Magnetic sludge and sewage treatment device

Abstract

The utility model relates to the technical field of sludge and sewage treatment, and discloses a magnetic sludge and sewage treatment device which comprises a Fenton reaction tank, a neutralization tank, a solid-liquid separation tank, a biochemical tank, a sludge mixing tank, a sludge dewatering unit and a sludge carbonization unit. According to the utility model, the hydraulic load of the Fenton reaction solid-liquid separation tank is increased, the hydraulic retention time is reduced, and meanwhile, the removal rate of refractory organics in the Fenton tank is increased. The magnetic sludge carbon is added to the tail end of a Fenton neutralization tank, amino groups on the surface of the magnetic sludge carbon can react with residual acid in Fenton reaction, the addition amount of alkali in the neutralization stage is reduced, the specific gravity of particles in the sludge carbon is large, the particles can serve as flocculation crystal nucleuses to accelerate floc precipitation, meanwhile, the sludge carbon has certain adsorbability, and the adsorption capacity of the sludge carbon is improved. Organic matters which are difficult to biodegrade in the sewage can be synchronously adsorbed, so that the volume of the solid-liquid separation tank can be reduced, and the removal rate of organic pollutants which are difficult to biodegrade can be increased.

Description

Technical Field

[0001] The utility model relates to the technical field of sludge and sewage treatment, in particular to a magnetic sludge and sewage treatment device. Background Art

[0002] The conventional Fenton oxidation process generally consists of a Fenton reaction tank, a neutralization tank and a solid-liquid separation tank. Acid is first added to the sewage in the Fenton reaction tank to adjust the pH value to 3-4, and then Fe 2+ and H2O2, the Fenton reaction cell undergoes the following reaction:

[0003] Fe 2+ + H2O2 + H + → Fe 3+ + H2O + ·OH (1)

[0004] R(organic pollutant)+·OH→CO2+H2O(2)

[0005] The following reactions occur in the Fenton neutralization cell:

[0006] Fe 3+ + 3 OH - → Fe(OH)3↓ (3)

[0007] The Fe(OH)3 sludge flocs generated in the Fenton neutralization tank are separated from the water in the solid-liquid separation tank. After the Fenton reaction, the BOD / COD ratio (B / C value for short) of the sewage increases. When the B / C value of the sewage is greater than 0.3, the sewage can be treated by biochemical methods. Organic pollutants are further decomposed by microorganisms in the biochemical tank, reducing the organic matter content in the sewage.

[0008] The surface hydraulic load of the traditional Fenton reaction solid-liquid separation tank is generally designed to be 1-2m 3 / m 2 h. Improving the surface hydraulic load of the Fenton solid-liquid separation tank can reduce the hydraulic retention time and the cost of the tank body, which is of great significance for the implementation of the project. For this purpose, a magnetic sludge sewage treatment device is designed. Utility Model Content

[0009] The utility model aims to solve one of the technical problems in the related art at least to a certain extent. To this end, one purpose of the utility model is to propose a magnetic sludge sewage treatment device to increase the hydraulic load of the Fenton reaction solid-liquid separation tank, reduce the hydraulic retention time, and increase the removal rate of the difficult-to-biodegrade organic matter in the Fenton tank. The magnetic sludge carbon is added to the end of the Fenton neutralization tank. The amino groups on the surface of the magnetic sludge carbon can react with the remaining acid in the Fenton reaction, reducing the amount of alkali added in the neutralization stage. The particles in the sludge carbon have a large specific gravity and can be used as flocculation crystal nuclei to accelerate the precipitation of flocs. At the same time, the sludge carbon has a certain adsorption capacity and can simultaneously adsorb the difficult-to-biodegrade organic matter in the sewage, which can not only reduce the volume of the solid-liquid separation tank, but also improve the removal rate of difficult-to-biodegrade organic pollutants.

[0010] The magnetic sludge sewage treatment device proposed by the utility model comprises a Fenton reaction tank, a neutralization tank, a solid-liquid separation tank, a biochemical tank, a sludge mixing tank, a sludge dehydration unit and a sludge carbonization unit, wherein the Fenton reaction tank, the neutralization tank, the solid-liquid separation tank and the biochemical tank are sequentially connected.

[0011] Preferably, Fenton iron sludge is produced inside the solid-liquid separation tank, and excess sludge is produced inside the biochemical tank.

[0012] Preferably, the Fenton iron sludge and the excess sludge are both collected and stored in the sludge mixing tank.

[0013] Preferably, the sludge treatment system comprises a sludge dewatering unit and a sludge carbonization unit.

[0014] Magnetic sludge sewage treatment method, the method steps are as follows:

[0015] S1-First, the sewage is passed into the Fenton reaction tank, where the sewage undergoes Fenton reaction and generates Fe 3 + ;

[0016] S2-the sewage that has completed the Fenton reaction is passed into the neutralization tank and an alkaline solution is added. At this time, the sewage forms Fe(OH)3 flocs;

[0017] S3-the sewage after neutralization adjustment is passed into the solid-liquid separation tank for preliminary fixed liquid separation to obtain Fenton iron mud and sewage containing a small amount of sludge, and then the sewage containing a small amount of sludge is passed into the biochemical tank for further reaction. After the biochemical tank completes precipitation and discharges water, the residual sludge deposited at the bottom of the biochemical secondary sedimentation tank is obtained. The Fenton iron mud obtained by the preliminary solid-liquid separation and the residual sludge deposited at the bottom of the biochemical tank are put into the sludge mixing tank;

[0018] S4-centrally treat the wet sludge collected in the sludge mixing tank, put the wet sludge into the sludge dehydration unit for dehydration treatment to obtain dehydrated sludge, and then put the dehydrated sludge into the sludge carbonization unit for carbonization treatment. Carbonization is carried out under inert atmosphere conditions, with a preparation temperature of 350-850°C and a heat preservation time of 30-120 minutes to finally obtain magnetic sludge carbon;

[0019] S5- Add part of the magnetic sludge carbon into the neutralization tank to adsorb organic pollutants in the sewage. The magnetic sludge carbon is added to the end of the neutralization tank in a dry powder manner with a dosage of 10-200 mg / L. The excess magnetic sludge carbon can be outsourced for treatment.

[0020] Preferably, the magnetic sludge carbon in S4 is composed of iron, iron oxide, carbon and sand, etc., and the carbon surface contains hydroxyl, carboxyl, carbonyl, amino and other groups. The particle size of the magnetic sludge carbon is 0.01mm-1mm, and the specific surface area is 50-200m 2 / g, average pore size 5-20nm, iodine value 200~800mg / g.

[0021] Sludge carbon is added at the end of the Fenton neutralization tank. The amino groups on the surface of the sludge carbon can react with the acid as follows:

[0022] NH3-Carbon+H + →NH 4+ +charcoal(4)

[0023] Preferably, the inert atmosphere condition in S5 refers to one or more of nitrogen, helium and argon.

[0024] The beneficial effects of the present invention are:

[0025] 1. Adding magnetic sludge carbon powder at the end of the Fenton reaction neutralization tank can provide flocculation nuclei, promote the growth of Fe(OH)3 flocs, accelerate the precipitation of Fe(OH)3 flocs, and increase the surface hydraulic load.

[0026] 2. Magnetic sludge charcoal has adsorption characteristics. While accelerating flocculation and sedimentation, it can also adsorb organic pollutants that are difficult to biodegrade in sewage and improve the removal rate of organic pollutants. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 This is a structural schematic diagram of the magnetic sludge sewage treatment device proposed by the utility model. DETAILED DESCRIPTION

[0028] Example 1, reference Figure 1 The magnetic sludge sewage treatment device includes a Fenton reaction tank, a neutralization tank, a solid-liquid separation tank, a biochemical tank, a sludge mixing tank, a sludge dewatering unit and a sludge carbonization unit. The Fenton reaction tank, the neutralization tank, the solid-liquid separation tank and the biochemical tank are connected in sequence.

[0029] Fenton iron mud is produced inside the solid-liquid separation tank, and excess sludge is produced inside the biochemical tank.

[0030] The Fenton iron sludge and the excess sludge are collected and stored in the sludge mixing tank.

[0031] Preferably, the sludge treatment system comprises a sludge dewatering unit and a sludge carbonization unit, the sludge dewatering unit is treated by means of a sludge dewatering device, and the sludge carbonization unit is treated by means of a sludge carbonization device.

[0032] Magnetic sludge sewage treatment method, the method steps are as follows:

[0033] S1-First, the sewage is passed into the Fenton reaction tank, where the sewage undergoes Fenton reaction and generates Fe 3 + ;

[0034] S2-the sewage that has completed the Fenton reaction is passed into the neutralization tank and an alkaline solution is added. At this time, the sewage forms Fe(OH)3 flocs;

[0035] S3-the sewage after neutralization adjustment is passed into the solid-liquid separation tank for preliminary fixed liquid separation to obtain Fenton iron mud and sewage containing a small amount of sludge, and then the sewage containing a small amount of sludge is passed into the biochemical tank for further reaction. After the biochemical tank completes precipitation and discharges water, the residual sludge precipitated at the bottom of the biochemical secondary sedimentation tank is obtained. The Fenton iron mud obtained by the preliminary solid-liquid separation and the residual sludge precipitated at the bottom of the biochemical secondary sedimentation tank are put into the sludge mixing tank;

[0036] S4-centrally treat the wet sludge collected in the sludge mixing tank, put the wet sludge into the MDT-301 type spiral sludge dehydrator for dehydration, and then put the dehydrated sludge into the YX1400 type sludge carbonization atmosphere furnace for carbonization treatment. The carbonization is carried out under inert atmosphere conditions, the preparation temperature is 500℃, and the insulation time is 60min, and finally the magnetic sludge carbon is obtained;

[0037] S5- Add part of the magnetic sludge carbon into the neutralization tank to adsorb organic pollutants in the sewage. The magnetic sludge carbon is added to the end of the neutralization tank in a dry powder manner with a dosage of 100 mg / L. The excess magnetic sludge carbon can be outsourced for treatment.

[0038] The magnetic sludge carbon in S4 is composed of iron, iron oxide, carbon and sand. The carbon surface contains hydroxyl, carboxyl, carbonyl, amino and other groups. The particle size of magnetic sludge carbon is 0.01mm-1mm, and the specific surface area is 50-200m 2 / g, average pore size 5-20nm, iodine value 200~800mg / g.

[0039] The inert atmosphere condition in S5 refers to one or more of nitrogen, helium, and argon.

[0040] Example 2, the method steps are the same as Example 1, and the different process parameters are: the carbonization temperature for preparing magnetic sludge carbon in S4 is 400°C, the insulation time is 90 minutes, and the dosage of dry powder magnetic sludge carbon added to the neutralization tank in S5 is 150 mg / L.

[0041] Example 3, the method steps are the same as Example 1, and the different process parameters are: the carbonization temperature for preparing magnetic sludge carbon in S4 is 650°C, the insulation time is 45min, and the dosage of dry powder magnetic sludge carbon put into the neutralization tank in S5 is 50mg / L.

[0042] Comparative example: The wastewater from an industrial park has a COD of 1600 mg / L, a BOD of 150 mg / L, ammonia nitrogen of 25 mg / L, and a B / C value of less than 0.1. It is treated by traditional Fenton treatment, with sulfuric acid added to control the pH to 3.5, ferrous sulfate heptahydrate added at a ratio of 10 g / L, a mass ratio of hydrogen peroxide to divalent iron of 5:1, and reacted for 2 hours. NaOH was added during the precipitation stage to adjust the pH to 10, and PAM 2 mg / L was added. The surface hydraulic load of the Fenton reaction solid-liquid separation tank was 1.02 m 3 / (m 2 ·h), after treatment, the effluent COD decreased to 640mg / L, BOD decreased to 200mg / L, and the B / C value increased to 0.3.

[0043] In this case, the wastewater from an industrial park has a COD of 1600 mg / L, a BOD of 150 mg / L, ammonia nitrogen of 25 mg / L, and a B / C value of less than 0.1. A wastewater treatment system that uses magnetic sludge carbon to enhance Fenton flocculation and simultaneous adsorption of pollutants is used. Sulfuric acid is added to control the pH to 3.5, the addition ratio of ferrous sulfate heptahydrate is 10 g / L, the mass ratio of hydrogen peroxide to divalent iron is 5:1, and the reaction lasts for 2 hours. NaOH is added in the precipitation stage to adjust the pH to 10, PAM 2 mg / L is added, and 200 mg / L of magnetic sludge carbon is added at the same time. The surface hydraulic load of the Fenton reaction solid-liquid separation tank is 2 m 3 / (m 2 ·h), after treatment, the effluent COD was reduced to 580mg / L, BOD was reduced to 190mg / L, and the B / C value was increased to 0.33.

Claims

1. Magnetic sludge sewage treatment device, characterized by: The invention comprises a Fenton reaction tank, a neutralization tank, a solid-liquid separation tank, a biochemical tank, a sludge mixing tank and a sludge treatment system, wherein the Fenton reaction tank, the neutralization tank, the solid-liquid separation tank and the biochemical tank are connected in sequence.

2. The magnetic sludge sewage treatment device according to claim 1 is characterized in that: Fenton iron mud is produced inside the solid-liquid separation tank, and excess sludge is produced inside the biochemical tank.

3. The magnetic sludge sewage treatment device according to claim 2 is characterized in that: The Fenton iron sludge and the excess sludge are collected and stored in the sludge mixing tank.

4. The magnetic sludge sewage treatment device according to claim 1 is characterized in that: The Fenton reaction tank, the neutralization tank, the solid-liquid separation tank and the biochemical tank are connected by opening pipelines.

5. The magnetic sludge sewage treatment device according to claim 1 is characterized in that: The sludge treatment system includes a sludge dewatering unit and a sludge carbonization unit; The sludge dewatering treatment unit is used to dewater the sludge in the sludge mixing tank, and the dewatered sludge is sent to the sludge carbonization treatment; The sludge carbonization treatment unit: inert atmosphere conditions, carbonization temperature 350-850°C, insulation time 30-120min, to generate magnetic sludge carbon.

Images