title: Insights into real cotton-textile dyeing wastewater treatment using solar advanced oxidation processes.
abstract: Different advanced oxidation processes (AOPs) were applied to the treatment of a real cotton-textile dyeing wastewater as a pre-oxidation step to enhance the biodegradability of the recalcitrant compounds, which can be further oxidized using a biological process. Tests were conducted on a lab-scale prototype using artificial solar radiation and at pilot scale with compound parabolic collectors using natural solar radiation. The cotton-textile dyeing wastewater presents a lilac color, with a maximum absorbance peak at 641 nm, alkaline pH (pH = 8.2), moderate organic content (DOC = 152 mg C L(-1), COD = 684 mg O2 L(-1)) and low-moderate biodegradability (40 % after 28 days in Zahn-Wellens test). All the tested processes contributed to an effective decolorization and mineralization, but the most efficient process was the solar-photo-Fenton with an optimum catalyst concentration of 60 mg Fe(2+) L(-1), leading to 98.5% decolorization and 85.5% mineralization after less than 0.1 and 5.8 kJUV L(-1), respectively. In order to achieve a final wastewater with a COD below 250 mg O2 L(-1) (discharge limit into water bodies imposed by the Portuguese Legislation-Portaria no. 423/97 of 25 June 1997), considering the combination of a solar-photo-Fenton reaction with a biological process, the phototreatment energy required is 0.5 kJUV L(-1), consuming 7.5 mM hydrogen peroxide, resulting in 58.4% of mineralization [Formula: see text].
authors.affiliation: LSRE-Laboratory of Separation and Reaction Engineering-Associate Laboratory LSRE/LCM, Faculdade de Engenharia, Universidade do Porto, Rua Dr. Roberto Frias, 4200-465, Porto, Portugal.
authors.forename: Petrick A
authors.initials: PA
authors.lastname: Soares
authors.forename: Tânia F C V
authors.initials: TF
authors.lastname: Silva
authors.forename: Diego R
authors.initials: DR
authors.lastname: Manenti
authors.forename: Selene M A G U
authors.initials: SM
authors.lastname: Souza
authors.forename: Rui A R
authors.initials: RA
authors.lastname: Boaventura
authors.forename: Vítor J P
authors.initials: VJ
authors.lastname: Vilar
mesh_terms: D001673:Biodegradation, Environmental; D004396:Coloring Agents / Q000737:chemistry*; D003368:Gossypium; D006861:Hydrogen Peroxide / Q000737:chemistry; D007220:Industrial Waste; D007501:Iron / Q000737:chemistry; D010084:Oxidation-Reduction; D055668:Photochemical Processes; D013472:Sunlight; D013783:Textile Industry; D014865:Waste Disposal, Fluid / Q000379:methods*; D062065:Wastewater / Q000737:chemistry*; D014874:Water Pollutants, Chemical / Q000737:chemistry*; D018508:Water Purification / Q000379:methods*
chemical_list: D004396:Coloring Agents; D006861:Hydrogen Peroxide; D007220:Industrial Waste; D007501:Iron; D062065:Wastewater; D014874:Water Pollutants, Chemical