Electrochemical wastewater treatment equipment, used for semiconductor wastewater treatment.

I. Product Overview

Semiconductor wastewater originates from processes such as chip manufacturing (wafer fabrication, packaging and testing), liquid crystal panels (TFT-LCD, OLED), photovoltaic cells, and electronic component production. It is one of the types of wastewater with the highest water quality requirements and the greatest difficulty in treatment within the electronics industry. Semiconductor manufacturing processes are complex and involve numerous steps, resulting in significant differences in wastewater quality across different processes. These can be mainly categorized as follows: Ammonia-nitrogen-containing wastewater: Primarily originates from developing solutions, stripping solutions, and cleaning solutions, with ammonia nitrogen concentrations typically ranging from 100 to 1000 mg/L. Total nitrogen in some quaternary‑ammonium pollutants wastewater can reach thousands of mg/L. Organic wastewater originates from photoresist, stripping solution, developer, cleaning agents, etc., and contains various recalcitrant organic solvents and polymers. Acidic and alkaline wastewater originates from cleaning and etching processes and contains H₂SO₄, HCl, HNO₃, H₃PO₄, NaOH, etc. Chemical mechanical polishing wastewater contains nano-sized abrasive particles, oxidants, and surfactants. Semiconductor wastewater treatment has distinct industry-specific requirements: chip manufacturing demands extremely high water purity; any chemical residue can affect wastewater reuse and discharge; wastewater contains various characteristic pollutants that inhibit or toxicize microorganisms, making direct treatment by conventional biological systems difficult; discharge standards are extremely stringent; and companies generally face water scarcity and stringent wastewater reuse targets.

This system employs electrochemical oxidation technology, which can be flexibly applied to various semiconductor wastewater treatment scenarios: For wastewater containing quaternary‑ammonium pollutants/high ammonia nitrogen—it efficiently electrochemically oxidizes and degrades quaternary‑ammonium pollutants ((CH₃)₄NOH) into low-toxicity intermediates such as small-molecule amine by‑products, ultimately converting them into N₂, CO₂, and H₂O. The total nitrogen removal rate can reach over 90%, and the effluent ammonia nitrogen can be reduced to 5-10 mg/L, completely solving the problems of quaternary‑ammonium pollutants's poor biodegradability and biotoxicity.

For organic wastewater (photoresist/stripping solution/developer solution, etc.)—it directly oxidizes and decomposes photoresist resins, polymers, and organic solvents, opening rings and breaking chains. The COD removal rate is 70%-90%, and the effluent can safely enter subsequent biological treatment systems or directly meet discharge standards.

For comprehensive wastewater deep treatment and reuse—deeply removing residual COD, ammonia nitrogen, and TOC, with effluent COD ≤30~50 mg/L and ammonia nitrogen ≤5 mg/L, meeting the requirements for ultrapure water pretreatment or direct reuse in cleaning processes.

The entire process consumes only electricity, without adding chemical agents (quaternary‑ammonium pollutants treatment requires no external carbon source or acid/alkali adjustment), and does not produce large amounts of chemical sludge (fluoride-containing sludge is reduced by 50%~80%). The electrodes can still operate efficiently in wastewater with low conductivity, operating at normal temperature and pressure, ensuring safety and stability. It is an ideal technology choice for upgrading semiconductor industry wastewater treatment from "meeting discharge standards" to "resource reuse".

II. Difficulties in semiconductor wastewater treatment and solutions with this equipment

III. Working Principle

Depending on the water quality and treatment objectives, semiconductor wastewater undergoes the following purification reactions in an electrochemical reactor:

(1) High-efficiency oxidative degradation of quaternary‑ammonium pollutants (tetramethylammonium hydroxide) (a core function unique to semiconductors)

quaternary‑ammonium pollutants ((CH₃)₄NOH) is the most representative nitrogen-containing organic pollutant in the semiconductor industry, possessing biotoxicity and being difficult to biodegrade. In the electrochemical reactor:

quaternary‑ammonium pollutants is directly oxidized by losing electrons on the anode surface—tetramethylammonium ions (quaternary‑ammonium ions) are gradually demethylated.

Total nitrogen removal rate ≥90%, and total nitrogen in the effluent can be reduced to 10~20. (2) Oxidative degradation of organic wastewater (photoresist/stripping solution/developer, etc.) Semiconductor organic wastewater contains photoresist resin, stripping solution, surfactants in developer, etc.: Macromolecular polymers are oxidized and broken on the anode surface, and long carbon chains and aromatic rings are gradually decomposed into small molecule organic acids. Organic solvents (IPA, PGMEA, NMP, etc.) are directly oxidized to CO₂ and H₂O at the anode. Hydroxyl radicals (·OH) indiscriminately oxidize various organic substances, ensuring thorough COD removal. Naturally present chloride ions (introduced during semiconductor cleaning) generate active chlorine, which supplements the oxidation of organic matter in the solution that cannot directly contact the anode.

(3) Removal of ammonia nitrogen and total nitrogen

Besides quaternary‑ammonium pollutants, semiconductor wastewater also contains other forms of ammonia nitrogen (developer, cleaning solution, etc.):

Chloride ions are electrolyzed at the anode to generate active chlorine (Cl₂, HOCl, OCl⁻).

Active chlorine rapidly oxidizes ammonia nitrogen into nitrogen gas, and organic nitrogen (NH₄⁺ in quaternary‑ammonium pollutants degradation intermediates) is also converted into N₂.

Total nitrogen in the effluent can be reduced to below 10~20 mg/L.

IV. Core Advantages (Targeting Semiconductor Wastewater)

V. Technical Parameters (Customizable)

VI. Process Location

Option 1: Specialized Wastewater Treatment

quaternary‑ammonium pollutants/Developer Wastewater → Collection and Equalization Tank → Electrochemical Treatment Equipment → Effluent (B/C ≥ 0.30) → Enters Integrated Wastewater Equalization Tank → Conventional Biological System → Discharge Meets Standards/Reuse

Option 2: Advanced Biological Effluent Treatment

Integrated Wastewater → Pretreatment → Biological System → Secondary Sedimentation Tank → Advanced Electrochemical Treatment Equipment (Removal of Residual COD/TOC/Ammonia Nitrogen/Total Nitrogen) → Effluent → Reuse/Discharge Meets Standards

Option 3: High-Concentration Wastewater Reduction (Alternative to Hazardous Waste Transportation)

High-concentration organic wastewater (detergent wastewater, stripping wastewater, developer wastewater, etc.) → Collection Tank → Electrochemical Treatment Equipment → Treated Wastewater (significantly reduced COD) → Continued Biological Treatment