Instruments and Filters for Pharmaceutical Water Treatment Plants

The water in the pharmaceutical industry has a direct relationship with manufacturing, product, quality, and safety. It is used in a variety of manufacturing and support functions.

The entire product portfolio is dependent on water for manufacturing.

Every pharma product has its criticality for human life and must be treated with most quality & safe procedures. For example, parenteral product’s method of administration bypasses the usual safety system of the human body. Due to these reasons and many more, water in the pharmaceutical industry must be of pharma grade standards

Water Treatment plants are critical equipment in the pharmaceutical industry to ensure water quality. Raw water undergoes chemical and physical transformations that make it fit for critical pharmaceutical applications. The plant consists of multiple stages that have specific functions in removing various types of impurities and contaminants. 

Filters and instruments are integral to water treatment, among many other components and parts. Filters provide an essential method of clearing out impurities of all sizes and levels. Instrumentation offers insight into the process, equipment, and water conditions at all stages of treatment. This, in turn, is used to monitor different aspects of treatment operations for process improvement, quality, safety, and compliance purposes. 

Filters in the treatment Plants

Filters in Water Treatment Plants are used to filter out impurities present in the water. Since water contains different types of impurities, a single filter type can be ineffective in removing impurities .

Filters are strategically installed in different stages of the treatment plant. As the water flows through these stages and filters, the filter filters out the relevant impurities and contaminants. The process is repeated throughout the plant until the purified water emerges from the output section. 

Some common uses in water treatment plants are described below.

Multimedia Filter

They are used in the pre-filter section of a water treatment plant to filter out large particles. The section is made up of layers of different media, such as sand, gravel, and anthracite. The advantage of using different media is that it can filter out variable-sized particles in a single stage. 

These media are arranged in layers. Water enters from the top, where large particles are removed, while small or fine particles are filtered out at the bottom.

Activated Carbon Filter

Activated Carbon filters remove organic components and chlorine from the water. They are deployed in the pre-treatment stage of the treatment plant. They are also capable of removing odor and taste from the water and improving turbidity. 

Activated Carbon filters consist of a purpose-made carbon material made from carbon-containing materials such as coal or coconut husk. The carbon is burnt at a high temperature with reduced oxygen concentration. Depending on the application and/or process, various forms, such as granular or powder, can be used to fit the filtration process. 

They are used to filter in initial stages before the water is fed to higher filtration technologies such as Reverse Osmosis and EDI, to increase their performance and life.

Microfiltration

Microfiltration is a type of membrane filtration that is deployed after the pre-filtration stage. It is made of polymer materials and has good mechanical and chemical strength. However, it is only effective for particles from 0.1μm to 10μm. 

The water to be filtered is forcefully passed through the microfiltration. Particles greater than the pore sizes are blocked, while particles smaller than the pore sizes pass through the filter. They come in different categories, including pipe-shaped and flat-sheet-shaped.  

Ultrafiltration

Ultrafiltration is also a membrane-based filter suitable for small particle sizes from 0.01μm to 0.1μm. It can block suspended solids, bacteria, and viruses. The water to be purified is passed through the filter under pressure.

Ultrafiltration in pharmaceutical water treatment is used to filter out large particles and bacteria that can threaten the Reverse Osmosis section and increase its life.

Reverse Osmosis - RO section

This is also a membrane-based technology and uses a semi-permeable membrane. It can filter out dissolved solids and microorganisms to produce high-purity water. Like other membrane-based filters, water is forcefully passed through the RO filter for filtration purposes. 

As mentioned earlier in this article, the feed water for RO units must be pre-filtered to remove large particles and suspended solids. Otherwise, these large particles will damage the RO membrane and cause scaling.

Instruments in the treatment Plants

Instrumentation and sensors are integral to the pharmaceutical industry’s water treatment plant. They help monitor the entire process at the unit stage level and provide valuable information regarding the process, product, and plant’s performance. This information can then be used to detect and rectify problems, enhance performance, and increase the life span of different plant components. 

There are various instruments for water treatment plants, each with different technology, process, and quality parameters. 

Let’s discuss some of these instrumentation.

Conductivity Sensors

A conductivity sensor measures water conductivity by generating an electrical current in water. The electrodes measure the resistance, which is converted to equivalent electrical conductivity of the water.

The conductivity in water is directly proportional to the ions present, which is a function of impurities. The value of conductivity can be correlated with quantities of impurities in the water, followed by process adjustment, until value falls within the acceptable limits

The conductivity sensor can be used in portable or online design. 

In portable design, the water sample is taken, and conductivity is measured at another location, usually in in-process labs or quality laboratories. These devices are used for intermittent monitoring, and delays can be induced between water sampling and the generation of results. These types may require process hold until result is finalized.

In online design, the conductivity sensor is attached to the water treatment plant through an appropriate port. Water is made to pass through the port, allowing it to monitor conductivity continuously. The change in conductivity is immediately communicated to the concerned personnel so they can adjust the parameters. In online type, the process parameters are automatically adjusted when deviation from acceptable ranges are detected.

Total Organic Carbon analyzer 

A Total Organic Carbon (TOC) is an analytical instrument used to measure the organic concentration in water, which in turn represents contamination in the water. 

The TOC analyzers use oxidization of carbon content and convert it into carbon dioxide. The concentration of CO2 can then be detected, indicating the water’s organic content.

pH Meter

The pH meter measures the acidity or alkalinity of a solution or water sample, and its scale ranges from 0 to 14. In pharmaceutical water treatment plants, pH is adjusted, because drug manufacturing is directly proportional to pH values, and it is necessary to maintain it within limits. Additionally, the stability of pharmaceutical products is directly proportional to the pH values. 

A pH meter is used in water treatment plants to monitor pH values. Suppose the pH values deviated from acceptable limits. Concerned personnel adjust process parameters to restore normal pH values. Online and offline pH meters can be deployed in water treatment plants.

Temperature Sensor

Temperature sensors in treatment plants measure water temperature. They help determine the exact value of water and adjust if necessary. 

There are different types of temperature sensors, and appropriate range must be selected. Some sensors are used in low temperature ranges, while some are designed to measure higher ranges. Additionally, the temperature sensor must be 

• Able to easily clean and sanitize, due to high pharma standards. 

• The material must resist corrosion & degradation due to water usage.

In a water treatment plant, temperature sensors are used to measure

• Temperature of he outfeed water

• Distillation process in WFI generation

• Water temperature in storage tanks

Pressure Sensors

Pressure sensors in water treatment plants measure pressure across various plant components and stages. They are usually used to monitor the treatment process’s performance, monitor flow across various components, and prevent damage. 

Like other process industries, there are two types of pressure sensors - manual and electronic.

• Manual pressure sensors are gauges that indicate a scale and often display a single component.

• Electronic types are pressure transmitters that convert the pressure value into electronic signals, which are then sent to the main controller for electronic display or process automation. 

Pressure sensors in water treatment plants are used to 

• Monitor the filter’s performance. An increase in pressure drop through the filter indicates filter clogging. The value can then be used to change or clean      the filter.

• Detecting leakage in different components of the plant 

Flow and Level sensors

Flow sensors measure flow through various components and stages of the treatment plant. Since the plant is designed to use water per unit of time, flow is monitored for normal function and problem detection to ensure optimal performance. Level sensors measure the water level in the storage tanks to indicate the present volume of water. 

Readings of both flow and level sensors are used to monitor the treatment process. These values are transmitted to the main control, which can generate an alert if these values cross the acceptable limits. Manual indicators can also be used, depending on the process and product requirements.

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.