Drinking Water

Pretreatment Objectives The primary objective of pretreatment is to make the feed water to the RO compatible with the membrane. Pretreatment is required to increase the efficiency and life expectancy of the membrane elements by minimizing fouling, scaling and degradation of the membrane. Improper Pretreatment will lead to Increased downtime, labour, chemical costs and potential premature aging of membranes (degradation) associated with more frequent cleaning. Ozone in Pretreatment : In general, Ozonation can be accompanied by and made part of the Pretreatment process through microflocculation. This is the phenomenon by which organic material, when partially oxidized, becomes more polar. Since the raw water always contains polyvalent cations, like calcium, magnesium, iron, aluminum, and manganese, these organic polar groupings combine with the polyvalent cations. Complex materials being formed which are insoluble and can readily be filtered. Turbidity will also be affected by ozonization. By definition, turbidity forms through the suspension of microscopic particles or colloidal particles which can be organic or inorganic in nature. These particles often have the same electrical charge – namely being positive. Ozone has a negative charge, and upon reaction, the particles are neutralized and will precipitate. Advantages of Ozone in Pretreatment:

• Reduction or complete elimination of coagulants like Alum, Ferric Chloride and lime in the pre-treatment process.
• Ozone can be called as a sterilizer and not a disinfectant. Chlorine can be eliminated.
• By micro flocculation with Ozone the pH is not altered.
• Contact time is very less.
• Through micro flocculation the load on the activated carbon is less as the formed insoluble complex can be filtered in the Pressurized Sand filter.
• By using the ozonated water for the back wash of the PSF and ACF microbial growth can be completely ruled out. The performance and the life of the media can be extended.
• The use of Sodium bisulfate which is used to neutralize Chlorine can be eliminated as the chlorine is not used in the pre treatment.
• Chemical attacks by Chlorine on the RO membrane can be reduced. As Ozone concentration is very less and there are no Disinfectant by products formed which can affect the RO membrane. The life of RO membrane can be increased.
• Through micro flocculation and disinfection through ozone the dissolved carbon dioxide will be less and conversion of this CO2 to carbonic acid is also less. pH boosters usage at the outlet of the RO can be reduced.
• As the Calcium and sulfates are partially oxidized it forms gelatinized insoluble complex that can rejected by the RO and there is a less chance of scale formation within the RO membrane so the Antiscalant usage can be reduced.

In summary, when the ozonation process  is properly engineered and designed in the Pretreatment,  water quality can be achieved without any exception which cannot be matched with any type of chemical treatment. Ozone in Post treatment Ozone treatment is the most commonly used disinfection process in water bottling today. With the application of a single ozone treatment step, the water bottler can disinfect the water, the bottling equipment, the bottle, the air above the water and the sealed cap of the bottle, thereby provide a most effective barrier to microbiological contamination for the protection and benefit of the consumer. Benefits of Ozone:

• Safe & aesthetically pleasing water.
• Improved taste.
• Elimination of odour.
• A 2 year long sustainable & stable product.
• Ozone is the most powerful broad-spectrum microbiological control agent available.
• Ozone is 51% more powerful on bacteria cell walls than chlorine and kills bacteria 3100 times faster.
• Ozone virtually eliminates all chemical usage and produces no toxic by-products.
• Ozone is clean and environmentally friendly; its only by-product is oxygen.
• Ozone has full FDA approval for direct-food contact application.
• Ozone is extremely effective as a disinfectant at relatively low concentrations.