Integrated Application of Struvite Precipitation and Biological Treatment in Treating Autothermal Thermophilic Aerobic Digestion Supernatant Liquid

Abstract

Abstract This work dealt with the integrated application of struvite precipitation and biological treatment of the supernatant liquor after autothermal thermophilic aerobic digestion (ATAD). To the best of our knowledge, no feasibility study of NH4-N and PO4-P removal from ATAD supernatant by struvite precipitation has been performed before. Furthermore, it was worthwhile and interesting to evaluate the biological treatability of combined wastewater, in which the struvite supernatant was mixed with sewage wastewater. Batch experiments were conducted to examine the effects of pH, dosage of magnesium and orthophosphate, and the addition of preformed struvite deposits as a seeding material on the removal of NH4-N and PO4-P from the ATAD supernatant of sewage sludge. The struvite precipitation experiments showed that pH was an important factor in the simultaneous removal of NH4-N and PO4-P. It was noticeable that the high concentration of heavy metals in ATAD supernatant liquid could significantly inhibit NH4...