How to Select a Purified Water Generation System for the Medical Industry

Selecting a purified water system in the medical industry is a critical decision that impacts product quality, patient safety, and regulatory compliance. The choice extends beyond just the equipment to include the supplier's expertise and validation support.

Here are the key factors to consider:

1. Define Your Water Quality Specifications and Compliance Requirements

• Pharmacopoeia Standards: The system must reliably produce water that consistently meets the required quality standards.

  • Purified Water (PW): For device cleaning, lab tests, and as an ingredient.

  • Water for Injection (WFI): For parenteral products, final rinse of devices contacting blood. Traditionally requires distillation, though modern regulations (like EU GMP) now also allow purification technologies like Two-Pass RO.

• Internal Specifications: Define additional parameters critical to your specific process (e.g., TOC, conductivity, endotoxins, microbial action limits).

2. Determine Your Capacity and Demand

• Peak Demand: Calculate the maximum water consumption rate (gallons per hour or liters per hour) your facility will need at its busiest point.

• Total Daily Volume: Estimate the total amount of water used per day.

• Storage & Distribution: The generation system's capacity must work in tandem with the storage tank and distribution loop design to ensure continuous supply without stagnation.

3. Evaluate Key System Design and Technology Features

• Sanitary Design:

  • Materials: 316L or 316L VL stainless steel for all wetted surfaces.

  • Surface Finish: A high-polished internal surface (e.g., Ra ≤ 0.6 µm or better) is mandatory to prevent microbial adhesion and facilitate cleaning.

  • Dead Legs: Piping and fittings must be designed to minimize dead legs (typically meeting the 3D rule or better).

  • Drainability: The entire system must be fully drainable with proper slope.

• Pretreatment System: A robust pretreatment (multimedia filters, carbon filters, water softeners) is crucial to protect the downstream Reverse Osmosis (RO) membranes and ensure consistent performance.

• Core Purification Technology:

  • Reverse Osmosis (RO): The industry standard for primary purification. A Double-Pass RO configuration is highly recommended for superior purity and reduced load on polishing components.

  • EDI (Electrodeionization): Often used after RO for continuous deionization without the need for chemical regeneration. A common configuration is RO + EDI.

  • Distillation: Essential for WFI production in some regions (like the US for USP WFI) and the only option for some applications. It can also serve as a robust polishing step for PW systems.

• Sanitization Capability:

  • The system must be designed for regular and effective sanitization to control microbial growth.

  • Common methods include Hot Water Sanitization (for RO/EDI units), Pure Steam Sanitization, and Chemical Sanitization (e.g., with ozone or peracetic acid).

4. Assess the Supplier's Expertise and Support

• Regulatory Knowledge: The supplier must have deep expertise in cGMP, GAMP 5, and relevant pharmacopoeias (USP, EP, JP, ChP).

• Validation Support: They must provide comprehensive documentation packages to support your DQ, IQ, OQ, and PQ (Design/Installation/Operational/Performance Qualification). This is non-negotiable.

• Service and Lifecycle Support: Ensure they offer reliable technical support, maintenance services, and supply of spare parts.

5. Consider Lifecycle Costs (TCO)

The purchase price is only a part of the total cost. Consider:

• Operational Costs: Energy consumption, water efficiency (reject rate), chemical consumption for cleaning/CIP.

• Maintenance Costs: Cost and frequency of membrane replacements, filter changes, and general upkeep.

• Validation & Compliance Costs: Costs associated with ongoing monitoring, requalification, and regulatory audits.