In this study, a novel photoelectrocatalytic membrane (PECM) reactor was tested as an option for the desalination, disinfection, and detoxification of biologically treated textile wastewater (BTTWW), with the aim to reuse it in hydroponic farming. The anionic ion exchange (IEX) process was used before PECM treatment to remove toxic residual dyes. The toxicity evaluation for every effluent was carried out using the Vibrio fischeri, Microtox^® test protocol. The disinfection effect of the PECM reactor was studied against E. coli. After PECM treatment, the 78.7% toxicity level of the BTTWW was reduced to 14.6%. However, photocatalytic desalination during treatment was found to be slow (2.5 mg L⁻¹ min⁻¹ at 1 V potential). The reactor demonstrated approximately 52% COD and 63% TOC removal efficiency. The effects of wastewater reuse on hydroponic production were comparatively investigated by following the growth of the lettuce plant. A detrimental effect was observed on the lettuce plant by the reuse of BTTWW, while no negative impact was reported using the PECM treated textile wastewater. In addition, all macro/micronutrient elements in the PECM treated textile wastewater were recovered by hydroponic farming, and the PECM treatment may be an eco-safe wastewater reuse method for crop irrigation.

Innovative textiles have been concern of emerging risk of nanoparticles (NPs) to human and environment. This study aimed to investigate the aggregation, removal and biological, and ecotoxicological effects of sol–gel-based TiO₂ NPs while the treatment of textile wastewater. Fe(II) and alum coagulants were applied for the removal of spiked TiO₂ NPs from textile wastewater. Particle size distribution, absorbance values (UV–vis range), and residual TiO₂ NPs were followed to define aggregation mechanism, including pH variation during treatment of wastewater. The effect of TiO₂ on activated sludge treatment was followed by monitoring of oxygen uptake rate (OUR). Ecotoxicity of sol–gel and coagulated samples was observed by Ceriodaphnia magna immobilization test. Adjustment of pH to 8 enlarged mean particle size distribution of sol–gel-based TiO₂ NPs from 30 to 450 nm. After alum and Fe(II) coagulations, average particle size distributions were observed to be 650 and 960 nm, respectively. Coagulation with alum and Fe(II) resulted over >95% removal of TiO₂ from biologically treated textile wastewater (BTTWW). The value for residual TiO₂ concentration in BTTWW was reduced from 120 μg/L to around 8 μg/L TiO₂ NPs exhibited slight/no toxicity on the OUR while toxicity to Ceriodaphnia dubia increased in some coagulated samples, most probably due to higher residual coagulant concentrations.