Efficiency of attached-growth sequencing batch reactor in the treatment of recycled paper mill wastewater

In this study, an attached-growth bioreactor was operated using granular activated carbon (GAC) with additional biomassand evaluatedits performance in the treatment of real recycled paper mill effluent at chemical oxygen demand (COD) level in the range of 800-1300 mg/L, a fixed hydraulic retention time of 24 hours and COD:N:P ratio of about 100:5:1. A laboratory-scale aerobic sequencing batch reactor (SBR) was used. The efficiency of this biological treatment processwas studiedover a 300-day period, in order to evaluate their performance, especially for the removal of nitrogen compound and of biodegradable organic matter. It has been found that this process was able to remove organic matter (expressed as COD91-99%) and turbidity (89-99%) almost completely and simultaneouslythe removal of nitrogen (expressed as NH3-N70-94%), phosphorus (expressed as PO43-P42-71%), suspended solid (81-99%) and colour (72-91%) were sufficiently achieved. The overall performance confirmed that an attached-growth SBR system using additional biomass on GAC is a promising configuration for wastewater treatment in terms of the performance efficiency and process stability under fluctuations of organic load