A silica-containing wastewater recycling system
By combining multi-stage sedimentation and CTUF desiliconization tank with an RO system to treat wastewater, the problem of removing high-concentration silica wastewater in existing technologies has been solved, achieving efficient wastewater reuse and a long RO membrane lifespan.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- NANJING SHENGXIN SEMICON MATERIAL CO LTD
- Filing Date
- 2025-08-19
- Publication Date
- 2026-07-24
AI Technical Summary
In existing technologies, coagulation/flocculation methods are insufficient to effectively remove high concentrations of dissolved silicon from silica-containing wastewater generated during semiconductor chip manufacturing, resulting in poor wastewater treatment performance.
Wastewater is treated using a multi-stage sedimentation, CTUF desiliconization tank, and RO system, including a high-density sedimentation tank, an ammonia oxidation stabilization tank, an activated carbon filter, spiral wound ultrafiltration membranes, and various types of RO membranes. The multi-stage sedimentation and filtration process removes silicon from the wastewater and prevents colloidal particles from clogging the RO membranes.
It effectively removes high concentrations of silicon from wastewater, extends the service life of the RO membrane, and improves the wastewater reuse efficiency.
Smart Images
Figure CN224548237U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of wastewater treatment technology, and in particular to a system for reusing silica-containing wastewater. Background Technology
[0002] Semiconductor chip manufacturing processes generate large amounts of wastewater containing high concentrations of silica. The main pollutants in this wastewater include TDS (Total Dissolved Solids), calcium and magnesium ions, and silicon. Currently, a commonly used method for silica removal is coagulation / flocculation. This method involves adding coagulants (such as PAC and PFS) and flocculants (such as PAM) to destabilize and aggregate colloidal silica (such as silica sol), which then settles or is separated by flotation. However, this method has limited effectiveness in dissolving silica (such as monosilicic acid) and is not very effective for high-concentration silica-containing wastewater. Utility Model Content
[0003] Purpose of the invention: To address the above-mentioned shortcomings, this utility model provides a silica-containing wastewater reuse system, which can effectively improve the removal efficiency of silicon in wastewater and realize wastewater reuse.
[0004] Technical Solution: To solve the above problems, this utility model adopts a silica-containing wastewater reuse system, comprising a first sedimentation tank, a primary CTUF desiliconization tank, a primary RO water treatment system, a secondary RO water treatment system, a second sedimentation tank, a secondary CTUF desiliconization tank, a tertiary RO water treatment system, and an MVR system connected in sequence; the primary RO water treatment system is equipped with a brackish water membrane, the secondary RO water treatment system is equipped with a seawater desalination membrane, and the tertiary RO water treatment system is equipped with a STRO membrane; both the primary and secondary CTUF desiliconization tanks are equipped with spiral wound ultrafiltration membranes; the MVR system is used to evaporate and concentrate the concentrated water discharged from the tertiary RO water treatment system; the primary, secondary, and tertiary RO water treatment systems and the MVR system are also connected to a reuse water tank.
[0005] Furthermore, an ammonia oxidation stabilization tank is provided between the high-density sedimentation tank and the primary CTUF desiliconization tank, which is used to remove ammonia nitrogen from the water.
[0006] Furthermore, an activated carbon filter is installed between the primary CTUF desiliconization tank and the primary RO water treatment system.
[0007] Furthermore, it also includes a sludge tank, and the first sedimentation tank and the second sedimentation tank are connected to the sludge tank.
[0008] Furthermore, the first sedimentation tank is a high-density sedimentation tank.
[0009] Furthermore, the second sedimentation tank is an inclined tube sedimentation tank.
[0010] Furthermore, the first sedimentation tank is connected to the first feeding tank, and the second sedimentation tank is connected to the first feeding tank.
[0011] Beneficial effects: Compared with the prior art, the significant advantage of this utility model is that it treats wastewater through multi-stage sedimentation, CTUF desiliconization tank and RO system, effectively removing high concentrations of silicon in wastewater and realizing wastewater reuse; two-stage CTUF desiliconization tanks are set before the RO water treatment system to remove colloidal particles in the water, avoid clogging of RO membrane in subsequent treatment, and extend the service life and efficiency of RO membrane. Attached Figure Description
[0012] Figure 1 This is a schematic diagram of the overall structure of the silica-containing wastewater reuse system of this utility model. Detailed Implementation
[0013] like Figure 1 As shown, a silica-containing wastewater reuse system in this embodiment includes, in sequence, an equalization tank, a high-density sedimentation tank, an ammonia oxidation stabilization tank, a primary CTUF silica removal tank, an activated carbon filter tank, a primary RO water treatment system, a secondary RO water treatment system, an inclined tube sedimentation tank, a secondary CTUF silica removal tank, a tertiary RO water treatment system, and an MVR system.
[0014] The equalization tank is used for wastewater collection, from which wastewater enters the high-density sedimentation tank. The high-density sedimentation tank is connected to the first feeding tank, where magnesium is added. The magnesium reacts with silicon in the wastewater in the sedimentation tank to form magnesium silicate, which then undergoes sludge-water separation in the high-density sedimentation tank. The treated supernatant enters the ammonia oxidation stabilization tank, and the separated precipitate enters the sludge tank. Sodium hypochlorite is added to the ammonia oxidation stabilization tank to remove ammonia nitrogen from the wastewater. The reaction process is as follows: 3ClO - +2NH4 + =N2+3Cl - +2H + +3H2O.
[0015] The primary CTUF desiliconization tank is equipped with a spiral wound ultrafiltration membrane, which effectively removes colloidal particles from the water, preventing clogging of the RO membrane during subsequent treatment and extending the RO membrane's lifespan and efficiency. Compared to column-type ultrafiltration membranes, spiral wound ultrafiltration membranes are more resistant to suspended solids in the feed water, up to 200 mg / L. Compared to curtain-type ultrafiltration membranes, they increase the flow rate at the membrane surface, avoiding fouling caused by high suspended solids, with a flux of 200-300 L / m³. 2 The filtered water, after being treated in the primary CTUF desiliconization tank, enters the next stage of treatment, and the wastewater is then injected back into the equalization tank.
[0016] Activated carbon filters are used to adsorb organic matter and residual chlorine from sodium hypochlorite in water. Wastewater treated by activated carbon filters enters the primary RO water treatment system.
[0017] Typically, the influent salinity of a primary RO water treatment system is 2000-3000 mg / L. The RO membrane in the primary RO system is a brackish water membrane, which can achieve preliminary desalination of wastewater. The filtered water treated by the primary RO system is stored in a reuse tank, while the concentrated water enters the secondary RO system for further treatment.
[0018] Typically, the influent salinity of a two-stage RO water treatment system is 10,000-15,000 mg / L. The RO membrane in the two-stage RO system is a seawater desalination membrane, which can treat wastewater with higher salinity to achieve further desalination. The filtered water after treatment by the two-stage RO water treatment system is stored in a recycled water tank.
[0019] After two stages of RO concentration, the silicon concentration in the wastewater increases. To prevent silicon from clogging subsequent RO membranes, an inclined tube sedimentation tank and a secondary CTUF desiliconization tank are installed after the secondary RO water treatment system. The inclined tube sedimentation tank is connected to the second feed tank, where magnesium is added. The magnesium reacts with the silicon in the wastewater in the sedimentation tank to form magnesium silicate, which then undergoes sludge-water separation in the inclined tube sedimentation tank. The supernatant after treatment enters the secondary CTUF desiliconization tank, and the separated precipitate enters the sludge tank. The secondary CTUF desiliconization tank is also equipped with a spiral wound ultrafiltration membrane, and its working principle is the same as that of the primary CTUF desiliconization tank. The treated wastewater then enters the tertiary RO water treatment system for further treatment.
[0020] Typically, the influent salinity of a three-stage RO water treatment system is around 30,000 mg / L. The RO membrane in the three-stage RO water treatment system is a STRO membrane, which performs a third desalination of the wastewater. The filtered water after treatment by the three-stage RO water treatment system is stored in a recycled water tank, while the concentrated water enters the two-stage MVR system for evaporation and concentration, obtaining concentrated wastewater or crystals. The condensate produced by evaporation is also stored in the recycled water tank.
[0021] This invention treats wastewater through multi-stage sedimentation, CTUF desiliconization tanks, and an RO system, effectively removing high concentrations of silicon and enabling wastewater reuse. Two CTUF desiliconization tanks are installed before the RO water treatment system to remove colloidal particles from the water, preventing colloids from clogging the RO membrane during subsequent treatment and extending the RO membrane's lifespan and efficiency.
Claims
1. A silica-containing wastewater reuse system, characterized in that, The system comprises, in sequence, a first sedimentation tank, a primary CTUF desilication tank, a primary RO water treatment system, a secondary RO water treatment system, a second sedimentation tank, a secondary CTUF desilication tank, a tertiary RO water treatment system, and an MVR system. The primary RO water treatment system contains a brackish water membrane, the secondary RO water treatment system contains a seawater desalination membrane, and the tertiary RO water treatment system contains a STRO membrane. Both the primary and secondary CTUF desilication tanks contain spiral wound ultrafiltration membranes. The MVR system is used to evaporate and concentrate the concentrated water discharged from the tertiary RO water treatment system. The primary, secondary, and tertiary RO water treatment systems, and the MVR system are also connected to a recycled water tank.
2. The silica-containing wastewater reuse system as described in claim 1, characterized in that, An ammonia oxidation stabilization tank is also provided between the high-density sedimentation tank and the primary CTUF desiliconization tank. The ammonia oxidation stabilization tank is used to remove ammonia nitrogen from the water.
3. The silica-containing wastewater reuse system as described in claim 1, characterized in that, An activated carbon filter is also installed between the primary CTUF desiliconization tank and the primary RO water treatment system.
4. The silica-containing wastewater reuse system as described in claim 1, characterized in that, It also includes a sludge tank, and the first sedimentation tank and the second sedimentation tank are connected to the sludge tank.
5. The silica-containing wastewater reuse system as described in claim 1, characterized in that, The first sedimentation tank is a high-density sedimentation tank.
6. The silica-containing wastewater reuse system as described in claim 1, characterized in that, The second sedimentation tank is an inclined tube sedimentation tank.
7. The silica-containing wastewater reuse system as described in claim 1, characterized in that, The first sedimentation tank is connected to the first feeding tank, and the second sedimentation tank is connected to the first feeding tank.