Water is a critical raw material in pharmaceutical and chemical manufacturing operations; consistent and high-quality water supplies are required for a range of operations including production, material processing, and cooling. The various categories of water which need treatments as part of water management are potable water, process water; feed water for utilities, water recycling, and wastewater, water coming from byproduct treatment, water used for odor treatment, water from desalination, and water for irrigation.
We will restrict this review to pharmaceutical water, wherein it is widely used as a raw material, ingredient, and solvent in the processing, formulation, and manufacture of pharmaceutical products, APIs and intermediates, compendia articles, and analytical reagents.
Process water quality management is of great importance in Pharmaceuticals manufacturing and is also a mandatory requirement for the sterilization of containers or medical devices in other healthcare applications include water for injection. Process waste waters are a term used to deﬁne wastewater in any industry coming from the processes occurring in the industry. Process waste waters thus cover any water which at the time of manufacturing or processing comes in contact with the raw materials, products, intermediates, byproducts, or waste products, which are handled in diﬀerent unit operations or processes.
Different Source of Water:-
- Ground Water
The water that is obtained from some deep ground water may have fallen as rain many years ago. Rock and soil and layers naturally filter the ground water to a high degree of clarity and often does not require additional treatment other than adding chlorine or chloramines as secondary disinfectants. Such water may emerge as springs, artesian springs, or may be extracted from boreholes or wells. Deep ground water is generally of very high bacteriological quality (i.e., pathogenic bacteria or the pathogenic protozoa are typically absent), but the water may be rich in dissolved solids, especially with carbonates and sulfates of calcium and magnesium. Depending on the strata through which the water has flowed, other ions may also be present including chloride, and bicarbonate. There may be a requirement to reduce the iron or manganese content of this water to make it acceptable for drinking, cooking, and laundry use.
2. Upland lakes and reservoirs
Typically located in the headwaters of river systems, upland reservoirs are usually sited above any human habitation and may be surrounded by a protective zone to restrict the opportunities of contamination. Bacteria and pathogen levels are usually low, but some bacteria, protozoa or algae will be present. Where uplands are forested or peaty, humic acids can color the water. Many upland sources have low pH which requires adjustment
3. Rivers, canals and low land reservoirs
Low land surface waters will have a significant bacterial load and may also contain algae, suspended solids and a variety of dissolved constituents. Atmospheric water generation is a new technology that can provide high quality drinking water by extracting water from the air by cooling the air and thus condensing water vapor. Rainwater harvesting or fog collection which collects water from the atmosphere can be used especially in areas with significant dry seasons and in areas which experience fog even when there is little rain.
Below report is just a formal presentation for understanding about the water parameters need to design right water system-
Treated Output Quality of Pharmaceutical water:
pH : 5 to 7
Microbial Limit : < 100 cfu/ml
TOC : < 500 ppb
Conductivity @ 25 °C: < 1.3 µS/cm
PHARMA WATER SYSTEM PROCESS FLOW
Based on water sources and parameters and require output quality as per FDA following processes are the widely used in especially in pharmaceutical industries-
The most common disinfection method involves some form of chlorine or its compounds such as chloramine or chlorine dioxide. Chlorine is a strong oxidant that rapidly kills many harmful micro-organisms. Because chlorine is a toxic gas, there is a danger of a release associated with its use. This problem is avoided by the use of sodium hypochlorite, which is a relatively inexpensive solution that releases free chlorine when dissolved in water. Chlorine solutions can be generated on site by electrolyzing common salt solutions. A solid form, calcium hypochlorite, releases chlorine on contact with water. Generally this process used to disinfect or destruction of pathogenic organism and odor control.
- Multi grade Filtration (Sand Filters)
Chlorinated Raw Water is pumped through auto Multi Grade Filter to reduce turbidity and suspended solids. It consists of graded sand and gravel which removes suspended particles from the feed water. MGF is designed for either once a day backwash or when the pressure drop across MGF is more than 0.5 bar. Normal Operation, Rinsing & Backwash of the MGF is done automatically.
Hardness causes scaling and salt precipitation on the RO membranes and other equipment’s like piping, Storage tanks etc.; hence an IX Softener is used to replace divalent ions like Ca & Mg with Na. The softener is designed for hardness reduction up to 5 ppm as CaCO3. After producing the design water quantity the Softener is regenerated with Brine solution and is ready for operation again. Normal Operation, Rinsing, Backwash and regeneration of the Softener is done automatically.
4. Ultra filtration System
The UF is effective and useful in achieving a consistent RO feed water quality having a SDI less than 3. Important advantages of UF in the RO feed are as below:
- Reduced membrane fouling due to particulate matter and hence longer membrane life
- Acts as an effective barrier against bacteria and organics hence reduced membrane sanitization
- The Ultra Filtration System consists of HFF (Hollow Fine Fibres) modules made out of PVDF or modified PES which have a very high chemicals tolerance.
- The UF system operation involves several steps like backwash, forward flush, chemically enhanced backwash etc. All the sequential action is carried out automatically based on the pre-programmed sequential logic. The water generated from ultra-filtration is then collected in UF Treated Water Storage Tank.
5. Dosing Systems
- ANTISCALENT DOSING SYSTEM: – Dosage of Anti scalent solution into RO Feed water to control the scaling of RO membrane due to high amount of silica in raw water. Sodium hexametaphosphate (NaPO3)6 dosing is considered for this purpose.
- SMBS DOSING SYSTEM: – The de chlorination is carried out with the help of Sodium Meta Bi-Sulphate, which removes the presence of chlorine in feed water. This dosing helps to avoid oxidation of membranes. The SMBS solution should be freshly prepared daily.
- pH Dosing:- pH correction dosing is done to keep the pH in the range of 7.8 to 8.85. Carbon dioxide content in water considered as important water & process parameter. As carbon dioxide in gaseous form pass easily the RO membrane & could affect negatively on Softener process. pH dosing is to eliminate carbon dioxide before Softener which formed as ion due to pH dosing and can be easily eliminated by the RO process. NaOH dosing is considered for this purpose.
Purified Water Generation System (RO+ EDI)
- Reverse Osmosis
Reverse Osmosis is a water purification process that uses a partially permeable membrane to separate ions, unwanted molecules and larger particles from drinking water. In reverse osmosis, an applied pressure is used to overcome osmotic pressure, a colligative property that is driven by chemical potential differences of the solvent, a thermodynamic parameter. Reverse osmosis can remove many types of dissolved and suspended chemical species as well as biological ones (principally bacteria) from water, and is used in both industrial processes and the production of potable water. The result is that the solute is retained on the pressurized side of the membrane and the pure solvent is allowed to pass to the other side. To be “selective”, this membrane should not allow large molecules or ions through the pores (holes), but should allow smaller components of the solution (such as solvent molecules, i.e., water, H2O) to pass freely.
2. EDI System
The typical EDI installation has the following components: anode and cathode, anion exchange membrane, cation exchange membrane and the resin. The most simplified configuration consist in 3 compartments, to increase the production these number can be increased.
The cations flow towards the cathode and the anions flows toward the anode. Only anions can go through the anion exchange membrane and only cations can go through the cation exchange membrane. This configuration allows anions and cations to only flow in one direction because of the membranes and the electric force, leaving the feed water free of ions, (deionized water).
The concentration flows (right and left of the feed flow) are rejected and they can be wasted, recycled, or use in another process. The purpose of the ion exchange resin is to maintain stable conductance of the feed water. Without the resins, the conductance will drop dramatically as the concentration of ions is decreasing. Such drop off of conductance makes it very difficult to eliminate 100% of the ions, but using resins makes it possible.