Borehole drilling for sewage disposal and rise of the hole's bottom at Asuka Station, East Antarctica

Abstract

A borehole for sewage disposal was drilled in the snow at Asuka Station (71°31′34″S, 24°08′17″E, 930m a. s. l.) in January 1987. The borehole, 400mm in diameter and 27.5m in depth, was drilled at 50m apart from the main hut using a steam drilling system. The drilling speed was 4m/h between the surface to 20m depth. Total amount of kerosene used for melting snow and steam generation was 110l. Sewage stored in three tanks is directed to the borehole through a heated pipe. The bottom of the borehole rose about 7m in first 5 months, but after that the rising speed decreased gradually. The bottom rose 11.6m up during a period of three years when 594kl waste water was discharged. If we assume the contaminated area is cone-shaped, the cone's radius is calculated as 13.7m.