Characteristics and performance of aerobic granular sludge technology in the treatment of real batik textile wastewater

Batik wastewater contains complex and toxic pollutants. The current applied technologies for treating batik wastewater have drawbacks that need to be addressed. The potential application of aerobic granular sludge has been widely explored because of its features and capabilities for wastewater treatment. The present study proposes the application of aerobic granular sludge to treat batik wastewater treatment and aims to investigate the characteristics and performance of removal pollutants. Aerobic granular sludge seed was derived from conventional activated sludge, initially cultivated with acetate as substrate, in a sequencing batch reactor of 5 h. The development of aerobic granular sludge in the experiment was marked by an increase in the ratio of mixed liquor volatile suspended solid to mixed liquor suspended solid to 0.92, settling velocity to 16 cm/min, and percentage of granules to 94.80%. The steady-state granulation system was achieved after 32 days of operation, indicated by the sludge volume index ratio of 30–5 min of 0.97. The study shows that increasing concentration of batik wastewater negatively affects the system condition and pollutant removal performance. The use of acetate as co-substrate increases chemical oxygen demand, biochemical oxygen demand, total suspended solids, and color removal of 73.8%, 73.44%, 85.65%, and 43.25% respectively. Foaming conditions in the aerobic phase and open-design reactor caused a lot of biomass wash-out and decreased the overall pollutant removal. Therefore, the findings suggest that supplementation of easily biodegradable carbon sources and process acclimatization are proposed to increase the stability and efficiency of wastewater treatment.