KR100812569B1 - Method to purify polluted river water - Google Patents

Abstract

The present invention is rotatably provided with a non-powered water gate on the water storage side adjacent portion of the rubber dam, and the water gate is closed through the siphon passage formed by the spacer by rotatably provided a siphon operation plate equipped with a spacer on the water storage side of the water gate The present invention relates to a method for purifying polluted river water, which is configured to purify polluted river water by smoothly discharging the bottom water of the reservoir space by the amount of inflow.

The present invention is configured to be inclined toward the discharge side by constituting the hydrology with no power, the bottom of the discharge side of the gate is in contact with the discharge side of the gate while increasing or decreasing the volume depending on the presence or absence of air injection, standing or conducting the gate A plurality of rubber dam members are installed side by side to be spaced apart from each other, and the siphon operation plate having an inlet formed at the bottom thereof is located at the water storage side adjacent part of the sluice to fix both sides of the lower end to the supporting structure, On the opposite side of the gate, a water storage system is constructed so that the lower water in the reservoir can be discharged as much as the inflow through the siphon passage formed through the space between the gate and the siphon operating plate by fixing a plurality of spacers having a "TT" shape. To clean up polluted river water.

Description

Method to purify polluted river water

The present invention relates to a method for purifying contaminated river water, and more particularly, a non-powered hydrologic gate is rotatably provided at a water storage side adjacent portion of a rubber dam, and a siphon operating plate equipped with a spacer is rotatable at the reservoir water side. In order to purify the contaminated river water by smoothly discharging the lower layer water in the reservoir space as much as the inflow amount even in the state that the water gate is closed through the siphon passage formed by the spacer.

As is well known, it is obvious that large amounts of contaminants are included in the incoming water since water is introduced through various paths into reservoirs such as rivers or reservoirs. Therefore, various methods have been proposed to purify the stored water, and conventional water purification methods include gravel contact oxidation method, reverse contact oxidation method, sewage treatment plant water purification method, chlorine input purification method, etc. Compared to the effect was insignificant.

In order to improve this, a device has been introduced to implement water purification by forming a vortex in water through a separate device to float contaminants and removing it, but this has the disadvantage of having a separate device to improve the water quality. Of course, the water purification area is very limited, so it was vulnerable to water quality improvement in a wider range.

In addition, the "natural water quality improvement method using a multi-stage water storage device" of the Patent Publication No. 2001-0000343, which was created by the present applicant, has a natural self-cleaning effect due to aeration because it is composed of one hydrology. There was a low flaw, and this defect further exacerbated the stored water by causing the algae phenomenon due to the aggregation of substances and contaminants generated by the confinement of water and contaminants trapped inside the water gate. There was a great fault letting.

Here, the term applied to this invention is demonstrated in order to raise the technical value of this invention.

"Material Acceleration" and "Material Scavenging" and "Law of Material Preservation Instinct" and "Material Aggregation" and "Material Coupling" and "Material Rejection" in which contaminated water quality contained in river water is naturally purified or deteriorated. Effect ”and“ material release ”.

Due to the difference in the mass and specific gravity of the substance, all the substances flow in the different places of the material, ie in different states, depending on the specific gravity of the substance.

By this action, clean water with heavy gravity flows in the lower layer of river water, and polluted water with light gravity flows in the upper layer of river water. The reality is that it flows faster than the lower seawater. This action occurs because the amount of pollutants contained in the water, ie the pollutant load, is high. This principle is defined as the "material acceleration phenomenon."

The reason why the water flowing in the stream is more polluted is because of the "acceleration of substance" and "agglomeration". Lightweight polluted water flows into the lower part of the river while lightly polluted water flows to the lower part of the stream by the action of gravity caused by the rotation of the Earth and the solar system. Pollution in river waters is further aggravated by the deterioration of contamination by "agglomeration", which combines with other pollutants that have been introduced.

The following describes the process of the "material indentation" that occurs when the material acceleration phenomenon is reversed. There is a close relationship between mass cutting action and material acceleration. The process of material ingestion is performed when contaminated river waters try to pass through the lower part of the hydrology, and the waters forming the river water are pushed to the upper part of the clean water with heavy gravity and then to the upper layer. Through the lower part, it tries to escape first. This principle is called "material cutting action". It is defined as. All materials on earth are different in volume or specific gravity, even if they are the same size, depending on the atomic weight and molecular weight of the materials that make up the material.

Next, all substances are "laws of substance preservation instinct" that seek to instinctively preserve the substance's constituents, and "material massing" exerted by these actions, and "material release" caused by material thrust. The operation will be described. Water has the characteristic of inducing another substance by instinctively accepting the penetrating substance and integrating the substance when water other than water penetrates into the structure of the water by the structural characteristic of water. In the present invention, such an action is defined as a "mass aggregation action".

In addition, when a certain impact is applied to water to shake off the contaminants that penetrate into the pure water molecular structure forming water crystals, the contaminants contained in the pure molecular structure of the water are immediately released from the water molecule. The action that comes out is "material release". It is defined as. In other words, the action of cleaning the polluted water by the force of impact from the outside is the "material release action". It is defined as. As described above, the mass-aggregation action is generated when the water storage system is constructed in such a way that the water storage system for confining the river water is discharged to the upper end of the inflowing river water such as concrete beams, conductive water gates, or rubber dams. Pollution is aggravated by, but if you install a hydrologic system that discharges the river water to the lower end, the contaminated river water will be naturally purified as the natural material grabbing action, material jungle action and material release action. Large dams can also be constructed in this way so that they do not add pollution. In addition, the installation of a hydrologic system configured to discharge only a portion of the stream water in the lower part of the water storage system increases the pollution. As the material is pushed by these heavy clean waters, it is pushed out of the outlet, and the pollution is further aggravated by the agglomeration of substances that combine with other pollutants. Due to material jungle action and mass aggregation, contaminated river water with a light weight other than the hydrosphere's outlet is absolutely impossible to move downstream of the stream itself, and combines with other substances. Contamination of contaminated materials becomes more and more contaminated by condensation. More specifically, if a siphon-type hydrology configured to selectively discharge only a portion of the discharge water formed at the lower portion of the rubber dam or the lower portion of the conducting hydrology selectively discharges the clean water, Polluted waters, which are light in gravity, are pushed down by the light exiting material first and then pushed out of the water first. In the state that absolutely can not escape to the part of the contaminated material is aggravated by the condensation of the substance and the contaminant to combine the contaminated materials to create another substance, the contamination is bound to be further aggravated. When the water is confined using the submerged beam which discharges the inflow water to the upper part by these actions, the material condensation action and the substance generated by condensing the contaminants and water molecules together while confining the water inside the reservoir system There is a significant problem that contamination is rather weighted by the binding action.

The following describes the "law of substance conservation instinct," which is one of the findings of this study.

All matters are rejected and pushed away if other foreign matter penetrates into the material structure of the material by the natural property of the material by the structural property of the material. Or the action of trying to escape from the substance or contaminants to permanently preserve the pure structure of the substance is defined as "law of the substance conservation instinct" in the present invention.

The following describes the "substance rejection action" caused by the "law of substance conservation instinct".

When all substances enter the water, they are diluted with the substances mixed in the water, and the aggregation of substances that add water pollution is not exerted from the beginning, but the structures of pure water molecules are bound directly by the substance rejection action that rejects the pollutants. In other words, it rejects the agglomeration effect of substances and substances, and after a certain period of time, pollutants are released by natural reactions such as dissolved oxygen, solar heat, microorganisms and osmotic pressure. It gradually combines with water molecules and transforms into contaminants. As these substances are decomposed naturally, the particles generated by natural decomposition are combined with other substances, which increases the pollution of water. This is caused by the active green algae and the red tide occurring in the sea. A substance called a terrestrial animal is a by-product of the aggregation of organic and inorganic substances.

The following describes mass decomposition, mass binding and mass flotation. The pure molecules of water react to try not to combine with other substances due to substance rejection caused by the "law of substance preservation instinct" to maintain pure water molecules. They are bound by mass-binding action that binds to molecules and at the same time become heavy, and decompose by the natural decomposition that occurs naturally while sitting on the bottom layer of the river. A repetitive action occurs in which the material binds to the water molecules and some of the pollutants coming from the upstream.

Contaminants contained in water molecules change into microparticles by self-decomposing self-decomposition, and then repeatedly bind to other contaminants while exerting repetitive flotation, which moves to the upper layer of the reservoir. The water molecules bound by are repeatedly bonded to become heavy at the same time as they are bound and sink to the bottom of the reservoir, increasing the pollution of the river water. They are called "mass decomposition", "material binding" and " Material injury action ".

The following is the definition of "material decomposition" and "material binding" found in this study.

Even though all materials are lighter or heavier than water, they are gradually worn out as the sharp parts of the water molecules come into contact with the materials by the pressure generated by the earth's gravity and water pressure as they enter the water. Substances begin to decompose spontaneously without action, at which point the particles of decomposed matter are subjected to the viscous and magnetic forces contained in the microparticles and the viscous and magnetic forces contained in the microparticles decomposed from another substance. There is material binding between the liver, which is the "material binding action". Particles produced by decomposition of materials naturally have "viscosity" and "magnetism" because the surface tension naturally occurs as water molecules move and wear the surface of the material over hundreds of millions of times. Will have.

The new materials produced by the material binding action generated through this process are heavier than the specific gravity of the water, so that the material binding action is combined with other materials, and the sedimentary sludge is settled in the lower part of the water storage system.

Substances contained in the sedimentation sludge generated at this time generate a huge amount of fine particles through the process of naturally occurring decomposing, which is again generated. The process of the material binding action combined with them is repeated, and the sedimentation sludge is produced by the repeated process. The green algae phenomenon is caused by the sedimentation sludge generated by the material binding action generated by this circulation process. Over-red tide occurs. The cold rust produced by iron rust is the fine particles of the material broken down by water molecules, and these particles combine with other particles to produce other materials.

Organic and inorganic substances, phosphorus and nitrogen contained in water are responsible for the natural decomposition of pollutants by gravity, oxygen degradation, microorganism degradation, solar heat decomposition and friction of water molecules. Through the circulation process in which all the substances contained in the water are converted into fine fine particles, the material binding action that combines with other fine particles is made into fine particles which are heavier than the specific gravity of the water, and are stacked on the lower layer of the water system. It is just a sediment.

However, if only the bottom water where water is stored is extracted and discharged by using the siphon passage formed in the rubber dam or the sluice or the water flowing down from the upstream through the lower part, Due to the inherent mass of the substance due to the laminar flow, the location of herpes inside the water storage system is not correct, so that no material binding action occurs, so that the polluted water is naturally purified. This will be done.

At this time, it should be noted that a rubber dam discharge system or a floating or conductive floodgate is to be installed over the full width of the stream.

 The reason is that clean water that is heavy has a heavy weight in the part where the siphon passage is not formed by the material cutting action that pushes out the lighter polluted water and escapes first.

Therefore, if the water is confined to a certain place for a long time, the pollution is further increased by the material decomposition action and the material binding action, so that the lower end of the rubber dam or the siphon passage coupled with the rubber dam constitutes the water gate, The method of discharging only the influent that flows through the bottom of the siphon or the hydrologic gate is the best way to prevent the contamination of the river water and to purify the contaminated water, and also to discharge the water in the reservoir space. It is discharged to the lower part of the door and discharges pollutants such as sedimentation sludge which is aggregated by material binding action, and it is composed on the water gate along with the method of purifying water by the principle of material acceleration phenomenon, material cutting phenomenon, material decomposition action and material flotation action. It discharges only the lower water which is stored through the cell phone to the upper part of the water. It is most desirable to allow the pollutants with a light floating specific gravity to be naturally purified.

In the case of general floodgates, the support shaft of the floodgates is located at the lower side of the support structure and conducts water according to the water level while conducting floodgates discharges the stored water to the upper part of the floodgate. Before the fall, there was a structural limitation that could not discharge foreign substances such as sedimentary sludge that accumulate in the lower part of the reservoir, and the support shaft of the sluice was located on the upper part of the supporting structure so that the floating water was discharged to the lower part of the sluice. In the case of the door, the water is discharged only to the lower part of the sluice, so there is an advantage of discharging the lower layer of the reservoir, but there is a problem of the generation of secondary pollutants due to the aggregation of substances due to the failure to discharge the foreign substances floating in the upper part of the reservoir. Of course, there is a sudden increase in water, such as a flood, It concerned damaged by these large debris when even was come down hydrological that.

In order to improve this, the present applicant can automatically discharge water, including sedimentary sludge at the bottom of the reservoir by the siphon principle, without opening the gate in the utility model No. 320510, etc., to prevent water pollution. The guard flood gates have been initiated.

However, the water gate having the siphon passage disclosed in the various patent cases filed or filed by the applicant, including the above-mentioned Utility Model No. 320510, all uses the siphon principle to discharge water from the lower side of the reservoir, such as sludge. In order to discharge the foreign substances together, most of the siphon passages are fixed in width, and only the doors are opened to open and close the siphon passages according to the amount of inflow or water pressure. It was not possible to discharge the water quickly, especially in the event of large inflows and large water pressures, such as flooding, which could cause water to break through the siphon passages and damage the water gate.

In addition, after the water gate is formed at the rear of the rubber dam, a cyphone is formed at a part of the rubber dam to discharge the inflow water or to trap the water and discharge the air injected into the rubber dam. The water gate installed at the rear of the rubber dam is also inverted at the same time. In the case of the rubber dam of this type, the water has a low specific gravity to other parts than the siphon discharge passage while the water is trapped inside the rubber dam. There is a serious problem that pollution is caused by mass jungle and mass cutting, which are pushed by heavy waters.The hydrological gate combined with rubber dams is rather weak due to the drawback of not being able to completely discharge water from the lower part of the reservoir. There is a significant shortcoming that will increase water pollution.

The present invention is rotatably provided with a non-powered water gate on the water storage side adjacent portion of the rubber dam, and the water gate is closed through the siphon passage formed by the spacer by rotatably provided a siphon operation plate equipped with a spacer on the water storage side of the water gate The present invention intends to provide a method for purifying contaminated river water to purify contaminated river water by smoothly discharging the subsurface water in the reservoir as much as the inflow.

In order to solve the above problems, the present invention is installed inclined toward the discharge side in a non-powered manner, the discharge side bottom of the gate in contact with the discharge side of the gate while increasing or decreasing the volume depending on the presence or absence of air injection Install a plurality of rubber dam members to stand up or fall side by side to be spaced apart from each other, and the siphon operation plate having an inlet formed in the lower portion is located in the water storage side adjacent parts of the sluice to fix both ends of the lower end to the support structure, A plurality of spacers having a "TT" shape are fixed on the surface of the siphon operation plate opposite to the water gate so that the lower layer water in the reservoir can be discharged as much as the inflow amount through a siphon passage formed through the space between the water gate and the siphon operation plate. Purification of contaminated river water is carried out using a reservoir system.

According to the present invention, the non-powered sluice allows the rubber dam member to stand or fall upon injecting or extracting air into the rubber dam member so that the sluice can be opened and closed smoothly without a separate mechanical power means. In addition to saving energy required for the opening and closing operation of the door, there is an advantage that the opening and closing operation of the gate can be made stably.The water storage side of the gate is equipped with a siphon operation plate equipped with a spacer, so that the amount of inflow, without opening the gate, Depending on factors such as flow rate and low water level, it is possible to properly discharge the lower layer water in the reservoir through the siphon channel formed by the spacer, so that the polluted substances in the river water can be naturally purified. Material cut-off, "" the law of conservation of substance, "and Naturally occurring "substance binding", "substance rejection", "substance removal" and "substance decomposition" acts to purify contaminated river water cleanly. There is a significant effect.

In other words, the polluted water is not only purified naturally while staying in the reservoir, but also prevents secondary pollutants that create new pollutants by blocking the mass aggregation caused by the condensation of contaminants and pollutants. As the water is discharged, the aeration is caused by a drop, which makes it possible to realize more active water purification through the natural purification of the water itself and the floating of foreign substances by the aeration. If installed, the water can be purified more naturally through each step.

Therefore, this system can be used to purify polluted river water easily at low cost even in the case of large rivers, and it can produce completely clean river water because it uses the natural purification system naturally generated by nature. It is effective in producing clean water without using chemicals such as chlorine and fluorine. When applied to a large dam it is possible to reduce the occurrence of sedimentation sludge in the dam, there is a significant action effect that can prevent the green algae caused by the above actions at the source.

In addition, there is a significant effect that blocks the source of the red tide caused by the flow of polluted river water from the land of the land flow into the sea.

Also, no matter how much water is trapped, the stored water does not decay, so you can not only trap a large amount of water, but also because of the capillary phenomenon caused by the trapping of the water, Due to its status, there is a significant action that promotes the growth of trees growing in the mountains, and this action prevents the desertification of the land caused by drought, and has a significant action effect that transforms the desert into clay. .

1 is a cross-sectional view at the time of closing the river water purification gate according to the invention, Figure 2 is a cross-sectional view at the time of opening the river water purification gate according to the present invention.

As shown, the river water purification hydrology according to the present invention is a composite application of the rubber dam and the conductive hydrology, the waterway is formed between the support structure (1) on both sides, so that the waterway of the water gate 10 can be opened and closed Support shafts 11 formed on both sides of the lower side are rotatably installed between the support structures 1, and are configured to discharge or confine water while opening and closing according to the water quantity or the water pressure on the reservoir side.

The sluice gate 10 is installed to be inclined toward the discharge side with no power, and the discharge side bottom portion of the sluice gate is in contact with the discharge side of the sluice gate 10 as the volume increases or decreases depending on whether air is injected. 10) Install a plurality of rubber dam members (50 ') standing up or conducting side by side spaced apart from each other, and the siphon operation plate formed in the inlet (36) in the lower portion adjacent to the reservoir side of the water gate (10) Position both ends of the lower end to the support structure 1, and a plurality of spacers 34 having a planar " TT " Through the siphon passage 32 formed through the space between the operating plate 30 is configured to discharge the lower layer water in the reservoir space by the amount of inflow water.

At this time, the lower end of the water gate 10 is located at a position higher than the installation position of the rubber dam member 50 'by a height equal to or higher than the height at the time of contraction of the rubber dam member 50', and the lower end of the siphon operation plate 30 is a water gate ( 10) is located at a position higher than the lower end position of the water gate 10 by adding the height of the spacer 34 to the height of the spacer 34 so that the rubber dam member 50 'and the water gate 10, when the rubber dam member 50' is contracted, The water gate 10 and the siphon operation plate 30 is configured to be in close contact with each other.

When air is injected into the rubber dam member 50 'in the state configured as described above, the rubber dam member 50' is swollen and the rubber dam member 50 'is pushed against the water reservoir 10, which is in close contact with the reservoir side. By standing, a water storage space is formed, and the siphon operation plate 30 is closely contacted with a spacer 34 at a water storage side adjacent portion of the water gate 10 in such a state that water is stored in the water storage space. This is constantly filling up.

At this time, since the water gate 10 and the siphon operation plate 30 are not connected to any power means and are moved only by their own weight and water pressure, the water gate 10 and the siphon operation plate are brought into close contact with the rubber dam member 50 '. It is obvious that the water gate 10 and the siphon operating plate 30 should be positioned inclined toward the discharge side when the 30 is in close contact with the water gate 10.

Air is injected into the rubber dam member 50 'so that the water gate 10 stands up, and when the water fills up in the reservoir space while the water gate is closed, the water gate 10 and the siphon operating plate 30 The rubber dam member 50 'and the water gate 10 are kept in close contact with each other, and the planar " TT " -shaped spacer 34 is in contact with the water gate 10, so that the water gate 10 and the siphon operating plate The interval between 30 is always kept constant.

When the water level in the reservoir space exceeds the upper end of the closed water gate 10, the water flows through the siphon passage 32 formed by the water gate 10 and the siphon operating plate 30 by the amount of inflow from this time. Since the inlet 36 of the siphon passage 32 is located under the reservoir side of the sluice 10, the lower layer water of the reservoir is introduced through the inlet 36 of the siphon passage 32 and the siphon passage 32. In this process, foreign matters such as sedimentation sludge deposited on the bottom of the river are discharged like river water by material aggregation in this process, causing material acceleration, material cutting, material desorption and material injury. Water can be purified.

By the way, the stream is not always flowing water at a constant rate, the inflow amount may increase rapidly due to various factors, in this case, the inflow amount flowing through the siphon passage 32 also increases, the amount of inflow Due to the increase in the siphon operating plate 30 in the direction opposite to the hydraulic pressure acting from the reservoir, the siphon operating plate 30 is separated from the water gate 10 so that the width of the siphon passage 32 is widened. Therefore, even if the amount of inflow increases abruptly, a large amount of water can be discharged as it corresponds to discharge the air injected into the rubber dam member 50 'to maintain a low water level without conducting the water gate 10. I can do it.

In addition, when the quantity of water is very high and the water pressure becomes very large, such as flooding, huge hydraulic pressure is applied to the support structure 1, the water gate 10, and the rubber dam member 50 ', and water overflows the support structure 1. In this case, by discharging all the air injected into the rubber dam member 50 ', the rubber dam member 50' is brought into close contact with the bottom portion, and the water gate 10 is conducted to open the water channel completely. Will be discharged in a short time.

At this time, the lower end of the water gate 10 is located at a position higher than the installation position of the rubber dam member 50 'by a height equal to or higher than the height at the time of contraction of the rubber dam member 50', and the lower end of the siphon operation plate 30 is It is located at a position higher than the lower end position of the sluice 10 by adding the height of the spacer 34 to the height of the spool 10 so as to be pushed by the water pressure of the reservoir and rotated to the discharge side, the sluice 10 is the contracted rubber. It may be in close contact with the dam member 50 ', the siphon operating plate 30 may be in close contact with the water gate 10, and thus, the rubber dam member 50', the water gate 10 by the foreign matter floated with the water. And it prevents the siphon operation plate 30 is damaged.

At this time, although not shown in detail in the drawing, the sensor is installed in the storage space, through which the inlet water quantity, the low water level, the flow rate, and the like to automatically discharge or inject air into the rubber dam member 50 'through a comprehensive control system. It is apparent that the administrator can directly control or manually inject or discharge air into the rubber dam member 50 'so that the water gate 10 can stand or fall.

In addition, the rubber dam member 50 'applied to the present invention is basically composed of flexible natural rubber, artificial rubber, flexible synthetic resin, or the like, and any material can be applied as long as it is flexible and can withstand water pressure. Therefore, even if the configuration of the rubber dam member (50 ') by changing the material of these modified embodiments are naturally within the scope of the present invention.

In addition, the siphon operation plate 30 may be made of any material such as metal, synthetic resin, wood, etc., the siphon operation plate 30 in a variety of shapes depending on the shape of the river, such as adding a heavy material or made in a hollow state. It is natural that such modified embodiments also belong to the scope of the present invention.

In addition, the method of purifying the contaminated water quality using the method of installing the configuration according to the present invention in the river in multiple stages is also within the scope of the present invention.

1 is a cross-sectional view of the river water purification hydrograph according to the present invention.

Figure 2 is a cross-sectional view at the time of opening the river water purification gates in accordance with the present invention.

*** Explanation of symbols for the main parts of the drawing ***

1: support structure 10: sluice 11: support shaft

30: siphon operation plate 31: rotation axis 32: siphon passage

34: spacer 36: inlet 50 ': rubber dam member

Claims (2)

A water channel is formed between the support structures 1 on both sides, and the support shafts 11 formed on both lower sides of the water gate 10 so as to open and close the water channel are rotatable between the respective support structures 1. In the sluice for river water purification installed and discharged or confined while opening and closing according to the water volume or water pressure of the reservoir, The sluice gate 10 is installed to be inclined toward the discharge side with no power, and the discharge side bottom portion of the sluice gate is in contact with the discharge side of the sluice gate 10 as the volume increases or decreases depending on whether air is injected. And install a plurality of rubber dam members 50 'for standing or conducting the water gate 10 side by side to be spaced apart from each other, and the siphon operation plate 30 having an inlet 36 formed at a lower portion thereof. 10) fixed to both sides of the lower end of the water storage side of the support structure (1), and a plurality of spacers 34 having a "tt" shape on the water surface facing surface of the siphon operation plate 30 is fixed. Contaminated using a water storage system configured to discharge the lower water of the storage space by the amount of inflow water through the siphon passage 32 formed through the space between the water gate 10 and the siphon operation plate 30. Purifying river water Way. The method of claim 1, The lower end of the water gate 10 is located at a position higher than the installation position of the rubber dam member 50 'by a height equal to or higher than the height of the rubber dam member 50', and the lower end of the siphon operation plate 30 is located. The rubber dam member 50 'is located at a position higher than the lower end position of the water gate 10 by adding the height of the spacer 34 to the height of the water gate 10, when the rubber dam member 50' is contracted. ) And the sluice (10), the sluice (10) and the siphon operating plate (30) is configured to be in close contact with each other, the method for purifying contaminated river water.

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