Advanced Treatment of Wastewater Containing Ammonia Nitrogen in the Chip Manufacturing Industry Through Upgrading

Preface: With the rise of the electronics and computer industries, chips, as the "heart" of computers, have naturally become a hot topic in the industry, and the chip manufacturing industry has also ushered in a period of rapid development. In the past decade, major international chip manufacturers such as Texas Instruments, Intel, TSMC, etc. have established manufacturing bases in China. Some domestic companies have also started to independently develop chips and establish chip manufacturing bases. For domestic chip companies, as they are in the initial stage of the industry, various processes must be strictly controlled to obtain greater profits. Environmental protection is an important cost control aspect, and it is of paramount importance for the developing Chinese chip industry.

1. Current situation of treatment of wastewater containing ammonia nitrogen

For the chip manufacturing industry, due to process reasons, a large amount of wastewater containing ammonia nitrogen will inevitably be generated in the cleaning, etching, and de gluing stages. Ammonia nitrogen, as one of the important indicators of wastewater, can cause eutrophication in regions and seriously damage the ecological environment if it accumulates in large quantities in the natural environment. In 2019, the National Development and Reform Commission, the Ministry of Ecology and Environment, and others issued the "Evaluation Index System for Clean Production in Electronic Device (Semiconductor Chip) Manufacturing Industry", which stipulated the treatment technology of volatile organic compounds, wastewater treatment, and solid waste disposal in the production process.

At present, there are several common methods for treating wastewater containing ammonia nitrogen

① Hot blow off

As a relatively mature physical treatment method for ammonia nitrogen, hot stripping is used in a distillation tower to strip high ammonia nitrogen wastewater using hot steam when the wastewater is alkaline. Ammonia enters the steam and is discharged from the top of the tower. Cooling can recover ammonia water. The remaining wastewater is discharged from the bottom of the tower. Hot blow stripping is particularly suitable for high concentration ammonia nitrogen wastewater, but its efficiency is low when facing low concentration ammonia nitrogen wastewater. It is generally used as a pretreatment for upgrading and deep treatment.

② Biochemical treatment

Biochemical treatment, as a mature and comprehensive treatment method in the sewage treatment industry, has low operating costs and excellent treatment effects. The ammonia nitrogen content of the wastewater treated by biochemical treatment can directly meet the discharge standards. However, biochemical treatment has a high selectivity for wastewater, and can only achieve good treatment effects when the ratio of carbon, nitrogen, and phosphorus is 100:5:1, which is more suitable for the chemical and pharmaceutical industries. It is not very suitable for the chip manufacturing industry, where pollutants are relatively single. And biochemical systems generally require complex chemical pretreatment, which requires high initial investment costs and occupies a large area. Microorganisms have different survival performance and poor impact resistance in high and low temperature environments. Heavy metals and high salts in wastewater from the chip manufacturing industry can have a huge impact on them.

③ Flocculation sedimentation method

This method directly adds chemicals to the wastewater to generate insoluble precipitates of ammonia nitrogen substances, achieving separation effect. This method is very mature, with a simple process, small footprint, low initial investment, and promising prospects for new flocculants. However, this method also puts certain pressure on upgrading deep processing and generates a large amount of solid waste. The cost of solid waste treatment is also high, making it more suitable as a pre-treatment or pretreatment.

2. Haipu customized processing technology

Jiangsu Haipu Functional Materials Co., Ltd. is committed to the research and industrialization of high-performance adsorbents and catalysts. In 2018, it was approved as the Suzhou Adsorption and Catalytic Functional Nanomaterials Engineering Technology Research Center. Through years of independent research and development, it has achieved international leading levels in ion exchange technology and adsorption technology, nano inorganic material hybridization technology, etc., realizing the serialization of adsorption and catalytic products and successfully applying them in the fields of environmental protection and resource recycling.

With a series of independently developed high-performance adsorbents and catalysts as the core, combined with self-developed process technology, Haipu has become a professional supplier of green and environmental protection solutions.

The special adsorption material developed by Haipu Company can selectively adsorb ammonia nitrogen substances in wastewater, achieving efficient adsorption and complete desorption of ammonia nitrogen substances. The ammonia nitrogen content in the desorbed wastewater can meet the discharge standards. When using Haipu's adsorption process to treat ammonia nitrogen wastewater, the wastewater is pre filtered to remove suspended and particulate matter, and then enters the adsorption tower for adsorption. The special adsorption material filled in the adsorption tower can adsorb ammonia nitrogen in the wastewater on the surface of the material, and the effluent ammonia nitrogen can meet the discharge standards. After adsorption saturation, specific desorption agents are used to desorb the adsorbent material, allowing it to regenerate, and this process is continuously repeated. The process flow of ammonia nitrogen wastewater adsorption treatment is shown in the following figure.