Treatment of textile dyeing industry effluent using hydrodynamic cavitation in combination with advanced oxidation reagents
Introduction
In recent years, effluents from the textile processing industry have become a cause of serious environmental concern. The use of synthetic chemical dyes by the textile industries in the various textile processing operations such as dyeing, printing, bleaching and finishing operations has resulted in the release of large amounts of dye-containing industrial wastewater. There are about 2324 textile industries in India [1]. More than ten thousands dyes are being used commercially and approximately 7 × 105 tons of synthetic dyes are produced per annum worldwide [2], [3]. Textile wastewaters are found to have large quantity of suspended particles, varied pH, dark colored, with high chemical oxygen demand (COD) and high total organic carbon (TOC) [4], [5], [6]. The presence of highly suspended solid particles with their strong color provides high turbidity in the textile effluents. Even very low concentration of these dyes (less than 1 ppm for some dyes) induce color in water that is highly observable and undesirable and adversely affects the water bodies such as rivers, lakes etc. [7], [8]. Most of the dyes are toxic and bio-recalcitrant in nature and therefore conventional biological processes are found to be inefficient for treatment of textile effluents [3]. The untreated textile wastewaters due to the presence of carcinogenic compounds are therefore very hazardous and toxic to human beings and animals also. Considering the fact that the aquatic environment is damaged by the wastewaters discharged from textile dyeing industries, it is required to develop an eco-friendly and energy efficient technique to treat the textile effluent before its discharge into the aquatic environment. Several conventional strategies comprised of various combinations of physical, chemical, and biological oxidation processes were developed for treatment of textile effluents in last one decade [6], [9], [10], [11], [12], [13]. However, these processes produce large amount of secondary pollutants which ultimately increase the load on overall treatment facility [5], [13]. In recent years, cavitation as an advanced oxidation process (AOP) has been receiving greater attention for the treatment of wastewater [14], [15], [16]. Cavitation comprises of the nucleation, growth, and subsequent collapse of micro-bubbles or cavities, occurring in a small time interval at multiple locations in the reactor and thus releases large magnitude of energy [17]. The collapse of cavities creates the ‘hot spots’ (a very high temperature and pressure region) resulting in the formation of OH, H, HO2 and also H2O2 [18], [19]. In the last two decades, ultrasonication has been studied for wastewater treatment [20], [21], [22], however it has not found any application so far on an industrial scale due to the higher maintenance costs involved and lower energy efficiency [15]. An alternative cavitation technology i.e. HC has been found to be more energy efficient as compared to acoustic cavitation for the degradation of organic pollutants and which can also be operated in a continuous mode [14], [17], [23], [24], [25], [26]. The degradation efficiency of HC can be improved by combining with other advanced oxidation processes/oxidizing agents such as H2O2, Fenton’s reagent, ozone and photocatalytic oxidation [15], [16], [24], [27], [28], [29]. Mishra and Gogate [27] investigated the degradation of Rhodamine B dye using HC in the presence of intensifying additives. They found that almost 59.3% degradation and 30% TOC reduction were achieved using HC alone at an optimized inlet pressure of 4.84 atm and solution pH of 2.5. The degradation efficiency was further increased to 99.9% along with 55% reduction in TOC when HC was combined with hydrogen peroxide (200 mg/L). Gogate and Bhosale [28] studied the combined approach for the degradation of Orange Acid II dye and reported that combination of HC with oxidizing agents such as sodium persulfate, H2O2 and NaOCl was found to be better as compared to use of the individual oxidants. Almost complete degradation of Orange Acid II was obtained in 60 min using HC in combination with sodium persulfate (535.72 mg/L) oxidant.
Although many studies report on the degradation of synthetically prepared dye wastewater using HC coupled with various oxidative additives mostly at low concentration ranges (i.e. 50–100 ppm), however no study has been reported so far for real textile dying industry (TDI) effluent. It is necessary to study the efficacy of HC and its hybrid processes for treating real TDI effluents before applying on an industrial scale. This study focuses on investigating the performance of HC system for treating the TDI effluent. Effects of process parameters (operating inlet pressure and dilution) on the TOC, COD and color reduction were investigated. In order to enhance the efficiency of HC, the effect of advanced oxidative reagents such as oxygen, ozone, and Fenton in combination with HC were also studied.
Section snippets
Textile dyeing industry (TDI) effluent
TDI effluent was taken from the collection tank after dyeing, printing, and finishing processes in a textile dyeing industry (details not given due to confidentiality issues), located at Sanganer industrial zone, Jaipur, India. The characteristic of the TDI effluent is presented in Table 1. Dyes (reactive, direct, and acid dyes), detergents, chlorinated compounds and dissolved salts are the likely pollutants that make up the TOC and COD of the TDI effluent. The TDI effluent was initially
Effect of operating inlet pressure
The inlet pressure and cavitation number are the two major parameters that affect the cavitational conditions inside the cavitating device and influencing the efficiency of HC system [15], [16], [17]. In order to investigate the effect of inlet pressure on the treatment of TDI effluent, experiments were performed by varying inlet pressure from 3 to 10 bar. The obtained results are shown in Fig. 2 and Table 2 presents the cavitation number, velocity, and flow rate through cavitating device. It
Conclusions
The present work reports the effective use of HC in combination with advanced oxidative reagents such as air, oxygen, ozone and Fenton’s reagent to reduce TOC, COD and color of the TDI effluent. The efficiency of HC reactor is affected by process parameters such as inlet pressure and dilution. Maximum reduction in TOC, COD, and color were 17.27%, 12%, and 25% respectively using HC alone at 5 bar operating inlet pressure. The dilution study did not show any significant impact on the actual
Acknowledgement
Dr.Virendra Kumar Saharan would like to thank Department of Science & Technology, New Delhi, India for providing financial support under Inspire Faculty Fellowship (DST/INSPIRE Faculty Award/2013/IFA13-ENG49).
References (38)
- et al.
Remediation of dyes in textile effluent: a critical review on current treatment technologies with a proposed alternative
Bioresour. Technol.
(2001) - et al.
Treatment of textile wastewaters by electrocoagulation using iron and aluminum electrodes
J. Hazard. Mater.
(2003) - et al.
Treatment of textile wastewater by electrochemical methods for reuse
Water Res.
(1997) - et al.
Treatment of textile wastewater by electrochemical method
Water Res.
(1994) - et al.
Physical removal of textile dyes and solid state fermentation of dyeadsorbed agricultural residues
Bioresour. Technol.
(2000) - et al.
Effect of organic load on decolourization of textile wastewater containing acid dyes in upflow anaerobic sludge blanket reactor
J. Hazard. Mater.
(2010) - et al.
Methods of decoloration of textile wastewaters
Dye Pigm.
(1998) - et al.
Pre-oxidation and coagulation of textile wastewater by the Fenton process
Chemosphere
(2002) - et al.
Electrochemical oxidation of a textile dye wastewater using a Pt/Ti electrode
J. Hazard. Mater.
(1999) - et al.
Degradation of Reactive Red 120 dye using hydrodynamic cavitation
Chem. Eng. J.
(2011)
Degradation of a cationic dye (Rhodamine 6G) using hydrodynamic cavitation coupled with other oxidative agents: reaction mechanism and pathway
Ultrason. Sonochem.
Degradation of reactive blue 13 using hydrodynamic cavitation: effect of geometrical parameters and different oxidizing additives
Ultrason. Sonochem.
Modeling of hydrodynamic cavitation reactors: a unified approach
Chem. Eng. Sci.
Destruction of Rhodamine B using novel sonochemical reactor with capacity of 7.5 l
Sep. Purif. Technol.
Degradation of dichlorvos containing wastewaters using sonochemical reactors
Ultrason. Sonochem.
Ultrasound enhanced degradation of Rhodamine B: optimization with power density
Ultrason. Sonochem.
Cavitationally induced biodegradability enhancement of a distillery wastewater
J. Hazard. Mater.
Treatment of the pesticide industry effluent using hydrodynamic cavitation and its combination with process intensifying additives (H2O2 and ozone)
Chem. Eng. J.
Treatment of industrial wastewater effluents using hydrodynamic cavitation and the advanced Fenton process
Ultrason. Sonochem.
Cited by (138)
Synergistic degradation of Congo Red by hybrid advanced oxidation via ultraviolet light, persulfate, and hydrodynamic cavitation
2024, Ecotoxicology and Environmental SafetyApplication of combined hydrodynamic cavitation and Fenton reagent for COD reduction of cellulosic fiber industry effluents
2023, Journal of Water Process EngineeringDegradation of neomycin using hydrodynamic cavitation based hybrid techniques
2023, Chemical Engineering and Processing - Process Intensification