In situ bioremediation of uranium with emulsified vegetable oil as the electron donor.
In situ bioremediation of uranium with emulsified vegetable oil as the electron donor.
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DOI：
10.1021/es3033555
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发表时间：
2013-06
影响因子：
11.4
通讯作者：
D. Watson;Wei-Min Wu;T. Mehlhorn;G. Tang;J. Earles;K. Lowe;T. Gihring;Gengxin Zhang;J. Phillips
中科院分区：
文献类型：
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作者：
D. Watson;Wei-Min Wu;T. Mehlhorn;G. Tang;J. Earles;K. Lowe;T. Gihring;Gengxin Zhang;J. Phillips
进行了一次乳化植物油（EVO）注射的现场试验，以评估EVO的能力，以维持铀生物还原在高渗透性砾石层与地下水浓度（mM）U，0.0055;钙，2.98; NO3（-），0.11; HCO 3（-），5.07;和SO 4（2-），1.23。溴化物和EVO迁移和分布的比较表明，大部分注入的EVO保留在地下从注入威尔斯到50米的下降梯度。硝酸盐，铀和硫酸盐依次从地下水中去除1-2周内，伴随着乙酸盐，锰，铁和甲烷浓度的增加。由于EVO随时间缓慢释放和降解，还原条件持续了大约一年，每天U排放到一条小溪，距离注入威尔斯井约50 m，在100天内减少了80%。在一年期间，铀排放总量减少了50%。回收含水层固体的同步加速器分析证实了U（VI）还原为U（IV）。氧化剂（例如，在EVO耗尽后，从沉积物中流入的溶解氧、硝酸盐）似乎使铀再氧化和再活化，如U浓度瞬时增加到环境值以上所证明的。偶尔（例如，年）EVO注入到一个可渗透的钙和碳酸氢盐含水层可以维持铀的生物还原/固定和减少U迁移/排放。
A field test with a one-time emulsified vegetable oil (EVO) injection was conducted to assess the capacity of EVO to sustain uranium bioreduction in a high-permeability gravel layer with groundwater concentrations of (mM) U, 0.0055; Ca, 2.98; NO3(-), 0.11; HCO3(-), 5.07; and SO4(2-), 1.23. Comparison of bromide and EVO migration and distribution indicated that a majority of the injected EVO was retained in the subsurface from the injection wells to 50 m downgradient. Nitrate, uranium, and sulfate were sequentially removed from the groundwater within 1-2 weeks, accompanied by an increase in acetate, Mn, Fe, and methane concentrations. Due to the slow release and degradation of EVO with time, reducing conditions were sustained for approximately one year, and daily U discharge to a creek, located approximately 50 m from the injection wells, decreased by 80% within 100 days. Total U discharge was reduced by 50% over the one-year period. Reduction of U(VI) to U(IV) was confirmed by synchrotron analysis of recovered aquifer solids. Oxidants (e.g., dissolved oxygen, nitrate) flowing in from upgradient appeared to reoxidize and remobilize uranium after the EVO was exhausted as evidenced by a transient increase of U concentration above ambient values. Occasional (e.g., annual) EVO injection into a permeable Ca and bicarbonate-containing aquifer can sustain uranium bioreduction/immobilization and decrease U migration/discharge.