Innovative ultrafiltration for wastewater reuse

The paper describes a case of rationalization of the use of the waters of a textile factory located in the northern part of Italy. The water used in t he factory comes from deep wells located about 170 m below the level of the factory. The yearly used amount of water is about 540,000 m(3). Inside the factory the water goes to different uses as such for cooling or for genera l uses or treated as softened or demineralized water where needed. After us e the water that has been polluted is sent for biological treatment where t akes place a first step of decontamination. Upon exiting the biological tre atment, the water quality achieved is not enough for discharge into the ope n environment; consequently, the water has to be sent for additional extern al treatment. The complete water cycle has a sizeable cost due to all the e xisting steps: pumping of all the raw water, internal biological treatment, external after-treatment, and process water treatment by ion-exchange demi neralization or softening. Based on all the above, the factory has foreseen a rationalization of the economics of the cycle of the water based on the reuse of part of the waters today sent for discharge. The base of the chose n process is the treatment of part of the water coming from the biological internal treatment as a first step on "innovative" ultrafiltration and as a second step on reverse osmosis. The two treatments positively influence th e economics of the ion-exchange treatments in the factory. Pilot tests are currently in progress for fine-tuning.