Comamonas sp. UVS was able to decolorize Reactive Blue HERD (RBHERD) dye (50 mg L−1) within 6 h under static condition. The maximum dye concentration degraded was 1,200 mg L−1 within 210 h. A numerical simulation with the model gives an optimal value of 35.71 ±â€‰0.696 mg dye g−1 cell h−1 for maximum rate (Vmax) and 112.35 ±â€‰0.34 mg L−1 for the Michaelis constant (Km). Comamonas sp. UVS has capability of decolorization of RBHERD in the presence of Mg2+, Ca2+, Cd2+, and Zn2+, whereas decolorization was completely inhibited by Cu2+. Metal ions also affected the levels of biotransformation enzymes during decolorization of RBHERD. Comamonas sp. UVS was also able to decolorize textile effluent with significant reduction in COD. The biodegradation of RBHERD dye was monitored by UV–vis spectroscopy, FTIR spectroscopy, and HPLC.

The performance of raw bagasse (RB), and tartaric acid-modified bagasse (TAMB) as adsorbents on decolorization and chemical oxygen demand (COD) reduction of methylene blue (MB) aqueous solution was studied. The effects of five factors namely: adsorbent dosage, pH, shaking speed, contact time, and temperature on decolorization and COD reduction were studied and optimized using central composite design (CCD). The results of the analysis show that all selected factors exhibit significant effect on decolorization and COD reduction. Maximum decolorization (78.16%) and COD reduction (77.95%) for RB was achieved at 0.82 g of adsorbent dosage, pH 9.4, 122 rpm of shaking speed, 44 min of contact time, and 55°C. For TAMB, maximum decolorization (99.05%) and COD reduction (98.45%) was achieved at 0.78 g adsorbent dosage, pH 9.4, shaking speed of 120 rpm, 34 min contact time, and 49°C. TAMB was found to be more effective than RB in decolorization and COD reduction of MB aqueous solution.

Purpose Textile dyeing and sago industries are the most polluting industries in South India, especially in industrial cities like Salem, Tamil Nadu, where textile dyeing and sago industries are clumped together geographically. Conventional physicochemical treatment followed by biological processes for the effluent generated from these industries are ineffective, costlier and produce huge quantities of hazardous sludge and harmful by-products which requires further treatment and safe disposal. Hence, the development of an alternative treatment method will become important. The main objective of this investigation is to establish a sustainable biotreatment technology for the treatment of textile dyeing effluent using sago effluent as co-substrate in a two-phase upflow anaerobic sludge blanket (UASB) reactor. Methods In this study, influence of hydraulic retention time (HRT) in a two-phase UASB reactor treating textile dyeing effluent using sago effluent as co-substrate was investigated with different HRTs (36, 30, 24 and 18 h) with an optimum mixing ratio of 70:30 (sago to textile dye wastewaters). Results The results revealed that the HRT had a high influence on the chemical oxygen demand (COD) and colour removal. The maximum COD removal efficiency of 39.4% and 88.5% and colour removal efficiency of 43.7% and 84.4% in the acidogenic and methanogenic reactors, respectively was achieved at 24 h of HRT. The biogas production was 312 L/day. Conclusion The biphasic UASB reactor could be a very feasible alternative, cost-effective, eco-friendly and sustainable treatment system for textile dyeing effluent with sago effluent as a co-substrate.

PURPOSE: The dyes and dye stuffs present in effluents released from textile dyeing industries are potentially mutagenic and carcinogenic. Phytoremediation technology can be used for remediating sites contaminated with such textile dyeing effluents. The purpose of the work was to explore the potential of Glandularia pulchella (Sweet) Tronc. to decolorize different textile dyes, textile dyeing effluent, and synthetic mixture of dyes. METHODS: Enzymatic analysis of the plant roots was performed before and after decolorization of dye Green HE4B. Analysis of the metabolites of Green HE4B degradation was done using UV–Vis spectroscopy, high-performance liquid chromatography (HPLC), Fourier transform infrared spectroscopy (FTIR), and gas chromatography–mass spectroscopy (GC-MS). The ability of the plant to decolorize and detoxify a textile dyeing effluent and a synthetic mixture of dyes was studied by a determination of the American Dye Manufacturer’s Institute (ADMI), biological oxygen demand (BOD), and chemical oxygen demand (COD). Phytotoxicity studies were performed. RESULT: Induction of the activities of lignin peroxidase, laccase, tyrosinase, and 2,6-dichlorophenol indophenol reductase was obtained, suggesting their involvement in the dye degradation. UV–Vis spectroscopy, HPLC, and FTIR analysis confirmed the degradation of the dye. Three metabolites of the dye degradation were identified, namely, 1-(4-methylphenyl)-2-{7-[(Z)-phenyldiazenyl] naphthalen-2-yl} diazene; 7,8-diamino-2-(phenyldiazenyl) naphthalen-1-ol; and (Z)-1,1′-naphthalene-2,7-diylbis (phenyldiazene) using GC-MS. ADMI, BOD, and COD values were reduced. The non-toxic nature of the metabolites of Green HE4B degradation was revealed by phytotoxicity studies. CONCLUSION: This study explored the phytoremediation ability of G. pulchella (Sweet) Tronc. in degrading Green HE4B into non-toxic metabolites.

INTRODUCTION: Acid orange 52 (AO52), extensively used in textile industries, was decolorized by Pseudomonas putida mt-2. AO52 azoreduction products such as N,N′-dimethyl-p-phenylenediamine (DMPD) and 4-aminobenzenesulfonic acid (4-ABS), were identified in the static degradation mixture. These amines were identified only in media of static incubation, which is consistent with their biotransformation under shaken incubation (aerobic conditions). MATERIALS AND METHODS: Tests with azo products were carried out, and whole cells were found able to easily degrade DMPD contrary to 4-ABS. However, this last could be attacked by cell extract, and an oxygen uptake was observed during the reaction. RESULTS: Degradation of DMPD by entire cells led to the formation of catechol. These results show that P. putida was able to decolorize AO52 and metabolize its derivative amines. In addition, the ability of tested compounds was evaluated in vitro to reduce human plasma butyrylcholinesterase (BuChE) activity. CONCLUSION: Azoreduction products seem to be responsible for BuChE inhibition activity observed in static biodegradation extract. However, toxicity of AO52 completely disappears after shaken incubation with P. putida, suggesting that bacterium has a catabolism which enables it to completely degrade AO52 and especially, to detoxify the dye mixture.