Provided in one embodiment is a continuous process for converting waste plastic comprising polyethylene and/or polypropylene into recycle for polyethylene polymerization. The process comprises selecting waste plastics containing polyethylene, polypropylene, or a mixture thereof, and passing the waste plastics through a pyrolysis reactor to thermally crack at least a portion of the polyolefin waste and produce a pyrolyzed effluent. The pyrolyzed effluent is separated into offgas, a pyrolysis oil comprising a naphtha, diesel and heavy fractions, and char. The pyrolysis oil, or at least a fraction, is passed to a filtration/metal oxide treatment, with the treated product passed to a refinery FCC unit. A liquid petroleum gas C3 olefin/paraffin mixture fraction is recovered from the FCC unit, as well as a C4 olefin/paraffin mixture fraction. The liquid petroleum gas C3 olefin/paraffin mixture fraction is passed to a steam cracker for ethylene production.