A Gong Farmer was a person who cleaned cesspits and privies of human waste (excrement), especially from 1485 - 1603 (Tudor period). "Gong" was the common name for the locations where human waste went into as well as the contents of the pits. Because the stench and sight of removal of the waste was very unpleasant, gong farmers were required to perform their cleaning at night.

As newer and advanced sewage systems were developed, the need for a gong farmer lessened. Today, a suction truck is used to clean out septic tanks and other sewage lines. India still employs 100,000+ "manual scavengers" that clean out sewage lines, cesspits and septic tanks. These employees often are afforded no protective gear to perform their work.

The gong farmer was considered well paid by Tudor's standards (sixpence a day). The gong farmer was usually waist deep in the muck throughout the work night and required to live in designated areas due to the stench they acquired during their daily chores.

More Info: en.wikipedia.org