Alenka Ojstršek

The use of constructed wetland for dye-rich textile wastewater treatment.

The objective of the present paper was to examine the treatment efficiency of constructed wetlands (CW) for the dye-rich textile wastewater with special focus on colour reduction. Preliminary, a series of dynamic experiments was performed in the CW model packed with gravel, sand, and zeolitic tuff on three synthetically prepared wastewaters using chemically differ dyestuffs, auxiliaries and chemicals, in order to investigate the potential of low-cost materials as media for textile dye-bath wastewater treatment. The obtained results evidence that applied CW model reduces colour by up to 70%, and COD and TOC by up to 45%. Based on these results, the pilot CW with vertical (VF) and horizontal flow (HF) was constructed near textile factory mainly for cotton and cotton/PES processing with intention to treat real textile wastewater in situ. It was designed for 1m3/day, covering 80 m2, packed with sand and gravel, and planted with Phragmites australis. The average treatment efficiency of the CW for the selected pollution parameters were: COD 84%, BOD5 66%, TOC 89%, Ntotal 52%, Norganic 87%, NH4-N -331%, sulphate 88%, anion surfactant 80%, total suspended solids (TSS) 93%, and colour 90%, respectively. The results unequivocally proved that the CW could offer an optimal solution to meet the environmental legislation as well as requirements for effective and inexpensive textile wastewater treatment.

Optimization of removal of colour and organic pollutants from textile wastewater treated with UV/H2O2 adopting the Plackett–Burman factorial design

Abstract In the research work presented here, a Plackett–Burman two-level partial factorial design was adopted as a multivariate strategy to determine the optimum UV/H2O2 process conditions for maximizing the treatment efficiency of dye-rich textile effluents. The influence of wastewater parameters, i.e. type and concentration of dye (C Dye), 100–300 mg/L; concentration of NaCl (C NaCl), 2.5–3.5 g/L; and concentration of urea (C Urea), 5–15 g/L; and the amount of NaOH (C NaOH), 1–2.4 mL/L; as well as the operational parameters, i.e. intensity of UV irradiation (I UV), 1.2–1.4 kW; the amount of H2O2 , 0.7–8.3 mL/L; and treatment time (t), 6–30 min; on the colour and the removal of organic pollutants was investigated. After determining seven variables, laboratory-scale experiments were conducted using two synthetically-prepared wastewaters solutions that were polluted with two structurally different reactive dyes and selected chemicals. The assessment of the UV/H2O2 pilot plant’s performance was by monitori...

Thermal, Mechanical and Optical Features of Aluminosilicate-Coated Cotton Textiles via the Crosslinking Method

The presented study focuses on the development of a pad-dry-thermofix functional coating process using a mixture of microporous aluminosilicate particles in diverse bath formulations to impart UV-ray-blocking, thermal stability and easy-care properties to the cotton fabric. The results of Scanning Electron Microscopy (SEM) and X-ray powder Diffraction (XRD) revealed the presence of three different types of zeolites within the examined sample, i.e., the largest amount being zeolite A, followed by the zeolite X, and the zeolite ZSM-5. The surface characterization results of zeolite-coated/cross-linked textiles provided evidence of acceptable UV-ray-blocking properties and increased thermal stability, as well as enhanced tensile strength and breaking tenacity without considerably decreasing the whiteness degree. Moreover, the dry crease recovery angle increased for the cotton fabric cross-linked via an mDMDHEU, and decreased significantly using 30 g/L zeolites negatively influencing qualitative values. TG/DTA results have proven the enlarged thermal stability of aluminosilicate-coated cotton, although combustion was not prevented.

The performance of a fixed-bed treatment system packed with layered textiles for their filtration/adsorption potential for salt and organic pollutant

Abstract The main contribution of the research work presented here was to select and investigate a few commercially available textiles to study their filtration/adsorption potential for salt and total organic carbon (TOC) reduction during wastewater treatment. First, several physical–mechanical properties, such as tensile strength, thickness, weight, density and structural aspect of two woven (polyamide and polyester) and two nonwoven (polypropylene [PP] and PP/polyethylene [PE]) textiles, were determined. Also, the void amount and total void area percentage of textiles were measured, which influence the wastewater flow (clog) and filtration efficiency. With the intention of examining the adsorption ability of the selected textiles, kinetic experiments were carried out in shake-flasks using three commonly-used salts. Afterwards, small-scale column experiments were conducted in a continuous-flow operation to assess the TOC and salt reduction. It was found that both nonwoven textiles (either made from PP or...

Layered compact textiles applied in fixed-bed column as filters for dye-rich textile wastewaters treatment—a case study

Abstract The presented case study examined the possibility of using four commercially available compact textiles in small-scale column purifying system conducted in a continuous-flow operation as filters for colour, organic pollutants and salt reduction. Two wastewaters were prepared for the experimental purposes by combining chemically different dyestuffs, auxiliaries and chemicals in order to simulate dye-bath effluents from cotton (reactive) and wool (acid) dyeing, respectively. Treatment of the laboratory-prepared wastewaters was carried out in columns packed with alternating layers of sand and individual compact textile and, for comparison, in a column comprised merely of sand. It was found that both non-woven textiles, either made from polypropylene (PP) or bicomponent PP/polyethylene (PE) yarn with more complex structure and higher total void area, were more suitable for adsorption/filtration of colour and organic pollutants from dye-rich textile wastewaters in comparison to both woven fabrics. Mon...