Ice Pigging eliminates septicity in rising sewer

June 2024

United Utilities, a water and wastewater services provider in northwest England, regularly uses Ice Pigging to maintain their wastewater assets and prevent harmful substance build-up. Recently, they enlisted the Ice Pigging team to reduce septicity levels in the rising mains at their Inskip wastewater pumping station.

The mission was to clean 1,900 metres of DN100 pipeline to reduce septicity. Before the operation, ORP levels were recorded at -250 to -300 millivolts (mV), indicating high septicity due to low flow rates and biofilm build-up. This biofilm reduces oxygen levels and produces hydrogen sulphide (H2S), a foul-smelling and corrosive gas.

Ice pigging involves sending semi-solid ice slurry through pipes to remove deposits and biofilm, improving water quality and hydraulic performance. Unlike traditional methods, Ice Pigging is quick, non-intrusive and cost-effective, using less water and adapting to complex pipe networks. The team completed the cleaning in just four hours, using a waste tanker to manage incoming flows.

The results were impressive, with a +323mV improvement in ORP levels, shifting conditions from highly anaerobic to aerobic. This shows Ice Pigging’s effectiveness in eliminating septicity in wastewater rising mains.

Stephen Boyall, United Utilities Production Manager, praised the team’s swift and effective work, noting the successful outcome achieved within a day.