Characterization of Pure Cultures Isolated from Sulfamethoxazole-acclimated Activated Sludge with Respect to Taxonomic Identification and Sulfamethoxazole Biodegradation Potential

Abstract

Free nitrous acid (FNA), which is the protonated form of nitrite and inevitably produced during biological nitrogen removal, has been demonstrated to strongly inhibit the activity of polyphosphate accumulating organisms (PAOs). Herein we reported an efficient process for wastewater treatment, i.e., the oxic/anoxic/ oxic/extended-idle process to mitigate the generation of FNA and its inhibition on PAOs. The results showed that this new process enriched more PAOs which thereby achieved higher phosphorus removal efficiency than the conventional four-step (i.e., anaerobic/oxic/anoxic/oxic) biological nutrient removal process (41 6 7% versus 30 6 5% in abundance of PAOs and 97 6 0.73% versus 82 6 1.2% in efficiency of phosphorus removal). It was found that this new process increased pH value but decreased nitrite accumulation, resulting in the decreased FNA generation. Further experiments showed that the new process could alleviate the inhibition of FNA on the metabolisms of PAOs even under the same FNA concentration.

Feasibility of enhancing short-chain fatty acids production from waste activated sludge after free ammonia pretreatment: Role and significance of rhamnolipid

“…Biological nutrient removal (BNR) is an effective and widely used technique for treating municipal wastewater (Zhao et al, 2015a;Wang et al, 2015a;Wang et al, 2017a). However, in real-world operations of wastewater treatment plants (WWTPs), the available carbon sources (e.g., short-chain fatty acids (SCFA)) in the wastewater usually cannot meet the needs of BNR (Wang et al, 2017b;Wang et al, 2017c).…”