Toilet waste from Greater Anglia trains is regularly dumped straight onto the tracks within the station.
The e-petition started by Anne Arcus says: "Toilet waste is dropped directly onto the track from many Greater Anglia trains. Liverpool Street is a covered station and so this waste is not washed away or subject to natural weathering processes.
"I believe this is health hazard for passengers and rail workers.
"This practice should be stopped, it is not reasonable that vast numbers of people using Liverpool Street are being exposed to the risks associated with raw sewage on a daily basis."
Arcus wrote to Greater Anglia trains who said they do not have any plans to change the toilet systems on board their trains.
She said: "This is just utterly disgusting and I think it does speak to the fact that customer service has not always been at the centre of railways because customers I think are very concerned about this issue … we could indeed use some help from the industry in trying to tackle that problem."
Bob Crow, RMT General Secretary, said the practice was a "shocking indictment on the state of our railways 20 years after privatisation".
He added: "Not only is it a filthy way of disposing of human waste, but it also poses real health risks and dangers for RMT members out there working on the tracks.
"To claim that the union has not repeatedly raised the issue within the industry is complete nonsense and we will now be renewing our campaign, alongside the passenger groups, to end this appalling practice once and for all."
The petition currently only has 55 signatories but if it reaches 100,000 then it may be debated in the Commons.