BIOVENTING IN SHALLOW TUNDRA OVERLYING PERMAFROST

The purpose of this research was to investigate the feasibility of suc tion bioventing for treatment of contaminated tundra soil. Two laborat ory-scale venting reactors were prepared with tundra from Arctic Alask a and operated, one for 32 d and the other for 52 d For each rectangul ar reactor, suction was applied to a central well screened at mid-dept h, while opposite ends of the reactor were screened to serve as air in take zones. The volume of liquid and gas recovered from the suction we ll was quantified daily. Numbers for heterotrophic organisms, pH, and dissolved organic carbon were quantified in the recovered liquid. The suction pump held a full vacuum (ie., 101 kPa vac) for the duration of both experiments, indicating continuous obstruction of pneumatic and hydraulic conductivity. In both reactors, the soil in the proximity of the suction well separated from the bulk of the soil, precluding hydr aulic communication. Furthermore, the soil nearest the well screen com pacted forming a barrier to appreciable pneumatic conductivity. At the end of operation, the soil was removed and sampled for moisture conte nt, pH, and numbers of heterotrophic organisms at various locations. T he results of this study showed that for suction bioventing to be succ essful in tundra, consolidation of the soil around the well screen mus t be prevented, as it will cause well isolation and limit both pneumat ic and hydraulic conductivities.