Photodegradation of olive mill effluent with hydrogel-coated Fe 3

In this study, hydrogel-coated Fe3O4 magnetite composite was used for the photocatalytic degradation of pollutant parameters [polyphenols, chemical oxygen demand (COD) components, total aromatic amines (TAAs) ] from the olive mill effluent wastewater at different pH (4.0-7.0-9.0) conditions, at temperatures (21, 30, and 40 degrees C), at different H2O2 concentrations (50, 100, 200, and 1,000mg/l), at different retention times (15, 30, 45, and 60 min), and increasing hydrogel-coated Fe3O4 magnetite composite concentrations under 100W ultraviolet (UV) and 29W sunlights. The maximum CODtotal, polyphenols, and TAAs yields were 96%, at between 88 and 94%, and at between 83 and 94%, respectively, at 3g/l of hydrogel-coated Fe(3)O(4)magnetite nano composite concentration, at 100W UV light irradiation, at pH 4.0, after 60min retention time, respectively. At the lowest molar ratio of 1/5 in the iron(II) chloride tetrahydrate and iron(III) chloride hexahydrate to hydrogel the highest photodegradation obtained at 30 degrees C. When the molar ratio of the iron(II) chloride tetrahydrate and iron(III) chloride hexahydrate to hydrogel was 1/3 to the maximum photodegradation reached at 40 degrees C. At the higher molar ratio of 1/2, the best photodegradation yields were obtained at 40 degrees C. The maximum CODtotal, polyphenols, and TAAs yields were obtained at acidic pH, and at 50mg/l H2O2 concentration. The Fe3O4 nanoparticles exhibited high catalytic recyclability under magnetic conditions resulting in significant decrease in treatment costs

Advanced oxidation of commercial textile biocides in aqueous solution: effects on acute toxicity and biomass inhibition

In the present study, the decomposition of two biocides used in the textile finishing process with Advanced Oxidation Processes (AOPs) has been studied. Different AOPs, i.e O-3/OH-, TiO2/UV-A and Fe2+/H2O2 have been used representing mutually combined components of the chemically and photochemically driven advanced oxidation systems. The course of reaction was examined by changes in chemical oxygen demand (COD), total organic carbon (TOC) and acute toxicity towards the water flea Daphnia magna (assessed in terms of the effective dilution ratio LD50). Particular attention has been paid to determine the inhibitory effect of raw and ozonated biocides on biological activated sludge consortium at concentrations typically encountered in textile finishing effluents. Significant oxidation and mineralization of both biocides could be achieved employing ozonation at pH = 11.5 and heterogeneous photocatalysis (TiO2/UV-A) at pH = 5.0, whereas Fenton's reagent appeared to be less effective in COD and acute toxicity abatement

Treatment of olive mill wastewater by photooxidation with ZrO 2

Zirconium dioxide (zirconia, ZrO2)-doped TiO2 (TiO2/ZrO2) nanocomposite was used for the photocatalytic oxidation of pollutant parameters [COD components (CODtotal, CODdissolved and CODinert)], polyphenols (catechol, 3-hydroxybenzoic acid, tyrosol and 4-hydroxybenzoic acid) and total polyaromatic amines [aniline, 4-nitroaniline, o-toluidine and o-anisidine] from the olive mill effluent wastewaters at different operational conditions such as at different mass ratios of ZrO2 (50, 25, 14, 10 and 5 wt%) in the TiO2/ZrO2 nanocomposite, at different TiO2/ZrO2 photocatalyst concentrations (1, 4, 15 and 50 mg/L) and pH values (4.0-7.0-10.0) under 300 W UV irradiations, respectively. Under the optimized conditions (pH = 4.6, 15 mg/L ZrO2/TiO2 nanocomposite with a ZrO2 mass ratio of 14 wt%, 300 W UV light, after 60 min photooxidation time, at 21 degrees C), the maximum CODdissolved, total phenol and total aromatic amines photooxidation yields were 99%, 89% and 95%, respectively. High pollutant removal (89%) yields after sequential five times utilization of ZrO2/TiO2 nanocomposite show that this catalyst can be effectively used commercially in the treatment of olive mill effluent

Pollutant footprint analysis for wastewater management in textile dye houses processing different fabrics

BACKGROUND: This study investigated the water and pollution footprints of a dye house, which processed cotton knits, polyester (PES) knits and PES-viscose woven fabrics. Experimental evaluation was carried out for each processing sequence. Variations in wastewater flow and quality were established as a function of the production program in the plant. A model evaluation of wastewater dynamics was performed and defined specifications of an appropriate treatment scheme. RESULTS: The plant was operated with a capacity of 4300 t year−1 of fabric, which generated a wastewater flow of 403 500m3 year−1 and a COD load of 675 t year−1. The overall wastewater footprint of the plant was computed as 91m3 t−1 and the COD footprint as 160 kg t−1 of fabric. Depending on the fabric type, results indicated expected changes in wastewater flow between 600 and 1750m3 day−1 in COD load between 1470 and 2260 kg day−1 and in COD concentration between 1290 and 3400mgL−1. CONCLUSION: A model simulation structured upon COD fractionation and related process kinetics revealed partial removal of slowly biodegradable COD, coupled with high residual COD, which would by-pass treatment. Resulting biodegradation characteristics necessitated an extended aeration system, which could also enable partial breakdown of residual COD. Effluent COD could be reduced to 220–320mgL−1 with this wastewater management strategy. © 2018 Society of Chemical Industr