The integrated water cycle in the textile industry
I. Primary Water Treatment:
Clarification, deferrization, dechlorination, decarbonation, softening, demineralization with resins or osmosis. These treatments are used for water coming from well, river or form municipal supply in order to guarantee a correct quality before its industrial use.
II. Discharge Water Treatment:
Biologic plant with low charge activated sludge. The management costs and the quantity of sludge produced are the lowest obtainable for this kind of discharge.
III. Tertiary Treatment:
Quartz and resin filter treatment for colour, COD and suspended solids removal. At this point it is possible to recover around 50% of the water. The same treatment is used to prepare the water before it enters the membrane and the osmosis stage.
IV. Removal of Calcium:
After the dyeing and bleaching stage the hardness of the discharged water can reach 250 ppm of concentration. If the zero discharge process with two or three stages of R.O is used, it is necessary to remove the calcium to avoid irreversible obstructions on the membranes, that can causes the block of the recovery process.
V. Reverse Osmosis Treatment:
With this treatment the soluble salts are removed and high quality water is obtained, available to be reused in the production process. It is possible to apply two stage, followed by a third nano filteration or RO in order to recover up to 95% of the treated water.
Vi. Evaporator for the Treatment of the concentrates from the reverse osmosis:
With this treatment an extra 3-4% of the water rejected from the reverse osmosis membrane is recovered for distillation. Form the final concentrated brine you can obtain a dry residual which is made from TDS from the present organic frication.