Preliminary Studies on Integrated Process of Microfiltration and Photocatalysis Used in Laundry Wastewater Treatment

Industrial laundries generate wastewater in very large quantities. This wastewater is characterized by a high value of chemical oxygen demand (COD) and it contains substances suspended in the liquid that are responsible for wastewater turbidity. Furthermore, wastewater from industrial laundries contains several grams of detergents per litre of washing substances, mostly surfactants. Environmental and legal requirements force factories, including industrial laundries, to look for new and cost-effective methods of wastewater treatment. In the case of wastewater from industrial laundries, it is also important that a treatment method involves closing of the water loop in the plant and allows the plant to recover some of the detergents to be reused in another washing cycle. In order to address the problems related to wastewater from industrial laundries, the authors proposed an integrated process, which combined microfiltration and photocatalytic oxidation. This study presents preliminary results of the research carried out on actual wastewater generated in an industrial laundry. Results demonstrated the possibility of recovery of large amounts of purified water with detergents for the subsequent washing cycles. Thus, the integrated system of microfiltration and photocatalysis can be used in the technology of recovering water and detergents from industrial laundries. This technology enables to eliminate turbidity and remove some detergents associated with contamination caused by washing processes. Furthermore, purification degree is sufficient to reuse water in the pre-wash cycle.