Pre-treatment
It goes without saying, with challenging feed water conditions, higher and higher emphasis are now put on designing and qualifying pre-treatment systems. The focus hence has shifted from the terminal stages of purified and WFI generation to the starting stages of pretreatment.
Pretreatment systems are designed for removal of Physico-chemical impurities & antimicrobial treatment solutions from the incoming water. These typically comprise of following unit processes
Removal of Physico Chemical Impurities -
Multi-Grade filters/Mixed Bed Filters
For removal of suspended impurities coming from raw water. Mixed bed filters are useful for removal of Iron if it is present as a trace element
Softeners
Reduction of scale-forming ions namely Calcium and Magnesium
Ultra-filtration Units
For removal of suspended impurities, reduction of Silt Density Index (SDI)<5
Reverse Osmosis Membrane Systems
These are available with chemically sanitizable or hot water sanitizable configuration used for removal of dissolved solids. It also helps in the reduction of organic impurities thereby helping in reduction of TOC.
Microbial Treatment Solutions
Sodium Hypochlorite
Preferred where the pathogens are absent in raw water and help in reduction in microbial load reduction.
Chlorine Dioxide Generation
These are onsite Chlorine Dioxide (ClO2) generators which are used for dosing in raw water which has proved effective against pathogen like Pseudomonas, E Coli etc
Ozonation
Proved most effective against all pathogen coming in from feed water. PHS specializes in configuration and control of ozonation to make it's most effective and lethal for pathogenic loads and at the same time safe for human presence.
Pretreatment
