Petrochemical wastewaters have high ammonium contents that can cause serious environmental pollutions. Among different treatment methods, biological ammonia removal using bacteria has been attracted more attention due to their environmental friendly and high efficiency. The aim of the present study was to isolate heterotrophic nitrogen removal and aerobic denitrifying bacteria from petrochemical wastewater to be used for bioremediation. Wastewater and sludge samples were prepared and their chemical parameters were analyzed. Bacterial isolation was done through enrichment in mineral salt medium and basal salt medium and identified through 16S rRNA gene sequencing. The ability of isolates was evaluated at different concentrations of ammonia, nitrate, and carbon sources and at different time intervals. As a result, ten bacterial isolates were obtained that 5 strains were identified as heterotrophic nitrogen removal bacteria and 5 strains were able to do aerobic denitrification. From these, Pseudomonas guguanensis strain 4-n-1 with 93.2% ammonia removal during 24 h at 40 mg/L ammonium sulfate concentration and Pseudomonas guariconensis strain 5-d-1 with 89.2% denitrification during 24 h at 100 mg/L nitrate concentration were the best isolates. Finally, based on the efficiency of these isolates it can be concluded that effective ammonia removal can be achieved using these species as consortium and simultaneous heterotrophic nitrogen removal with aerobic denitrification is suitable method for efficient ammonium removal from petrochemical wastewater and reduction of ammonia concentration.

中文翻译：

---

石化制氨装置废水异养脱氨和好氧反硝化细菌的筛选

石化废水氨含量高，对环境造成严重污染。在不同的处理方法中，细菌生物除氨以其环保、高效等优点备受关注。本研究的目的是从石化废水中分离异养脱氮菌和好氧反硝化菌，用于生物修复。制备废水和污泥样品并分析其化学参数。通过在矿物盐培养基和基础盐培养基中富集进行细菌分离，并通过16S rRNA基因测序进行鉴定。在不同浓度的氨、硝酸盐和碳源以及不同的时间间隔评估分离株的能力。因此，获得10株细菌分离株，其中5株被鉴定为异养脱氮菌，5株能够进行好氧反硝化。从这些中，古关假单胞菌菌株 4-n-1 在 40 mg/L 硫酸铵浓度下在 24 小时内去除了 93.2% 的氨，而在 100 mg/L 硝酸盐浓度下，假单胞菌菌株 5-d-1 在 24 小时内脱氮率为 89.2%是最好的分离株。最后，基于这些分离物的效率，可以得出结论，使用这些物种作为聚生体可以实现有效的氨去除，同时异养脱氮和好氧反硝化是从石化废水中有效去除氨和降低氨浓度的合适方法。