Selenium-containing wastewater treatment system
By adopting a stirring reaction unit, an oxidation-reduction potential detection and control system, and a magnetic recovery system in the selenium-containing wastewater treatment system, deep reduction and resource recovery of selenium are achieved, solving the problems of large equipment footprint and low resource utilization in the existing technology, and improving the water output efficiency and the recycling of the reducing agent.
Patent Information
- Application Number
- CN202422629657.6
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-10-29
- Publication Date
- 2025-10-28
- Estimated Expiration
- 2034-10-29
AI Technical Summary
In the existing technology for treating selenium-containing wastewater, the biological process is complex and cumbersome to operate, the chemical method equipment occupies a large area and has low resource utilization rate, the single-stage chemical method is inefficient, and the multi-stage chemical method is time-consuming.
A processing system including a stirring reaction unit, an oxidation-reduction potential detection and control system, and a magnetic recovery system is used to achieve deep reduction of selenium and resource recovery through two-stage selenium reduction reaction and magnetic recovery of iron powder.
Simplify the number of equipment, reduce equipment footprint and construction costs, achieve deep reduction of selenium and resource recovery, improve water output efficiency, reduce waste residue volume, achieve ultra-low emissions of selenium resources and recycling of reducing agents.
Smart Images
Figure CN223480959U_ABST
Abstract
Description
Technical Field
[0001] This utility model belongs to the field of water treatment technology, and in particular relates to a selenium-containing wastewater treatment system. Background Art
[0002] Selenium pollution is widely found in industrial wastewater from metallurgy, electronics, and photovoltaic industries, with primary valence states of -2, +4, and +6. In environmental water bodies, it exists as selenate (SeO4). 2- ) and selenite (SeO3) 2- High concentrations of selenate and selenite wastewater are highly toxic to organisms. Selenate and selenite can be reduced to elemental selenium by adding a certain amount of reducing agent. Due to the insolubility of elemental selenium in water, selenium pollution can be separated and recovered from the aquatic environment through solid-liquid separation.
[0003] Selenium pollution is commonly removed using chemical and biological methods. Biological methods primarily employ MBR reactors and rising anaerobic sludge fluidized bed reactors. However, this process requires precise control of various conditions, including hydraulic retention time, temperature, dissolved oxygen concentration, and pH, resulting in a complex and cumbersome operation. Chemical methods mainly utilize flocculation and sulfidation. Single-stage chemical methods have low selenium removal efficiency, while multi-stage methods are time-consuming, require multiple reactors, have large footprints, and suffer from low resource utilization rates. Utility Model Content
[0004] In view of this, the purpose of this utility model is to provide a selenium-containing wastewater treatment system that can fully remove selenium ions from selenium-containing wastewater and recover iron powder, thereby reducing the amount of waste residue.
[0005] This utility model provides a selenium-containing wastewater treatment system, including a stirring reaction unit, an oxidation-reduction potential detection and control system, and a magnetic recovery system. The stirring reaction unit is equipped with a stirring reaction vessel.
[0006] The stirred reactor performs a two-stage selenium reduction reaction; the magnetic recovery system is used to recover iron powder.
[0007] A secondary booster pump is connected to the stirred reactor;
[0008] A multi-media filter connected to the secondary booster pump.
[0009] In some embodiments of this utility model, a selenium-containing wastewater inlet is provided above the stirred reactor;
[0010] The stirred reactor is equipped with a selenium-containing wastewater outlet at the bottom.
[0011] In some embodiments of this utility model, the stirred reactor includes a primary stirred reactor and a secondary stirred reactor; the secondary stirred reactor is connected to a secondary booster pump;
[0012] The first-stage stirred reactor carries out the first-stage selenium reduction reaction;
[0013] The secondary stirred reactor carries out the second-stage selenium reduction reaction.
[0014] In some embodiments of this invention, a primary booster pump is provided between the primary stirred reactor and the secondary stirred reactor.
[0015] In some embodiments of this utility model, the primary stirred reactor is provided with a primary reducing agent inlet;
[0016] The secondary stirred reactor is equipped with a secondary reducing agent iron powder inlet.
[0017] In some embodiments of this utility model, the oxidation-reduction potential detection and control system includes an online ORP detector, an ORP oxidation-reduction electrode, and a support.
[0018] The ORP redox electrode is in contact with the surface of the reaction liquid in a stirred reactor.
[0019] In some embodiments of this invention, the magnetic recovery system is installed in a stirred reactor.
[0020] In some embodiments of this invention, the magnetic recovery system is installed in a two-stage stirred reactor.
[0021] In some embodiments of this utility model, the redox potential detection and control system includes an online ORP detector, an ORP redox electrode, and a support.
[0022] The ORP redox electrode is in contact with the reaction liquid surface in a two-stage stirred reactor.
[0023] This utility model provides a selenium-containing wastewater treatment system, comprising a stirring reaction unit, an oxidation-reduction potential detection and control system, and a magnetic recovery system. The stirring reaction unit is equipped with a stirred reactor; the stirred reactor performs a two-stage selenium reduction reaction; the magnetic recovery system is used to recover iron powder; a secondary booster pump is connected to the stirred reactor; and a multi-media filter is connected to the secondary booster pump. The treatment system provided by this utility model simplifies the required number of equipment, optimizes the utilization rate of reaction equipment, reduces equipment footprint, and lowers equipment construction costs; it can deeply reduce selenium, achieving selenium resource recovery and ultra-low wastewater discharge; the oxidation-reduction potential detection and control system has simple indicators, provides accurate and timely indication of the reaction endpoint, reduces pre-effect operation steps, and improves effluent efficiency; the magnetic recovery system can recover the iron powder reducing agent from the wastewater, enabling the reducing agent to be recycled. Attached Figure Description
[0024] Figure 1 A schematic diagram of the composition of the selenium-containing wastewater treatment system provided by this utility model. DETAILED DESCRIPTION
[0025] This utility model provides a selenium-containing wastewater treatment system, including a stirring reaction unit, an oxidation-reduction potential detection and control system, and a magnetic attraction recovery system; the stirring reaction unit is equipped with a stirring reaction vessel;
[0026] The stirred reactor performs a two-stage selenium reduction reaction; the magnetic recovery system is used to recover iron powder.
[0027] A secondary booster pump is connected to the stirred reactor;
[0028] A multi-media filter connected to the secondary booster pump.
[0029] The processing system provided by this utility model simplifies the required number of equipment, optimizes the utilization rate of reaction equipment, reduces equipment footprint, and lowers equipment construction costs; it can deeply reduce selenium, realize selenium resource recovery and ultra-low wastewater discharge; the oxidation-reduction potential detection and control system has simple indicators, accurate and timely indication of reaction endpoint, reduces pre-effect operation steps, and improves effluent efficiency; the magnetic attraction recovery system can recover iron powder reducing agent from wastewater, enabling the reducing agent to be recycled.
[0030] The selenium-containing wastewater treatment system provided by this utility model includes a stirring reaction unit, an oxidation-reduction potential detection and control system, and a magnetic attraction recovery system; the stirring reaction unit is equipped with a stirring reaction vessel.
[0031] The stirred reactor of this invention has a selenium-containing wastewater inlet at the top and a selenium-containing wastewater outlet at the bottom. The stirred reactor of this invention performs a two-stage selenium reduction reaction.
[0032] In some embodiments of this utility model, the stirred reactor can be a single reactor in which both stages of selenium reduction reactions are carried out; alternatively, two stages of stirred reactors can be provided.
[0033] In some embodiments of this invention, the stirred reactor may further include a primary stirred reactor and a secondary stirred reactor; the secondary stirred reactor is connected to a secondary booster pump; the primary stirred reactor performs a first-stage selenium reduction reaction; and the secondary stirred reactor performs a second-stage selenium reduction reaction. In specific embodiments of this invention, the primary and secondary stirred reactors may share the same reactor; alternatively, they may be two separate stirred reactors. A primary booster pump is provided between the primary and secondary stirred reactors. Specifically, a primary reduction outlet for selenium-containing wastewater is located below the primary stirred reactor, and a primary reduction inlet for selenium-containing wastewater is located above the secondary stirred reactor. The primary reduction outlet for selenium-containing wastewater is connected to the primary booster pump via a pipe, and the primary booster pump is connected to the primary reduction inlet for selenium-containing wastewater above the secondary stirred reactor. After the secondary reduction in the secondary stirred reactor, secondary reduction effluent of selenium-containing wastewater is obtained and discharged from the secondary reduction outlet of the secondary stirred reactor to the secondary booster pump.
[0034] The primary stirred reactor of this invention is equipped with a primary reducing agent inlet; the primary reducing agent is selected from one or more of sodium sulfite, thiourea, and ferric chloride; the primary reducing agent efficiently reduces hexavalent selenium in selenium-containing wastewater to tetravalent selenium. The system provided by this invention can treat high-concentration selenium-containing wastewater; the selenium ion content in the wastewater is 1–10 g / L. The selenium-containing wastewater occupies 65–75% of the volume of the stirred reactor. In this invention, the selenium concentration of the wastewater is measured, and a certain amount of primary reducing agent is added according to the selenium concentration; the reaction is carried out under stirring conditions for 20–40 minutes.
[0035] The two-stage stirred reactor of this invention is equipped with a secondary reducing agent iron powder inlet; the secondary reducing agent further reduces tetravalent selenium to elemental selenium. The secondary reduction reaction is carried out under stirring conditions for 1 to 1.5 hours.
[0036] The oxidation-reduction potential (ORP) detection and control system in the selenium-containing wastewater treatment system provided by this invention, also known as the ORP indication and control system, can realize automatic control of the endpoint of multi-stage reduction reactions, improve the automation level of selenium-containing wastewater treatment, reduce labor and management costs, and facilitate standardized and regulated management. The ORP detection and control system of this invention includes an online ORP detector, an ORP oxidation-reduction electrode, and a support. The ORP electrode is placed inside the stirred reactor and in contact with the reaction liquid surface to detect the potential at the endpoint of the reduction reaction. When the endpoint potential is detected, the reaction is stopped. The online ORP detector is located outside the stirred reactor and reads the oxidation-reduction potential. The endpoint potential of the second-stage reduction is preferably 220–265 mV; in a specific embodiment, the endpoint potential of the second-stage reduction is 250 mV.
[0037] If the reactor is divided into a primary stirred reactor and a secondary stirred reactor, the ORP (oxidation-reduction) electrode included in the oxidation-reduction potential detection and control system is installed in the secondary stirred reactor and is in contact with the surface of the reaction liquid.
[0038] The magnetic recovery system described in this invention is installed in a stirred reactor; if the stirred reactor is divided into two independent reactors, the magnetic recovery system is placed in the secondary stirred reactor. In this invention, the magnetic recovery system is activated after the secondary reduction reaction reaches its endpoint potential; the magnetic recovery system can recover iron powder, reduce waste residue, and maximize the utilization of iron powder resources; it also has significant effects on saving reagent costs, testing costs, and wastewater treatment management costs.
[0039] The selenium-containing wastewater treatment system provided by this utility model includes a two-stage booster pump connected to the stirred reactor; the reaction liquid produced after the two-stage reduction reaction is completed in the stirred reactor is finally pumped to the multi-media filter by the booster pump.
[0040] The selenium-containing wastewater treatment system provided by this utility model includes a multi-media filter. The multi-media filter performs solid-liquid separation on the wastewater after magnetic adsorption recovery.
[0041] Figure 1 This is a schematic diagram of the composition of the selenium-containing wastewater treatment system provided by this utility model; specifically, it includes: transporting selenium-containing wastewater to the primary stirred reactor in the stirred reaction unit, after the primary selenium reduction reaction, pumping it to the secondary stirred reactor by the primary booster pump for the secondary selenium reduction reaction, stopping the reaction when the redox potential detection and control system detects the endpoint potential; activating the magnetic recovery system to recover residual iron powder in the wastewater through magnetism; and transporting the wastewater to the multi-media filter by the secondary booster pump for solid-liquid separation to obtain selenium-removed wastewater.
[0042] To further illustrate this utility model, the following detailed description of a selenium-containing wastewater treatment system provided by this utility model is provided in conjunction with embodiments, but these descriptions should not be construed as limiting the scope of protection of this utility model.
[0043] Example 1
[0044] Selenium-containing wastewater is pumped into a primary stirred tank at a volume of 60%–70% of the tank's capacity. The selenium concentration in the wastewater is measured to be Se = 0.32 g / L. Based on this concentration, a certain amount of sodium sulfite, a primary reducing agent, is added. The mixture is stirred for 30–40 minutes to reduce hexavalent selenium in the wastewater to tetravalent selenium. In this embodiment, the primary and secondary stirred tanks share the same reactor. Iron powder, a secondary reducing agent, is added to the primary stirred tank, and the mixture is stirred for 1–1.5 hours to further remove tetravalent selenium.
[0045] A redox potential detection system installed in the two-stage continuous stirred tank stops the reaction when the endpoint potential reaches approximately 225mV. A magnetic recovery system is then activated to recover residual iron powder from the wastewater using magnetism. The wastewater is then pumped to a multi-media filter for solid-liquid separation to obtain selenium-removed wastewater. ICP analysis shows that the selenium concentration in the treated wastewater is ≤0.2mg / L, with a selenium removal rate of 99.9%, achieving ultra-low discharge of selenium-treated wastewater.
[0046] Example 2
[0047] Selenium-containing wastewater is first pumped into a primary continuous stirred tank at a flow rate of 65%–75% of the tank's volume. The selenium concentration in the wastewater is measured to be Se = 1.14 g / L. Based on this concentration, a certain amount of sodium sulfite, a primary reducing agent, is added, and the mixture is stirred for 20–40 minutes to reduce hexavalent selenium in the wastewater to tetravalent selenium. Then, iron powder, a secondary reducing agent, is added to a secondary continuous stirred tank, and the mixture is stirred for 1–1.5 hours to further remove tetravalent selenium.
[0048] A redox potential detection system installed in the two-stage continuous stirred tank stops the reaction when the endpoint potential reaches approximately 250mV. A magnetic recovery system is then activated to recover residual iron powder from the wastewater using magnetism. The wastewater is then pumped to a multi-media filter for solid-liquid separation to obtain selenium-removed wastewater. ICP analysis shows that the selenium concentration in the treated wastewater is ≤0.2mg / L, with a selenium removal rate of 99.9%, achieving ultra-low discharge of selenium-treated wastewater.
[0049] As can be seen from the above embodiments, the selenium-containing wastewater treatment system provided by this utility model includes a stirring reaction unit, an oxidation-reduction potential detection and control system, and a magnetic recovery system. The stirring reaction unit is equipped with a stirring reaction vessel. The stirring reaction vessel performs a two-stage selenium reduction reaction. The magnetic recovery system is used to recover iron powder. A secondary booster pump is connected to the stirring reaction vessel. A multi-media filter is connected to the secondary booster pump. The treatment system provided by this utility model simplifies the required number of equipment, optimizes the utilization rate of reaction equipment, reduces equipment footprint, and lowers equipment construction costs. It can deeply reduce selenium, reducing selenium from selenate and selenite to elemental selenium, realizing selenium resource recovery and ultra-low wastewater discharge. The oxidation-reduction potential detection and control system has simple indicators, accurate and timely reaction endpoint indication, reduces pre-effect operation steps, and improves effluent efficiency. The magnetic recovery system can recover iron powder reducing agent from the wastewater, enabling the reducing agent to be recycled. Experimental results show that the selenium concentration in the treated wastewater is ≤0.2mg / L, the selenium removal rate is 99.9%, and ultra-low discharge of selenium wastewater is achieved.
[0050] The above description is only a preferred embodiment of the present utility model. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present utility model, and these improvements and modifications should also be considered within the protection scope of the present utility model.
Claims
1. A selenium-containing wastewater treatment system, characterized in that, It includes a stirring reaction unit, a redox potential detection and control system, and a magnetic recovery system; the stirring reaction unit is equipped with a stirred reaction vessel; The stirred reactor performs a two-stage selenium reduction reaction; the magnetic recovery system is used to recover iron powder. A secondary booster pump is connected to the stirred reactor; A multi-media filter connected to the secondary booster pump.
2. The selenium-containing wastewater treatment system according to claim 1, characterized in that, The stirred reactor is equipped with a selenium-containing wastewater inlet at the top; The stirred reactor is equipped with a selenium-containing wastewater outlet at the bottom.
3. The selenium-containing wastewater treatment system according to claim 1, characterized in that, The stirred reactor includes a primary stirred reactor and a secondary stirred reactor; the secondary stirred reactor is connected to a booster pump. The first-stage stirred reactor carries out the first-stage selenium reduction reaction; The secondary stirred reactor carries out the second-stage selenium reduction reaction.
4. The selenium-containing wastewater treatment system according to claim 3, characterized in that, A primary booster pump is installed between the primary stirred reactor and the secondary stirred reactor.
5. The selenium-containing wastewater treatment system according to claim 3, characterized in that, The primary stirred reactor is equipped with a primary reducing agent inlet; The secondary stirred reactor is equipped with a secondary reducing agent iron powder inlet.
6. The selenium-containing wastewater treatment system according to claim 1, characterized in that, The oxidation-reduction potential detection and control system includes an online ORP detector, an ORP oxidation-reduction electrode, and a support. The ORP redox electrode is in contact with the surface of the reaction liquid in a stirred reactor.
7. The selenium-containing wastewater treatment system according to claim 1, characterized in that, The magnetic recovery system is installed in the stirred reactor.
8. The selenium-containing wastewater treatment system according to claim 3, characterized in that, The magnetic recovery system is installed in a two-stage stirred reactor.
9. The selenium-containing wastewater treatment system according to claim 3, characterized in that, The redox potential detection and control system includes an online ORP detector, an ORP redox electrode, and a support. The ORP redox electrode is in contact with the reaction liquid surface in a two-stage stirred reactor.