In the late 20th century Swansea Bay was prone to pollution problems, primarily because of a poorly sited main sewer at Mumbles Head, which screened and stored sewage in four underground tanks before releasing it back down the outfall on the ebb tide. Swansea Bay is home to one of the highest tidal ranges in the world and at low tide the sea retreats so far from the high tide marks that it exposes remnants of a prehistoric forest. As a result, the natural current in Swansea Bay often didn’t transport the polluted water far enough out to sea and recirculated it instead around the Bay and then down the Bristol Channel.
In the late 1990s, construction was completed on the Swansea Wastewater Treatment Works (WwTW) near Port Tennant and was considered at that time to be one of the most technologically advanced wastewater treatment plants in the world. However, in recent years, Swansea WwTW required a replacement of the previously installed TrojanUV4000® because of the continued cost to maintain compliance with water standards. The TrojanUVSigna® was selected because it was the most energy-efficient UV system on the market and fit into the existing channel with only minor modifications.