An intermediate hydrogen separation and purification system is integrated with a hydrotreating and an aromatic saturation process for the production of relatively lower molecular weight products from a relatively heavy feedstock including sulfur-containing and aromatic-containing hydrocarbon compounds. The integrated process allows the processing of heavy hydrocarbon feedstock having high aromatic and high sulfur contents in a single-stage configuration and the using of noble metal catalyst in the aromatic saturation zone. The integrated process increases the overall catalytic activity and hydrogenation capability to produce superior distillate products.