CN114892749B

CN114892749B - Treatment method of black and odorous river channel

Info

Publication number: CN114892749B
Application number: CN202210541286.9A
Authority: CN
Inventors: 张世仪
Original assignee: Hohai University HHU
Current assignee: Hohai University HHU
Priority date: 2022-05-17
Filing date: 2022-05-17
Publication date: 2023-02-07
Anticipated expiration: 2042-05-17
Also published as: CN114892749A

Abstract

The invention discloses a treatment method of a black and odorous river channel, which comprises the following steps: step 1, surveying a dredging river channel, dividing the dredging river channel into a plurality of dredging areas, and selecting a plurality of dredging areas at intervals among the plurality of dredging areas for dredging; step 2, building a cofferdam; step 3, a water pump is arranged, water in the cofferdam is pumped out and is discharged to the downstream of the river channel side by side, and water pumping is stopped when the water depth in the cofferdam is 1 m: step 4, cleaning the muddy water in the cofferdam through a sludge cleaning device, performing harmless treatment on the muddy water, and returning the muddy water to the field; step 5, preparing a modified medium, and backfilling the modified medium to a dredging area; step 6, dismantling the cofferdam, and planting emergent aquatic plants and submerged plants in the desilting area; and 7, when the next dredging is carried out on the dredging river channel after one to two years, selecting the area which is not dredged for the last time for dredging, and then repeating the steps 2 to 6, so that the treatment method capable of delaying the blackening and stinking speed of the river water and improving the treatment effect of the river channel is provided.

Description

Treatment method of black and odorous river channel

Technical Field

The invention belongs to the technical field of river channel treatment, and particularly relates to a treatment method of a black and odorous river channel.

Background

At present, serious black and odorous phenomena occur in riverways of partial cities, and the blackness and the odor of river water influence the life of urban residents and the safety of drinking water.

The reasons for causing the river to become black and smelly are: the organic pollution load in the river exceeds the self purification capacity, namely, the organic pollutants consume a large amount of dissolved oxygen in the water body, so that the anoxic phenomenon in the water body is aggravated, plankton dies a large amount, the water body is blackened, and stink is emitted. A large amount of organic pollutants are settled and enriched in bottom mud of the river, so that the sludge in the river is an important reason for blackening and smelling river water. Therefore, the sludge in the river channel is cleaned regularly, which is the most effective method for treating the black and odorous river water.

The existing river channel dredging method is characterized in that the flaky sludge is completely removed, the method is too rough, the sludge is an important reason causing the black and odorous river water, but the sludge is also a carrier for the existence of a microbial community, and after the flaky sludge is removed, a large number of microbial communities and the sludge are removed together, so that the microbial quantity in a dredging area is reduced sharply, the degradation speed of the microorganisms on pollutants is greatly reduced, and the blackening and odorous speed of the river water is relatively accelerated.

Disclosure of Invention

The invention aims to provide a treatment method of a black and odorous river channel, which solves the technical problem that a large number of microbial communities and sludge are cleaned together by a river channel dredging method in the prior art, and the blackening and odorous speed of river water is relatively accelerated.

The technical scheme adopted by the invention for solving the technical problems is as follows:

a treatment method of a black and odorous river channel comprises the following steps:

step 1, surveying a dredging river channel, dividing the dredging river channel into a plurality of dredging areas, and selecting a plurality of dredging areas at intervals among the plurality of dredging areas for dredging;

step 2, building a cofferdam in the dredging area of the dredging;

step 3, a water pump is arranged, water in the cofferdam is pumped out through the water pump and is discharged to the downstream of the river channel side by side, and water pumping is stopped when the depth of water in the cofferdam is 1 m:

step 4, cleaning the muddy water in the cofferdam by a sludge cleaning device, performing harmless treatment on the muddy water, and returning to the field;

step 5, preparing a modified medium, and backfilling the modified medium to a dredging area of the dredging;

step 6, dismantling the cofferdam, and planting emergent aquatic plants and submerged plants in the dredging area of the dredging;

and 7, when the next desilting is carried out on the desilting river channel after one to two years, selecting the area which is not desilted for the last time for desilting, and then repeating the steps 2 to 6.

The dredging river channel is divided into a plurality of dredging areas, a plurality of dredging areas are selected at intervals from the plurality of dredging areas to be used as the dredging area for dredging, and the rest dredging areas are used as next dredging areas, namely, one or two next dredging areas are arranged at intervals between two adjacent dredging areas; the cost is saved on the basis of meeting the dredging requirement by cleaning the dredging river channel in sections; the water pump is arranged to pump out the water in the cofferdam and discharge the water to the downstream of the river channel; the water depth is about 1m, and the sludge diffusion layer is arranged in the range of the water depth, so that the water depth of 1m is reserved in the cofferdam, and the pollutants in the sludge can be prevented from being diffused under the action of pumping disturbance; the mud water is returned to the field after harmless treatment, so that the mud can be reused; the modified medium can provide a proper growing environment for microorganisms, emergent aquatic plants and submerged plants, and the microorganisms in the modified medium can consume organic matters in water through metabolism of the microorganisms, so that the black and odorous water body is purified, and the treatment effect of a river channel is enhanced; through setting emergent aquatic plants and submerged plants, the roots of the emergent aquatic plants can absorb nutrient substances in the water body; the submerged plant can absorb the nutrient substances such as nitrogen, phosphorus and the like in the water body in the growth process, play a role in purifying the river water and delay the blackening and smelly speed of the river water.

Further, in step 1, before dividing the dredging area, plants, construction waste and other impurities in the sideline range of the river channel excavation are firstly cleaned.

Clearing plants, construction waste and other sundries in the excavated sideline range to clear obstacles for subsequent dredging work; the cleaning work can be carried out in a mode of matching manual cleaning with cleaning of an excavator, surface vegetations such as reeds are manually removed, construction wastes, reed roots, tree roots and the like are dug to a designated place outside a construction site by the excavator to be stacked or buried, and the removed plant roots and the like are intensively burned in the designated place of a owner.

Further, in the step 5, the modifying medium comprises loam, gravel and clay, and the mass ratio of the loam to the gravel to the clay is 2:4:1, uniformly mixing a carbon source substance in a modification medium; the carbon source substance is one of rice straw, corn stalk and wheat stalk.

The loam has the advantages of wide adaptability and long ploughing period, is beneficial to planting emergent aquatic plants and submerged plants, is beneficial to seepage of water in the modified medium by arranging the gravel, and has the advantages of cohesiveness and rich nutrients compared with sandy soil by arranging the clay; by arranging the carbon source substance, sufficient nutrient substances are provided for the growth of the microorganisms; the rice straw, corn stalk and wheat stalk have the advantages of convenient acquisition and low price.

Further, the harmless treatment in the step 4 comprises:

step 1, setting a solarization field on a river bank of a desilting river channel;

step 2, solarizing, namely conveying muddy water to an solarization place, and after carrying out muddy water separation, obtaining solidified sludge through insolation;

step 3, sorting, namely sorting out large-particle impurities doped in the solidified sludge;

step 4, fertilizing, namely adding a soil conditioner into the solidified sludge, and fertilizing through aerobic composting;

and 5, returning the fertilized sludge to the field after drying and screening.

The method comprises the steps that a insolation field is arranged to provide a place for mud-water separation and insolation, an area is selected on a river bank at first, then the surface of the area is cleaned, the surface cleaning comprises the steps of cleaning vegetation, construction waste and other sundries, and the area is leveled after the surface is cleaned; a sedimentation tank is arranged in the insolation site, muddy water is firstly conveyed into the sedimentation tank for sedimentation, and water on the upper layer in the sedimentation tank is pumped out through a water pump and discharged into a sewage pipeline or a sewage treatment plant. Cleaning the sludge on the lower layer in the sedimentation tank out of the sedimentation tank, and flatly paving the sludge on a sunning ground for insolation; after the sludge is solidified, large-particle impurities such as stones, metals, garbage and the like are sorted out; the soil conditioner is added into the soil, so that the physical, chemical and biological properties of the soil can be improved, and the soil is more suitable for plant growth; the sludge can be fertilized through aerobic composting, and the sludge is made into nutrient soil or organic fertilizer to be returned to the field; drying and screening can dry the fertilized sludge and remove large particulate matter from the fertilized sludge.

Further, in the step 4, in the range of 5m to 8m away from the inner slope foot of the cofferdam, a drainage ditch is formed in the length direction of the cofferdam, and a water collecting pit is formed at the lowest part of the drainage ditch; more ponding in the cofferdam is led to the sump through the escape canal, then takes out the water of gathering in the sump through the water pump, reaches the low reaches in river course side by side.

After the water in the cofferdam is pumped out by the water pump, if more river water continues to seep into the cofferdam, when more accumulated water exists in the cofferdam, a drainage ditch and a water collection pit can be arranged, so that the water seeping into the cofferdam is drained to the water collection pit through the drainage ditch, then the water in the water collection pit is drained to the downstream of the river channel under the action of the water pump, and the water flows to the water collection pit from the drainage ditch, so that the sludge in the water can be deposited in the drainage ditch or the water collection pit, and the sludge is prevented from being pumped out by the water pump to pollute the downstream river.

Specifically, in the step 4, the sludge cleaning device is a sludge suction pump, and the sludge suction pump conveys muddy water to the solarization field through a sludge conveying pipeline.

Specifically, in the step 4, the dredging depth is more than 40cm and less than 60cm. The dredging depth can ensure that the surface sludge is excavated and removed, and the surface sludge is not excavated too deep, thereby causing resource waste.

Specifically, in the step 6, the emergent aquatic plants are one or more of reed, lotus and cattail; the submerged plant is one or more of hydrilla verticillata, waterhead foxtail algae and water peltate grass.

Furthermore, herbivorous fishes and carnivorous fishes are put into the dredging river channel after the dredging river channel is cleaned.

The number of emergent aquatic plants and submerged plants can be controlled by arranging herbivorous fishes such as carps, grass carps, loaches and the like, and the number of herbivorous fishes can be controlled by arranging carnivorous fishes such as snakeheads, catfishes, weever and the like; when emergent aquatic plants and submerged plants are planted, herbivorous fishes and carnivorous fishes are put in the river bed, so that a food chain can be lengthened, the stability of a river channel ecological system is improved, the degradation of organic pollutants in a water body is promoted, and the blackening and smelly speed of river water is delayed.

Further, a waterfowl, cormorant or pelican was dropped after the clearing of the dredging river channel.

By arranging the waterfowl, herbivorous fishes and carnivorous fishes can be prey to prevent certain fishes from being excessively bred.

The beneficial effects of the invention are:

1. through dividing the desilting river course into a plurality of desilting area, a plurality of desilting areas are selected at the interval in a plurality of desilting area and are carried out the desilting as this desilting area, all the other desilting areas are as next desilting area, the interval sets up one or two next desilting areas between two adjacent this desilting areas promptly, through carrying out the segmentation clearance to the desilting river course, the cost has both been saved on the basis of satisfying the desilting needs, keep a certain amount of microbial biomass in making the river course again, a certain amount of microbial community can degrade the pollutant, the relative speed that the river water blackens and smells has been delayed, so the treatment effect in river course has been improved.

2. Water in the cofferdam is pumped out and is discharged to the downstream of the river channel by arranging a water pump; as the water depth is in the range of about 1m, the water depth is 1m reserved in the cofferdam, and the pollutants in the sludge can be prevented from being diffused under the action of pumping disturbance.

3. The mud water is returned to the field after harmless treatment, so that the mud can be reused; the modified medium can provide a proper growing environment for microorganisms, emergent aquatic plants and submerged plants, and the microorganisms in the modified medium can consume organic matters in water through metabolism of the microorganisms, so that the black and odorous water body is purified, and the treatment effect of a river channel is enhanced; through setting emergent aquatic plants and submerged plants, the roots of the emergent aquatic plants can absorb nutrient substances in the water body; the submerged plant can absorb the nutrient substances such as nitrogen, phosphorus and the like in the water body in the growth process, play a role in purifying the river water and delay the blackening and smelly speed of the river water.

Drawings

Fig. 1 shows a schematic structural diagram of the present invention.

Figure 2 shows a flow chart of the present invention.

Parts, elements and numbering in the figures: a third dredging area 1, a first dredging area 2, a fourth dredging area 3, a second dredging area 4, a side slope 5, an open ground 6 and aquatic plants 7.

Detailed Description

The following provides a detailed description of the embodiments of the present invention, and the technical solutions of the present invention are clearly and completely described with reference to the accompanying drawings. All other embodiments, which can be obtained by a person skilled in the art without any inventive step based on the embodiments of the present invention, are within the scope of the present invention.

The first embodiment is as follows:

as shown in fig. 2, a treatment method for a black and odorous river channel comprises the following steps:

in the step 1, before dividing a dredging area, firstly, cleaning plants, construction waste and other sundries in a sideline range of river channel excavation; the length of the single dredging area in step 1 is between 200m and 500m, and the length of the single dredging area in the embodiment is 300m.

Step 2, building a cofferdam in the dredging area of the dredging;

in this embodiment, the detoxification treatment includes: step 1, setting a solarization field on a river bank of a desilting river channel; step 2, solarizing, namely conveying muddy water to an solarization place, and after carrying out muddy water separation, obtaining solidified sludge through insolation; step 3, sorting, namely sorting out large-particle impurities doped in the solidified sludge; step 4, fertilizing, namely adding a soil conditioner into the solidified sludge, and fertilizing through aerobic composting; and 5, returning the fertilized sludge to the field after drying and screening.

In the embodiment, a drainage ditch is formed in the inner part of the cofferdam at a position 6m away from a slope toe in the cofferdam along the length direction of the cofferdam, and a water collection pit is formed at the lowest part of the drainage ditch; more accumulated water in the cofferdam is guided to the water collecting pit through the drainage ditch, and then the water collected in the water collecting pit is pumped out through the water pump and is discharged to the downstream of the river channel.

In this embodiment, silt cleaning device is silt hank suction pump, and silt hank suction pump passes through silt pipeline and carries muddy water to insolate the place.

In this example, the dredging depth was 50cm.

in this embodiment, the modifying medium includes loam, gravel and clay, and the mass ratio of the loam, the gravel and the clay is 2:4:1, uniformly mixing a carbon source substance in a modification medium; the carbon source material is straw.

Step 6, removing the cofferdam, and planting emergent aquatic plants and submerged plants in the dredging area of the dredging;

in this example, emergent aquatic plants were reed and lotus; the submerged plant is Myriophyllum spicatum and Scutellaria lagopus.

And 7, when dredging is carried out on the dredging river channel for the next time after one to two years, selecting the area which is not dredged for the last time for dredging, and then repeating the steps 2 to 6.

In this example, herbivorous fishes, grass carp, carnivorous fish, snakehead and cormorant were put into the river after the dredging.

As shown in fig. 1, only a part of the dredging channel and the divided dredging area thereof are shown in fig. 1, the part of the dredging channel is divided into four dredging areas, the four dredging areas are sequentially marked as a first dredging area 2, a second dredging area 4, a third dredging area 1 and a fourth dredging area 3, the first dredging area 2 and the second dredging area 4 are dredged at this time, the third dredging area 1 and the fourth dredging area 3 are dredged after one year, two sides of the channel are side slopes 5, one side of each side slope 5 far away from the channel is an open ground 6, an exposure field is arranged on the open ground 6, aquatic plants 7 are planted on one side of the channel close to the side slopes 5, and the aquatic plants 7 comprise emergent aquatic plants and submerged plants.

By using the method provided by the invention, COD in the river channel is treated,

Detecting TN and TP; after one year of dredging, the COD is treated,

Detecting TN and TP; the results of this measurement are shown in Table 1.

TABLE 1 river course test results in mg/L

As shown in Table 1, after one year of completion of the desilting, COD was measured,

TN and TP contents of 39.24mg/L, 2.73mg/L, 2.47mg/L, 8.42mg/L and 0.47mg/L in this order, COD, oxygen demand, and the like before dredging,

The removal rates of TN and TP are 50.28%, 55.61%, 57.63%, 46.16% and 48.35% in sequence, so the river channel treatment is carried out by using the method provided by the invention, and the blackening and stinking speed of river water is delayed.

The above examples are merely examples for clarity of illustration and are not intended to limit the embodiments. Other variations and modifications will be apparent to persons skilled in the art in light of the above description. This need not be, nor should it be exhaustive of all embodiments. And obvious variations or modifications therefrom are within the scope of the invention.

Claims

1. A treatment method of a black and odorous river channel is characterized by comprising the following steps:

step 2, building a cofferdam in the dredging area of the dredging;

step 3, setting a water pump, pumping water in the cofferdam through the water pump and discharging the water to the downstream of the river channel, and stopping pumping water when the water depth in the cofferdam is 1 m:

the innocent treatment comprises the following steps:

step 4.1, setting a solarization field on the river bank of the dredging river channel;

4.2, solarizing, namely conveying muddy water to an solarization field, and after carrying out muddy water separation, obtaining solidified sludge through insolation;

4.3, sorting and sorting large-particle impurities doped in the solidified sludge;

step 4.4, fertilizing, namely adding a soil conditioner into the solidified sludge, and fertilizing through aerobic composting;

step 4.5, returning the fertilized sludge to the field after drying and screening;

the modifying medium comprises loam, gravel and clay, and the mass ratio of the loam to the gravel to the clay is 2:4:1, uniformly mixing a carbon source substance in a modification medium; the carbon source substance is one of rice straw, corn stalk and wheat stalk;

2. The method for governing the black and odorous river channel according to claim 1, wherein in the step 1, plants, construction waste and other impurities in a sideline range of the river channel excavation are firstly cleaned before a dredging area is divided.

3. The method for governing the black and odorous river channel according to claim 2, wherein in the step 4, drainage ditches are formed in the cofferdam along the length direction of the cofferdam within a range of 5m to 8m from a slope foot in the cofferdam, and a water collection pit is formed at the lowest part of each drainage ditch;

more ponding in the cofferdam is led to the sump through the escape canal, then takes out the water of gathering in the sump through the water pump, reaches the low reaches in river course side by side.

4. The method for treating the black and odorous river channel according to claim 3, wherein in the step 4, the sludge cleaning device is a sludge suction pump, and the sludge suction pump conveys muddy water to the solarization field through a sludge conveying pipeline.

5. The method for governing a black and odorous river channel according to claim 4, wherein in the step 4, the dredging depth is more than 40cm and less than 60cm.

6. The method for treating the black and odorous river channel according to claim 5, wherein in the step 6, the emergent aquatic plants are one or more of reed, lotus and cattail;

the submerged plant is one or more of hydrilla verticillata, waterhead foxtail algae and water peltate grass.

7. The method for governing a black and odorous river channel according to claim 6, wherein herbivorous fishes and carnivorous fishes are thrown into the dredging river channel after the dredging river channel is cleaned.

8. The method for controlling a black and odorous river according to claim 7, wherein waterfowl is cormorant or pelican is put after the desilted river is cleaned.