| 摘要 |
<p>A digestor tank (1) for sewage sludge has gas circulation pipes (4) opening low down in the tank for bubbling gas through the sludge to agitate the sludge. Some of these pipes are individuaily associated with heat exchanger jackets (3B, 3C) of heaters (3). Each gas circulation pipe (4) opens low down in the tank and such that gas exiting from the pipe does so in the direction towards the base (1C) of the tank and low down in the sludge so that the sludge is scoured downwards to impinge on the tank base to remove sedimented materials and hence to prevent build up of such materials in the bottom of the tank.</p> |
