Engineered sulfate application has been proposed as an effective remedy to enhance the rate-limited biodegradation of petroleum-hydrocarbon-contaminated subsurface environments, but the effects of dissolved organic phase composition and salinity on the efficiency of this method are unknown. A series of flow-through experiments were conducted for 150 days and dissolved benzene, toluene, naphthalene, and 1-methylnaphthalene were injected under sulfate-reducing and three different salinity conditions for 80 pore volumes. Then, polycyclic aromatic hydrocarbons (PAHs) were omitted from the influent solution and just dissolved benzene and toluene were injected to investigate the influence of dissolved phase composition on treatment efficiency. A stronger sorption capacity for PAHs was observed and the retardation of the injected organic compounds followed the order of benzene < toluene < naphthalene < 1-methylnaphthalene. Mass balance analyses indicated that 50 and 15% of toluene and 1-methlynaphtalene were degraded, respectively. Around 5% of the injected naphthalene degraded after injecting > 60 PVs influent solution, and benzene slightly degraded following the removal of PAH compounds. The results showed substrate interactions and composition can result in rate-limited and insufficient biodegradation. Similar reducing conditions and organic utilization were observed for different salinity conditions in the presence of the multi-component dissolved organic phase. This was attributed to the dominant microbial community involved in toluene degradation that exerted catabolic repression on the simultaneous utilization of other organic compounds and were not susceptible to changes in salinity.

中文翻译：

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溶解有机相组成和盐度对流通系统中工程硫酸盐应用的影响。

工程硫酸盐的应用已被提议作为一种有效的补救措施，以增强石油-烃污染的地下环境的限速生物降解，但是溶解的有机相组成和盐度对该方法效率的影响尚不清楚。进行了150天的一系列流通实验，并在还原硫酸盐和三种不同盐度条件下注入了80个孔体积的溶解苯，甲苯，萘和1-甲基萘。然后，从进液中省去多环芳烃（PAHs），仅注入溶解的苯和甲苯，以研究溶解相组成对处理效率的影响。观察到对PAHs的吸附能力更强，所注入的有机化合物的阻滞遵循苯<甲苯<萘<1-甲基萘的顺序。质量平衡分析表明，分别降解了50％和15％的甲苯和1-甲基萘。注入> 60 PVs的进水溶液后，大约有5％的萘会降解，而去除PAH化合物后苯会略有降解。结果表明底物的相互作用和组成可能导致速率限制和生物降解不足。在存在多组分溶解的有机相的情况下，对于不同的盐度条件，观察到相似的还原条件和有机利用率。