Abstract:

In order to study the mechanism of migration and transformation of nitrate in aquitard under different Eh, the process of migration and transformation of nitrate in groundwater by passing through aquitard was modeled by adopting clay as aquitard in laboratory under high osmotic pressure. The results showed that at most 1.45 mg nitrate could be blocked by 1 g clay and the blocking rate R=92%. The blocking capacity of aquitard is very strong for nitrate when Eh is at 0 mV, －100 mV and －200 mV. Low Eh is benefit for nitrate adsorption in aquitard. The transformational mechanism of nitrate in aquitard showed that micro-pore blocking, filtering, ion adsorption, cooperative adsorption and microorganisms give aquitard a very strong blocking capacity for nitrate.

Key words: Eh conditions, aquitard, nitrate, interdiction capabilities