Resumen
Groundwater is an important part of the water resources, crucial for human production and life. With the rapid development of industry and agriculture, organic pollution of groundwater has attracted great attention. Enhanced in-situ bioremediation of groundwater technology has gradually gained attention because of its high efficiency and low environmental impact. Bioremediation agents are crucial for bioremediation technology. In this review, bioremediation agents were classified into three categories: biological nutrition agents, slow-release agents, and microbial agents. Biological nutrition agents are a specific mixture of mineral salt and carbon source; slow-release agents may contain mineral salt, carbon source, pH buffers, and oxygen-releasing material and microbial agents with specific microbial culture. By adding bioremediation agents to the polluted sites, they can improve population density and degradation efficiency for microbial degradation of pollutants. To assist future development and application of bioremediation agents, the development of different agents in laboratory and commercial to date was retrieved online via publisher sites and cooperation case studies. The data collected were analyzed and reviewed, as well as application and remediation effects of enhanced in-situ bioremediation agents were summarized. Current studies mainly focus on laboratory development and experiments, while field tests and remediation effects between different agents are of less concern. Further study may focus on developing new materials, especially coating or loading materials, and systematic evaluation of different agents, considering both laboratory research and on-site experiments, in order to improve the efficiency of in situ organically contaminated groundwater bioremediation.