On-site treatment of dyeing wastewater by a bio-photoreactor system

Abstract

Synthetic dyeing wastewater consisting of the three different commercial dyes with different strengths of COD (about 900 and 3000 mg/l respectively) was initially treated by an aerobic biological process, Intermittently Decanted Extended Aeration reactor (IDEA), for BOD removal, and then continuously treated by a TiO2 sensitised photoreactor for a further COD removal and decolorization. The catalysed photooxidation process can degrade those non-biodegradable organic substances in the effluent treated by the IDEA process and also decolorize the effluent completely. It is also found that some nonbiodegradable organic substances can be converted to biodegradable forms by the sensitized photo-oxidation reaction. A bio-photoreactor system was designed to combine this photocatalytic reactor with the IDEA reactor for the treatment of dyeing wastewater. The performance of this combined bio-photoreactor system with and without recirculation was investigated and compared. The system with recycled water has similar efficiency for decolorization and COD removal to that without recirculation, but has a high capacity to eliminate the effects caused by a shock loading, and also the system can treat dyeing wastewater with a higher organic concentration.

Operational conditions of a membrane filtration reactor coupled with photocatalytic oxidation

“…titanium dioxide, TiO 2 ) receives ultraviolet (UV) photons and generate hydroxyls [5] as oxidant [6]. Industrial wastewaters [7][8][9], effluents of biologically treated wastewaters [10,11] and polluted river water [12] have been tested and confirmed effective by photocatalytic oxidation. So far the photocatalytic reactors use mainly supported * Corresponding author.…”

Incorporating biodegradation and advanced oxidation processes in the treatment of spent metalworking fluids

“…However, the chemicals required to lower the pH during the photo-Fenton process and to adjust it back afterwards should be considered. The main advantage of the UV/TiO 2 process is that no chemicals are required, and it was previously found to be very effective at removing colour and COD from high organic load wastewater [16]. Although not very successful here in removing COD during the CB trials, high removals were achieved in the photocatalytic reactor, although at a much higher power input (0.6 kW).…”

“…They have also been reported to significantly enhance the biodegradability of recalcitrant compounds such as pesticides and pharmaceuticals as well as remove the recalcitrant organics in the post-biological stage [10,15]. Further, UV/TiO 2 proved to be a very economical and effective method in treating biological effluent of dying wastewater [16]. However, the treatment of a high organic load and complex waste such as spent MWFs has not been widely reported to the best of our knowledge.…”

Advanced Oxidation Processes (AOPs) for Removal of Pesticides from Aqueous Media

“…Relatively few works on the application of this kind of coupled methodologies are available in literature. Most of them corresponds to ozonation processes (Marco et al, 1997;Helble et al, 1999;Yeber et al, 1999;Beltran et al, 1999;Benitez et al, 2001;Ledakowicz et al, 2001), H 2 O 2 /UV (Adams and Kuzhikanni, 2000; Ledakowicz et al, 2001), TiO 2 /UV oxidation (Li and Zhang, 1996;Li and Zhao, 1997;Chum and Yizgohon, 1999;Hess et al, 1998;, Fenton and Fenton-like (Pulgarin et al, 1999;Chamarro et al, 2001;Sarria et al, 2003;Rodriguez et al, 2002;Sarria et al, 2001;Sarria et al, 2002) and wet oxidation (Donlagic and Levec, 1998). It is clear that pesticide removal from water should be one of the main applications of this coupled methodology.…”