Biological wastewater treatment system containing a salt-rejecting membrane filter and recycle conduit

A wastewater treatment system includes a biological reactor having anaerobic, anoxic, and aerobic chambers. A lift station including a pump is operatively connected to a tertiary filter downstream of the biological reactor. The lift station receives biologically treated liquid from the tertiary filter and pumps the liquid from the lift station. A filtration subsystem is operatively connected to the lift station. The filtration subsystem receives and filters the liquid pumped by the lift station. The filtration subsystem includes a preliminary filter and a salt-rejecting membrane filter having a recycle conduit operatively connected to recirculate salt-rejecting membrane filter, thereby forming a salt concentration loop between biological reactor and the salt-rejecting membrane filter. A post-filtration subsystem is operatively connected to receive salt-rejecting membrane filter permeate, and includes an adsorbent and oxidation system.