CN114772883B - Treatment method of black and odorous water body substrate sludge and application of black and odorous water body substrate sludge in preparation of baking-free bricks - Google Patents

Abstract

The invention discloses a treatment method of black and odorous water body substrate sludge and application thereof in preparing baking-free bricks, comprising the following steps: s1, removing sundries in bottom mud; s2, taking the bottom mud obtained in the step S1, and performing ultrasonic cracking; s3, adding calcium silicate hydrate into the substrate sludge subjected to ultrasonic cracking in the step S2, and uniformly stirring and mixing; s4, adding a composite microbial preparation into the sediment obtained in the step S3, and stirring every day to carry out biodegradation; s5, taking the substrate sludge after biodegradation in the step S4, and carrying out suction filtration to obtain a treated substrate sludge cake. The method can effectively reduce the water content and the organic matter content of the bottom mud of the black and odorous water body of the urban river and improve the dehydration performance, obviously inhibit the adverse effect of heavy metal of the bottom mud, and can meet the requirements of the sludge for brick making (GB/T25031-2010) for sludge disposal in urban sewage treatment plants on the muddiness of bricks by rapid suction filtration of the bottom mud after combined treatment, thereby being convenient to be used as a baking-free brick base material.

Description

A treatment method for black and odorous water bottom sludge and its application in the preparation of unburned bricks

technical field

The invention relates to a treatment method for black and odorous water bottom sludge and its application in preparing unburned bricks, belonging to the fields of water body pollution control, solid waste recycling and green building materials.

Background technique

Sediment is one of the important causes of black and odorous phenomena in urban rivers. After some exogenous pollutants enter the water body, they accumulate through various methods such as natural precipitation, particle attachment, and animal and plant absorption, forming black and odorous sediment in the still or slow-flowing water body, which can easily lead to the water body turning black and smelly.

The composition of sediment in black and odorous water bodies is complex, and its organic matter content is generally in the range of 5%-20%. Copper, zinc, cadmium, chromium, nickel, lead and other heavy metal elements exceed the standard, mostly fluctuating in the range of tens to thousands of mg/kg, with strong biological toxicity and not suitable for direct use. At present, the treatment of black and odorous water sediments is mainly divided into two categories: in-situ method and ex-situ method. Among them, ex-situ treatment is effective and is especially suitable for sediment pollutants whose concentration is 2-3 times higher than the environmental background value. place. After the sediment is dredged, the ex-situ treatment can not only realize the treatment of black and odorous water bodies, but also promote the resource utilization of the sediment. Building materials are a relatively extensive way of sludge resource utilization in recent years. On the one hand, it does not need to rely on land as a carrier for sludge; on the other hand, dredged sediment is mainly composed of SiO ₂ , Al ₂ O ₃ , CaO, etc., and its chemical composition It is close to clay, and can save a lot of clay resources through raw material substitution.

Unburned bricks are a typical green building material, which can save a lot of energy consumption compared with traditional fired bricks, and effectively reduce carbon emissions in the brick-making process. The chemical coagulation method is usually used to adjust the sludge properties and improve the dehydration effect, but its water content and organic matter treatment efficiency of the sludge cannot meet the "Mud Quality for Sludge Disposal of Urban Sewage Treatment Plants for Bricks" (GB/T25031-2010 ) in the preparation of non-fired brick mud quality requirements, but also need to add sludge filtration, drying and other links, the cost is relatively high.

Contents of the invention

Aiming at the above-mentioned problems in the prior art, the present invention provides a treatment method for black and odorous water bottom sludge, which reduces treatment cost on the basis of improving bottom sludge dehydration efficiency, is easy to operate, and helps to promote energy saving and emission reduction.

The present invention also provides the application of the bottom sludge treated by the above treatment method in preparing unburned bricks.

In order to achieve the above object, the processing method of a kind of black and smelly water bottom mud that the present invention adopts may further comprise the steps:

S1, remove the sundries in the bottom mud;

S2. Take the sediment in step S1 and perform ultrasonic cracking;

S3, add hydrated calcium silicate to the bottom mud after ultrasonic cracking in step S2, stir and mix evenly;

S4, adding compound microbial preparation to the bottom mud obtained in step S3, stirring every day for biodegradation;

S5, taking the biodegraded bottom sludge in step S4, and suction filtering to obtain a treated bottom sludge cake.

As an improvement, the ultrasonic frequency of the ultrasonic cracking in the step S2 is 20-60 kHz, and the flow rate of the continuous ultrasonic treatment of the sediment is 20-60 L/h.

As an improvement, the dosage of hydrated calcium silicate in the step S3 depends on the heavy metal content in the bottom mud, and is based on 0-15g/g heavy metal.

As an improvement, the compound microbial preparation in the step S4 includes a live bacterial agent and a biological enzyme, and the mass ratio of the biological enzyme to the live bacterial agent is (4-22): 1; the live bacteria adopts nitrifying bacteria, At least one of photosynthetic bacteria, denitrifying bacteria and Bacillus subtilis, and at least one of neutral protease, papain, α-amylase and cellulase as the biological enzyme.

As an improvement, the dosage of the compound microbial preparation in the step S4 is 2-4.5g/L bottom mud, that is, adding 2-4.5g of the compound microbial preparation in every 1L of the bottom mud obtained by step S3.

As an improvement, the biodegradation temperature in step S4 is 10-30°C.

As an improvement, the biodegradation in step S4 adopts agitation for oxygen supply, and the agitation frequency is 30-200 times/day.

As an improvement, the bottom mud cake in step S5 has a water content of 15%-20% and an organic matter content of 0%-4%.

Finally, the present invention also provides an application of the bottom sludge treated by the treatment method in preparing unburned bricks.

Principle of the present invention:

The treatment method of the black and odorous water bottom mud of the present invention uses the combined method of ultrasonic cracking, heavy metal stabilization and biodegradation to reduce the water content and organic matter content of the black and odorous bottom mud and improve the dehydration performance, and then the bottom mud after rapid suction filtration can reach The clay quality requirements for preparing unburned bricks.

Compared with the prior art, the present invention has the following beneficial effects:

(1) The treatment method of the black and odorous water bottom mud of the present invention has a better treatment effect on the water content and organic matter content of the bottom mud than the traditional chemical coagulation treatment method, and complies with the goal of energy saving and emission reduction.

(2) The amount of sediment treatment is large, which is convenient for large-scale treatment, and is conducive to the stabilization of heavy metals in the sediment, which is convenient for subsequent use, and can effectively solve the land occupation problem after dredging urban rivers.

(3) The scheme is relatively simple, with strong operability and low cost.

Description of drawings

Fig. 1 is a diagram of the preparation process of unburned bricks in Example 1 of the present invention; in the figure (a) pulverizer, (b) raw materials after mixing and stirring, (c) unburned brick mold, (d) electro-hydraulic servo rock mechanics test system , (e) quick curing box for cement, (f) natural curing at normal temperature;

Fig. 2 is the unburned brick finished product figure of the embodiment of the present invention 1;

Fig. 3 is the SEM figure of the finished unburned brick section of the embodiment of the present invention 1;

Fig. 4 is the contrast figure of joint treatment method of the present invention and traditional chemical coagulant PAC, PAM about bottom mud mud cake suction filtration time, mud cake moisture content and organic matter content; Among the figure (a) mud cake moisture content and suction filtration time , (b) mud cake organic matter content;

Fig. 5 is a scanning electron microscope image of an unburned brick prepared from the bottom sludge with excessive zinc content in Example 2 of the present invention treated with hydrated calcium silicate.

Detailed ways

In order to make the object, technical solution and advantages of the present invention clearer, the present invention will be further described in detail below. However, it should be understood that the specific embodiments described here are only used to explain the present invention, and are not intended to limit the scope of the present invention.

Unless otherwise defined, all technical terms and scientific terms used herein have the same meaning as commonly understood by those skilled in the technical field of the present invention, and the terms used in the description of the present invention herein are only to describe specific implementations The purpose of the example is not intended to limit the present invention.

Example 1

A method for processing black and odorous water bottom sludge, comprising the following steps:

S1. Remove branches, snails, plastics and other sundries in the bottom mud;

S2, take the bottom sludge after pretreatment in step S1, through 40kHz ultrasonic cracking, the sludge flow rate is 30L/h;

S3. Under the condition that the ambient temperature is 20°C, add 2.2 g of compound microbial preparation to the bottom mud after ultrasonic cracking in step S2, and add nitrifying bacteria agent + neutral protease For compound microbial preparations, the mass ratio of nitrifying bacteria agent to neutral protease is 1:10, the treatment time is 7 days, the stirring operation is carried out for oxygen supply every day, and the stirring frequency is 100 times/day;

S4. After the biodegraded bottom mud in step S3 is quickly suction-filtered, a bottom mud cake with a water content of 18.67% and an organic matter content of 3.43% is obtained, which meets GB/T25031-2010 "Sludge Disposal System of Urban Sewage Treatment Plants" Requirements for brick-making mud quality in "Mud Quality for Bricks".

The method for preparing unfired bricks from the above-mentioned treated bottom mud, the specific steps are as follows:

(1) After the processed bottom mud cake is crushed by a pulverizer (Fig. 1a), pass through a 50-mesh sieve, and the oversize material continues to be crushed until all the bottom mud is sieved, and set aside;

(2) Mix cement, quicklime, and phosphogypsum evenly in a mass ratio of 2:1:1, and use them as cementitious materials for later use;

(3) Mix water and water glass evenly according to the mass ratio of 2:1, and use it as a cement for later use;

(4) Mix the sediment particles, cementitious material and consolidation agent obtained in steps (1), (2), and (3) evenly in a mass ratio of 5:5:1 (Fig. 1b) and stir with a mixer for 15 minutes;

(5) Fill the raw materials that have been stirred in step (4) into an unburned brick mold (Fig. 1c), and use a pressing machine (Fig. 1d) to press and form under a pressure of 20Mpa;

(6) Place the brick body pressed and formed in step (5) in a cement rapid curing box (Fig. 1e) for constant temperature and humidity curing at a temperature of 90°C for 3 hours;

(7) Place the bricks cured at high temperature in step (6) in a natural environment for 7 days of normal temperature curing (Fig. 1f), and brush water every day. After natural curing, the bricks are prepared. The finished unfired brick body is shown in Figure 2.

Carry out performance test to the unburned brick that makes:

Figure 3 is the cross-sectional SEM image of the finished unburned brick. It can be seen that the prepared unburned brick has a relatively dense structure, and the cross-section is mostly agglomerated substances, indicating that the hydration of the material inside the brick body is relatively sufficient, and the internal particles adhere to the surface of the brick. A large number of spherical crystals are mainly composed of hydration products such as cement and quicklime, which have gelling properties and can bond sediment particles together to form a brick structure with a certain strength.

Fig. 4 is a comparison chart of the method of the present invention and the traditional chemical coagulants PAC and PAM about the suction filtration time of the bottom mud cake, the water content of the mud cake and the organic matter content. It can be seen that the water content of the mud cake after the method of the present invention is treated and suction-filtered is lower than 20%, the organic matter content is lower than 4%, the suction-filtration time is short, and the energy consumption is low, fully satisfying the "Sludge Disposal System of Urban Sewage Treatment Plants" The clay used for bricks" (GB/T25031-2010) requires brick-making mud to be far superior to the treatment effect of traditional chemical coagulation.

Example 2

A method for processing black and odorous water bottom sludge, comprising the following steps:

S1. Remove branches, snails, plastics and other sundries in the bottom mud;

S2, take the bottom sludge after pretreatment in step S1, through 30kHz ultrasonic cracking, the sludge flow rate is 22L/h;

S3. The content of zinc in the bottom mud cracked by ultrasonic cracking in step S2 is 400 mg per 1 kg, and calcium silicate hydrate is added to the bottom mud after ultrasonic cracking according to the ratio of 6 g/g Zn, stirred and mixed evenly, and stabilized for 1 day to inhibit the release of heavy metals. Negative Effects;

S4. Under the condition that the ambient temperature is 25°C, add a compound microbial preparation of Bacillus subtilis agent + cellulase to the bottom sludge after the stabilization treatment in step S3 at a rate of 4.2g/L, Bacillus subtilis The mass ratio of bacterial agent to cellulase is 1:20, the treatment time is 5 days, the stirring operation is carried out to supply oxygen every day, and the stirring frequency is 200 times/day;

S5. After rapidly suction-filtering the biodegraded bottom mud in step S4, a bottom mud mud cake with a moisture content of 16.54% and an organic matter content of 3.52% is prepared;

The above-mentioned bottom mud cake is prepared into an unburned brick according to the method in Example 1;

Fig. 5 is a scanning electron microscope image of unfired bricks prepared from the bottom sludge with excessive zinc content in Example 2 after being treated with hydrated calcium silicate. Using the EDS function of the scanning electron microscope, the percentage of Zn element is analyzed to be 0.17%.

According to the hazardous waste identification standard leaching toxicity identification (GB 5085.3-2007) and sulfuric acid nitric acid leaching method (HJ/T299-2007), the heavy metal stabilization performance of the above unburned bricks was tested, and the results showed that Zn was not detected in the leachate. Elements, indicating that heavy metal elements in the bottom mud of black and odorous water bodies, such as Zn, can be effectively solidified and stabilized in the bottom mud and bricks by hydrated calcium silicate.

Example 3

A method for processing black and odorous water bottom sludge, comprising the following steps:

S1. Remove branches, snails, plastics and other sundries in the bottom mud;

S2. Take the pretreated bottom sludge in step S1, and crack it through 60kHz ultrasonic, and the sludge flow rate is 60L/h;

S3. Under the condition that the ambient temperature is 10°C, add denitrifying bacteria agent + photosynthetic bacteria agent + α-amylase to the bottom mud after ultrasonic cracking in step S2 according to the ratio of 3.0g/L bottom mud The compound microbial preparation, the mass ratio of denitrifying bacteria agent, photosynthetic bacteria agent and α-amylase is 1:2:15, the treatment time is 5 days, the stirring operation is carried out for oxygen supply every day, and the stirring frequency is 150 times/day;

S4. After rapid suction filtration of the biodegraded bottom mud in step S3, a bottom mud cake with a water content of 17.2% and an organic matter content of 3.59% is prepared.

The method of the present invention can effectively reduce the water content and organic matter content of the black and odorous water body sediment in urban rivers, improve the dehydration performance, and significantly inhibit the adverse effects of heavy metals in the sediment. Sludge Treatment Plant Sludge Disposal Mud Quality for Brick Making "(GB/T25031-2010) requires brick mud quality, which is convenient for use as unburned brick base material. The technical scheme of the invention is simple, and the operability is strong, and the effect of reducing the water content and organic matter content of the bottom mud and improving the dehydration performance of the bottom mud is better than that of the traditional chemical coagulation method, saves energy consumption, and has low operating costs.

The above description is only a preferred embodiment of the present invention, and is not intended to limit the present invention. Any modification, equivalent replacement or improvement made within the spirit and principles of the present invention shall be included in the protection of the present invention. within range.

Claims (6)

1. a processing method for preparing unburned bricks of black and odorous water body bottom mud, is characterized in that, the processing method of described black and smelly water body bottom mud comprises the following steps; S1, remove the sundries in the bottom mud; S2. Take the sediment in step S1 and perform ultrasonic cracking. The ultrasonic frequency of ultrasonic cracking is 20-60 kHz, and the flow rate of continuous ultrasonic treatment of sediment is 20-60 L/h; S3, add hydrated calcium silicate to the bottom mud after ultrasonic cracking in step S2, stir and mix evenly; S4. Add a compound microbial preparation to the bottom mud obtained in step S3. The compound microbial preparation includes a live bacterial agent and a biological enzyme, and the mass ratio of the biological enzyme to the live bacterial agent is (4-22):1; The living bacteria adopts at least one of nitrifying bacteria, photosynthetic bacteria, denitrifying bacteria and Bacillus subtilis, and the biological enzyme adopts at least one of neutral protease, papain, α-amylase and cellulase, and stirs it every day undergo biodegradation; S5, taking the biodegraded bottom sludge in step S4, and suction filtering to obtain a treated bottom sludge cake. 2. a kind of processing method that is used to prepare the black smelly water body bottom mud of unburned brick according to claim 1, is characterized in that, the dosage of hydrated calcium silicate in the described step S3 depends on the Heavy metal content, calculated according to 0-15 g/g heavy metal. 3. A kind of processing method for preparing unburned bricks according to claim 1, characterized in that, the dosage of the compound microbial preparation in the step S4 is 2-4.5 g/L Bottom mud. 4. A method for treating black and odorous water bottom sludge for preparing unburned bricks according to claim 1, characterized in that, the biodegradation temperature in the step S4 is 10-30°C. 5. A kind of processing method for preparing unburned bricks according to claim 1, characterized in that, in the biodegradation of the step S4, agitation is used to supply oxygen, and the agitation frequency is 30-200 times/day. 6. A kind of processing method for preparing unburned bricks according to claim 1, characterized in that, the bottom mud cake of the step S5 has a moisture content of 15%-20%, The organic matter content is 0%-4%.