PURPOSE: To split the water-in-oil emulsion to make it possible to easily recycle the oil phase as fuel by using polymers of ethylene oxide and/or 1,2-propylene oxide as a splitting agent.

CONSTITUTION: The oil-in-water emulsion is split by using polymers and/or oligomers of ethylene oxide and/or 1,2-propylene oxide, oxyalkylated phenol resins, block polymers or copolymers of ethylene oxide and 1,2-propylene oxide which are crosslinked with diisocyanates, dicarboxylic acids, formaldehyde and/or diglycidyl ethers, polyether urethanes and/or salts of alkylbenzene sulfonic acids as the splitting agent. About 60-90 wt.% of water contained din oil phase can be removed, and the oil can easily be burnt up, thereby the water- in-oil type emulsion can easily be treated as a waste by this excellent process.