A continuous primary sewage sludge thermochemical conversion system was designed, built, and operated for over 100 hr during 1984 at Battelle-Northwest. This was designated as the STORS (Sludge-to-Oil-Reactor System), because the major product was a burnable oil. Starting with 20% solids primary sludge, mixed with 5% by weight of sodium carbonate and heated to 300 C, products obtained included a pourable oil, a char containing most of the inorganic materials, some gas, and an aqueous phase containing most of the inorganic materials, some gas, and an aqueous phase containing dissolved organics and salts. The oil and char under certain conditions separated spontaneously from the aqueous phase. The energy recovery in burnable products reached 73% of the initial energy in the wet sludge, the oil having the highest energy density with approximately 90% of the heating value of diesel fuel.