Water Treatment Plant in the Pharmaceutical Industry

Water is the basic raw material used in the pharmaceutical industry for a variety of processes, departments and products. It is also used in various associated processes, such as cleaning and as a solvent.

For using water in pharmaceutical processes, it is critical and essential that it be of high quality, free from contaminants, and possess the desired chemical characteristics. Because water quality can make or break pharma process and product.

Considering water’s importance in the pharmaceutical industry, regulatory and standardization bodies have developed water-related regulations. These regulations help pharmaceutical manufacturers to ensure water quality, regulatory compliance, & an efficient production process, if followed effectively

Types of Water used in the Pharmaceutical Industry

Pharma industry comprises of various critical processes for manufacturing, and each has different water quality requirements. Because of this, water with different quality levels is manufactured, with the highest being used for critical processes. 

Let’s briefly discuss some types of water used in the pharma manufacturing.

Potable Water

Potable water is usually supplied from municipal authorities, wells, or rivers. This type of water can be used to clean non-critical parts. It cannot be used to manufacture USP dosage forms and laboratory reagents. 

Purified Water

Purified water is produced from potable water using filtration methods, such as distillation, softening, and RO. These methods remove impurities such as organic matter, microorganisms, and metallic elements, and make it suitable for critical pharma processes.

It can be used to manufacture non-injectable products and to clean critical equipment. Since it is directly used in pharmaceutical drug manufacturing, it is subject to strict regulatory regulations.

Water for injection – WFI

Water for Injection—WFI is the highest grade of purified water used in the pharmaceutical industry. It is manufactured from Purified Water through the distillation process and is free from pathogens, pyrogens, and microorganisms. It is used in the manufacturing of injectable products.

The WFI is stored in a circulation manner, i.e., it continuously circulates and is maintained at elevated temperatures. The temperature is usually 80 °C and is maintained to prevent microbial growth.

Sterile Water for injection – WFI

When Water for Injection—WFI is sterilized, it becomes sterile WFI. It is used as a diluent for injectable and vaccines and packaged in unit dosage containers. 

Operation

The water treatment plant has multiple stages, each with a different function and technology. Raw water is taken from one end and passes through various phases. As water is processed at each stage, other changes occur in the water’s characteristics. 

At the discharge from the final stage, the water is free from all the impurities, foreign bodies, and contaminants, making it suitable for relevant pharma applications. 

When water becomes purified, it is not directly transferred to the point of application. Instead, it is stored in storage vessels for later distribution. The storage vessels and distribution systems must comply with pharmaceutical regulations to prevent water contamination.

Monitoring

Monitoring is an essential element of water treatment. Different sensors and instruments are installed at different stages to continuously check for quality variables, such as pH, hardness, conductivity, and TOCs. This allows personnel to adjust process parameters if they deviate from acceptable levels. 

Some standard instruments used in water treatment include the following.

pH meters measure water’s pH value, which is important because the pH value of purified water impacts the stability of APIs and chemical reactions. 

Conductivity - it is used to measure the conductivity of water during production. The conductivity indicates the ability of water to conduct electricity, which is a function of dissolved substances and water purity. 

Total Organic Carbon - used to indicate carbon content in the water. It is essential because carbon content in water can be dangerous for pharma products, as it directly interacts with the human body.

Turbidity sensor: This sensor monitors the cloudiness and haziness of the water. The values are indicative of the suspended particles in the water that can be caused by unwanted particles.

Flow Sensor: used to monitor the flow of water through different stages of the treatment plant, which are monitored to maintain optimum plant performance.

Level Sensor - used to measure the level of storage tanks. They are used to prevent overflows and low-level conditions. 

Types of Water Treatment Plants

Purified Water and Water for Injection are the common types used in the pharmaceutical industry. These have separate generation methods, and similarly, different treatment plants are deployed for them. Purified water, such as purified water generators, has been used for generations, while distillation plants have been used for WFI.

Let’s briefly discuss each of these types.

Purified Water Plant

The Purified Water Treatment Plant consists of multiple sub-components that perform their specific functions, including the following.

Pre-treatment 

It is the first step in treating water in a treatment plant. Its main function is to remove higher-level impurities and make water suitable for further stages of treatment. It consists of sand filtration, activated carbon filters, and a Softener.

• Sand filtration removes suspended particles and turbidity. It helps prevent the blocking and clogging of further stages of components, such as membranes and piping.

• Total activated carbon filters are used to remove chlorine and organic compounds.

• Softeners like magnesium and Calcium remove hardness ions and prevent scaling.

Purification

The purification unit of the water treatment plant consists of the following sub-components

Reverse Osmosis - This section consists of a semi-permeable membrane through which water is forced to pass. Pressure is applied to produce force against the membrane’s osmotic pressure. The process only passes water through it, leaving behind organic compounds and dissolved solids. 

Deionization Unit - The deionization unit in the water treatment plant removes dissolved ions from the water, such as minerals. It consists of charged resins that attract ions within the water as it passes through it. Positive resin, called Cation resin, removes positively charged ions, such as Calcium. Negative resin, called Anion resin, removes negatively charged ions, such as Nitrate. 

Ultra-filtration Unit - Ultrafiltration Unit—UF uses the latest membrane technology to remove not only suspended particles but also particles and contaminants of microscopic size. It consists of a small membrane. Filtration is performed under the forceful passing of water through it. 

Water for Injection 

Water for Injection - WFI is the highest quality type of water in the pharma industry. They are used to manufacture injectable products and are made to adhere to strict quality & safety requirements.

Distillation plant is used to generate WFI. Following is the brief overview of distilled water plant.

Feed Water

To make it highly purified, tap or usual municipal supplied water cannot be used as a feed water. Instead, output of purified water plant is used to easily attain highest quality WFI.

Distillation Water Plant

The plant that produces water for injection – WFI is called Distillation plant. In it, the feed water is heated to its boiling point and converted into steam. In the next stage, the steam is condensed and converted into water, which becomes the output or WFI. 

Distillation is used because when water is converted into steam, impurities do not convert to steam and are left behind. Thus, high-purity water is obtained through the distillation process. Steam generation and conversion into water are repeated multiple times to ensure quality, a process called Multiple-Effect Distillation.

Storage

The treated or output water is not directly fed to the point of use. Instead, it is stored in storage tanks and then supplied to the required area. The storage ensures that the water supply is managed in times of high requirement (even greater than the total per-hour capacity of the plant). 

The storage systems must follow standard pharmaceutical regulations to prevent contamination and impurity ingress into the water. This can be enabled by following surface finish requirements, such as using Stainless steel-grade material, surface finishing, dead points, and many others. 

Like other pharma equipment, storage systems are supplied with necessary instrumentation such as level, temperature, pressure, and conductivity, which depends on the application and process requirement.

Purified water is stored at room temperature, around 25 °C, while WFI is stored at around 80°C.

Typically, the storage is integrated with the purified or distillation plant to optimize the water supply by using different interlocking sensors. These interlocking sensors synchronize the storage operations with water generation operation.

For example, if the water level in the storage drops below a certain level, the valve at the plant side is opened to fill the storage. Similarly, if the water level in storage tanks reaches a certain level, the supply valve to the storage is shut down to prevent overflowing water from the storage. 

Distribution

Distribution is responsible for transferring the water to its intended location, area, equipment, or department. It mainly consists of a pump, piping network, valves and relevant actuators for the safe and efficient delivery. 

The distribution unit is designed to keep the water in continuous flow. The continuous motion of water helps prevents microbial growth and stagnation. The water’s flow can be controlled and adjusted through pump operation. Its speed can be increased to increase the flow, and vice versa.

About the Author

Muhammad Asim Niazi has a vast experience of about 11 years in a Pharmaceutical company. During his tenure he worked in their different departments and had been part of many initiatives within the company. He now uses his experience and skill to write interested content for audiences at PharmaSources.com.