Can I challenge an arbitral award after the fact on grounds that the arbitrator was biased?

Yes, but the threshold is high. Under both the Arbitration Law 1968 and the ICA Law 2024, an award may be set aside if the arbitral tribunal was not properly constituted or if the arbitrator's partiality caused a denial of natural justice. However, if you were aware of the potential conflict during the arbitration and chose not to challenge it at the time, an Israeli court will very likely hold that you waived the right to raise it post-award.