Urine becomes drinking water on the space station.

The urine and sweat of astronauts on the International Space Station (ISS) will be reprocessed into drinking water. However, the current processing efficiency is only 75%, lower than the 85% achieved during testing on Earth.

Toilet on the International Space Station (ISS). Photo: Science Photo Library

An astronaut is estimated to use around 730 liters of recycled water from urine and sweat during a year working on the ISS, according to the BBC.

The wastewater treatment process on the ISS is as follows: collected urine and sweat are treated with chemicals to prevent decomposition and bacterial growth. This is the pre-treatment step. Next, the water is channeled into the main treatment system, using vacuum distillation technology to obtain pure water. This is a water distillation technology that operates at room temperature, without the need for additional heat.

Scientists have found that the reason for the reduced efficiency of water recycling lies in the pre-treatment stage. The urine of astronauts on the ISS contains added calcium. This calcium then reacts with pre-treatment chemicals to form calcium sulfate. This salt gradually settles and hinders the operation of the urine treatment system. Astronauts would have to spend more time maintaining the treatment system, and would need to transport more water from Earth than anticipated.

Currently, a team of scientists, led by Jennifer Pruitt of the Marshall Space Center, is researching replacing certain components of pretreatment chemicals to address the issue of calcium in urine and improve wastewater treatment efficiency.

According to VnExpress