Industrial wastewater biological system sludge treatment system

Abstract

The utility model discloses an industrial wastewater biochemical system sludge treatment system, it belongs to industrial wastewater treatment field, it will fluid power cavitation, thermal effect and alkaliolysis effect system integration, break through the limitation of single technology, realized the high -efficient sludge disintegration under low energy consumption. It mainly includes sludge pump, the sludge pump is connected with the pretreatment unit through valve no.

Description

Technical Field

[0001] This utility model relates to the field of industrial wastewater treatment, and more specifically, to an industrial wastewater biochemical system sludge treatment system. Background Technology

[0002] Current Status of Chemical Sludge Treatment: Chemical sludge is a semi-solid waste generated during chemical production processes, characterized by high organic matter concentration, complex composition, high toxicity, and difficulty in degradation. Current main treatment methods include: Landfilling: Simple and easy to implement, but it occupies land resources, poses a risk of leachate pollution, and with increasingly stringent environmental protection requirements, available landfills are decreasing; Incineration: Achieves volume reduction and energy recovery, but has high investment and operating costs, easily generates toxic gases such as dioxins, and requires strict flue gas treatment; Composting: Applicable to some organic sludge, but the heavy metals and toxic organic matter in chemical sludge limit its agricultural value; Anaerobic Digestion: Can simultaneously achieve sludge stabilization, volume reduction, and energy recovery, and is considered a promising technological route.

[0003] Limitations and Pretreatment Technologies of Anaerobic Digestion: The anaerobic digestion process includes four stages: hydrolysis, acidification, acetic acid production, and methanogenesis. Among these, the hydrolysis stage is the key step limiting overall efficiency. The complex cell wall structure of microorganisms in chemical sludge makes it difficult to release intracellular substances, resulting in slow hydrolysis rates, long digestion cycles, and low methane yields. To improve the efficiency of anaerobic digestion, various pretreatment technologies have been extensively studied: Ultrasonic treatment: utilizes cavitation to destroy cell structure, with high efficiency, but high energy consumption, frequent equipment maintenance, and difficulty in large-scale application; High-pressure homogenization: breaks cells through high-pressure shearing, but equipment wears out quickly and is prone to clogging when treating high-concentration sludge; Microwave treatment: provides uniform heating and can promote the dissolution of organic matter, but has high investment costs and relatively low energy efficiency; Alkaline treatment: destroys cell membranes through saponification and promotes the hydrolysis of organic matter, but consumes a large amount of reagents and requires subsequent neutralization; Acidic treatment: effective for some sludge, but prone to corrosion and requires high-quality equipment; Oxidative treatment: such as ozone and hydrogen peroxide, with strong oxidizing power, but high operating costs and may produce toxic intermediate products; High-temperature treatment (>120℃): can effectively destroy cell structure and improve biodegradability, but has high energy consumption and may produce Maillard reaction products that inhibit digestion; Low-temperature treatment (<100℃): has relatively low energy consumption, but its effect is limited when used alone and often needs to be combined with other methods.

[0004] Advances in Hydraulic Cavitation Technology Research: As an emerging physical treatment technology, hydraulic cavitation has attracted attention in the field of sludge treatment in recent years. Technical Principle: When liquid flows through a contraction zone, the local pressure is lower than the saturated vapor pressure, forming cavitation bubbles. These bubbles collapse as the pressure recovers, releasing strong shock waves, microjets, and high temperature and pressure, generating mechanical, chemical, and thermal effects. Equipment Types: Orifice plate type: Simple structure, but prone to clogging and high energy loss; Venturi type: Good cavitation effect, but high pressure requirements; Rotary disc type: High energy utilization rate, can treat high-concentration sludge, and is a research hotspot in recent years. Limitations: Single hydraulic cavitation has limited effectiveness in treating complex chemical sludge; there is a lack of targeted research based on the characteristics of chemical sludge; there is significant room for optimization in energy consumption and operating costs.

[0005] The development trend of synergistic pretreatment technology: Single pretreatment technology is often difficult to achieve ideal results, while the synergistic application of multiple technologies can produce a "1+1>2" effect: 1. Heat-alkali synergy: Temperature can promote the effect of alkaline reagents and reduce the amount of alkali used; 2. Cavitation-chemical synergy: Free radicals generated by cavitation can enhance the effect of chemical oxidation; 3. Cavitation-heat synergy: Local high temperature generated by cavitation can enhance the effect of heat treatment.

[0006] However, existing collaborative technology research focuses mainly on municipal sludge, with less research on the characteristics of chemical sludge, and has the following problems: harsh treatment conditions (high temperature, high alkali), high energy consumption and cost; lack of consideration for special components such as heavy metals and high salt; low system integration and insufficient resource utilization. Utility Model Content

[0007] The purpose of this invention is to provide an industrial wastewater biochemical sludge treatment system that integrates fluid dynamic cavitation, thermal effect and alkaline hydrolysis, breaking through the limitations of single technology and achieving high-efficiency sludge treatment with low energy consumption.

[0008] This utility model is achieved through the following technical solution: An industrial wastewater biochemical sludge treatment system includes a sludge pump. The sludge pump is connected to a pretreatment unit via valve one. The pretreatment unit is connected to a thermally activated alkali regulating tank via valve two. The thermally activated alkali regulating tank is connected to an alkali tank, a steam source, and a pH analyzer. The discharge port of the thermally activated alkali regulating tank is connected to a bypass valve and valve five. Valve five is connected to the inlet of a cavitation device via a pressure transmitter one. The cavitation device is connected to an oxidation-reduction potentiometer. The discharge port of the cavitation device is connected to a pressure transmitter two. The pressure transmitter two is connected to a valve six. Valve six and the bypass valve are both connected to the inlet of a fermenter. The fermenter is also connected to a methane leak detector.

[0009] Furthermore, the pretreatment unit includes a grid and a regulating tank, the grid and the regulating tank are connected, valve one is connected to the grid, and the regulating tank is connected to valve two.

[0010] Furthermore, the sludge pump is also connected to a pressure gauge, which is connected to a flow transmitter. The flow transmitter is connected to a valve to control the flow rate and pressure of the sludge pumped into the pretreatment unit.

[0011] Furthermore, the alkali tank is connected to a metering pump, which is connected to valve three. Valve three is connected to the alkali inlet of the thermally activated alkali regulating tank to control the amount of alkali added. The steam source is connected to the steam inlet of the thermally activated alkali regulating tank through valve four.

[0012] Furthermore, the thermally activated alkali regulating tank is also equipped with a temperature transmitter and a level transmitter for monitoring temperature and level.

[0013] Furthermore, the drain outlet of the thermally activated alkali regulating tank is connected to a drain valve.

[0014] Furthermore, the cavitation device includes a motor and a cavitator. The output shaft of the motor is connected to the power input shaft of the cavitator. The cavitator is connected to a second temperature transmitter. The inlet of the cavitator is connected to a first pressure transmitter. The outlet of the cavitator is connected to a second pressure transmitter to monitor the pressure and temperature of the cavitator.

[0015] Furthermore, the vent port of the cavitation unit is connected to a vent valve.

[0016] Furthermore, the cavitation device includes an odd number of rotor pins and an even number of stator pins.

[0017] Compared with the prior art, the beneficial effects of this utility model are: 1. By integrating hydrodynamic cavitation, thermal effects and alkaline hydrolysis, a synergistic multiplication mechanism among the three is proposed, which breaks through the limitations of single technologies and achieves stable and optimized operation of complex processes.

[0018] 2. The cavitation device achieves a high-intensity, uniform cavitation field with low energy consumption through a unique pin design and optimized arrangement.

[0019] 3. A complete process chain from pretreatment to resource recycling has been constructed, achieving the triple goals of "reduction, energy recovery, and resource recovery" of chemical sludge.

[0020] 4. A high-efficiency sludge decomposition method with low energy consumption was achieved by using a fluid dynamic cavitation-coordinated temperature-controlled alkaline decomposition technology. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the structural principle of this utility model. Detailed Implementation

[0022] The present invention will now be further described.

[0023] like Figure 1 As shown in the embodiment, an industrial wastewater biochemical system sludge treatment system includes a sludge pump, a sludge tank connected to the sludge pump, the sludge pump connected to a pretreatment unit via valve one, the pretreatment unit connected to a thermally activated alkali regulating tank via valve two, the thermally activated alkali regulating tank connected to an alkali tank, a steam source and a pH analyzer, the discharge port of the thermally activated alkali regulating tank connected to a bypass valve and valve five, valve five connected to the inlet of a cavitation device via a pressure transmitter one, the cavitation device connected to an oxidation-reduction potentiometer, the discharge port of the cavitation device connected to a pressure transmitter two, the pressure transmitter two connected to a valve six, valve six and the bypass valve both connected to the inlet of a fermenter, the fermenter also connected to a methane leak detector.

[0024] Specifically, the fermentation tank can be connected to a solid-liquid separation unit (centrifuge / sedimentation tank) to extract the supernatant. After adding MgO to the supernatant and stirring to settle, the struvite product is obtained. Finally, the residual liquid is recycled or discharged in compliance with standards.

[0025] The pretreatment unit includes a grid and a regulating tank, which are connected together. Valve 1 is connected to the grid, and the regulating tank is connected to Valve 2.

[0026] Specifically, in the raw sludge pretreatment section: the pretreatment unit uses multi-stage gradient screening to remove foreign particles with a diameter greater than 1.0 mm, and then dilutes and adjusts the sludge through a regulating tank to control the sludge solid content within the range of 15-50 grams of dry matter per liter of slurry.

[0027] Thermal activation alkali conditioning section: Add an alkaline regulator to the pretreated sludge to adjust the pH of the system to the range of 8.5-10.5, and stir and mix for 10-30 minutes at a temperature range of 50-70℃.

[0028] Cavitation and crushing section: The prepared material is transported to the cavitation device and circulated cavitation treatment is carried out for 10-60 minutes under the conditions of inlet pressure difference of 2.5-5.5 bar and cavitation number of 2.5-9.5. During the process, the temperature is maintained at 50-70℃ through the heat exchange unit.

[0029] Methanogenic fermentation and energy recovery section: The cavitation-treated slurry is introduced into a constant temperature fermentation tank, where methanogenic fermentation is carried out at the optimal activity range of thermophilic bacteria (34.5-37.5℃) and a near-neutral buffer environment (pH 6.8-7.6). The biogas produced is collected and purified.

[0030] Nutrient crystallization and recovery section: Magnesium source is added to the supernatant after fermentation based on the principle of stoichiometry, according to Mg² +:NH4 + :PO4³ - The molar ratio of (1.0-1.2):1.0:1.0 induces the crystallization of magnesium ammonium phosphate, thereby achieving solid-phase recovery of nitrogen and phosphorus resources.

[0031] The sludge pump is also connected to a pressure gauge, which is connected to a flow transmitter. The flow transmitter is connected to a valve to control the flow rate and pressure of the sludge pumped into the pretreatment unit.

[0032] The alkali tank is connected to a metering pump, which is connected to valve three. Valve three is connected to the alkali inlet of the thermally activated alkali regulating tank to control the amount of alkali added. The steam source is connected to the steam inlet of the thermally activated alkali regulating tank through valve four.

[0033] The thermally activated alkali regulating tank is also equipped with a temperature transmitter and a level transmitter for monitoring temperature and level.

[0034] The drain outlet of the thermally activated alkali regulating tank is connected to a drain valve.

[0035] The cavitation device includes a motor and a cavitator. The output shaft of the motor is connected to the power input shaft of the cavitator. The cavitator is connected to a second temperature transmitter. The inlet of the cavitator is connected to a first pressure transmitter. The outlet of the cavitator is connected to a second pressure transmitter to monitor the pressure and temperature of the cavitator.

[0036] The motor uses variable frequency drive, automatically adjusting its speed according to sludge concentration and flow rate. Pumps utilize high-efficiency permanent magnet motors with an overall electrical efficiency >94%.

[0037] The vent port of the cavitation unit is connected to a vent valve.

[0038] The cavitation device includes an odd number of rotor pins and an even number of stator pins.

[0039] Specifically, to avoid periodic pressure fluctuations caused by the parallel passage of the pins, a logarithmic spiral arrangement of the pins is used to make the pressure pulsations in the flow field more uniform, avoiding energy waste caused by excessive local cavitation; the pin cross-section is streamlined, and the tip is chamfered with an ellipse, which reduces the overall pressure loss while generating sufficient flow resistance. Through the above unique pin design and arrangement optimization, the cavitation device achieves a high-intensity, uniform cavitation field with low energy consumption.

[0040] The cavitation device consists of a stator, a rotor, and a housing. The cavitation intensity is adjusted based on dissolved oxygen and redox potential: the ORP value is monitored online, and the rotor speed and system back pressure are dynamically adjusted to keep the system in the optimal cavitation state.

[0041] 1) Treatment of oily sludge from petrochemical plants: Characteristics of raw material sludge: It is oily sludge taken from the wastewater treatment section of a refining and chemical enterprise. The solid content of the material is about 28-32 g / L (typical test value is 29.2 g / L), the volatile component accounts for 68-72%, the total organic load is equivalent to COD 24000-26500 mg / L, the initial soluble COD is 280-340 mg / L, the system is weakly acidic, and the pH is about 6.7-6.9.

[0042] Processing flow and parameters: 1. Pretreatment stage: The sludge is first screened to remove fibers and hard particles, and then water is added to the equalization tank to adjust the solid content to 30 g / L.

[0043] 2. Hot alkaline conditioning stage: Add sodium hydroxide solution to raise the pH of the system to 9.8-10.2, transfer to a heated stirring tank, and stir continuously for 20 minutes at 60±2℃.

[0044] 3. Cavitation and Crushing Stage: The conditioned material is conveyed to the cavitation unit (rotor diameter 250mm, pin diameter 10mm, pin length 25mm, speed 3000 rpm, inlet pressure difference 4.0±0.3bar) by a screw pump and circulated for 30 minutes. During the process, the temperature is maintained at 60±3℃ by a plate heat exchanger.

[0045] 4. Fermentation and methanogenesis stage: The treated sludge is mixed with anaerobic granular sludge at a volume ratio of 1:1 and placed in a constant temperature fermenter at 35±1℃. The pH is stabilized at 7.2-7.5 by automatically adding sodium bicarbonate. The fermentation cycle is 15 days.

[0046] 5. Nutrient Recovery Stage: The fermentation supernatant is transferred to the crystallization reactor. Based on the concentrations of ammonium nitrogen and phosphate in the liquid phase (approximately 210 mg / L and 45 mg / L, respectively), nutrient recovery is carried out according to Mg²⁺. + :NH4 + :PO4³ - = 1.1:1.0:1.0 Add magnesium oxide powder, stir and react for 40 minutes, then let it stand to precipitate.

[0047] Processing effect: 1. Organic matter release: Soluble COD increased to 1350-1480 mg / L, an increase of about 4.2-4.8 times; cell rupture efficiency (CPE) was measured at 36-40%.

[0048] 2. Fermentation performance: The methane conversion per unit COD reached 180-190 ml / g, which is an increase of about 130-140% compared with the 75-82 ml / g of the untreated control group.

[0049] 3. Changes in particulate matter: The average particle size of sludge flocs decreased from the initial 95-105 micrometers to 12-18 micrometers, while the specific surface area increased by 280-320%.

[0050] 4. Nutrient recovery: Phosphate removal rate 89-92%, ammonium nitrogen removal rate 86-90%, and the purity of the obtained magnesium ammonium phosphate crystal product is 91-93%.

[0051] 5. Energy efficiency: The specific energy consumption of the system is controlled within the range of 3500-3800 kJ / kg dry matter, which is about 40-45% lower than that of the traditional hot alkaline method.

[0052] Technical Mechanism Analysis: The periodic pressure pulsations generated by the rotor pins induce the formation and collapse of micron-sized cavitation. The microjet generated during collapse (with velocities reaching 100-300 m / s) directly impacts the sludge flocs and microbial cell surfaces, causing physical tearing. Simultaneously, localized high temperatures (theoretically calculated to reach 2000-5000 K) promote the saponification reaction of cell membrane lipids under alkaline conditions. Both factors synergistically accelerate the dissolution of intracellular organic matter. During cavitation, the homolytic cleavage of water molecules generates hydroxyl radicals (•OH), which further oxidize some recalcitrant organic matter, improving subsequent bioavailability.

[0053] 2) Treatment of heavy metal-containing sludge from the electroplating industry: Characteristics of raw material sludge: Comprehensive sludge from a certain electroplating industrial park, with a solid content of 33-37 g / L, a volatile component ratio of 62-65%, a total COD of 18000-19500 mg / L, and containing characteristic heavy metals: copper 380-450 mg / kg, lead 170-200 mg / kg, and zinc 2750-2950 mg / kg.

[0054] Processing flow and parameters: 1. Alkali selection: Calcium hydroxide is used as an alkaline regulator to simultaneously fix some heavy metals by utilizing its precipitation effect, and the pH is adjusted to be controlled at 9.2-9.8.

[0055] 2. Temperature optimization: The conditioning temperature is set at 55±2℃ to avoid excessively high temperatures causing changes in the form of heavy metals.

[0056] 3. Cavitation parameter adjustment: A rotor design with a smaller needle diameter (8 mm) is adopted, the rotation speed is 2800 rpm, the inlet pressure difference is 3.0±0.2 bar, and the processing time is extended to 40 minutes to enhance mass transfer.

[0057] 4. Fermentation process monitoring: Focus on the potential inhibition of microorganisms by heavy metals, and assess the health of fermentation by monitoring coenzyme F420 activity and specific metabolites.

[0058] Processing effect: 1. Organic matter release: Soluble COD increases to 920-1040 mg / L, and cell rupture efficiency is 28-31%.

[0059] 2. Heavy metal behavior: Changes in total heavy metal content in the solid phase of treated sludge: copper decreased by 20-24%, lead by 65-70%, and zinc by 25-29%. The significant reduction in lead may be related to the cavitation-induced reduction and adsorption mechanism on the surface of iron oxides.

[0060] 3. Fermentation output: The methane conversion rate was 148-156 mL / g COD, which is 90-100% higher than the control.

[0061] 4. Safety of crystallized products: The leaching concentration of heavy metals in the recovered magnesium ammonium phosphate is lower than the limit of the "Identification Standard for Hazardous Waste".

[0062] Technical adaptability description: By adjusting the type of alkali agent and the cavitation intensity, it can effectively treat chemical sludge containing heavy metals, and achieve partial fixation and separation of heavy metals while promoting the degradation of organic matter.

[0063] 3) Treatment of high-salinity sludge from pesticide production: Characteristics of raw material sludge: Sludge from the biochemical treatment of a pesticide factory, with a solid content of 38-42 g / L, a chloride ion concentration of 11000-13000 mg / L, a total COD of 21500-23000 mg / L, and containing characteristic organic pollutants (pesticide intermediates).

[0064] Processing flow and parameters: 1. Pretreatment dilution: Dilute the raw mud to a solid content of 25 g / L to reduce the direct impact of osmotic pressure on microorganisms.

[0065] 2. Conditioning with KOH: Utilize the antagonistic effect of potassium ions on sodium ions to adjust the pH to 10.3-10.7, and maintain the temperature at 65±2℃.

[0066] 3. Enhanced cavitation mixing: High cavitation conditions (3200 rpm) and pressure (5.0 ± 0.3 bar) are used to promote sludge homogenization and pollutant mass transfer.

[0067] 4. Adaptation and domestication of fermentation microorganisms: The inoculated sludge is domesticated by gradually increasing the salinity, and a high carbon-to-nitrogen ratio is maintained during the fermentation process.

[0068] Processing effect: 1. Organic matter dissolution and transformation: Soluble COD increased significantly to 1750-1950 mg / L, an increase of about 6.5-7.5 times; methane conversion reached 162-172 mL / g COD, an increase of about 100-110%.

[0069] 2. Mitigation of salinity impact: Cavitation and hot alkaline pretreatment alter the colloidal properties of the sludge, releasing some of the salt encapsulated in extracellular polymers and separating it with the supernatant, thus reducing the salt load entering the fermentation unit.

[0070] 3. Degradation of characteristic pollutants: Gas chromatography-mass spectrometry analysis showed that the concentrations of two typical pesticide intermediates decreased by 50-60% after cavitation treatment, presumably due to oxidation by hydroxyl radicals.

[0071] 4. System stability: No obvious microbial inhibition was observed throughout the entire treatment cycle, and the fermentation gas composition remained stable (methane content 58-62%).

Claims

1. An industrial wastewater biochemical system sludge treatment system, comprising a sludge pump, characterized in that: The sludge pump is connected to the pretreatment unit via valve one. The pretreatment unit is connected to the thermally activated alkali regulating tank via valve two. The thermally activated alkali regulating tank is connected to the alkali tank, steam source, and pH analyzer. The discharge port of the thermally activated alkali regulating tank is connected to the bypass valve and valve five. Valve five is connected to the inlet of the cavitation device via pressure transmitter one. The cavitation device is connected to an oxidation-reduction potentiometer. The discharge port of the cavitation device is connected to pressure transmitter two. Pressure transmitter two is connected to valve six. Valve six and the bypass valve are both connected to the inlet of the fermenter. The fermenter is also connected to a methane leak detector.

2. The industrial wastewater biochemical system sludge treatment system according to claim 1, characterized in that: The pretreatment unit includes a grid and a regulating tank, which are connected together. Valve 1 is connected to the grid, and the regulating tank is connected to Valve 2.

3. The industrial wastewater biochemical system sludge treatment system according to claim 1, characterized in that: The sludge pump is also connected to a pressure gauge, which is connected to a flow transmitter, and the flow transmitter is connected to a valve.

4. The industrial wastewater biochemical system sludge treatment system according to claim 1, characterized in that: The alkali tank is connected to a metering pump, which is connected to valve three, which is connected to the alkali inlet of the thermally activated alkali regulating tank; the steam source is connected to the steam inlet of the thermally activated alkali regulating tank through valve four.

5. The industrial wastewater biochemical system sludge treatment system according to claim 1, characterized in that: The aforementioned thermally activated alkali regulating tank is also equipped with a temperature transmitter and a level transmitter.

6. The industrial wastewater biochemical system sludge treatment system according to claim 1, characterized in that: The drain outlet of the thermally activated alkali regulating tank is connected to a drain valve.

7. The industrial wastewater biochemical system sludge treatment system according to claim 1, characterized in that: The cavitation device includes a motor and a cavitator. The output shaft of the motor is connected to the power input shaft of the cavitator. The cavitator is connected to a second temperature transmitter. The inlet of the cavitator is connected to a first pressure transmitter. The outlet of the cavitator is connected to a second pressure transmitter.

8. The industrial wastewater biochemical system sludge treatment system according to claim 7, characterized in that: The vent port of the cavitation unit is connected to a vent valve.

9. The industrial wastewater biochemical system sludge treatment system according to claim 7, characterized in that: The cavitation device includes an odd number of rotor pins and an even number of stator pins.

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