Sequential anaerobic–intermittently aerated treatment of textile and domestic wastewater

ABSTRACT A laboratory-scale biological system operated in a batch sequential anaerobic–intermittently aerated reactor was used to treat textile wastewater. The anaerobic system was aimed at colour and chemical oxygen demand (COD) removal while the intermittently aerated reactor was responsible for the removal of aromatic amines, nitrogen, and phosphates. Additionally, intermittent aeration was responsible for further removal of COD and colour from the wastewater. Domestic wastewater was added to the raw textile wastewater as a source of easily biodegradable organics. The anaerobic reactor removed colour up to 66%, at hydraulic retention time (HRT) of 9 days and pH of 8.6. COD removal of up to 62% was realized at HRT of 9 days and pH of 7.8. A subsequent intermittently aerated reactor reduced more colour and COD to 68 and 71% respectively at HRT of 3 days. Moreover, 100% removal of nitrates and ammonia was realized in intermittently aerated reactor HRT of 3 days. The HRT of 9 days, pH of 7.8, and the textile wastewater fraction of 0.8 in the anaerobic treatment stage had the highest removal of pollutants. The study revealed that the sequential anaerobic–intermittently aerated reactor system was able to remove colour, COD, and nutrients from wastewater.