Treatment of phenols and NH3–N with activated carbon and polyurethane carrier in biological enrichment reactor

Abstract

Coal pyrolysis wastewater contains a large number of phenols, ammonia, and various monocyclic and polycyclic aromatic compounds. In the study, activated carbon (AC) or polyurethane (PU) suspension carriers were comprehensively compared from efficiency, influencing factors, extracellular polymeric substances, and microbial population distribution to explore the suitable carrier in biological enrichment reactor the treatment of coal pyrolysis wastewater. In the start-up stage, the treatment effect of COD and total phenol (TPh) in the PU group (COD 86%, TPh 75%) was lower than that of the AC group (COD 94%, TPh 88%). However, with the loading of biofilm on PU, the treatment effects in the PU group began to improve. When COD was approximately 1000 mg/L and TPh was 500 mg/L, both the AC group and PU group showed sound treatment effects on COD (≥87%) and TPh (∼99%). Moreover, the PU group showed a higher removal effect of NH3–N (32.22%) and TN (30.85%). HRT should be 24 h to ensure partial degradation of organic matter and save carbon source dosage of the subsequent A/O treatment unit. Moreover, it had a removal effect on NH3–N and TN, which could effectively reduce the load of the subsequent multistage A/O treatment unit. The dominant functional bacteria in the AC and PU groups included Acidovorax, Alicycliphilus, Chryseobacterium, Rhodanobacter, and Thermomonas. Acidovorax, Alicycliphilus, and Chryseobacterium were the main functional bacteria involved in TPh and COD degradation. AC was suitable for rapidly reducing the concentration of pollutants or dealing with sudden increases in pollutants, while PU was more conducive to the long-term and stable operation of the biological enrichment reactor.