Scrubber

A cleaning professional, commonly on a spaceship or space station.

The Inevitabilities of Organic Life

To support and sustain organic life in space indefinitely requires complex life support systems to run at all times. Maintaining these systems is widely considered the most important job on space stations and spaceships however, it is also one of the least desirable professions.
It is a dirty and disgusting profession. Air filtering and processing systems get blocked by dead skin, scales, fur, and other things shedded by organic inhabitants. Vents and ducts controlling air flow, pollution, and environmental values (temperature, humidity etc.) get similarly blocked. Water pipes get blocked by slimes and other natural excretions of organic inhabitants; a mixture of personal, home, and industrial products for different species; and general rubbish that should not have gone in the water. Sewage systems have similar issues.
If any one of these systems becomes blocked, overheated or, in serious situations, damaged the balance of the space station or spaceship is knocked out and puts organic life at risk.
A Scrubber's day involves closing off areas of the system, getting inside, and cleaning away any mess before it becomes a blockage, fixing any blockages, and fixing any damage to the systems.
The work is difficult, smelly, and endless. Systems that are unblocked can become blocked again in days and the mess from organic species is never-ending.

Robots need not apply

In the modern day, robots, artificial intelligences, and automation processes are used widely in every industry. However, there is a general unease from sentiet, organic life at the idea of entrusting such a vital job to bots. Urban legends and pop culture tell tales time and time again of robots taking over organic space stations or ships. While none of these have any roots in reality, the prospect, and the fear it provokes, is deeply ingrained in the general public's mind. Most space stations and spaceships do not use them to help the Scrubbers. Those that do are usually the biggest space stations/spaceships with the largest and most complicated systems of waste management. They might use small drones fitted with various sensors to fly through different parts of the system to give the Scrubbers an overview of what areas have the most issues.

Constant Flow

The cleaning and maintenance is endless and while the profession suits some people very well even the high pay cannot slow the high employee turnover. Many travellers needing cash and inhabitants down on their luck will take on a few days work as a Scrubber to earn money and then move on. On long-distance commercial spaceships e.g. taking passengers across multiple star sysems, some companies will offer reduced or free passenger fares in exchange for daily work as a Scrubber. On ships manned by the same crew for extended e.g. explorer or military ships, Scrubber duties are usually put on a regular rotation so no one is doing it long and everyone pitches in.