WO2023098663A1

WO2023098663A1 - Stepped sediment modifier for ecological restoration of deepwater rivers and lakes

Info

Publication number: WO2023098663A1
Application number: PCT/CN2022/135042
Authority: WO
Inventors: 黄佳音; 钱泽朋; 胡保安; 董先锋; 刘璟
Original assignee: 中交（天津）生态环保设计研究院有限公司
Priority date: 2021-12-01
Filing date: 2022-11-29
Publication date: 2023-06-08
Also published as: LU504481B1; CN113845284B; CN113845284A; AU2022400828A1

Abstract

Disclosed in the present invention is a stepped sediment modifier for the ecological restoration of deepwater rivers and lakes. The modifier is composed of a flocculation layer, an oxidation layer, a nutrition layer and an oxygenation layer. The flocculation layer is formed by uniformly and proportionally mixing polyacrylamide, polyaluminum chloride, disodium ethylene diamine tetraacetate and polyvinylpyrrolidone and then pre-tabletting the mixture. The oxidation layer is formed by uniformly and proportionally mixing citric acid, humic acid and composite potassium hydrogen persulfate and then pre-tabletting the mixture on the basis of the flocculation layer. The nutrition layer is formed by uniformly and proportionally mixing calcium bentonite, magnesium chloride, calcium chloride, anhydrous sodium sulfate, an alkali-activated modified mineral powder and diatomite and then pre-tabletting the mixture on the basis of the flocculation layer and the oxidation layer. The oxygenation layer is formed by uniformly and proportionally mixing a porous biological polymerization agent, sodium percarbonate, percarbamide and polyvinylpyrrolidone and then tabletting the mixture on the basis of the flocculation layer, the oxidation layer and the nutrition layer. The modifier has both biological and chemical effects, and has no secondary pollution and low investment.

Description

Stepped substrate modifier for ecological restoration of deep-water rivers and lakes

technical field

The invention relates to the fields of ecological restoration of river and lake bottoms and water quality purification of rivers and lakes, in particular to a stepped bottom quality modifier for ecological restoration of deep-water rivers and lakes.

Background technique

At present, there are many reports on sediment restoration agents used in aquaculture, and there are few sediment restoration agents used for ecological restoration of river and lake sediments. Aquatic ecology and river and lake ecology are different due to different environments, and the contents and types of sediment substances are also different. The two sediment restoration agents cannot be mixed and must be used according to different situations.

Most of the existing sediment ecological restoration agents are chemical composite and microbial composite restoration agents prepared by direct mixing. This type of sediment restoration agent has certain effects on the ecological restoration of rivers and lakes, but it exists through direct dosing. Due to the shortcomings of low utilization rate in a short period of time, slow reaction efficiency, and low follow-up utility, the role of each component in its corresponding stage cannot be fully exerted, and a large amount of sediment repair agent is required to have a certain effect. Effectiveness, there is a risk of secondary pollution.

However, when applied to deep-water rivers and lakes, the active ingredients that specifically act on the sediment quickly disperse and float in the water environment during the descent process, and cannot further act on the sediment. Only by increasing the amount can the desired effect be achieved. effect, so it will produce secondary pollution.

Contents of the invention

In order to solve the problems existing in the prior art, an object of the present invention is to provide a step-type substrate improvement agent for ecological restoration of deep-water rivers and lakes, which has a high utilization rate and can fully utilize each component in the process of each stage of sediment restoration. It can reduce the use of sediment restoration agent, effectively reduce the investment of sediment ecological restoration projects, and reduce the risk of secondary pollution in the process of ecological restoration.

Another object of the present invention is to provide a preparation method of the above-mentioned step-type substrate modifier.

For this reason, the present invention provides following technical scheme:

A step-type substrate improvement agent for ecological restoration of deep-water rivers and lakes, which consists of a flocculation layer, an oxidation layer, a nutrient layer, and an oxygenation layer arranged in sequence, wherein: the flocculation layer is composed of polyacrylamide, polyaluminum chloride , disodium edetate and polyvinylpyrrolidone are uniformly mixed according to the mass ratio of 1:1:(1~2):1 and then pre-pressed into tablets; the oxide layer is made of citric acid, humic acid, compounded Potassium hydrogen sulfate (potassium hydrogen persulfate compound salt (potassium monopersulfate, potassium monopersulfate)) in parts by mass (1~2): (1~2): (2~4) after uniform mixing The flocculation layer is pre-pressed on the basis of the flocculation layer; the nutrient layer is composed of calcium-based bentonite, magnesium chloride, calcium chloride, anhydrous sodium sulfate, alkali-activated modified mineral powder, and diatomite in parts by mass (2 to 3 ): 1:1:1: (2~3): (2~3) After uniform mixing, it is formed by pre-pressing on the basis of the flocculation layer and the oxidation layer; the oxygenation layer is made of porous biopolymer , sodium percarbonate (fast release speed), percarbamide (slow release speed), and polyvinylpyrrolidone in parts by mass (2-4): (2-3): (2-3): 1 and mix uniformly in the described Tablets are formed on the basis of floc layer, oxide layer and nutrient layer.

Among the above-mentioned modifiers, the mass percent of the flocculated layer, the oxidized layer, the nutrient layer, and the oxygenated layer consists of:

Optimally, the mass percentages of the above-mentioned flocculation layer, oxidation layer, nutrient layer, and oxygenation layer are composed of:

Preferably, before use, the alkali-activated modified mineral powder is washed with water for 3 to 4 times, and then dried at 105°C.

Preferably, the total thickness of the flocculation layer and the oxygenation layer is no more than 0.2cm, the total thickness of the flocculation layer and the oxygenation layer is proportional to the water depth, and the total thickness of the oxidation layer and the nutrient layer is proportional to the bottom mud pollution. Proportional to the serious situation.

Preferably, the overall length of the substrate improving agent is 5cm-11cm, the width is 5cm-11cm, and the thickness is 0.3cm-0.8cm.

During the preparation process, to ensure the uniformity of mixing and the order of tabletting, the oxidation layer must be between the flocculation layer and the nutrient layer, and the nutrient layer must be between the oxidation layer and the oxygenation layer.

The present invention divides the product into four layers according to the process of water ecological restoration, and each layer plays a different main role. In the process of descending from the surface of deep-water rivers and lakes to the bottom, the flocculation layer and the oxygenation layer mainly play a role, which can effectively flocculate suspended colloids and other substances in the water and finally sink to the bottom of rivers and lakes. During the landing process, the porous biopolymer in the aerobic layer will leave beneficial microorganisms, which not only strengthens the self-purification ability of the water environment, but also ensures the continuity of the self-repair of the water environment. When falling to the bottom, a small part of the components in the flocculation layer and the aerobic layer will continue to act on the bottom mud, flocculate and compress the bottom mud, and provide a basis for the oxidation layer to play its role while expanding the water environment capacity of rivers and lakes.

In the present invention, each layer can keep stable when dry, will not self-react, and will quickly act on harmful substances in water after encountering water, and there is a certain synergistic effect between each substance, and the specific effects are as follows:

The flocculation layer and the oxygenation layer mainly play the roles of flocculation, complexation, oxygenation and stabilization respectively. The polyaluminum chloride, polyacrylamide and porous biopolymers have chemical and biological flocculation effects, and can remove part of suspended solids and colloids in the water environment during the descent in deep-water rivers and lakes. There is no porous biopolymers in the floc layer It is to prevent the oxidizing substances of the oxide layer from damaging some biological structures. Polyvinylpyrrolidone has anti-oxidation synergistic and stabilizing effects. On the one hand, it can ensure a certain degree of firmness after compression molding, and on the other hand, it can prevent the oxidizing and corrosive substances in the oxide layer from damaging the material structure of the floc layer. Disodium ethylenediaminetetraacetic acid (EDTA) in the floc layer is an antioxidant and complexing agent, which can complex the heavy metal ions in the water environment during the descent in the deep water of rivers and lakes. Sodium percarbonate and percarbonamide in the oxygenation layer play the role of rapid release and slow release of oxygen respectively, ensuring the instantaneous and continuous oxygen under water.

The oxide layer mainly plays the role of disinfection, removal of macromolecular organic matter and transformation of other substances. Under the action of citric acid and humic acid, it can effectively remove harmful microorganisms in the sediment and reduce the harm of virus bacteria. Under the action of compound potassium hydrogen persulfate, the oxidation-reduction potential of the mud-water interface can be increased, and the purpose of eliminating harmful bacteria can be achieved by destroying the permeability of microbial cells in the bottom mud; the ferrous iron and aluminum in the water can be eliminated through oxidation. Atoms are oxidized to trivalent, which promotes flocculation, improves water transparency and reduces the diffusion of heavy metal ions in sediment; it can oxidize nitrite in sediment to nitrate, hydrogen sulfide to sulfate, and remove toxic and refractory organic pollution Algae poisons such as liver toxins and other algae poisons produced by degrading and degrading the death of deposited algae.

The nutrient layer is mainly used to provide nutrients and nutrients needed by plants and microorganisms. The alkali-activated modified mineral powder and diatomite can also reduce heavy metal ions in water and sediment under the action of ion exchange and adsorption.

Compared with similar products, the present invention has the following beneficial effects:

1. The present invention combines porous biopolymers and other effective chemical substances through layering, and realizes that the same sediment restoration agent has both biological and chemical effects, which can ensure effective treatment of the current environment under the action of chemical reagents. It has a fast and good effect, and can also maintain a continuous effect under the action of microorganisms, while strengthening the self-purification ability of the water environment and sediment.

2. According to the conventional ecological restoration method, the present invention designs a hierarchical structure for the succession of different stages of ecological restoration, which ensures the maximum utilization rate of the corresponding effective substances at different stages and different timeliness, and will not cause excessive dosage and cause The problem of secondary pollution has effectively reduced the investment in ecological restoration projects, and the amount of injection under the same effect is about 1/2 of similar products in the market.

3. The present invention has guaranteed that this product has certain stability under normal temperature, dry condition by adding multiple stabilizing substances, and the shelf life time is 3.5 years longer, 2 years longer than the shelf life of similar products in the market.

Detailed ways

The improver of the present invention will be described in detail below in conjunction with the examples.

The porous biopolymer used in the present invention is a high-efficiency water purification product composed of various natural mineral powders, special compound microorganisms extracted from nature and their metabolites. The product is composed of various minerals, molds, yeasts, A variety of microorganisms such as actinomycetes are composed according to a specific formula. The preparation method of porous biopolymer is recorded in the Chinese invention patent whose publication number is CN111018282A and the name of the invention is "a kind of porous biopolymer for river and lake ecological dredging and sediment dehydration", and its content is included in the present invention, wherein the implementation The porous biopolymer agent used in Example 1 and Example 2 is the porous biopolymer agent prepared in Example 1 of the invention patent.

The polyaluminum chloride used in the present invention is a solid, commercially available product, and the mass fraction of aluminum chloride can be 26%, 28%, or 30%.

The calcium-based bentonite used in the present invention is a commercially available product, and its interlayer cation is Ca ²⁺ .

The alkali-excited modified mineral powder used in the present invention is a commercially available product, which is modified by the principle of alkali excitation.

Example 1

Use an outdoor medium-sized container to simulate the river and lake environment. The container is 1m long, 1m wide, and 1.5m high. The test materials are water and sediment from Qilu Lake in Tonghai County, Yunnan Province, and the seeds of bitter grass with strong adaptability. The container is placed outdoors to ensure natural conditions, and then the black and smelly bottom mud is spread all over the bottom of the container and the seeds of bitter grass are added at fixed points. The total thickness of the bottom mud is 0.2m, and the total water depth is 0.8m (not including the bottom mud). Three fixed-point monitoring instruments for dissolved oxygen are distributed in a triangle in the middle of the water environment.

The step-type substrate improvement agent used for ecological restoration of deep-water rivers and lakes in this embodiment is prepared by the following method:

First, wash the alkali-activated mineral powder in the nutrient layer with water for 3 to 4 times, then perform drying pretreatment at 105°C, and then prepare the components of each layer according to the following mass-to-number ratios, and mix them uniformly:

1) Polyacrylamide: polyaluminum chloride (mass fraction of aluminum chloride is 26%): disodium edetate: polyvinylpyrrolidone = 1:1:2:1;

2) Citric acid: humic acid: compound potassium hydrogen persulfate = 1:1:2;

3) Calcium-based bentonite: magnesium chloride: calcium chloride: anhydrous sodium sulfate: alkali-activated modified mineral powder: diatomaceous earth = 2:1:1:1:2:2;

4) Porous biopolymer: sodium percarbonate: percarbamide: polyvinylpyrrolidone = 2:2:2:1.

Quantitative samples are taken out according to the composition of flocculation layer, oxidation layer, nutrient layer and oxygenation layer according to the mass percentage of 15%, 20%, 50%, 15%,

Then the floc layer material is pre-pressed, and the oxide layer material is pre-pressed on the basis of the floc layer, and so on. The improved agent after forming is 7cm long and 7cm wide. The layer thicknesses are about 0.1 cm, 0.15 cm, 0.2 cm, 0.1 cm respectively, and the total thickness is about 0.55 cm.

Add the above-mentioned sediment modifier from the water surface, because it has a larger surface area and generates greater buoyancy, it will slowly sink to the bottom of the container, and the flocculation of the upper and lower layers and the effective components of increasing dissolved oxygen will be rapid during the sedimentation process. Digestion, the process of slowly producing flocs and further flocculation of floating substances in the water body can be observed. The time required for the overall water environment to be clear and transparent is 6 days, and the water environment can continue to remain clear within 5 days after that; according to the dissolved oxygen detector display , the dissolved oxygen is also slowly increasing; the sediment modifier settles to the bottom of the container and fully contacts with the sediment, the digestion of the sediment modifier and the sediment improvement process are carried out at the same time, through the slow release and the action of the biopolymerization agent, the sediment is in 7 The situation that turns yellow gradually occurs after 8 days, and bitter grass seed begins to germinate and grows in 8 days.

Example 2

Use an outdoor medium-sized container to simulate the river and lake environment. The container is 1m long, 1m wide, and 1.5m high. The test materials are water and sediment from Qilu Lake in Tonghai County, Yunnan Province, and the seeds of bitter grass with strong adaptability. Place the container outdoors to ensure natural conditions, then cover the bottom of the container with black odorous bottom mud and add bitter grass seeds at fixed points, the total thickness is 0.2m, and the total water depth is 1.2m. Three fixed-point monitoring instruments for dissolved oxygen are distributed in a triangle in the middle of the water environment.

First, the alkali-activated mineral powder in the nutrient layer is washed with water for 3 to 4 times and dried at 105°C for pretreatment, and then the components of each layer are prepared according to the following mass-to-number ratios, and mixed uniformly:

2) Citric acid: humic acid: compound potassium hydrogen persulfate = 1:1:2;

The flocculation layer, the oxidation layer, the nutrient layer and the oxygenation layer are composed according to the mass percentages of 20%, 28%, 28%, and 22%, and quantitative samples are taken out.

Then the floc layer material is pre-pressed, and the oxide layer material is pre-pressed on the basis of the floc layer, and so on. The forming modifier is 10 cm long and 10 cm wide. The thickness is about 0.11cm, 0.17cm, 0.18cm, 0.13cm respectively, and the total thickness is about 0.59cm.

Add the above-mentioned sediment modifier from the water surface, because of its large surface area and large buoyancy, it will slowly sink to the bottom of the container, and the flocculation of the upper and lower layers and the increase of dissolved oxygen in the effective component part will be rapid during the sedimentation process. Digestion, the process of slowly producing flocs and further flocculation of floating substances in the water body can be observed. The time required for the overall water environment to be clear and transparent is 3 days, and the water environment can continue to remain clear within 5 days after that; according to the dissolved oxygen detector, the dissolved oxygen Oxygen is also slowly increasing; the sediment modifier settles to the bottom of the container and fully contacts with the sediment, and the digestion of the sediment modifier and the sediment improvement process are carried out at the same time. The situation that turns yellow gradually occurs, and the bitter grass seed begins to germinate and grows when 10d.

Comparative example 1

Use an outdoor medium-sized container to simulate the river and lake environment. The container is 1m long, 1m wide, and 1.5m high. The test materials are water and sediment from Qilu Lake in Tonghai County, Yunnan Province, and the seeds of bitter grass with strong adaptability. Place the container outdoors to ensure natural conditions, then cover the bottom of the container with black odorous bottom mud and add bitter grass seeds at fixed points, the total thickness is 0.2m, and the total water depth is 0.8m. Three fixed-point monitoring instruments for dissolved oxygen are distributed in a triangle in the middle of the water environment.

As a blank control group, this embodiment does not add any sediment improver, and restores under natural ecological conditions. Starting from the arrangement of the necessary conditions, under the self-generation of beneficial microorganisms and the action of gravity settlement, some floating substances in the water environment are partially digested and most of them sink. The time required for the overall water environment to be clear and transparent is 15 days, but after 15 days, the water environment There are still small particles floating in the soil; due to the full incorporation of dissolved oxygen in the air, the sediment environment is gradually improved and loosened, some harmful substances in the sediment are released, and beneficial microorganisms are gradually activated with more types. Under the slow restoration of microorganisms, the sediment Gradual yellowing occurred after 25 days; and the seeds of the bitter grass did not guarantee their own nutritional needs within the natural recovery time of the small ecosystem and were eroded by harmful substances around the bottom mud, so that the seeds of the bitter grass were taken out after 25 days. Rot and spoilage.

Comparative example 2

Sprinkle 100g of commercially available powdered sediment modifier evenly into it, flocs are produced during the sedimentation process, and the overall water environment is quickly cleared within 6 days, but after 8 days, there is a phenomenon that the sediment floats upwards at the mud-water interface and some The insoluble matter continues to float in the water environment, and there are three layers of coexistence of water layer, mud layer and mud-water mixed layer. The height of the mud-water mixed layer is about 4cm, and the overall balance is reached after 10 days; the sediment modifier settles to the bottom of the container and the mud After full contact, the bottom mud gradually turned yellow after 7 days, and the seeds of bitter grass began to germinate and grow in 8 days.

Table 2 Differences added by each example

It can be seen from the above table that under the same conditions, the larger the proportion of flocculation and oxygenation components in the flocculation layer and oxygenation layer, the shorter the time required for the water environment to be transparent and clear. It takes longer to turn yellow. It is necessary to adjust the percentage of each layer according to the actual water depth and the pollution degree of the sediment.

Claims

A stepped substrate improvement agent for ecological restoration of deep-water rivers and lakes, characterized in that it consists of a flocculation layer, an oxidation layer, a nutrient layer, and an oxygenation layer arranged in sequence, wherein:

The flocculation layer is formed by uniformly mixing polyacrylamide, polyaluminum chloride, disodium ethylenediamine tetraacetate and polyvinylpyrrolidone according to the mass ratio of 1:1:(1-2):1, and then pre-pressing the tablets;

The oxidized layer is preformed on the basis of the flocculated layer after being uniformly mixed with citric acid, humic acid, and compound potassium hydrogen persulfate in parts by mass (1-2): (1-2): (2-4). pressed into tablets;

The nutrient layer is composed of calcium-based bentonite, magnesium chloride, calcium chloride, anhydrous sodium sulfate, alkali-activated modified mineral powder, and diatomite in parts by mass (2-3): 1:1:1: (2-3) : (2～3) pre-compressed on the basis of the flocculation layer and the oxide layer after uniform mixing;

The oxygen-increasing layer is uniformly mixed with porous biopolymer, sodium percarbonate, percarbamide, and polyvinylpyrrolidone in parts by mass (2-4): (2-3): (2-3): 1 and then placed on the Tablets are formed on the basis of floc layer, oxide layer and nutrient layer;

The mass percent of described flocculation layer, oxidation layer, nutrition layer, oxygenation layer consists of:
The step-type substrate improvement agent according to claim 1, characterized in that: the mass percentage of the flocculated layer, the oxidized layer, the nutrient layer, and the oxygenated layer consists of:
The stepped bottom texture improver according to claim 1, characterized in that: before use, the alkali-activated modified mineral powder is washed with water for 3 to 4 times, and then dried at 105°C.
The step-type bottom quality improvement agent according to claim 1, characterized in that: the thickness of the flocculation layer and the oxygenation layer is no more than 0.2cm, and the total thickness of the flocculation layer and the oxygenation layer is proportional to the water depth, The total thickness of the oxide layer and the nutrient layer is directly proportional to the seriousness of the sediment pollution.
The step-type bottom texture improving agent according to claim 4, characterized in that: the overall length of the bottom texture improving agent is 5 cm to 11 cm, the width is 5 cm to 11 cm, and the thickness is 0.3 cm to 0.8 cm.