Efeito da adição de carvão ativado granular e biocarvão na formação, desempenho e estabilidade de lodo granular aeróbio

Abstract

This study evaluated the effects of adding granular activated carbon (CAG) and biochar (BC) on the formation, morphology and performance of aerobic granular sludge (AGL) in reactors in sequential batches (RBS). Three reactors were operated (R1: control; R2: with 2 g L-1 of CAG; R3: with 2 g L -1 of BC) for 106 days, under progressive reduction of the processing time. sedimentation (from 20 to 5 minutes), followed by a maturation phase. Both additives accelerated biomass retention and granulation, but the BC performed top. The R3 reactor reached stable granules approximately 20 days earlier, with up to 40% of particles > 1.0 mm, SSV concentration greater than 5000 mg L-1 and high resistance mechanics. CAG showed limited adhesion due to its higher density, while BC particles adhered effectively, acting as nucleation sites and stimulating production of extracellular polymeric substances (SPE). Removal of organic matter remained consistently high across all reactors (>95%), while removal of ammonia reached values ​​above 98%. Total nitrogen removal stabilized between 60 and 65%, and phosphorus removal remained low (20-40%), without significant influence of additives. In general, BC increased the density and structural stability of the granules, confirming its potential as a sustainable additive to accelerate the formation of LGA