Analysis of oil derived from liquefaction of sewage sludge

The oil separated by steam distillation after liquefaction of sewage sludge was fractionated to strongly acidic, weakly acidic, basic, and neutral fractions by acid-base extraction. The total recovery of fractions was 77%. Each fraction was analysed by g.c.-m.s., and 71 types of compound were identified with reasonable certainty. No strongly acidic fraction was obtained. The weakly acidic fraction, comprising 2% of the oil, was exclusively composed of phenolic compounds. The basic fraction, comprising 20% of the oil, was exclusively composed of pyridines, pyrazines, quinolines, amines and methylphenylacetamide. The neutral fraction, comprising 56% of the oil, was exclusively composed of aliphatic compounds, alicyclic compounds, alcohols, ketones, aromatic compounds, sulphur-containing compounds, nitrogen-containing compounds and oxygen-containing heterocyclic compounds.