London is about to complete the 25km super sewer.

The massive sewer and stormwater tunnel deep underground will revolutionize London's sewer system when it opens in 2025.

The Tideway Tunnel is a seven-year-old super-sluice that runs from west London to a wastewater treatment facility at the mouth of the Thames. The tunnel intends to divert untreated sewage when heavy rains cause the sewer pipes to overflow, CGTN reported on August 10.

When fully operational, the project is expected to reduce 95 percent of the waste that usually flows into the River Thames and share some of the pressure on London's 150-year-old Victorian sewer system, which is struggling to deal with the amount of waste that goes into the River Thames—Huge emissions from a growing population.

Taylor Geall, communications manager at the Tideway Tunnel project, says the city's sewer network needs have increased over time. "When the old sewer system was built, overflow was infrequent, only about twice a year. Now it happens on average once a week. So in a year, 40 million tons. Sewage and rainwater, which pours directly into the Thames," Geall said.

Environmental groups back the new infrastructure, but runoff is a widespread problem nationwide and goes untested mainly outside of London. Environment Agency figures show that by 2022 there will be an average of more than 800 sewer overflows daily in the UK. Mathew Frith, a representative of the Wildlife Trust in London, said water management companies in the UK need to do more to protect the environment. While the Tideway tunnel will help protect the famous river flowing through London, UK waterways need a broader reclamation plan.