A Beginner’s Guide to Purified Water Generation System

There are different grades of water depending upon the application in pharmaceutical manufacturing. However, it is similar to the criticality of the process upon which different classes of cleanroom are based.

Essentially based on the application, the types of water can be categorized as follows:

• Potable Water– Used for drinking, gardening & domestic applications.
• Soft Water– Used for process equipment cleaning & in the boiler for black steam generation.
• Purified water (PW)- Used as an excipient of non-parenteral products.
• Water for Injection (WFI)- Used as an excipient of parenteral products.

Raw water supply to a pharma manufacturing facility could be carried out from one of the sources, viz. municipal supply, groundwater, bore well, etc. However, numerous impurities often get filled in the said sources of raw water, thereby demanding removal and the right treatment before the water is ready to be taken into final utilization. 

These impurities can be in the form of Suspended Solids, Colloidal Impurity, Microbial Impurity, Dissolved Impurity, Metallic Impurity, Gaseous Impurities or Organic Impurities. Therefore, a purified water purification & distribution system for pharmaceuticals undergoes minute, distinct processes to ensure that all impurities are thoroughly removed.

Thus, the path forward begins with Raw Water Analysis; a report on the same is attached below:

Sr No.	Description	Unit	Ref Protocol(only for information)
1	Appearance
2	Appearance after Filtration (0.45 microns membrane)
3	Colour (Hazen Units)	Hazen	IS:3025 PT-4-2002
4	Odour
5	PH @ 25 degrees C		IS:3025PT-11-2002
6	Electrical Conductivity at 25ºC ms/cm	us/cm
7	Total Dissolved Solids	mg/lit	IS:3025PT-16-2002
8	Silt Density Index (SDI)
9	Copper as Cu	mg/lit	ALPH 21st Ed.,3111
10	Dissolved Oxygen	mg/lit
11	Fluoride as F	mg/lit	ALPH 21st Ed.,4500-F
12	Free CO2	mg/lit
13	Manganese (as Mn)	mg/lit	ALPH 21st Ed.,3111
14	Turbidity in NTU	NTU	IS:3025 Pt-10-2002
15	Total Hardness as CaCo3   – ppm	mg/lit	IS:3025 Pt-21-2002
16	Carbonate Hardness as CaCo3 – ppm	mg/lit
17	Nitrate (as NO3)	mg/lit	IS:3025 Pt-34-2003
18	Nitrate as CaCO3	mg/lit
19	Nitrate	mg/lit
20	Non-carbonate hardness as CaCO3	mg/lit
21	Phenolphthalein Alkalinity (as CaCO3)	mg/lit	IS:3025 Pt-23-2003
22	Methyl Orange Alkalinity (as CaCO3)	mg/lit	IS:3025 Pt-23-2003
23	Alkalinity (as HCO3 -)	mg/lit
24	Phosphate, phosphor, PO4 –	mg/lit
25	Sodium as Na	mg/lit
26	Calcium as CaCO3	mg/lit
27	Magnesium as CaCO3	mg/lit
28	Chlorides as CI	mg/lit	IS:3025 Pt-32-2003
29	Sulphate as SO4	mg/lit	IS:3025 Pt-24-2003
30	Iron as Fe	mg/lit	ALPH 21st Ed.,3111
31	Total Suspended Solid (T.S.S.)	mg/lit
32	Reactive Silica as Si	mg/lit
33	Colloidal Silica as Si	mg/lit
34	Microbial Count: Total Viable Aerobic Count	CFU/ML

Understanding the different types of pharmaceutical water systems is essential for selecting the right solution for each specific need. The classification mentioned below will help us get a more holistic view of the pharmaceutical water purification system.

Classification of Pharmaceutical Water Purification Systems: 

1) Pre-treatment Systems

a) Chlorination:

This is the primary step of a water purification system that involves a Chlorination (NaOCl) Dosing System. Chlorine being a strong oxidant, rapidly kills harmful viruses and bacteria.

b) Filtration:

Filtration is the most traditional method where water purification is undertaken through filter media. The media selected is based on the raw water parameters where the raw water analysis plays a vital role. These are also known as sand filters and are largely employed to get rid of total suspended solids (TSS), which are called multigrade filters (MGF). The water at the outlet of MGF is Potable Water.

c) De-chlorination:

At the beginning of the purification system, the oxidation properties of chlorine play a significant role in the removal of viruses and bacteria. However, as the purification system proceeds, the same oxidation properties pose a great threat to certain critical components like the RO membrane or the piping. The presence of free chlorine can often put these components at risk of scaling and salt precipitation. 

De-chlorination can be done by the following 2 methods:

• Activated Carbon Filter
• SMBS (Sodium Meta Bi Sulphate) Dosing System

d) Softening:

In this method, the introduction of softener has a good effect on the ion exchange principle as it replaces calcium and magnesium ions (hard water) with Sodium Chloride Ions NaCl (Soft Water). Hence, the water available after softening is termed Soft Water.

e) Ultra-filtration (UF):

UF is carried out by forcing water through a hollow fiber membrane which helps in reducing the Silt Density Index (SDI) of water. SDI also contributes to increasing the RO unit’s efficiency by eliminating the possibility of choking the RO membrane. 

f) Dosing System:

Dosing system is the addition of external agents in water to achieve certain objectives. The three types of this system are hereunder:

• Anti-scale Dosing: This is done to prevent the tendency of scaling of RO membrane due to the high silica content in raw water.  
• pH Correction Dosing: Elimination of carbon dioxide before the softening process can harm the efficiency of this process. Correction of the pH level of water ensures that all its important properties remain intact. 
• SMBS Dosing: SMBS Dosing is carried out with Sodium Meta Bi-Sulphate, which removes the presence of chlorine in feed water. It helps achieve de-chlorination of water and increases the life of RO membranes.

2) Post-treatment System

a) Reverse Osmosis (RO):

RO is a water purification process that forces water through a partially permeable membrane. This process involves a high-pressure pump which increases the pressure on water to pass through the membrane. As a result, the water gets divided into ‘permeate’ and ‘reject’. While the former has low salt dissolved content, the latter comprises high salt dissolved content. Based on the applications, the RO systems employed can be of 2 types: –

• Hot Water Sanitization (HSRO)
• Chemical Sanitization (CSRO)

b) Electro-deionization (EDI):

As the name suggests, EDI works on the principle of ion exchange. The construction of an EDI is very simple; it consists of 2 membranes, namely, the cathode and the anode. The primary difference between the 2 electrodes is that while cations get attracted to the cathode, the anions get attracted to the anode. This principle essentially leaves the water free of ions (deionized water).

c) Ultraviolet Disinfection (UV):

UV light is used to disinfect various algae, molds, viruses, and other microorganisms. The UV light destroys the DNA of the microorganisms, thus preventing their further growth. UV is the final step in generating PW, and the output received is termed Pure Water. 

d) Water for Injection (WFI):

WFI generation is based on the process of distillation. The PW generated by the purification process is passed through a Multi Column Distillation Plant (MCDP), which works on the principle of heat exchange. The PW undergoes a series of columns subjected to distillation by the repeated heating and cooling process. The output obtained at the end of MCDP is termed Water for Injection. 

Every water purification and distribution system is unique, highly customized, and tailored to the raw water parameters, necessary end product parameters, and optimum design capacity. Therefore, the system must be neither over-designed nor under-designed to ensure maximum efficacy.

Pure water for Pharma Manufacturing with Fabtech, pharma turnkey project consultants in India

Fabtech’s Purified Water (PW) systems are engineered to transform any source water into high-quality purified water. Our Purified Water distribution system is designed with hygiene and efficiency at its core, ensuring a seamless flow of purified water via a closed-loop piping network throughout the entire facility. 

Additionally, Fabtech offers comprehensive pharmaceutical solutions tailored to your manufacturing facility’s unique needs.

Contact us today to optimize your pharmaceutical manufacturing processes with a customized solution designed specifically for your facility’s needs.