Conditioning and dewatering method for black and odorous sludge
By using an advanced oxidation process involving solid urea peroxide and ferrous salts to break down extracellular polymers in black and odorous sludge, the problems of low dewatering efficiency and poor safety in black and odorous sludge were solved, achieving a highly efficient and economical dewatering effect.
Patent Information
- Application Number
- CN202610092219.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2026-01-23
- Publication Date
- 2026-04-10
AI Technical Summary
In existing technologies, the filtration and dewatering efficiency of black and odorous sludge is low, and traditional oxidants are prone to decomposition and failure, difficult to store, and pose ecological risks, resulting in high costs and poor safety in the treatment of black and odorous sludge.
By using solid urea peroxide as a free radical precursor and combining it with ferrous salt as a catalyst, an advanced oxidation process is used to break down the extracellular polymer network, achieving efficient dewatering of black and odorous sludge.
It improves the filtration and dewatering efficiency of black and odorous sludge, reduces the cost and safety risks of chemicals, reduces the risk of soil and groundwater pollution, and promotes the restoration of aquatic ecosystems.
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Figure CN121823898A_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The present application relates to the technical field of black and odorous sludge treatment, and particularly relates to a conditioning and dewatering method of black and odorous sludge. BACKGROUND
[0002] With the rapid development of industrialization and urbanization in China, various pollutants gradually enter the water body, and then concentrate in black and odorous sludge sediments, which seriously damages the water ecological system. At present, an important means to repair the water environment and control the endogenous pollution of black and odorous sludge is environmental dredging, but the widespread application of this measure produces black and odorous sludge with large volume, high water content and poor filtration and dewatering performance. Therefore, it is urgent to realize efficient dewatering and volume reduction of black and odorous sludge.
[0003] The composition and structure of black and odorous sludge are extremely complex. It not only enriches many pollutants such as persistent organic matter, heavy metals, viruses and pathogenic bacteria, but also wraps a large amount of "bulk" substances such as water, microorganisms and their extracellular polymers, inorganic salts, and clay particles. Its filtration performance is subject to its bulk properties such as water binding form, apparent physicochemical properties, and key biochemical properties (such as extracellular polymer properties and intracellular physiological state). Among them, water binding form and extracellular polymer properties are usually considered as key influencing factors affecting the filtration performance of black and odorous sludge. Among them, extracellular polymers, as a functional microbial secretion, are mainly composed of high molecular weight proteins, long chain polysaccharides and complex structure humic acid, which are intertwined with each other to form a dynamic double-layer structure. The polymers in extracellular polymers not only can be adsorbed and combined with water through complex physicochemical action, but also are closely related to the apparent physicochemical properties of sediments, thereby affecting the filtration and dewatering efficiency.
[0004] In the prior art, coagulation / flocculation technology, as one of the most widely used chemical processes for conditioning black and odorous sludge in the world, (such as using inorganic iron and aluminum salts or organic polymer flocculants) promotes particle aggregation through charge neutralization, adsorption and bridging, but cannot effectively break the network structure of extracellular polymers, resulting in limited dewatering efficiency. To break this bottleneck, advanced oxidation technology based on the generation of strong oxidizing free radicals has attracted widespread attention. Cheng-Di Dong research team uses activated persulfate advanced oxidation process to reduce organic pollutants in black and odorous sludge and promote sediment stabilization. However, persulfate has chronic toxicity and is expensive, which poses risks and is not conducive to popularization.
[0005] To overcome the limitations of activated persulfate process, homogeneous Fenton advanced oxidation technology was developed for the treatment and disposal of black and odorous sludge. Professor Wei Shuhe's research team at the Shenyang Institute of Applied Ecology of the Chinese Academy of Sciences found that Fenton coupled with bioleaching process improved the filtration performance of black and odorous sludge, and stabilized the heavy metal content in it. This research work provides theoretical support for deep regulation of black and odorous sludge filtration. However, although the Fenton-based advanced oxidation process significantly improves the solid-liquid separation performance of black and odorous sludge and promotes the stability of the filter cake, the free radical precursor used in this type of catalytic technology is hydrogen peroxide, which is easily decomposed at room temperature and is in liquid form, which is not convenient for storage and transportation.
[0006] Therefore, it is crucial to find a stable, efficient and highly operable free radical precursor and equip it with an efficient catalyst to build a new advanced oxidation black and odorous sludge conditioning system. SUMMARY
[0007] The technical problem to be solved by the present application is to overcome the shortcomings of the prior art. The present application provides a conditioning and dewatering method for black and odorous sludge, which uses solid urea peroxide as a free radical precursor and ferrous salt as a catalyst, thereby solving the problems of easy decomposition and failure of the current popular black and odorous sludge advanced oxidation conditioning process, difficulty in storage and transportation, or ecological risk, thereby realizing the effects of black and odorous sludge filtration, dewatering, volume reduction and stabilization.
[0008] A conditioning and dewatering method for black and odorous sludge, characterized in that it comprises the following steps: (1) obtaining original black and odorous sludge, adjusting the water content of the original black and odorous sludge to obtain diluted black and odorous sludge; (2) adding acid to the diluted black and odorous sludge obtained in step (1), stirring and mixing, adjusting the pH of the system, and obtaining acidified black and odorous sludge; (3) adding ferrous salt to the acidified black and odorous sludge obtained in step (2), stirring and mixing at room temperature, and obtaining black and odorous sludge treated with ferrous salt; (4) adding urea peroxide to the black and odorous sludge treated with ferrous salt obtained in step (3), continuing to stir and mix, and performing oxidation conditioning reaction to obtain conditioned black and odorous sludge; (5) performing solid-liquid separation on the conditioned black and odorous sludge of step (4) to complete the dewatering process.
[0009] In the above conditioning and dewatering method, preferably, in step (1), the water content of the original black and odorous sludge is adjusted to 89-90%.
[0010] In the above conditioning and dewatering method, preferably, in step (2), the acid is 1 mol / L sulfuric acid, and the pH of the system is adjusted to 3.0-3.2.
[0011] The conditioning dehydration method, preferably, in the step (3), the room temperature is 23-25 DEG C.
[0012] The treatment method, preferably, in the step (3), the ferrous salt is ferrous sulfate heptahydrate, and the dosage is 30-45 mg / g TSS.
[0013] The conditioning dehydration method, preferably, in the step (3), the stirring speed is 630-650 r / min, and the stirring time is 5-6 min.
[0014] The conditioning dehydration method, preferably, in the step (4), the dosage of urea peroxide is 15-25 mg / g TSS.
[0015] The conditioning dehydration method, preferably, in the step (4), the stirring speed is 630-650 r / min, and the stirring time is 15-16 min.
[0016] The conditioning dehydration method, preferably, in the steps (2)-(4), the stirring process adopts a magnetic stirrer for mixing.
[0017] The conditioning dehydration method, preferably, in the step (5), the solid-liquid separation is vacuum filtration.
[0018] Compared with the prior art, the conditioning dehydration method has the following advantages: (1) The conditioning dehydration method for black and odorous sludge is provided, free radicals (Eq. (1)-(2)) generated in the ferrous salt / urea peroxide system can efficiently break down extracellular polymeric substances and microbial cells in the black and odorous sludge, release the wrapped water in the extracellular polymeric substances, further promote the formation of internal drainage structure, improve the permeability, and improve the filtration and dehydration efficiency of the black and odorous sludge.
[0019] (2) The conditioning dehydration method for black and odorous sludge is provided, the inexpensive and easily available ferrous salt is used as a catalyst, and the economical and environmentally friendly urea peroxide is used as an oxidant, which replaces the easily decomposed and difficult to store liquid hydrogen peroxide in the traditional Fenton process and the expensive and chronically toxic persulfate, greatly reduces the reagent cost and operation safety risk.
[0020] (3) The conditioning dehydration method for black and odorous sludge is provided, and there is no residual sulfate ion in the black and odorous sludge after the ferrous salt / urea peroxide treatment, which reduces the long-term pollution risk of soil and groundwater; compared with the Fenton process, the organic matter degradation ability of the process is stronger, has important engineering application value and promotion space, and is beneficial to promoting the recovery of aquatic ecosystems and the long-term safety of soil.
[0021] The specific chemical reaction equation is as follows: Attached Figure Description
[0022] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings.
[0023] Figure 1 This is a graph showing the effect of the dosage of ferrous salt and urea peroxide on the moisture content of black and odorous sludge filter cake in the embodiments of the present invention. Detailed Implementation
[0024] The present invention and its embodiments are described below. This description is not restrictive, and actual embodiments are not limited thereto. In summary, if those skilled in the art, inspired by this description, design similar structures and embodiments without departing from the spirit of the invention, such designs should fall within the scope of protection of the present invention.
[0025] Example
[0026] The materials and instruments used in the following examples are all commercially available.
[0027] Example 1: A method for conditioning and dehydrating black and smelly sludge includes the following steps: (1) Adjust the moisture content of the original black and odorous sludge sample to 90% to obtain a diluted black and odorous sludge sample; (2) Add 1 mol / L sulfuric acid to the diluted black and odorous sludge sample described in (1) and adjust the pH of the system to 3.0 to obtain an acidified black and odorous sludge sample; (3) Add 30 mg / g TSS ferrous salt to the black and odorous sludge sample described in (2), and stir at 650 r / min for 5 min at 25°C to obtain the ferrous-treated black and odorous sludge sample. (4) Add 25 mg / g TSS urea peroxide to the black and odorous sludge sample treated with ferrous iron as described in (3), and continue to stir with a magnetic stirrer at a speed of 650 r / min for 15 min to obtain the conditioned black and odorous sludge sample. (5) Take the prepared black and odorous sludge sample described in (4) out of the beaker, perform vacuum filtration and dehydration, and then measure the moisture content of the filtered black and odorous sludge.
[0028] The filter cake moisture content of the black and odorous sludge samples before and after conditioning was measured. The test results are shown in [link to relevant documentation]. Figure 1The black and odorous sludge sample diluted before conditioning was vacuum filtered, and the resulting filter cake had a moisture content of 72.4%. The black and odorous sludge after conditioning obtained in steps (2) to (4) was vacuum filtered, and the resulting filter cake had a moisture content of 48.5%.
[0029] Example 2: A method for conditioning and dehydrating black and smelly sludge includes the following steps: (1) Adjust the moisture content of the original black and odorous sludge sample to 90% to obtain a diluted black and odorous sludge sample; (2) Add 1 mol / L sulfuric acid to the diluted black and odorous sludge sample described in (1) and adjust the pH of the system to 3.0 to obtain an acidified black and odorous sludge sample; (3) Add 45 mg / g TSS ferrous salt to the black and odorous sludge sample described in (2), and stir at 650 r / min for 5 min with a magnetic stirrer at 23 °C to obtain the ferrous-treated black and odorous sludge sample. (4) Add 15 mg / g TSS urea peroxide to the black and odorous sludge sample treated with ferrous iron as described in (3), and continue to stir with a magnetic stirrer at a speed of 650 r / min for 15 min to obtain the conditioned black and odorous sludge sample. (5) Take the prepared black and odorous sludge sample described in (4) out of the beaker, perform vacuum filtration and dehydration, and then measure the moisture content of the filtered black and odorous sludge.
[0030] The filter cake moisture content of the black and odorous sludge samples before and after conditioning was measured. The test results are shown in [link to relevant documentation]. Figure 1 The black and odorous sludge sample diluted before conditioning was vacuum filtered, and the resulting filter cake had a moisture content of 72.4%. The black and odorous sludge after conditioning obtained in steps (2) to (4) was vacuum filtered, and the resulting filter cake had a moisture content of 46.3%.
[0031] Example 3: A method for conditioning and dehydrating black and smelly sludge includes the following steps: (1) Adjust the moisture content of the original black and odorous sludge sample to 90% to obtain a diluted black and odorous sludge sample; (2) Add 1 mol / L sulfuric acid to the diluted black and odorous sludge sample described in (1) and adjust the pH of the system to 3.0 to obtain an acidified black and odorous sludge sample; (3) Add 45 mg / g TSS ferrous salt to the black and odorous sludge sample described in (2), and stir at 650 r / min for 5 min with a magnetic stirrer at 25 °C to obtain the ferrous-treated black and odorous sludge sample. (4) Add 25 mg / g TSS urea peroxide to the black and odorous sludge sample treated with ferrous iron as described in (3), and continue to stir with a magnetic stirrer at a speed of 650 r / min for 15 min to obtain the conditioned black and odorous sludge sample. (5) Take the prepared black and odorous sludge sample described in (4) out of the beaker, perform vacuum filtration and dehydration, and then measure the moisture content of the filtered black and odorous sludge.
[0032] The filter cake moisture content of the black and odorous sludge samples before and after conditioning was measured. The test results are shown in [link to relevant documentation]. Figure 1 The black and odorous sludge sample diluted before conditioning was vacuum filtered, and the resulting filter cake had a moisture content of 72.4%. The black and odorous sludge after conditioning obtained in steps (2) to (4) was vacuum filtered, and the resulting filter cake had a moisture content of 42.3%.
[0033] In summary, these are merely preferred embodiments of the present invention and are not intended to limit the invention in any way. Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the invention. Any person skilled in the art can make many possible variations and modifications to the technical solutions of the present invention, or modify them into equivalent embodiments, without departing from the spirit and technical essence of the present invention. Therefore, any simple modifications, equivalent substitutions, equivalent changes, and modifications made to the above embodiments based on the technical essence of the present invention, without departing from the content of the technical solutions of the present invention, shall still fall within the scope of protection of the present invention.
Claims
1. A method for conditioning and dehydrating black and smelly sludge, characterized in that, Includes the following steps: (1) Obtain the original black and odorous sludge, adjust the moisture content of the original black and odorous sludge, and obtain diluted black and odorous sludge; (2) Add acid to the diluted black and odorous sludge obtained in step (1), stir and mix, adjust the pH of the system, and obtain acidified black and odorous sludge; (3) Add ferrous salt to the acidified black and odorous sludge obtained in step (2), stir and mix at room temperature to obtain ferrous-treated black and odorous sludge; (4) Add urea peroxide to the ferrous treated black sludge obtained in step (3), continue stirring and mixing, carry out oxidation conditioning reaction, and obtain the conditioned black sludge; (5) The black and smelly sludge after step (4) is subjected to solid-liquid separation to complete the dehydration process.
2. The conditioning and dehydration method according to claim 1, characterized in that, In step (1), the moisture content of the original black and odorous sludge is adjusted to 89-90%.
3. The conditioning and dehydration method according to claim 1, characterized in that, In step (2), the acid is 1 mol / L sulfuric acid, and the pH of the system is adjusted to 3.0~3.
2.
4. The conditioning and dehydration method according to claim 1, characterized in that, In step (3), the room temperature is 23~25 ℃.
5. The conditioning and dehydration method according to claim 1, characterized in that, In step (3), the ferrous salt is ferrous sulfate heptahydrate, and its dosage is 30~45 mg / g TSS.
6. The conditioning and dehydration method according to claim 1, characterized in that, In step (3), the stirring speed is 630~650 r / min and the stirring time is 5~6 min.
7. The conditioning and dehydration method according to claim 1, characterized in that, In step (4), the dosage of urea peroxide is 15~25 mg / g TSS.
8. The conditioning and dehydration method according to claim 1, characterized in that, In step (4), the stirring speed is 630~650 r / min and the stirring time is 15~16 min.
9. The conditioning and dehydration method according to claim 1, characterized in that, In steps (2) to (4), the stirring process is carried out using a magnetic stirrer.
10. The conditioning and dehydration method according to claim 1, characterized in that, In step (5), the solid-liquid separation is vacuum filtration.