Effect of Aeration Mode on Microbial Structure and Efficiency of Treatment of TSS-Rich Wastewater from Meat Processing

The present study investigated the effect of aeration mode on microbial structure and efficiency of treatment of wastewater with a high concentration of suspended solids (TSS) from meat processing in sequencing batch reactors (R). R-1 was constantly aerated, while in R-2 intermittent aeration was applied. DNA was isolated from biomass and analyzed using next-generation sequencing (NGS) and real-time PCR. As a result, in R-1 aerobic granular sludge was cultivated (SVI30 = 44 mL g(-1) MLSS), while in R-2 a very well-settling mixture of aerobic granules and activated sludge was obtained (SVI30 = 65 mL g(-1) MLSS). Intermittent aeration significantly increased denitrification and phosphorus removal efficiencies (68% vs. 43%, 73% vs. 65%, respectively) but resulted in decomposition of extracellular polymeric substances and worse-settling properties of biomass. In both reactors, microbial structure significantly changed in time; an increase in relative abundances of Arenimonas sp., Rhodobacterace, Thauera sp., and Dokdonella sp. characterized the biomass of stable treatment of meat-processing wastewater. Constant aeration in R-1 cycle favored growth of glycogen-accumulating Amaricoccus tamworthensis (10.9%) and resulted in 2.4 times and 1.4 times greater number of ammonia-oxidizing bacteria and full-denitrifiers genes in biomass, respectively, compared to the R-2.