Bioaugmented aerobic granular sludge reactor with a dye-decolorizing yeast for dye removal from textile industry wastewater

Textile industry is a worldwide economic activity that generates high volumes of harmfuleffluents used in fabric processing that are discharged in the environment causing potentialdamages to the aquatic ecosystems [1]. These discharged effluents loaded with synthetic dyes,salt and other chemicals, are resistant to biodegradation and persistent in water, and areresponsible for toxicity and mutagenic effects on the aquatic life [2]. Biological methods aregenerally considered more environmentally friendly and of major relevance [3]. Therefore,biological alternatives to aid the decolorization of dyes in textile wastewaters need to beimplemented. Aerobic granular sludge (AGS) technology has excellent potential inbiodegradation of many pollutants, due to the anoxic/anaerobic zones within granules and theirincreased tolerance to toxicity [4].The aim of this study is to assess the effectiveness of decolorization of textile effluents using abioaugmented aerobic granular sludge reactor. A proved decolorizing yeast, isolated from atextile wastewater treatment plant, was selected for its dye decolorization capacity, and usedto bioaugment the bioreactor while forming the granules from activated sludge. Theincorporation of the yeast with the granules was followed by plating and following the yeastwithin the microbial community. A commonly used textile azo dye was added to the reactor tofollow the biodegradation by the bioaugmented aerobic granular sludge and the efficiency ofthe process in decolorizing the effluent at varying operational parameters was followed to assessif this is a solution for a safer discharge of such effluents.