them freely move to the river through a permeable coarse-grained channel alluvium, which is almost always present under a relatively poor-permeable floodplain alluvium by bulk. As a result of this, river pollution occurs.

Known hydraulic dump with an impervious vertical diaphragm at the base along its perimeter, while the bottom of the diaphragm at a depth is associated with a water stop, and the top with a building [2]. In such a hydraulic dump, the diaphragm operates under high pressure of sewage, which does not ensure the reliability of the hydraulic dump during operation.

Known hydraulic dump, which in the lower pool of the enclosing structure contains a drainage trench at the base and a counterpressure trench more remote from the enclosing structure and two water supply devices: one for supplying wastewater intercepted from the drainage trench into the hydraulic dump and the other for supplying clean backpressure into the trench natural water [3]. The creation of such a hydraulic dump is associated with high costs for the implementation of the backpressure trench and its operation, while the reliability of the hydraulic dump is low. If the water levels in the trenches are not equal along the permeable layer at the base, water flows from one trench to another, which leads either to pollution of natural water or to its unproductive expenditure. The latter can cause an imbalance in the enterprise’s water recycling system.

An imbalance inevitably occurs in the event of an inflow of natural groundwater into the base of a hydraulic dump from higher terrain levels, for example, from a slope of a high river bank. This unbalance can be reduced by creating, at the site of natural water inlet to the base of the hydraulic dump, the discharge curtain from wastewater intercepted at the site of its exit from the base of the hydraulic dump [4]. In such a hydraulic dump, high costs are required for the implementation of injection wells and for the wastewater supply system to them.

The proposed invention solves the problem of improving the reliability of the floodplain hydraulic waste disposal site of the enterprise in operation and saving money on its creation. The technical result is the most complete prevention of the flow of wastewater from the hydraulic dump to the river (reservoir), as well as the river (reservoir) performing the functions of a counter-pressure trench and the participation of the internal drain of the hydraulic dump in creating a hydraulic curtain that reduces the flow of natural groundwater into the base of the hydraulic dump.

According to the present invention, a floodplain waste dump of enterprises is proposed, comprising an earth tank formed by the enclosing structure, a trench located at the base of the hydraulic dump between the enclosing structure and the river, and a protective dam located between the trench and the river. The level of the ridge of the protective dam is located above the maximum calculated water level in the river, its antifiltration element overlaps the water-permeable layer and at the depth is interfaced with water resistance, and the bottom of the trench is located below the household water level in the river, and the cavity of the trench is connected to the enterprise’s water recycling system . The hydraulic dump is equipped with a drain, which is disposed of in waste at a distance from the base and along the structure enclosing the river side and is equipped with water conduits located vertically and at a distance from each other, with the upper end of each water conduit being hydraulically connected with the drain and the lower end with a permeable base layer . The drain is made in the form of a drainage tape, is equipped with a drainage pipe, and an anti-filter layer is made at its base.

It is advisable to select the level of the crest of the protective dam from the ratio

where V _a - the amount of emergency earth capacity formed by the protective dam;

V _in - the estimated volume of emergency leakage of liquefied waste from the hydraulic dump in the direction of the river.

The essence of the technical solution lies primarily in the fact that the anti-filter element of the protective dam works in pressure-free conditions, which ensures almost complete interception of water from the hydraulic dump. At the same time, the river performs the functions of the backpressure trench. Simultaneously with such a qualitative interception of wastewater, in the event of the presence of pressurized natural groundwater at the base of the hydraulic dump, the flow of these off-balance groundwater into the enterprise’s recycling water supply system is prevented by means of a hydraulic curtain. In this case, a hydraulic curtain is created by means of a drain, which is performed according to special rules and which continues to perform its usual functions.

Figure 1 shows the plan of the floodplain hydraulic dump; figure 2 is a section aa in figure 1; figure 3 is a section aa in figure 1, a variant.

Example 1. A floodplain hydraulic dump of enterprise waste (hereinafter: a hydraulic dump) is located in the plan between the low bank 1 of river 2 and its high bank 3. The hydraulic dump includes an earth tank 4 formed by the enclosing structure 5, a trench 6 located in the base 7 between the enclosing structure 5 and river 2, and a protective dam 8, located between the trench 6 and river 2. The level 9 of the crest of the protective dam 8 (Fig.2) is located above the maximum design level 10 of water in the river 2, its anti-filter element is made in the form of a diaphragm 11, which overlaps the basics 7, the permeable layer 12 of coarse-grained channel alluvium and at a depth is interfaced with a stop 13. The bottom 14 of trench 6 is located below the household (minimum calculated) water level 15 in river 2, and the cavity of trench 6 is connected to the circulating water system 17 through a clarified water pool 17 with a circulating system water supply enterprises.

On the slope 18 of the high shore 3, a ditch ditch 19 and a mating portion of the diaphragm 11 are made (in Fig. 1, such a portion of the diaphragm is shown by a dotted line).

The enclosing structure 5 includes a deboning dam (primary) 20, located on the low-permeable layer 21 of the base 7 and forms the 1st tier of the soil tank 4, and secondary dams (extensions) 22 and 23, located mostly on the beaches 24 and 25 of waste 26 and forming respectively the 2nd and 3rd tiers of soil capacity 4.

Level 9 of the crest of the protective dam 8 is selected (checked) from the ratio

where V _a is the volume of the emergency earth tank 27 formed by the protective dam 8;

V _in - the estimated volume of emergency leakage of liquefied waste from the hydraulic dump in the direction of the river.

In figure 1, other elements of the hydraulic dump are indicated, namely:

28 - spillway well;

29 - collector clarified water;

30 - settling pond;

31 - pumping clarified water;

32 - pressure pipe of clarified water;

33 - the water level in the trench 6 (figure 2 and 3).

The creation of a floodplain hydraulic dump and its work are carried out as follows.

An embankment dam 20 and a protective dam 8 with a diaphragm 11 at the base 7 are being erected. At the same time, using the resulting soil materials, a trench 6 and a ditch 19 not flooded by the river 2 are created, and the diaphragm 11 is mated to a high bank 3. Waste is being washed 26 in the 1st tier of the hydraulic dump. The washing of waste 26 into each subsequent tier is carried out after the erection of the corresponding building dam.

Wastewater from the hydraulic dump through the permeable layer 12 enters the trench 6, from which the water supply device 16 is sent to the clarified water pool 17 or immediately to the clarified water discharge conduit 32. The wastewater from the trench 6 is supplied with an intensity providing the water level 33 to the trench 6 equal water level in river 2 or close to it. Therefore, the diaphragm 11 operates in almost pressure-free conditions, which prevents the flow of wastewater from the trench, and therefore from the ash dump, into river 2. Moreover, the river 2 itself with respect to trench 6 performs the functions of a counter-pressure trench, creating a hydraulic curtain, and the water level is 33 in trench 6 changes, like the water level in river 2, within Δh.

In the case of leakage of liquid waste from the hydraulic dump in the direction of the river in a volume of V _in , which can occur in a special case, for example, in case of a strong earthquake, the liquid waste is accumulated in an earth tank 27 formed by a protective dam 8 and having a volume of V _a . The volume of leakage V _in is determined, for example, from a two-year layer of alluvial waste [5]. After that, restoration work is performed at the hydraulic dump.

Example 2. The floodplain hydraulic dump is different from that described in example 1 in that the trench 6, the protective dam 8 and the antifiltration element are combined into one structure. In this case, the antifiltration element is made in the form of a screen 34 covering the slope of the trench 6 and continued to a predetermined level in the body of the protective dam 8. This allows to reduce the occupied space, simplify the work, save money and increase the maintainability of the antifiltration element.

Additionally, the hydraulic dump is provided with a drainage layer 35, which covers the upper slope of the embankment dam 20 and part of the low-permeability layer 21 and contains a drainage pipe 36. The beach of the alluvium 25 in front of the secondary dam 23 is covered with an antifiltration layer 37, on which a drainage tape 38 with a drainage pipe 39 is made along which conduits 40 are vertically and spaced apart from each other. The upper end of each conduit 40 is hydraulically connected to the drain pipe 39, and the lower end is perforated and inserted into the permeable layer 12 of the base 7. For the operation of the hydraulic dump, the wastewater from the drain pipe 39 through the water conduits 40 flows under pressure into the base 7 and creates a hydraulic curtain in the permeable layer 12, which provides backpressure on the natural ground water. This reduces the influx into the trench 6 of natural groundwater from the high bank 3, which prevents the formation of unbalance in the enterprise's water recycling system. At the same time, the antifiltration layer 37 prevents the saturation of waste water 26 underneath (the water saturation limit in Fig. 3 is indicated by a dotted line), which is facilitated by the removal of water from the drainage layer 35. Therefore, during seismic shaking, there is no dilution of granular waste in the zones 20 and 22 adjacent to the dams.

The creation of such a floodplain dump can be carried out during the reconstruction of existing ash dumps, many of which are located in the water protection zone of the river at its new borders and, for lack of new areas, continue to function with the reclamation of new tiers, for example, Krasnoyarskaya GRES-2. The hydraulic dump is most effective in the floodplain of the reservoir, in which the water level is almost constant, for example, at the cooling pond of the thermal station.

Sources

1. Recommendations for the design of ash and slag of thermal power plants. P 26-85 / VNIIG. Leningrad. - 1986, pp. 8-17.

2. Filatov A.L. et al. "Experience in the construction of structures using the" wall in soil "method. Kiev." Alarm clock. "- 1981, p. 192, fig. 71,

3. Kuzovlev G.M. "Hydraulic engineering facilities of the nuclear industry." Atomizdat. - 1973. P.230, Fig. 68.

4. Copyright certificate of the USSR No. 715699, cl. E 02 B 3/16, publ. 1980

5. RF patent No. 2157869, cl. E 02 B 7/06, publ. 10.20.2000 g.

Claims (4)

1. Floodplain hydraulic waste dump of enterprises, characterized in that it has an earth tank formed by the enclosing structure, a trench located at the base of the hydraulic dump between the enclosing structure and the river, and a protective dam located between the trench and the river, while the level of the crest of the protective dam is located higher the maximum estimated water level in the river, its anti-filtration element overlaps the water-permeable layer at the base and is interfaced with water resistance, and the bottom of the trench is located below the household water level in the river, and the cavity of the trench with a water supply device is in communication with the enterprise's water recycling system. 2. The hydraulic dump according to claim 1, characterized in that it is equipped with a drain, which is disposed of in waste at a distance from the base and along the structure enclosing the river side and is equipped with water conduits located vertically and at a distance from each other, with the upper end of each water conduit hydraulically connected to the drain, and the bottom with a permeable base layer. 3. The hydraulic dump according to claim 1, characterized in that the level of the crest of the protective dam is selected from the ratio

where V _a - the amount of emergency earth capacity formed by the protective dam; V _in - the estimated volume of emergency leakage of liquefied waste from the hydraulic dump in the direction of the river. 4. The hydraulic dump according to claim 2, characterized in that the drain is made in the form of a drainage tape, equipped with a drainage pipe, and an antifiltration layer is made at its base.

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