CN107311314A - A kind of method of black-odor riverway restoration of the ecosystem in situ - Google Patents

Abstract

A method for in-situ ecological restoration of a black and odorous river course disclosed by the invention comprises the following steps: (1) using a high-pressure water gun to overturn the sludge at the bottom of the target river to suspend the sludge in the water body; (2) in step (1) ) during the process, put microbial preparations into the target water body, establish a water body ecosystem, degrade pollutants in the water, and perform sludge reduction to purify water quality; (3) use nano-aeration to increase the dissolved oxygen content of the water body and oxidize and reduce organic pollutants; (4) One to two days after step (3) is completed, plant floating islands are set up on the target water area. The plants on the plant floating islands absorb the nutrients transformed by microorganisms and interact with the photosynthetic function of microorganisms to establish and maintain the underwater ecology Purify water quality. The invention has the advantages of low investment cost, simple operation, convenient maintenance, stable treatment effect, reliable and long-lasting maintenance of the ecological system of the treated water area, does not disturb the people, does not occupy the surrounding cultivated land, and has no pollution risk.

Description

A method for in-situ ecological restoration of black and odorous rivers

technical field

The invention relates to the technical field of river pollution control, in particular to a method for in-situ ecological restoration of black and odorous rivers.

Background technique

The river sediment is an important part of the river ecosystem. The self-purification of the river is mainly due to its dilution, adsorption, microbial degradation and other functions. Among them, sediment adsorption and microbial degradation are the main forms of conversion and reduction of river pollutants, and sediment plays an irreplaceable role in river self-purification.

A large amount of point source pollution such as industrial wastewater and domestic sewage is discharged into; surface runoff, agricultural runoff, atmospheric dry deposition and wet discharge and other non-point source pollution are imported in large quantities; long-term excessive pollution of rainwater and other pollutants lead to river sludge silting, water bodies Ecology caused serious damage. The mechanism of oxygen supply and consumption is out of balance, and the decomposition of aerobic microorganisms is dominated by anaerobic microorganisms, which makes the water body lose its self-purification ability and leads to black and odorous rivers.

River sludge consumes oxygen in the water body extravagantly, and releases a large amount of toxic substances (including harmful gases), which makes the water body in a state of severe anoxic state for a long time. The deteriorating water quality intensifies the oxygen consumption rate of the river, and completely destroys the river sediment. and native aquatic ecosystems. Therefore, a vicious circle leads to the formation of serious water pollution.

At present, the most commonly used and easiest way to control black and odorous rivers is to use better quality water from larger water systems to dilute and replace smaller or locally heavily polluted waters. Such a vicious cycle has led to the deterioration of the overall water quality, and even some major rivers have been polluted into Class IV or even Class V water, resulting in a water crisis.

The dredging method is used for sludge treatment, but its behavior has the following problems:

I. The cost is high, and the bottom mud needs about 99,000-247,000 US dollars for mechanical dredging of 1hm ³ ; II. Excessive dredging will destroy the original ecosystem, and bottom mud dredging may remove benthic organisms and destroy the food chain of fish . If the sediment is completely dredged, it may take 2 to 3 years to re-establish the benthic biome. III. The dredging and dredging works with small urban river sections are inconvenient for dredging boats to carry out water operations. IV. The amount of dredged sediment is large, the composition of pollutants is complex, and the water content is high, so it is difficult to deal with.

Contents of the invention

The technical problem to be solved by the present invention is to provide a method for in-situ ecological restoration of black and odorous rivers in view of the above-mentioned technical problems existing in the restoration process of existing black and odorous rivers. This method is based on following the principle of mutual generation and mutual restraint in nature and ecological laws, relying on modern microbial technology, combining technologies such as nano-bubbles and ecological floating islands, to dissolve oxygen in water bodies, establish microbial systems and long-term water body ecological maintenance. , To achieve the purpose of gradually reducing river bottom sludge, restoring the ecological function of bottom mud, and purifying black and smelly river water.

The technical problem to be solved by the present invention can be realized by the following technical solutions:

A method for in-situ ecological restoration of a black and odorous river course, comprising the steps of:

(1) Use a high-pressure water gun to stir the target river sludge, suspend the river sludge in the water body, and inject microbial agents at the same time to establish a water microbial system to biochemically degrade water pollutants;

(2) Use the nano-bubble generator to release a large number of nano-scale bubbles into the black and odorous water of the target river, and the cluster force of the nano-bubbles will float the organic matter in the black and odorous water to the water surface, and then collect them as resources for the preparation of bio-organic fertilizers , at the same time increase the dissolved oxygen content in the water body, and oxidize and reduce some pollutants in the water;

(3) One to two days after step (2) is completed, plant floating islands are set up on the waters of the treated river, and the plants on the plant floating islands absorb the nutrients released by the microbial transformation sludge; at the same time, they interact with the photosynthetic function of the microorganisms, Establish and maintain underwater ecology, and purify water quality by reducing sludge in situ;

In the above process, the step (2) is carried out until the requirement of the phase target is reached.

In a preferred embodiment of the present invention, the nanoscale bubbles have a diameter of 0.1-50um.

In a preferred embodiment of the present invention, when performing step (3), the amount of dissolved oxygen in the water body in the treated river course is 15-30 mg/L.

In the present invention, the microbial preparation is prepared from the bacterial species of the following colony number percentages:

In a preferred embodiment of the present invention, in the step (2), the microbial preparation is put into the black and odorous water body of the target river course, its usage amount and method are: 25 kg of microbial preparations are added to 250 kg of target river water, and mixed uniformly After that, evenly put it in the water body.

In a preferred embodiment of the present invention, aquatic plants are planted on the plant floating island and carbon fiber microbial hosts are arranged to ensure the sustainable function of the microbial system and the normal growth of the floating island plants.

Due to adopting the above technical scheme, the present invention has the following characteristics compared with the prior art:

1. The nanoscale bubbles adopted in the present invention are small in volume and stay in water for a long time. The self-pressurization effect of micro-nano bubbles can effectively improve the mass transfer efficiency and dissolved oxygen content of the gas-liquid interface. Under the condition of high oxygen content in water, the microorganisms used in the present invention can fully undergo biological reactions and degrade organic pollutants in water. In addition, nanobubbles have high interfacial zeta potential so that they have efficient adsorption properties. By absorbing fine suspended particles in water, they aggregate into larger flocs and float to the water surface to achieve the effect of air flotation dialysis.

2. The microbial preparation of the present invention is a composite microbial preparation formed by co-cultivating the main functional populations such as photosynthetic flora and nitric acid flora with yeast, phosphate-dissolving bacteria, lactic acid bacteria, nitrogen-fixing bacteria and other synergistic flora. It is a A beneficial microbial system that is harmless to animals and plants and does not damage the environment. The number of effective colonies is more than 10 billion per milliliter, and under ideal conditions, the number of units can be doubled every 20-30 minutes, and its reproduction speed is much higher than that of bacteria that cause various problems in sewage or water bodies, and can quickly spread in water bodies A functional microbial system is established in the environment to effectively inhibit the life behavior of various problematic bacteria.

The functional microorganism of the present invention utilizes the organic matter in the target water body, especially the sludge, to carry out metabolism under oxygen-enriched conditions, and is finally transformed into inorganic harmless matter such as carbon dioxide and water. Realize the gradual conversion and decomposition of pollutants in the river bottom sludge, so as to achieve the purpose of reducing sludge in situ, restoring the water body ecosystem, and maintaining a sustainable and good water body environment.

3. The plant floating island of the present invention utilizes the habit of aquatic plants, and is composed of ceramsite with microporous structure, microbial support (special carbon fiber microporous structure), buoyancy engineering structure and other engineering materials. Cultivated as plant planting baskets, the green plants on the floating island are iris, monkey tail and copper money grass, etc., using hydroponics, the plant coverage area accounts for 1/5 to 1/3 of the overall water surface, due to the different light areas of different rivers, the green plants The laying area is slightly different. On the one hand, the roots of floating island plants can absorb nitrogen and phosphorus substances released in the water by microorganisms decomposing sludge, and form a synergistic effect with microorganisms to jointly degrade nutrients in water. And the construction cost is low, and the river landscape can be improved.

Utilizing the method for in-situ ecological restoration of black and odorous rivers of the present invention, adhering to the concept of excellent ecology, establishing and improving the water body ecological system, and cultivating the self-purification function of the water body. And through the decomposition and conversion of specific microorganisms to the underwater sludge, it will be gradually reduced, so as to eliminate the sludge and restore the original ecological system of the bottom mud, and restore the ecological environment for the growth and reproduction of aquatic animals and plants. The invention has low investment cost, simple operation, convenient maintenance, stable treatment effect, reliable and long-lasting ecological system restored by it, does not disturb the people, does not occupy the surrounding cultivated land, and has no pollution risk.

detailed description

In the following, the present invention will be described in detail with a method of in-situ ecological restoration of a black and odorous river of the present invention, and the restoration process and effect of a certain black and odorous river in Shanghai.

Observation from the scene shows that the water body of the black-smelly river is yellowish-brown and has a foul smell. The source of pollutants in the water body is the disorderly discharge of nearby domestic sewage. According to the actual measurement on site, the average water depth is 2m, the sludge depth is 20-80cm, the visibility is 15cm, the water surface area is about 470m ² , and the water body volume is about 940m ³ .

The applicant conducted a water quality test on the black and smelly river, and the results are as follows:

Compared with the Surface Water Environmental Quality Standard (GB 3838-2002):

Dissolved oxygen content in the target water body: 2.50, reaching the specified value of Class V water standard, but lower than the prescribed value of Class IV water standard:

The COD content of the target water body: 97.15, which is 2.43 times the specified value of the V-class water standard;

Ammonia nitrogen content in target water body: 8.55, which is 4.28 times the specified value of Class V water standard;

The total phosphorus content of the target water body: 0.84, which is 2.1 times the specified value of the V-class water standard;

Target water pH: 7.52, in line with water quality standards.

Based on the comprehensive test results, the following conclusions were preliminarily drawn: the target water body was seriously polluted, the dissolved oxygen was low, and COD, ammonia nitrogen, and total phosphorus were seriously exceeded.

The test results are shown in Table 1.

Table 1

The treatment plan for the black and smelly river course is as follows:

1. Investigate the sources of river pollution, and intercept the culvert channels connected by side rivers. On the first day of entering the site, water samples were taken at a point 0.5m below the vertical line of the sampled water surface, and samples were taken at intervals of four to five days thereafter. The water body inspection results are shown in Table 2. According to the construction requirements, install and debug micro-nano bubble generators, high-pressure water guns and other construction equipment.

2. On the second day, from 9:00 to 11:00 and from 15:00 to 17:00, the sludge flushing operation will be carried out. At the same time, mix 25 kg of microbial preparations with 250 kg of target river water and put them into the water body (note that the microorganisms are put in before 9 o'clock), and then remove the floating objects.

Microbial agents are prepared from strains with the following percentages of colonies:

3. From the third day until the completion of the target, the micro-nano bubble generator works normally. The working hours are 9:00-11:00 and 13:00-17:00, so that the target water body can maintain a dissolved oxygen volume of 15-30mg/L. Thereafter, the working time and mode of the micro-nano bubble generator are appropriately adjusted according to the test results.

Nano aeration removes suspended particulate matter in water. At the same time, it supplies oxygen to the long-term low dissolved oxygen water body, provides a good ecological environment for photosynthesis of submerged plants, and provides a high dissolved oxygen environment for the aerobic microbial engineering flora. The water particles floated and removed by high-density micro-nano bubbles are rich in organic matter, which is a rare raw material for the preparation of bio-organic fertilizers, completely eliminating secondary pollution and realizing the utilization of resources.

4. Lay wet ecological floating islands. The green plants on the floating islands are iris, monkey tail and copper money grass, etc., and the method of hydroponics is adopted. The plant coverage area accounts for 1/4 of the overall water surface during the river channel management process.

Phased goals

The first stage eliminates the black and odor of the target water body and lays the foundation for the establishment of an excellent ecological system (the third day to the tenth day).

Dissolved oxygen 3.5mg/L;

COD 48.26mg/L;

Visibility 30cm;

Smell value, no abnormal water odor.

The second stage is to establish and improve the ecological system of the river course. This stage lasts for three months (starting from the tenth day).

At this stage, on the basis of maintaining the dissolved oxygen in the water body, the plants on the floating island will grow vigorously, and fully absorb and convert a large amount of ammonia nitrogen, phosphorus and other substances released by the functional microorganisms to decompose the river bottom sludge. And gradually enter the biochemical reduction of river bottom sludge to avoid the occupation and secondary pollution of the bank farmland by conventional dredging river sludge. Make its main water body projects achieve the following goals:

Dissolved oxygen ≥ 6mg/L;

COD≤35mg/L;

Visibility ≥ 45cm;

Sludge reduction basically completes the assimilation and decomposition of organic matter in river bottom sludge, eliminates black matter and makes it close to the local color, and revives the function of bottom mud.

Ammonia nitrogen ≥ 1.5mg/L, and entered a stable decline line.

Total phosphorus ≥ 0.2mg/L, and entered a stable decline line.

The third stage consolidates and maintains the excellent ecological system of the river, and cultivates the continuous self-purification function of the river.

This stage is a continuation of the second stage. On the basis of establishing a sound and excellent ecological system for the river, and ensuring that there is no serious external pollution inflow, the initial closure of the first stage of the water system circulation pipeline will be lifted;

Revocation of two-thirds of the initial floating islands to reduce the oxygen consumption of the target water body by the floating island plants. Manage the remaining floating island plants well to keep them growing vigorously and at an appropriate scale for a long time. Establish a natural water environment that is suitable for the reproduction and growth of fish, shrimp, snails and other organisms combined with submerged plants at the bottom of the river;

Regularly track and inspect the river system, and take active defensive maintenance measures to ensure that the main project indicators of the overall water quality of the river meet or exceed the V standard:

Dissolved oxygen ≥ 6mg/L (for Class II water quality standard);

C O D≤20mg/L (for Class III water quality standard);

Visibility ≥ 50cm (for normal water quality standard);

Ammonia and nitrogen ≥ 1.5mg/L (for Class IV-V water quality standards), the initial value passes through the peak value, and gradually drops below the initial value, and enters the downward line to stabilize at ≥ 1.5mg/L (this is because any However, there is a certain amount of scattered pollution sources entering);

Total phosphorus ≥ 0.2mg/L (for Class IV-V water quality standards), from the initial value through the peak, and gradually decreased to be lower than the initial value, and entered the decline line to stabilize at ≥ 0.2mg/L (this is because the two sides are still There is a certain amount of scattered pollution sources).

Ecology, keeping the bottom mud clean and continuous self-purification function, indigenous aquatic plants grow well, fish, shrimp, snails and other ecological systems are perfect.

Table 2

Claims (7)

1. A method for in situ ecological restoration of black and odorous river course, is characterized in that, comprises the steps: (1) Use a high-pressure water gun to overturn the target river bottom sludge, so that the river sludge is suspended in the water body; (2) During the process of step (1), inject microbial preparations into the target water body to degrade pollutants in the water and establish a water body ecosystem; (3) Use the micro-nano bubble generator to release a large number of nano-scale bubbles into the target black and odorous water body. The cluster support force of the nano-bubbles floats the suspended matter in the black and odorous water body to the water surface, and then collects it as a resource for preparing bio-organic fertilizers , while increasing the dissolved oxygen content in the water body, redoxing organic pollutants in the water; (4) One to two days after step (3) is completed, plant floating islands are set up on the target water area. The plants on the plant floating islands absorb the nutrients transformed by microorganisms and interact with the photosynthetic function of microorganisms to establish and maintain the underwater ecology , carry out sludge reduction to purify water quality; In the above process, the step (3) is carried out until the requirement of the stage target is reached. 2. The method for in-situ ecological restoration of a black and odorous river course according to claim 1, characterized in that the diameter of the nano-scale bubbles is 0.1-50um. 3. The method for in-situ ecological restoration of a black and odorous river course according to claim 1, characterized in that, when performing step (2), the amount of dissolved oxygen in the water in the treated river course is 15-30 mg/L. 4. the method for the in-situ ecological restoration of a kind of black and odorous river course according to claim 1, is characterized in that, described microbial preparation is prepared from by the bacterial classification of following colony number percentage: 5. the method for the in-situ ecological restoration of a kind of black-smelly river course according to claim 1, is characterized in that, in described step (1), in the black-smelly water body of target river course, puts microbial preparation, refers to 25 kilograms of microorganisms Add 200 kg of target river water to the preparation, mix well and then put it into the target water body. 6. the method for the in-situ ecological restoration of a kind of black and odorous river course according to claim 1, is characterized in that, plant aquatic plants and arrange carbon fiber microbial host body on the floating island of described plants, to ensure the reliability of microbial system function Persistence and normal growth of floating island plants. 7. The method for in-situ ecological restoration of a black-smelling river course according to claim 1, wherein the aquatic plant is one or a mixture of any two or more of iris, monkey tail, and pachymos.