Laundry Wastewater Treatment: Review and Life Cycle Assessment

Abstract

Accommodation providers produce large amounts of wastewater in laundering processes (12–25 L/kg of textile). The composition of this wastewater depends on the washing procedure. Between 2 and 100 mg/L methylene blue active substances (MBAS), between 1 and 30 mg/L total phosphorous, and up to 20,000 mg/L chemical oxygen demand (COD) have been reported. Many regions have regulated the concentration of surfactants and phosphorous that can be discharged into water bodies to a few milligrams per liter, due to the negative effects that these compounds can cause in the environment. Several techniques can be employed in laundry wastewater treatment, including coagulation, filtration, biological reactors, adsorption, or advanced oxidation processes. Frequently, a combination of the mentioned processes is needed to meet the desired water quality standards. Only a few studies have reported an economic assessment of the options employed for laundry wastewater reclamation. Lower costs have been reported for coagulation, biological reactors, and adsorption processes than for other treatments such as filtration techniques. Total treatment costs vary between €0.09/m3 (treatment with granular activated carbon) and €5/m3 (nanofiltration). Life cycle assessment (LCA) is important for decision-making when different alternatives can be applied. Few references include a LCA for laundry wastewater treatment. Electricity consumption has been reported as one of the main environmental hazards for laundry wastewater treatment: an equilibrium must be reached between energy consumption and the standards of treated water. Future works must lead with the full-scale application and long-term monitoring of general, cost-effective, simple, and environmentally friendly techniques for the treatment of industrial laundry wastewater.