Below is a process introduction for a 500L pharmaceutical-grade purified water system for medical use in a pharmaceutical plant:

### Raw Water Pretreatment

- **Raw Water Tank**: Raw water first enters the raw water tank, which serves for storage and buffering, balancing fluctuations in water pressure and volume, and providing a stable water source for subsequent treatment.

- **Multi-Media Filter**: The raw water is pressurized by the raw water pump and then enters the multi-media filter, which is filled with various filter media such as quartz sand and anthracite coal. Through layered filtration, it effectively removes large suspended particles, sediment, rust, and other impurities from the water, reducing turbidity and protecting downstream equipment from wear and clogging caused by large particles.

- **Activated Carbon Filter**: The water from the multi-media filter then enters the activated carbon filter. Activated carbon has a rich pore structure and a large specific surface area, enabling it to adsorb organic matter, residual chlorine, some heavy metal ions, odors, and pigments from the water, improving water purity and preventing oxidative damage to the downstream reverse osmosis membranes by residual chlorine.

- **Softener**: If the raw water has high hardness, it needs to be treated by a softener. The ion exchange resin inside the softener removes hardness ions such as calcium and magnesium through ion exchange reactions, preventing scale formation in pipelines and equipment, which could affect normal operation and the quality of purified water.

- **Security Filter**: The final step in pretreatment is the security filter, whose cartridge typically has a precision of 5 microns or smaller. It further removes tiny residual particles, colloids, and other impurities from the water, ensuring that the water entering the reverse osmosis system has extremely low particulate content, protecting the reverse osmosis membranes from contamination and clogging.

### Reverse Osmosis Treatment

- **Reverse Osmosis**: After pretreatment, the water enters the reverse osmosis system under the action of a high-pressure pump. Reverse osmosis membranes have extremely small pores, allowing only water molecules to pass through under high pressure, while almost entirely rejecting dissolved salts, heavy metal ions, microorganisms, colloids, and other impurities. The concentrated brine is discharged from the system. Reverse osmosis removes approximately 95%-99% of salts from the water, significantly improving its purity.

- **Secondary Reverse Osmosis**: For medical water in pharmaceutical plants, a two-stage reverse osmosis process is typically used. The product water from the first reverse osmosis stage is temporarily stored in an intermediate tank before being pressurized again by a secondary high-pressure pump and entering the secondary reverse osmosis system. The secondary reverse osmosis membranes have higher precision, further removing residual trace salts and other impurities, achieving higher water purity to meet stricter pharmaceutical and medical water requirements.

### Ion Exchange and EDI Treatment

- **Ion Exchange Resin Bed**: Although the water after reverse osmosis treatment is already highly pure, it may still contain trace ions. The ion exchange resin bed removes residual cations and anions through ion exchange, further reducing the water's conductivity and increasing its resistivity to meet higher purity standards.

- **EDI System**: Electrodeionization (EDI) technology is another deep desalination method. The EDI unit utilizes electrochemical reactions and the selective permeability of ion exchange membranes to continuously remove ions from the water under an electric field. It does not require acid or alkali regeneration, offering advantages such as simple operation, environmental friendliness, and energy efficiency. It stably produces high-purity ultrapure water, ensuring compliance with the stringent requirements for medical water in pharmaceutical plants.

### Post-Treatment and Storage

- **Sterilization and Disinfection**: Before the deeply treated purified water enters the storage tank, it undergoes sterilization and disinfection to prevent microbial growth and contamination of the purified water. Common sterilization methods include ultraviolet (UV) sterilization and ozone sterilization. UV sterilizers use specific wavelengths of ultraviolet light to irradiate the water, damaging the DNA structure of microorganisms and rendering them inactive. Ozone sterilization involves introducing ozone into the water, utilizing its strong oxidizing properties to kill bacteria, viruses, fungi, and other microorganisms.

- **Ultrafiltration**: To further remove trace amounts of high-molecular organic matter, colloids, bacterial endotoxins, and other impurities that may remain in the water, an ultrafiltration system can be installed after sterilization. Ultrafiltration membranes typically have pore sizes between 0.001 and 0.1 microns, effectively retaining these tiny impurities while allowing water molecules and small molecules to pass through, ensuring more stable and reliable purified water quality.

- **Storage Tank**: The treated purified water is finally collected in a storage tank. The storage tank is made of 316L stainless steel, with a polished interior and no dead corners to prevent microbial growth and impurity deposition. The tank is equipped with accessories such as vents, level sensors, and temperature sensors to ensure safety and stability during storage.

### Water Quality Monitoring and Automated Control

- **Online Water Quality Monitoring**: The entire purified water system is equipped with an online water quality monitoring system that continuously monitors key water quality parameters of the raw water, product water at various treatment stages, and the final purified water. These parameters include conductivity, resistivity, pH, dissolved oxygen, particle count, microbial content, and more.

- **Automated Control System**: The system uses an automated control system to achieve centralized control and automated operation of the entire process. Based on preset parameters and logic, it automatically controls the start/stop and operation status of components such as raw water pumps, high-pressure pumps, dosing devices, valves, sterilization equipment, and ultrafiltration systems. It also provides real-time monitoring and data logging of the system's operation.

This 500L pharmaceutical-grade medical purified water system, through the above process flow combined with strict water quality monitoring and automated control technology, stably and efficiently produces high-purity purified water that meets pharmaceutical and medical requirements. It ensures the quality and safety of drug production and provides reliable support for the smooth conduct of medical work.