RU71076U1 - SYSTEM FOR CLEANING THE BOTTOM OF SURFACE WATER OBJECTS - Google Patents

Abstract

The utility model relates to systems for collecting and processing bottom sediments of rivers, lakes, ponds and other surface water bodies. The inventive system includes a dredging projectile for lifting a slurry of bottom soil from the bottom of a water body and a pressure pulp line for delivering a slurry of bottom soil to the place of processing, characterized in that the pressure slurry pipe is configured to connect a mixer to it to introduce a flocculant solution into the pressure pulp, and the distance L from the place of introduction of the flocculant into the pressure pulp line to its outlet is determined from the condition:

where Q is the performance of the dredging projectile; S is the cross section of the pressure pulp line in the segment from the place of introduction of the flocculant into the pressure pulp line to its outlet; T is the minimum time required for mixing the flocculant and slurry of the bottom soil.

Description

The utility model relates to systems for cleaning the bottom of rivers, lakes, ponds and other surface water bodies from bottom sediments.

The problem of cleaning the bottom of surface water bodies from accumulated bottom sediments in order to restore shipping conditions, improve the environmental situation or for other reasons is relevant especially for large megacities located along rivers, lakes, reservoirs, etc. To raise sediments from the bottom of water bodies in world practice, many technologies have been developed, which in the most general case can be attributed to two different categories.

The first group of technologies is based on the extraction of sediment by excavation. When implementing this method, solid sediment from the bottom is lifted either by an excavator bucket (see US patent No. 6823616, publ. November 30, 2004) or using special drags (see US patent No. 6712979, publ. March 30, 2004).

An alternative method of raising sediment is the suction method, in which a hose is lowered to the bottom of a water body and a vacuum is created at the other end of this hose, as a result of which sediment from the bottom of the water body with a large amount of accompanying water rises to the surface and is poured into storage tanks, barges and so forth. An installation that implements the described method is disclosed, for example, in US patent No. 6640470, publ. 11/04/2003.

Each of the described methods has features that turn into advantages or disadvantages depending on the specific implementation conditions. So, in particular, when working with a mineral sediment of uniform composition, from the point of view of the efficiency of extracting it from the bottom, a suction method is more preferable. This method provides minimal volatility and slightly affects the ecosystem of the water body. Excavation, on the contrary, has a significant effect on the ecosystem, however, it has a very important advantage over suction: the volumetric content of solid matter in the mass raised from the bottom of the water body is much higher during its implementation, which means that the cost of transporting a unit of sediment volume to the processing site for him will be less.

A cardinal problem in the disposal of bottom sediments is their transportation to landfills after processing. Before proceeding with the movement of these sediments, it is necessary in some way to reduce the volumetric water content in the hydraulic mixture to 60-70%. The most common method in practice is the dewatering of bottom sediments in sedimentation tanks due to the long-term content and exposure of the hydraulic mixture to evaporation and seepage factors into the soil (see, for example, US patent No. 6881010, published on April 19, 2005). These processes occur very slowly due to the specific bound state of water in such hydraulic mixtures. In areas with a humid and cool climate, the removal of water from the sump due to evaporation can be extremely ineffective. In addition, the lack of free land in the coastal areas of water

objects, especially within megacities, significantly complicates the organization of sedimentation tanks, and in some cases makes it impossible.

The closest in technical essence and adopted for the prototype is a system for cleaning the bottom of surface water bodies described in US patent No. 6149811, publ. 11.21.2000 and including a dredging projectile for lifting the bottom soil slurry from the bottom of the water body, a pressure pulp line for delivering bottom slurry slurry to the place of its processing, a slurry flocculation unit and a slurry dehydration unit, including a set of separators for separating the slurry from the slurry.

The main disadvantage of this system is its low efficiency.

The task to which the proposed utility model is aimed is to increase the efficiency of the system in the form of cost reduction during its operation.

The problem is solved by achieving a technical result, which consists in increasing the efficiency of mixing a solution of a flocculant with a hydraulic mixture ..

This technical result is achieved by the fact that in the system for cleaning the bottom of surface water bodies, including a dredging projectile for lifting the bottom soil slurry from the bottom of the body of water and a pressure slurry pipe for delivering slurry of the bottom soil to the place of processing, the pressure slurry pipe is configured to connect a mixer to it for introducing a flocculant solution into the pressure pulp line, the distance L from

the place of input of the flocculant into the pressure pulp line to its outlet is determined from the condition:

where Q is the performance of the dredging projectile; S is the cross section of the pressure pulp line in the segment from the place of introduction of the flocculant into the pressure pulp line to its outlet; T is the minimum time required for mixing the flocculant and slurry of the bottom soil.

In addition, the place for processing slurry of bottom soil can be made in the form of a sludge map, which is a bunded part of the water area of a purified water body.

In addition, the pressure pulp line can be equipped with a pressure sensor, and the mixer contains a controllable solenoid valve electrically connected to the pressure sensor.

The essence of the proposed utility model, its novelty and significant difference from the prototype is that the pressure pulp line is configured to install a mixer for introducing the flocculant solution into the hydraulic mixture directly during its transportation through the pressure pulp line. The location of the mixer relative to the outlet of the pressure pulp pipe is selected based on the most effective mixing of the slurry with the flocculant solution.

As you know, the key problem of cleaning the bottom of surface water bodies is the dehydration of hydraulic mixtures of bottom soil, extracted from under the water in one way or another, for the convenience of its transportation to the place of further

processing or disposal. Immediately after extraction from the bottom of a surface water body, bottom sediments are a hydraulic mixture with a weight content of solid fractions from 10% to 40%, depending on the method of extraction and the nature of bottom sediments. In cases where the slurry is recovered by suction, the solids content in the slurry is minimal. This circumstance facilitates the transportation of the slurry through the pressure pulp line to the processing site, however, the problem of its dehydration is becoming more acute. The fact is that small silty-clay particles, which make up a significant part of bottom sediments and have a low density and high porosity, are in the slurry in a stable suspended state. The separation of the solid and liquid fractions of the slurry by sludge can last for years.

To effectively accelerate the deposition of particles suspended in the hydraulic mixture, special substances are used - flocculants. These include aqueous solutions of certain polymers, in particular polyacrylamides. When a small amount of such a substance is added to the hydraulic mixture, aggregation of suspended particles and further formation of large flakes occurs, which leads to a rapid precipitation, after which clarified water can be effectively removed, and the precipitate after additional dehydration can be sent for processing in any known manner.

The rate of precipitation, and therefore the efficiency of the inventive system is directly related to the efficiency of mixing the slurry and flocculant solution. In known to the authors of the bottom cleaning systems

surface water bodies, including the prototype, mixing of the hydraulic mixture and flocculant solution is carried out in special containers, requires additional time and energy. The authors propose mixing the flocculant solution with the hydraulic mixture directly in the slurry pipeline during transportation, i.e. without using additional tanks, without spending extra time and energy on it.

In the inventive system, a significant factor in its effective functioning is the correct choice of the distance from the place of introduction of the flocculant into the pressure pulp line to its outlet. This distance should be no less than the value of TQ / S, where Q is the productivity of the dredging projectile; S is the cross section of the pressure pulp line in the segment from the place of introduction of the flocculant into the pressure pulp line to its outlet; T is the minimum time required for mixing the flocculant and slurry of the bottom soil, ranging from 3 to 30 seconds, depending on the mode of movement of the pulp implemented in the slurry pipeline (structural, laminar or turbulent). If the distance from the place of introduction of the flocculant into the pressure pulp line to its outlet does not satisfy the claimed condition, then effective mixing of the flocculant solution with the hydraulic mixture does not occur, and, therefore, the claimed technical result is not achieved.

In the claimed utility model, the place of processing the bottom soil slurry by preliminary dehydration is proposed to be performed in the form of a bunded area of the water body to be cleaned. This is the simplest and most effective option for implementing the system. Part of the water being cleaned

the surface water body is bunded, a sludge map is formed and the outlet of the pressure pulp conduit is drawn inside this card, from which a flocculated hydraulic mixture of bottom soil comes in, sucked from the bottom of the surface water body outside the sludge map. In this case, obviously, the sludge card should be equipped with a discharge device for withdrawing clarified water released from the slurry card back to the water body.

To prevent overflow of the flocculant solution, it is proposed to equip the pressure pulp line with a pressure sensor, and equip the mixer with a controlled electromagnetic valve electrically connected to the pressure sensor and turn off the flocculant supply when the pressure drops in the slurry line. In this case, it is possible to maintain a precisely defined volumetric ratio of bottom soil slurry and flocculant solution in the system.

The inventive utility model works as follows:

A suction pump sucks in a hydraulic mixture of bottom sediments of a water body and directs it to a pressure pulp line. Through a pressure pulp line, the hydraulic mixture is delivered to the processing site, for example, within the limits of a bunded sludge map formed on a part of the water body. Before the slurry reaches the outlet of the pressure pulp pipe, a flocculant solution is introduced into the mixer through the mixer installed in the pressure pipe. The flocculant solution and the slurry, spreading together along the section of the pressure pulp line from the place of introduction of the flocculant solution into the pressure pulp line to its outlet, are effectively mixed due to convective and

diffusion processes. In the slurry coming from the slurry pipeline to the place of preliminary dewatering, the processes of deposition of solid particles and clarification of water quickly and efficiently pass, which significantly increases the efficiency of the system.

Thus, the claimed utility model is a new technical solution that provides increased cleaning efficiency of the bottom of surface water bodies by reducing the time of dewatering of bottom sediments and reducing costs during its operation.

Claims (3)

1. A system for cleaning the bottom of surface water bodies, including a dredging projectile for lifting the bottom soil slurry from the bottom of the body of water and a pressure slurry pipeline for delivering slurry of the bottom soil to the place of processing, characterized in that the pressure slurry pipe is configured to connect a mixer for input to it in the pressure pulp conduit of the flocculant solution, and the distance L from the place of introduction of the flocculant into the pressure pulp conduit to its outlet is determined from the condition:

, where Q is the performance of the dredging projectile; S is the cross section of the pressure pulp line in the segment from the place of introduction of the flocculant into the pressure pulp line to its outlet; T is the minimum time required for mixing the flocculant and slurry of the bottom soil. 2. The system for cleaning the bottom of surface water bodies according to claim 1, characterized in that the place for processing the slurry of the bottom soil is made in the form of a sludge map, which is a bunded part of the water area of the cleaned water body. 3. The system for cleaning the bottom of surface water bodies according to claim 1, characterized in that the pressure pulp line is equipped with a pressure sensor, and the mixer contains a controllable electromagnetic valve electrically connected to the pressure sensor.