RU2741081C1 - Method to increase productivity of water abstraction of underground water - Google Patents

Abstract

FIELD: water supply.SUBSTANCE: invention relates to water supply and can be used in regulation of underground water discharge of aquifers for improvement of reliability of water intake and its increase, mainly in coastal sea areas. Method includes creation in water-bearing formation of hydraulic curtain, creating along hydraulic line shaft, by supplying to formation water and raising level of underground water in it, at that, under water intake to the water-bearing horizon highly purified waste water is supplied by the high and low intensity cavitation influence on it, prior to feeding into water-bearing horizon purified water is deaerated and cooled to temperature 2-3 degrees below submarine unloading underground water temperature, and when water is supplied to an underground horizon, a gravity discharge is arranged, bringing the water velocity to filtration rates of the underground horizon, and its flow is changed from a turbulent flow into a laminar flow.EFFECT: method increases efficiency of water abstraction of underground water, increases degree of use of underground water in coastal sea areas by means of their artificial filling without deterioration of quality of underground water and prevent their irreversible losses due to their supply to submarine horizons, as well as to prevent supply of sea salt water in underground horizons.1 cl, 6 ex

Description

The invention relates to water supply and can be used to regulate the underground runoff of aquifers to improve the reliability of water withdrawal and its increase, mainly in coastal sea areas.

There is a known method of replenishing groundwater (USSR AS No. 1094921, MKI 5 E 03 B 3/32, publ. 05/30/84, bulletin No. 20) by creating a backwater of water levels in a watercourse feeding an exploited aquifer using a water-lifting dam , installed in the section below the water intake downstream, which is created at the onset of negative air temperatures by the artificial formation of ice in the watercourse and freezing of riverbed sediments, and the channel section is flattened, expanded and a heat exchanger connected to the atmosphere is installed on it. By increasing the intensification of infiltration recharge of the aquifer from the river channel, it is possible to ensure sufficient reliability of water intake or increase the flow rate of water intake in the cold season.

The disadvantage of the known technical solution is a decrease in efficiency due to an increase in unproductive losses of groundwater flow from the site for regulating groundwater reserves.

There is a known method of replenishing groundwater (Patent for A.S. USSR No. 1638274, MKI 5 E 03 B 3/32, publ. 03/30/91,) by creating a backwater of water levels in the watercourse feeding the exploited aquifer, using a water-lifting dam installed in the section below the water intake downstream, which is created at the onset of negative air temperatures by artificial formation of ice in the watercourse and freezing of riverbed sediments, and the section of the channel is flattened, expanded and a heat exchanger connected to the atmosphere is installed on it. To regulate the formation of an ice dam, the operational level of water in the river is determined, which is necessary to maintain the required flow rate of the water intake during the period of negative air temperatures, the flow of air into the heat exchanger is regulated when the water level in the river rises above the operational level, and the resumption of air flow is below the operational level.

The disadvantage of the known technical solution is a decrease in efficiency due to an increase in unproductive losses of groundwater flow from the site for regulating groundwater reserves.

There is a known method of periodically increasing water withdrawal from confined aquifers (Patent for AS USSR No. 1638274, MKI 5 E 03 B 3/32, publ. 03/30/91, bull. No. 12, rev. In the State register 04/21/92) , which consists in drilling additional wells in the area outside the boundaries of the influence of the wells of the main water intake and increasing the pressure in the aquifer by injecting air into additional wells with simultaneous water intake from the wells of the main water intake.

The known method is most effective in the absence of sources of artificial replenishment of groundwater reserves, for example, in the absence of runoff in a river during dry periods of the year. At the same time, an increase in the operational reserves of groundwater is ensured by attracting additional resources from adjacent sections of the aquifer due to the displacement of water from water-bearing rocks by air injected under pressure through wells located in the cross section of the groundwater flow.

The disadvantage of this method is a decrease in efficiency under conditions when the value of the outflow of groundwater outside the zone of influence of the water intake exceeds the deficit of water intake from the aquifer and the costs of ensuring the flow of groundwater from the adjacent site downstream of the flow of groundwater significantly exceed the cost of building an underground reservoir with the regulation of the underground drain.

In the coastal areas in the south of our country, where water resources are limited, the population is often supplied with groundwater. The volume of use is growing all the time. At the same time, the studies carried out show that groundwater is often discharged into submarine horizons, and in fact is lost for use (see Zektser I.S, Underground runoff and fresh groundwater resources p. 100. M. Scientific World 2012). In addition, groundwater abstraction can “pull up” saline waters from deep aquifers that are not suitable for drinking, and in coastal areas - salty sea waters (see Ibid., P. 37). The growing demand for water resources requires solving a number of practical problems , including the development of environmental restrictions on the intensification of groundwater withdrawal and increase the degree of use of groundwater, including by means of their artificial replenishment.

It is known the design and construction of concrete dams on the way of penetration of sea waters deep into the mainland through the karst gallery (see Zektser I.S. Underground runoff and fresh groundwater resources, M. Nauchny Mir 2012, p. 107) in order to optimize water supply by groundwater. The dam was built in the deepest part of the karst gallery at a distance of 500 m from its outlet to the sea. The dam makes it possible to prevent the ingress of sea water into the underground horizons, but its construction requires significant material costs.

A known method of reducing unproductive losses from an underground reservoir during low-water periods of the year by creating an anti-seepage curtain of low-permeable soils below the location of the water intake in the river valley, as well as backing up the levels in the river bed above the alignment of the location of the anti-seepage curtain (see AS USSR No. 1201433, E03V 3/32, publ. 12/30/1985). This method is not always applicable, in particular due to the lack of rivers.

Known is a method of water protection with the aid of horizontal (interstratal) impervious curtain (sm.patent RF № 2347034, E02V 3/16, publ. 20.02.2009). The method includes the construction within the boundaries of the lithological or hydrogeological "window" of a horizontal impervious curtain, i.e. artificial waterproofing. In the area where there is no water-resistant layer, a vertical shaft or shafts pass, from which a fan of horizontal beam injection wells is drilled. Along the length of the wells, 2-3 zones or intervals of injection of permeable rocks are distinguished in the "window" zone with different viscosity or mobility and the rate of setting or gelation of fixing compounds, after the expiration of the setting period of which a horizontal interstratal anti-filtration curtain is formed in the "window" section, preventing the flow of underground waters between adjacent horizons and the penetration of pollution into the aquifer used for water supply.

The method allows to prevent the depletion and pollution of aquifers, but this method is laborious.

The known "Method for preventing contamination of groundwater" (see RF patent No. 2052575, E02B 3/16).

The method provides for the formation of a dynamic hydraulic curtain, which makes it possible to create a barrier to the movement of pollution and replenish the water supply of the water intake.

In practice, the method is carried out as follows. Below the source of pollution along the flow of groundwater, a channel is normally cut off to the flow, buried to the water-resistant layer. For the hydraulic connection of the canal with the aquifer, a number of absorption wells are drilled along the canal axis. Water is supplied to the canal from water wells or ground water sources (rivers, lakes). At the same time, a shaft of supplied water is formed in the aquifer along the canal, which prevents the further movement of contaminated waters.

The method allows you to prevent the depletion and pollution of aquifers, but this method is laborious and requires the supply of clean water, which is in short supply, in addition, the supplied water evaporates from the canal, which leads to losses, it is possible that contaminants with dust, rain streams can enter the canal due to human factor a; over time, the canal becomes silted up and needs to be cleaned.

A known method of preventing the movement of liquid pollution in a rock mass, (see RF patent No. 2365709, E02B 3/16, publ. 27.08.2009), including the construction of a hydraulic curtain perpendicular to the flow of polluted water, creating a shaft in the aquifer along the path of the hydraulic curtain - by supplying clean water to the reservoir and raising the level of groundwater in it, while along the route of the hydraulic curtain, a linear or circular closed system of injection wells is constructed, united by a water supply pressure pipeline, which is connected to a pumping station and equipped with dispensers for supplying the injected water with contamination neutralizing compositions and a system control of the mode of pressure and productivity of water injection, which is taken as a prototype.

This method is devoid of a number of disadvantages of the technical solution according to the patent of the Russian Federation No. 2052575, however, it is quite laborious to implement, and also requires the supply of pure water to create a hydraulic curtain.

The technical task and the technical result of this technical solution is increasing the productivity of groundwater abstraction, increasing the use of groundwater in coastal sea areas by artificially replenishing it without deteriorating the quality of groundwater and preventing their irreversible losses due to their flow into submarine horizons, as well as preventing the influx of sea salt water into the underground horizons.

The specified technical result is achieved by the fact that there are differences in the method of increasing the productivity of groundwater intake by creating a hydraulic curtain that creates a shaft in the aquifer along the hydraulic curtain route by supplying water into the reservoir and raising the level of groundwater in it, there are differences, namely, below the water intake in the aquifer serves highly purified wastewater by exposure to high and low intensity cavitation, which provides high fluidity of treated water. Before being fed into the aquifer, the purified water is also de-aerated and cooled to temperatures 2-3 degrees below the temperature of submarine unloading groundwater. When water is supplied to the underground horizon, a gravity outlet is arranged, bringing the speed of water to the filtration rates of the underground horizon and transferring its flow from a turbulent mode of motion to a laminar one.

This prevents the discharge of the fresh aquifer into the submarine horizons and the salinization of the aquifer by sea waters. Thus, the productivity of the water intake increases and the treated waste water is utilized without compromising the quality of groundwater.

The method is as follows:

Below the water intake in the aquifer discharging into the submarine horizons, a hydraulic curtain is created by creating a shaft of water in the aquifer, for which highly purified waste water is fed into the reservoir, which is treated with high cavitation (with cavitation numbers G = 0.1 -0.5) and low intensity (with numbers G = 0.001-0.005 of cavitation), the supplied water is de-aerated and cooled to temperatures 2-3 degrees below the temperature of underground waters of submarine discharge. At the same time, the degree of wastewater treatment is ensured up to the requirements for discharge into the fishery reservoir, operating in the corresponding territory.

The positive effect of water treatment with high-intensity cavitation (with cavitation numbers G = 0.1-0.5) (see - I. Pirsol "Cavitation". M., "Mir", 1975, pp. 65-70), leads not only to the destruction of the shells of microorganisms and their death, but also to the destruction of the continuity of the flow of aquifers, while the treatment of water by low-intensity cavitation (with the numbers G = 0.001-0.005 cavitation) increases the fluidity of waste water, which prevents the passage of drinking water from the underflow aquifers.

The purified waste water is de-aerated, which leads to an increase in the density of the water supplied to the aquifer, and is also cooled to temperatures 2-3 degrees below the temperature of submarine unloading groundwater. Thus, the quality of the hydraulic curtain is improved.

When water is supplied to the underground horizon, a gravity outlet is arranged, bringing the speed of water to the filtration rates of the underground horizon and transferring its flow from a turbulent mode of motion to a laminar one. To implement the method, the following equipment can be used.

Waste water is fed into a device for the extraction of thermal energy, then, during pumping, devices for creating cavitation of high and low intensity are used. For the treatment of water with high-intensity cavitation, standard jet aerators are used.

For the treatment of water by low-intensity cavitation, a device made in accordance with RF patent No. 2260716 can be used.

When supplying waste water to the underground horizon, a gravity outlet is arranged and the water velocity is adjusted to the filtration rates of the underground horizon using a device made in accordance with RF patent No. 2244786. In underground horizons, with this method of supply, water is also freed from anthropogenic fields obtained by it as a result of economic use and returns to its natural qualities.

Example 1. In a dry period, an increase in the productivity of water intake up to 125 thousand m ³ / day is achieved by preventing the discharge of underflow waters into the submarine horizons. At the same time, the replacement requires at least 130 thousand m ³ / day of weighted treated waste water, which provides hydraulic support to several underground streams simultaneously: fresh water above, sea below.

Example 2. During the wet season, the amount of treated waste water supplied to the submarine horizons does not increase to back up the upper streams and from the bottom of the sea water. Therefore, the required amount of weighted water will be 125 thousand m ³ / day.

Example 3. To reduce the overexpenditure of treated waste water supplied for replacement by increasing its fluidity in a dry period, the low-intensity cavitation number G is increased from 0.001 to 0.005, and the high-intensity cavitation number G is decreased from 0.1 to 0.05.

Example 4. The speed of movement of the water supplied for replacement at the beginning is reduced from 0.7-0.5 to 0.003-0.002 m / s, while the speed of the water flow of the substituted under-channel horizon is 0.0003 m / s.

Example 5. At a temperature T = + 7 ° C of water of under-bed horizons, it is required to cool highly purified waste water to a value of T = + 4 ÷ 5 ° to create a retaining shaft in an aquifer, while its supply should be continuous, since the working hydraulic regime of all water flow is constant.

Example 6. At a temperature of chilled water up to 4-5 ° C, its viscosity is 1.51mx10 ³ N⋅s / m ² when exposed to high-intensity cavitation G = 0.14-0.5, the viscosity of water decreases to 0.28mx10 ³ N⋅ s / m ² , thereby increasing the fluidity of water, creating a kind of hydraulic dam, preventing the passage of fresh water from the aquifers of the water intake into the submarine flows.

Claims (1)

A method for increasing the productivity of groundwater intake, including the creation of a hydraulic curtain in the aquifer, creating a shaft along the hydraulic curtain route, by supplying water to the reservoir and raising the level of groundwater in it, characterized in that, below the water intake, highly purified waste water is supplied to the aquifer by affecting it by cavitation of high and low intensity, before being fed into the aquifer, the purified water is de-aerated and cooled to a temperature 2-3 degrees below the temperature of underground waters of submarine discharge, and when water is supplied to the underground horizon, a gravity outlet is arranged, bringing the water velocity to the filtration rates of the underground horizon , and transfer its flow from a turbulent flow to a laminar one.