Colour removal from fermentation industry effluents

Abstract

Large amounts of effluents from the fermentation industry are characterized by high COD and colour. Although significant reduction in COD is achieved through biological treatment processes, a substantial amount of colour remains. Coagulation and flocculation with alum and iron salts are not effective for colour removal. This is due to the nature of colour causing compounds which are almost totally dissolved and resistant to biodegradation. Hence, fermentation industries face difficulties in discharging their coloured effluents into either sewers or surface waters. In this study, colour removal from biological treatment plant effluents of a fermentation industry with lime and ozone was investigated experimentally. Optimum lime dose for reducing the colour to values around 1000 Pt-Co was found as 10.0 g/l, while 0.9 g/l ozone was necessary to obtain the same residual colour. Economic evaluation has indicated that cost of lime treatment was 1.3 to 1.4 USD/m3 while it was 2.5 USD/m3 for ozone treatment. Annual total costs for lime and ozone treatment were also estimated as 2 million USD and 3.65 million USD, respectively.

Wastewater treatment in molasses-based alcohol distilleries for COD and color removal: A review

“…Also, even though biological treatment results in significant COD removal, the effluent still retains the dark color (Inanc et al, 1999). The color imparting melanoidins are barely affected by conventional biological treatment such as methane fermentation and the activated sludge process (Migo et al, 1993).…”

Decolorization of synthetic melanoidins-containing wastewater by a bacterial consortium

“…Currently, the decolorization of melanoidins in wastewater is based mainly on physical and chemical methods such as ozonization, flocculation, chemical coagulation, precipitation, activated carbon adsorption and advanced oxidation of the wastewater [4,17,25,28,39]. However, the implement of physical and chemical methods eventually may generate significant amount of sludge, cause secondary pollution due to excessive chemical usage, and have some drawbacks such as high cost, formation of hazardous by-products and intensive energy consumption.…”

Combined Treatment of Vinasse by an Upflow Anaerobic Filter-Reactor and Ozonation Process

“…However, as noted above, an anaerobic treatment may not be entirely effective in vinasse processing; thus, it has been suggested that a combination of biological and physicalchemical treatments might guarantee the appropriate final disposal of vinasse. Numerous investigations of vinasse post-treatment methods have been conducted, including those of adsorption treatments (Figaro et al, 2009;Satyawali and Balakrishnan 2007) and coagulation-flocculation, electrocoagulation, ozonation and ultrasonic treatments (Zayas et al, 2007;Inanc et al, 1999;Peña et al, 2003;Sangave et al, 2007). The disadvantages of these posttreatments include their operational difficulties, the high doses of required reagents, the high energetic costs, the unsatisfactory coagulant-recovery rates and the production of polluted sludge.…”

“…Furthermore, most of the relevant studies of ozonation utilized a combination of anaerobic/aerobic treatments with high ozone dosification (Peña et al, 2003) or intermediate treatments between the anaerobic and the aerobic process (Inanc et al, 1999;Sangave et al, 2007).…”