air prior to its release referring again to fig2 and 3 in one embodiment steam coils 182 are incorporated into the side walls 158 160 and bottom portion 164 of the tank 110 the steam coils 182 include a steam inlet 184 for receiving steam from the boiler 102 steam is returned to the boiler 102 through a steam outlet 186 from the steam coils 182 the steam coils 182 direct steam along the sides and bottom of tank 110 the circulation of steam through the side walls 158 160 and bottom portion 164 of the tank 110 provide heat to the separated sludge fluid as well as solids along the tank floor 172 in one embodiment a single steam coil 182 is incorporated into the side walls 158 160 and bottom portion 164 of the tank 110 in one embodiment steam coils 182 are constructed immediately adjacent to the outer surface of the side walls 158 and 160 and bottom portion 164 in one embodiment a single steam coil 182 is constructed immediately adjacent to the outer surface of the sidewalls 158 and 160 and bottom portion 164 the hood 178 shown in fig3 insulates the tank 110 to reduce heat loss from the top of the tank 110 the heat keeps the fluid at a lower viscosity which improves the settling of solids from the fluid the heat also helps soften.