Household garbage produces large quantities of methane which leaks into the atmosphere and contributes to the greenhouse effect. A Swedish company has come up with an innovative method to tap methane from garbage dumps and use it for heating purposes. Swedish engineers overcame the problem of drilling through layers of garbage containing all types of objects by using a hollow stem auger, which can drill right through wood, concrete and stone
SINCE July last year, the municipal
garbage dump at Gladokvarn, outside
Stockholm, has been yielding gas at the
rate of 22,000 in per day from gas wells
up to 20 in deep. The gas is carried via a
13 km-long pipeline to a 5 mw heating
plant which, in turn, supplies central
heating to the nearby Skogas housing
estate - enough to heat some 2,500
It is a well known fact that household garbage, compacted over long periods of time, creates large quantities of methane gas. Many attempts have been made in the past to bring the gas to the surface and harness it, not just for commercial purposes but also to prevent it from leaking into the atmosphere and contributing to the greenhouse effect.
The technical problems involved, however, have been difficult to solve. The main problem is to be able to drill large and deep well holes through layer upon layer of material containing such a wide variety of waste. However, engineers in Sweden claim to have found almost a complete answer.
The drilling at Gladokvarn was carried out by Svenska Borr AB, using an Atlas Cop Geodrill 800E equipped with a six-inch-hollow stem auger, a drilling tool. The hollow stem auger is normally used for soil investigation, groundwater monitoring and well-drilling. The auger has no trouble with small metal objects and simply pushes larger objects aside. Wood, concrete and stone can give some problem by slowing the rotation down, but generally speaking, it drills right through without stopping.
During the first two weeks of drilling through the compacted household waste consisting of every conceivable type of material, eight holes varying from 15 in to 20 in deep were drilled. The engineers soon learned to operate the wireline system. The deepest hole drilled was 22 in deep and was completed in less than 24 hours. Now almost 70 holes have been drilled, of which about 50 are active.
The company claims that it is the first in Sweden and probably one of the first in Europe to use a hollow stem auger for this type of work, which although not problem-free, is vastly superior to conventional drilling in these circumstances.
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