Combined advanced oxidation and biological treatment of tannery effluent

Abstract

During leather processing in tanneries, considerable amount of wastes with organic and inorganic pollutants are generated. For removal of these pollutants and recovery of water, biological treatment methods and reverse osmosis (RO) based membrane technologies are adopted. While recovering water from treated tannery effluent using RO membranes, presence of residual organics, dye molecules, and other impurities in the effluent have been reported as the major drawback which leads to membrane fouling and failure. In this study, an attempt was made to improve the quality of the treated tannery effluent by subjecting the secondary treated tannery effluent by ozonation alone and ozonation of primary and secondary treated tannery effluent followed by aerobic biological Sequential Batch Reactor (SBR). Maximum color reduction of 98% at pH value of 12 with ozonation alone was observed for secondary treated tannery effluent. Ozonation of secondary treated tannery effluent followed by further biological treatment in aerobic SBR increased the chemical oxygen demand (COD) removal rate and resulted in COD values less than 300 mg/L. In case of primary treated tannery effluent, maximum COD reduction of 64% was achieved in SBR.

Development of Adsorbent from Sugarcane Bagasse for the Removal of Pollutants from Chrome Tanning Effl uents

“…The previous studies reported that only 60-70% of used chromium is consumed by the pelt in the traditional chrome tanning process and the rest is discharged into the chrome tanning effluent, causing a great waste of chrome and severe environmental pollution [6,7]. Effluent comes from tannery operations, containing huge amounts of pollutants and heavy metals [8]. These pollutants may cause serious environmental pollution and may be considered as one of the biggest challenges for the sustainability of the leather industry [9][10][11].…”

“…Effluent comes from tannery operations, containing huge amounts of pollutants and heavy metals [8]. These pollutants may cause serious environmental pollution and may be considered as one of the biggest challenges for the sustainability of the leather industry [9][10][11]. However, most of the developing countries do not have the proper technology to treat tannery effluents before discharging it in the natural environment [12].…”

Comparing treatment methods that remove color from the effluent of an Organized Industrial District (OID)

“…However, single-stage treatment methods removing color are not sufficient to achieve environmental discharge criteria. In the literature, numerous combined processes have been examined to remove color, such as chemical and physicochemical processes [17], aerobic and anaerobic biological treatment [18], activated sludge treatment with nanofiltration [19], electrochemical and advanced oxidation processes [20], nanofiltration and reverse osmosis [21,22], ozonation-coagulation processes [23], and advanced oxidation and biological treatment [24].…”

Improvement in treatment of soak liquor by combining electro-oxidation and biodegradation

“…3,5 The native concentration of chloride favours pre-treatment in electro-oxidation. Szpyrkowicz et al, 6 Srinivasan et al 7 and Kanagasabi et al 8 did pretreatment processes viz. electro-oxidation and chemical oxidation (ozone treatment) before biological treatment.…”