CN113940253A

CN113940253A - Method for improving solid waste dredged sediment and resource utilization thereof

Info

Publication number: CN113940253A
Application number: CN202110824220.6A
Authority: CN
Inventors: 王敬富; 陈敬安
Original assignee: Institute of Geochemistry of CAS
Current assignee: Institute of Geochemistry of CAS
Priority date: 2021-07-21
Filing date: 2021-07-21
Publication date: 2022-01-18

Abstract

The invention discloses an improved solid waste dredged sediment and a resource utilization method thereof, wherein the improved solid waste dredged sediment comprises the following components: dredging sediment; volcanic rock; perlite; mushroom dregs; peat; saw dust; earthworm cast; tea garden soil. The invention belongs to the technical field of solid waste improvement and utilization, and discloses a method for improving dredged sediment of solid waste and resource utilization of the dredged sediment of solid waste. The improved bottom mud is used as a substrate for growth of horticultural plants, so that the environmental risk of heavy metals is effectively reduced.

Description

Method for improving solid waste dredged sediment and resource utilization thereof

Technical Field

The invention relates to the technical field of solid waste improvement and utilization, in particular to a method for improving dredged sediment of solid waste and resource utilization thereof.

Background

Along with the development of rural economy and agricultural production, the eutrophication of water bodies in rivers and lakes is caused by the discharge of a large amount of domestic sewage, aquaculture wastewater, agricultural drainage and the like containing pollutants. With the accumulation of nutrients, sediments become a collection of the nutrients, and when the environment of the overlying water body changes (such as pH, oxidation-reduction potential and dissolved oxygen), the nutrients in the sediments can be released to the overlying water body again, so that local and even large-scale algal blooms are caused, and algae secrete a large amount of algal toxins, which seriously threatens the water safety of people.

Therefore, the sediment dredging technology is produced in order to completely eliminate the threat of the release of sediment nutrients to the water environment quality of the overlying water body. The dried sediment after dredging can not be directly applied to the planting of horticultural plants (the optimal pH for growth of the horticultural plants is 5.5-7.5) because the dried sediment has the characteristics of high pH (7.8), excessive heavy metal in part, air permeability, poor water permeability and the like. The problem of disposal of dredged sediment is therefore of great concern.

Disclosure of Invention

Technical problem to be solved

Aiming at the defects of the prior art, the invention provides a method for improving the dredged sediment of solid wastes and the utilization of resources thereof, which solves the problem that the dredged sediment of the solid wastes pollutes the environment.

(II) technical scheme

In order to achieve the purpose, the invention provides the following technical scheme: a modified solid waste dredged sediment consisting of:

dredging sediment;

volcanic rock;

perlite;

mushroom dregs;

peat;

saw dust;

earthworm cast;

tea garden soil.

A resource utilization method for improving dredged sediment of solid wastes comprises the following operation means:

s1, selecting the tested horticultural plants: violet, maidenhair, ryegrass, violet leaves creeping oxalis;

s2, preparing a violet matrix, adding a control and repeating the test; preparing substrates of creeping oxalis, malachite and ryegrass, and adding a control and repeating the test;

s3, daily management and observation: violet, violet leaf creeping oxalis and peacock seedlings (ryegrass is 20 seeds/pot directly) and matrix preparation, watering and placing for 15 days after the matrix preparation, transplanting and sowing, watering with tap water to ensure that the field water capacity is about 60 percent, and measuring the plant heights of the violet, violet leaf creeping oxalis and

peacock

15, 30, 45, 60, 75 and 90 days after transplanting (because the ryegrass is easy to fall, no plant height data exists);

s4, sample collection: harvesting ryegrass for the first time after planting for 45 days, harvesting ryegrass, violet, wood sorrel and maidenhair for the second time after planting for 90 days, collecting corresponding soil samples, cleaning the plant samples with deionized water on the day of sampling, deactivating enzymes at 105 ℃ for 30min, drying at 60 ℃, grinding by using a stainless steel plant grinder, filling the ground plant samples into self-sealing bags for numbering for later use, naturally air-drying the soil samples indoors, sieving by using a 100-mesh nylon sieve after grinding, filling the ground plant samples into self-sealing bags for numbering for later use, and analyzing;

and S5, analyzing the results, and determining the optimal proportion of the improved solid waste dredged sediment.

Preferably, the purple leaf creeping oxalis matrix is numbered TZCK, TZ1, TZ2, TZ3, TZ4 and TZ5, the ryegrass matrix is numbered THCK, TH1, TH2, TH3, TH4 and TH5, and the malachite matrix is numbered TKCK, TK1, TK2, TK3, TK4 and TK 5.

Preferably, the species of the prepared violet matrix in the S2 is 8-12, and the species of the prepared violet oxalis, malachite and ryegrass matrix is 4-6.

(III) advantageous effects

The invention provides a method for improving dredged sediment of solid waste and resource utilization thereof. The method has the following beneficial effects:

(1) according to the method for improving the dredged sediment of the solid wastes and the resource utilization of the dredged sediment, the pH value of the sediment is adjusted through different proportions, so that the pH value of the sediment is reduced to a range (the pH value is 5.5-7.5) suitable for the growth of horticultural plants, and then, the volcanic rock, the perlite, the mushroom residue, the peat, the sawdust and the earthworm cast in different proportions are added, so that the air permeability and the water permeability of the dried sediment are improved. The improved bottom mud is used as a substrate for growth of horticultural plants, so that the environmental risk of heavy metals is effectively reduced. The invention explores the method for manufacturing the horticultural plant culture medium by using the dredged sediment, the yellow soil and the like, is successfully used for planting common horticultural plants, and realizes the resource utilization of the dredged sediment.

Drawings

FIG. 1 is a graph showing the variation in plant height of Violet according to the present invention;

FIG. 2 is a diagram showing the variation of plant height of Oxalidis corniculata of the present invention;

FIG. 3 is a diagram showing the plant height variation of the present invention with respect to maidenhair.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

The first embodiment is as follows: a modified solid waste dredged sediment consisting of, by volume percent:

dredging sediment (10);

volcanic rock (20);

perlite (20);

mushroom grounds (10);

peat (10);

sawdust (20);

earthworm cast (10);

tea garden soil (0).

Example two: a modified solid waste dredged sediment consisting of, by volume percent:

dredging sediment (70);

a vesuvianite (10);

perlite (10);

mushroom grounds (5);

peat (0);

sawdust (5);

earthworm cast (0);

tea garden soil (0).

Example three: a modified solid waste dredged sediment consisting of, by volume percent:

dredging sediment (100);

vesuvianite (0);

perlite (0);

mushroom grounds (0);

peat (0);

sawdust (0);

earthworm cast (0);

tea garden soil (0).

The dredged sediment in the scheme has the following characteristics: the analysis result of the physicochemical properties of the sediment shows that (table 1), the pH of the dredged sediment is 7.82-7.78, the average pH is 7.8, and the sediment is weakly alkaline; the water content of the dredged sediment is 40.51-60.30%, and the average water content is 51.32%; the specific gravity of the dredged sediment is 2.34-2.54 g/cm³Average of 2.44 g/cm³(ii) a The porosity of the sediment is low, the dredged sediment is 31.88-33.27%, the average is 32.50%, if the sediment is directly used as a plant growth substrate, the defect of poor water permeability and air permeability exists, and the plant growth is not facilitated.

The organic matter content range of the dredged sediment is 70.73-166.62 g/kg, and the average content is 116.42 g/kg; the total nitrogen is 1.54-2.92 g/kg, the average is 2.50g/kg, the content of alkaline hydrolysis nitrogen is 49.60-151.34 mg/kg, and the average is 110.55 mg/kg; the effective phosphorus content is 20.50-79.20 mg/kg, and the average content is 42.44 mg/kg; the content of the quick-acting potassium is 139.00-230.50 mg/kg, the average content is 195.78mg/kg, and all the organic matter, the alkaline hydrolysis nitrogen, the effective phosphorus and the quick-acting potassium meet and far exceed the requirements of CJ/T340-. Referring to the national soil nutrient content grading standard, the average contents of organic matters, total nitrogen, available phosphorus and available potassium reach extremely high levels, and the content of alkaline hydrolysis nitrogen reaches high levels (Table 2).

TABLE 1 basic physical Properties of the sediment

TABLE 2 basic nutrient status of the bottom sediment

Heavy metal content:

in the dredged sediment, the content of As is 18.6-64.23 mg/kg, and the average content is 30.28 mg/kg; the Cr content is 8-150.35 mg/kg, and the average Cr content is 109.47 mg/kg; the Pb content is 41-201.95 mg/kg, and the average content is 109.83 mg/kg; the Cd content is 0.56-1.7 mg/kg, and the average Cd content is 1.12 mg/kg; the Hg content is 0.14-0.25 mg/kg, and the average Hg content is 0.21 mg/kg; the Zn content is 181.31-268.58 mg/kg, and the average content is 228.24 mg/kg; the Cu content is 46.52-101.9 mg/kg, and the average Cu content is 76.71 mg/kg; the Fe content is 80086.28-123472.39 mg/kg, and the average content is 101488.13 mg/kg; the Mn content is 1586.37-6495.25 mg/kg, and the average is 2804.68mg/kg (Table 4). According to the background value of the surface-generated sediments in Guizhou, the heavy metals in the dredged sediment exceed 1.18-15.38 times, and are the most serious in Fe enrichment; according to the mean value of the national water system sediments, the heavy metal content of the dredged sediment exceeds 2.88-8.00 times.

TABLE 4 comparison table of heavy metal content in sediment of Aha reservoir and partial lake

In the specific regulation (table 5) in CJ/T340-2011 greening planting soil, the heavy metal contents of different sediment utilization modes have different requirements, a) the heavy metals are controlled in the I-level range in the water source conservation forest green land; b) the heavy metals should be controlled in the class II range when the human contacts the green (forest) land more closely; c) human exposure to less green (forest) land, heavy metals should be controlled in class III range. d) Heavy metals, which have contaminated greenery, should be controlled within class IV. The dredged sediment is used for horticultural plant application, so that the dredged sediment is found to meet the requirements of a or b except the Cd content, the heavy metal pollution of the sediment is evaluated according to the requirement of b according to the utilization direction of the sediment, and the heavy metal content of the greening planting matrix meets the requirements of b and even a through treatment. Fe. The Mn content is very high (no control standard at present).

TABLE 5 soil heavy metal content index CJ/T340-2011 Green planting soil

The experimental scheme for the research on the use of dredged sediment for the cultivation of horticultural plants is as follows:

test matrix materials: dredging substrate mud, vesuvianite, perlite, mushroom residue, peat, sawdust, earthworm cast and tea garden soil.

Test horticultural plants: violet, maidenhair, ryegrass and violet leaf creeping oxalis.

Basic cases of test materials (table 6).

TABLE 6 basic conditions of the test materials

Preparing 12 kinds of violet substrates, adding 39 pots of contrast and repeated tests; 5 substrates of oxalis purpurea, malachite and ryegrass were prepared, and 54 pots of control and repeated tests were added (tables 7-8).

TABLE 7 mixture ratio of wood sorrel, rye grass and malachite grass planting ground substance

TABLE 8 formulation of Violet planting base

For the purpose of distinction, the purple leaf creeping oxalis matrix is numbered TZCK, TZ1, TZ2, TZ3, TZ4 and TZ5, the ryegrass matrix is numbered THCK, TH1, TH2, TH3, TH4 and TH5, and the malachite matrix is numbered TKCK, TK1, TK2, TK3, TK4 and TK 5.

Daily management and observation: violet, violet leaf creeping oxalis and peacock are used for seedling raising (the ryegrass is directly sown in 20 grains/pot) and matrix preparation, after the matrix preparation is finished, watering and placing for 15 days, transplanting and sowing are carried out, tap water is used for watering, the field water holding capacity of about 60% is ensured, and the plant heights of the violet, violet leaf creeping oxalis and peacock are measured (the plant height data does not exist because the ryegrass is easy to fall down) 15, 30, 45, 60, 75 and 90 days after transplanting.

Collecting samples: harvesting ryegrass for the first time after planting for 45 days, harvesting ryegrass, violet, wood sorrel and maidenhair for the second time after planting for 90 days, collecting corresponding soil samples, cleaning the plant samples with deionized water on the day of sampling, deactivating enzymes at 105 ℃ for 30min, drying at 60 ℃, grinding by using a stainless steel plant grinder, filling the ground plant samples into self-sealing bags for numbering for later use, naturally air-drying the soil samples indoors, sieving by using a 100-mesh nylon sieve after grinding, filling the ground plant samples into the self-sealing bags for numbering for later use, and analyzing.

And (4) analyzing results: effect of different substrate sludge substrate on horticultural plant growth:

(1) violet is a new type

During the test, all treated violet leaves grew yellow except for the control treated violet leaves. After planting for 15, 30, 45, 60, 75 and 90 days, the plant height of each treated violet is measured, and the result shows that (figure 1) different matrixes have certain promotion effect on the growth of the violet.

(2) Herba Oxalidis Corniculatae

During the experiment, the oxalis majus treated in each treatment can grow normally (figure 2). The plant height of the processed violet leaf creeping oxalis is measured after 15, 30, 45, 60, 75 and 90 days of planting, and the result shows that: compared with the control group, the purple leaves have similar heights to the creeping oxalis plants under different matrix ratios.

(3) All-grass of Peacock

During the experiment, the treated malachite grass grew normally (fig. 3). The plant height of each treated maidenhair was determined 15, 30, 45, 60, 75, 90 days after planting. The results show that: except that the height of the malachite grass under the TK1 matrix is obviously higher than that of other matrixes, the height of the malachite grass under the matrixes with other proportions is similar to that of a control group.

Content of nutrients

After harvesting, performing nutrient measurement on test plant plants, wherein the total nitrogen content of violet is 31.83-39.48 g/kg, the Z1 content is the highest, the ZCK and Z12 content is the lowest, the total phosphorus content is 1.83-4.16 g/kg, the Z1 content is the highest, the ZCK content is the lowest, the total potassium content is 26.1-45.58 g/kg, the ZCK content is the lowest, the Z4 content is the highest, and the Z1 total potassium content is slightly lower than Z4 and is 43.25g/kg (Table 9-12); z1 was seen to accumulate the best nutrients, with the worst ZCK; the total nitrogen content of the ryegrass is 31.83-38.87 g/kg, wherein the content of TH3 is the highest, the content of TH2 is the lowest, the content of total phosphorus is 1.37-1.7 g/kg, wherein the content of TH3 is the highest, the content of THCK is the lowest, the content of total potassium is 65.81-73.49 g/kg, wherein the content of TH3 is the highest, the content of TH1 is the lowest, so that the TH3 has the strongest accumulation of nutrients, and the TH2 is the weakest; the total nitrogen content range of the violet leaf creeping oxalis is 15.9-27.03 g/kg, wherein the TZ3 content is lowest, the TZ5 content is highest, the total phosphorus content range is 1.69-2.55 g/kg, wherein the TZ1 content is lowest, the TZ5 content is highest, the total potassium content range is 16.76-24.77 g/kg, wherein the TZ1 content is lowest, the TZ2 content is highest, the accumulation of the TZ5 to nutrients is strongest, and the TZ1 is weakest; the total nitrogen content range of the maidenhair is 16.68-33.82 g/kg, the TK1 content is highest, the TK3 content is lowest, the total phosphorus content range is 2.48-2.97 g/kg, the TK2 content is lowest, the TK1 content is highest, the total potassium content range is 35.95-76.61 g/kg, the TK2 content is lowest, the TK1 content is highest, and therefore the nutrient accumulation amount of the TK1 is stronger than that of other treatments.

TABLE 9 nutrient content in Violet plants

TABLE 10 nutrient content in Lolium perenne plants

TABLE 11 content of nutrients in Oxalidis yezoensis plants

TABLE 12 Nutrients content in plants of Malachite

Biomass

(1) Violet is a new type

The fresh weight and the dry weight of the violet are measured after harvesting, and the results show that (Table 13) different matrixes have certain promotion effect on the accumulation of dry substances of the violet, wherein the fresh weights of Z1, Z7 and Z11 are 21.54, 17.62 and 14.57g higher than those of a control, and the fresh weights of the rest treatments are 12.66-1.90 g higher than those of the control; the dry weight of each treatment is not changed greatly, wherein the dry weight of Z1, Z5, Z10 and Z7 is 3.33, 3.3, 3.09 and 3.00g higher than that of the control, and the dry weight of the rest treatments is 0.67-2.25 g higher than that of the control.

TABLE 13 biomass of violet

(2) Rye grass, violet leaf creeping oxalis and malachite

The fresh and dry weights of ryegrass, oxalis purple leaf and maidenhair were measured after harvesting and the results showed (table 14) that the fresh and dry weights of ryegrass control were 3.76, 0.53g, 1.75, 0.28g lower than TH3 and TH4 and higher than the rest of the treatments; the content of processed nutrients of the violet leaf creeping oxalis T2 is the highest, the fresh weight and the dry weight are 34 g and 5.9g higher than those of a control, and the content of processed nutrients of the T3 is the lowest; the fresh weight and the dry weight of the sparrow control are 2.97g and 1.6g less than TK1, and are respectively 2.41-32.66 g and 0.33-4.33 g higher than those of the rest treated fresh weights and dry weights.

TABLE 14 Biomass of Lolium perenne, Oxalidis yezoensis and Malachite

Variation of nutrient content before and after planting

The nutrients of the substrate before and after planting were analyzed, and the results are as follows (table 15). As other materials are added into the substrate before violet planting, the content of organic matters is 44.2-82.5 g/kg, the content of alkaline hydrolysis nitrogen is 195.88-385.05 mg/kg, the content of quick-acting potassium is 232-1540 mg/kg, the content of effective phosphorus is 41-183.8 mg/kg, the content of organic matters in each treatment is lower than that of a control, but with the increase of the addition amount of bottom mud, the contents of alkaline hydrolysis nitrogen, quick-acting potassium and available phosphorus are increased irregularly, but the contents are higher than the control because the bottom mud has finer particles and stronger adsorption effect on nutrients, so the effective nutrient is lower, and the substrate is added with the substrate with higher nutrient content such as mushroom residue, peat and wormcast, therefore, the available nutrients are increased, various substrates are mixed, the release of the nutrients is also influenced, and the content of all the treated nutrients is far higher than the requirement of CJ/T340-2011 greening planting soil.

The content range of organic matters in the matrix before the ryegrass, the violet wood sorrel and the maidenhair are planted is 78.3-95.31 g/kg, the content range of alkaline hydrolysis nitrogen is 109.33-124.45 mg/kg, the content range of quick-acting potassium is 178-206 mg/kg, the content range of available phosphorus is 17.2-24.7 mg/kg, the added materials are used for adjusting the texture due to the large proportion of bottom mud, the nutrients are reduced, and the nutrient content of each large treatment is smaller than that of a control, which is caused by the fact that the nutrient content of added perlite, wood chips, mushroom residues and tea garden soil is originally low.

After planting, the organic matter range of the violet matrix is 26-53.8 g/kg, which is reduced by 3.5-78.82 g/kg compared with that before planting, the content range of alkaline hydrolysis nitrogen is 195.88-385.05 mg/kg, which is reduced by 39.56-284.72 mg/kg compared with that before planting, the content range of quick-acting potassium is 232-1540 mg/kg, which is reduced by 22-1319 mg/kg compared with that before planting, the content range of effective phosphorus is 41-183.8 mg/kg, which is reduced by 4.4-102 mg/kg compared with that before planting; the organic matter content of the substrate after the ryegrass, the oxalis purpurea and the maidenhair are planted is 40.02-112 g/kg, is reduced by 4.42-46.94 g/kg compared with that before the ryegrass, the oxalis purpurea and the maidenhair, the content of alkaline hydrolysis nitrogen is 71.31-109.36 mg/kg, is reduced by 4.23-115.6 mg/kg compared with that before the ryegrass, the quick-acting potassium content is 75-29.3 mg/kg, is reduced by 6-521 mg/kg compared with that before the ryegrass, the content of effective phosphorus is 14.7-28.9 mg/kg, and is reduced by 0.5-22.44 mg/kg compared with that before the ryegrass; the nutrient content of each treatment is reduced compared with that before planting, because the plants need to absorb nutrients during the growth process, and part of nutrients are absorbed and utilized by the plants. However, all the treated nutrients meet the requirements of CJ/T340-2011 greening planting soil.

TABLE 15 Change in substrate nutrients after horticultural plants were planted

In conclusion, the method for improving the dredged sediment of the solid waste and the resource utilization of the dredged sediment of the solid waste adjusts the pH value of the sediment through different proportions, so that the pH value of the sediment is reduced to a range (the pH value is 5.5-7.5) suitable for the growth of horticultural plants, and then adds the vesuvianite, the perlite, the mushroom slag, the peat, the sawdust and the earthworm cast in different proportions, thereby improving the air permeability and the water permeability of the dried sediment. The improved bottom mud is used as a substrate for growth of horticultural plants, so that the environmental risk of heavy metals is effectively reduced. The invention explores the method for manufacturing the horticultural plant culture medium by using the dredged sediment, the yellow soil and the like, is successfully used for planting common horticultural plants, and realizes the resource utilization of the dredged sediment.

Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that changes, modifications, substitutions and alterations can be made in these embodiments without departing from the principles and spirit of the invention, the scope of which is defined in the appended claims and their equivalents.

Claims

1. A modified solid waste dredging sludge, characterized in that it consists of:

dredging sediment;

volcanic rock;

perlite;

mushroom dregs;

peat;

saw dust;

earthworm cast;

tea garden soil.

2. The resource utilization method for improving solid waste dredged sediment according to claim 1, comprising the following operating means:

s3, daily management and observation: violet, violet leaf creeping oxalis and peacock seedlings (ryegrass is 20 seeds/pot directly) and matrix preparation, watering and placing for 15 days after the matrix preparation, transplanting and sowing, watering with tap water to ensure that the field water capacity is about 60 percent, and measuring the plant heights of the violet, violet leaf creeping oxalis and peacock 15, 30, 45, 60, 75 and 90 days after transplanting (because the ryegrass is easy to fall, no plant height data exists);

3. The resource utilization method for improving solid waste dredged sediment of claim 2, wherein: for the purpose of distinction, the purple leaf creeping oxalis matrix is numbered TZCK, TZ1, TZ2, TZ3, TZ4 and TZ5, the ryegrass matrix is numbered THCK, TH1, TH2, TH3, TH4 and TH5, and the malachite matrix is numbered TKCK, TK1, TK2, TK3, TK4 and TK 5.

4. The resource utilization method for improving the dredged sediment of solid wastes according to claim 2, wherein: the types of the prepared violet orchid substrates in the S2 are 8-12, and the types of the prepared violet oxalis, malachite and ryegrass substrates are 4-6.