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Effect of ferric iron and nitrate on hydrogen sulfide control in lab-scale reactors
Environmental Science: Water Research & Technology ( IF 5 ) Pub Date : 2021-08-09 , DOI: 10.1039/d1ew00460c
Zhi Yang 1, 2 , David Z. Zhu 1 , Tong Yu 1 , Adam Shypanski 3 , Guijiao Zhang 4 , Yongchao Zhou 4
Affiliation  

Four bioreactors imitating force mains of pump stations were operated over 8 months to evaluate sulfide generation rate in force mains. Ferric iron and nitrate were added into two of the four bioreactors to investigate their effects on sulfide control. The half order kinetics regarding dissolved COD was capable of predicting the sulfide formation in the bioreactors and the rate constant was around 0.005–0.010 g S g COD−0.5 m−0.5 h−1. Sulfide controlled by ferric iron was only via chemical oxidation and precipitation and total sulfate reducing bacteria (SRB) population did not change. The heterotrophic nitrate reducing bacteria (hNRB), Thauera, outcompeted SRB for organic matter as electron donor as the dominant bacteria when nitrate was added at the beginning of the pump cycle. The sulfide generation was controlled by hNRB activities. The amount of nitrate required for sulfide control depended on heterotrophic denitrification rate which can be well described by half order kinetics with regard to DCOD concentration. A modified empirical equation was proposed and the modelled empirical rate constant was around 0.05 g N g COD−0.5 m−0.5 h−1. A cost-effective nitrate dosing strategy is proposed to add the nitrate at the end of the pump cycle instead of at the beginning of the pump cycle which can save up to 75% nitrate dosage. The co-existence of sulfide and nitrate stimulated the development of nitrate-reducing, sulfide-oxidizing bacteria (NR-SOB), Sulfurovum, which was responsible for sulfide removal in the presence of nitrate. Both ferric iron and nitrate did not have the long-lasting inhibitory/toxic effect on sulfate reduction.

中文翻译:

三价铁和硝酸盐对实验室规模反应器中硫化氢控制的影响

四个模拟泵站总管的生物反应器运行了 8 个月,以评估总管中的硫化物生成率。将三价铁和硝酸盐添加到四个生物反应器中的两个中,以研究它们对硫化物控制的影响。关于溶解 COD 的半级动力学能够预测生物反应器中硫化物的形成,速率常数约为 0.005–0.010 g S g COD -0.5 m -0.5 h -1。三价铁控制的硫化物仅通过化学氧化和沉淀,并且总硫酸盐还原菌(SRB)数量没有变化。异养硝酸盐还原菌(hNRB),Thauera,当在泵循环开始时添加硝酸盐时,作为主要细菌的电子供体在有机物质方面超过 SRB。硫化物的生成受 hNRB 活性的控制。硫化物控制所需的硝酸盐量取决于异养反硝化速率,这可以通过关于 DCOD 浓度的半阶动力学很好地描述。提出了一个修正的经验方程,模拟的经验速率常数约为 0.05 g N g COD -0.5 m -0.5 h -1. 提出了一种具有成本效益的硝酸盐计量策略,在泵循环结束时而不是在泵循环开始时添加硝酸盐,这样可以节省高达 75% 的硝酸盐剂量。硫化物和硝酸盐的共存刺激了硝酸盐还原、硫化物氧化细菌 (NR-SOB) Sulfurovum 的发展,它负责在硝酸盐存在下去除硫化物。三价铁和硝酸盐对硫酸盐还原没有持久的抑制/毒性作用。
更新日期:2021-08-16
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