Abstract

In environmental study, optimization of different factors is crucial to obtain high removal of specific pollutants. The sequence of important factors that were considered in optimization studies is less concerned, and this part is crucial before proceeding to full-scale bioremediation study. This study focuses on bioremediation of polycyclic aromatic hydrocarbons (PAHs) contaminated soil with the potential bacteria, Corynebacterium urealyticum which is isolated from municipal sludge. The bacterial strain has evaluated the effectiveness of PAHs degradation at various factors on soil pH, soil temperature, initial PAHs concentration, initial bacteria number, and heavy metals concentration. The optimum condition for phenanthrene biodegradation was pH 7, 30 °C, 500 mg/kg of phenanthrene concentration, 10⁹ cells/g soil, and without the addition of Zn. In establishing the ranking, we attempt to use a simple method based on the analysis of p values. Based on the analysis of degradation rates, the initial phenanthrene concentration shows the lowest p value, which means that it shows the highest ranking; the most significant factor to achieve highest degradation. In vice versa, the soil pH shows the highest ranking based on the analysis of bacteria growth rates, which is a very limited study that focuses on growth rates in the optimization study. The establishment of these rankings may reduce time, energy and cost in pilot or field study and at the same time achieve highest degradation in bioremediation work. Thus, it is highly recommended to develop the ranking before proceeding to design work in pilot and field study.

摘要

在环境研究中，不同因素的优化对于获得特定污染物的高去除率至关重要。在优化研究中考虑的重要因素的顺序不太关心，这部分在进行全面的生物修复研究之前是至关重要的。本研究的重点是利用从市政污泥中分离出的潜在细菌解脲棒杆菌对多环芳烃 (PAHs) 污染的土壤进行生物修复。该菌株评估了土壤 pH 值、土壤温度、初始 PAHs 浓度、初始细菌数和重金属浓度等各种因素下 PAHs 降解的有效性。菲生物降解的最佳条件为 pH 7、30 °C、500 mg/kg 菲浓度、10⁹细胞/g 土壤，不添加 Zn。在建立排名时，我们尝试使用基于p值分析的简单方法。根据降解率分析，初始菲浓度显示最低pvalue，这意味着它显示了最高的排名；实现最高降解的最重要因素。反之亦然，根据细菌生长速率分析，土壤 pH 值排名最高，这是一项非常有限的研究，主要关注优化研究中的生长速率。这些排名的建立可以减少试点或实地研究的时间、精力和成本，同时实现生物修复工作的最高降解。因此，强烈建议在进行试点和实地研究的设计工作之前制定排名。