Innovation For United Utilities

27 March 2014

Innovative use of existing technology is helping Costain meet the challenges of building a huge wastewater treatment works next to a world heritage site.

GCA (Galliford Try Costain Atkins) JV is building the UK’s first multi-storey CASS (Cyclic Activated Sludge System) sequencing batch reactor plant in partnership with United Utilities.

The 16 basin, dual-level concrete structure has a 165m x 110m footprint and stands 21m high. It is being built in the redundant Wellington Dock that lies inside a world heritage site buffer zone on the River Mersey. Construction of the SBR structure is almost complete and the installation is well underway. Commissioning is expected to begin in October this year. When up and running by 2016, the plant will be capable of processing 4750 litres per second of wastewater which is a treatment of population equivalent of more than one million people from Liverpool.

Use of BIM (Building Information Modelling) has enabled the designers to come up with a space saving stacked design that allows the plant to fit inside the dock and minimizes impact on the adjacent world heritage site. The innovative design will also enable the plant to be decommissioned and taken down at the end of the asset life without damaging the dock.

The design has also achieved a robust, flexible system. Its ability to run in different modes allows it to cope with varying flows of wastewater arriving at the works. It is also able to treat the maximum daily flow with only 14 of the available 16 basins in operation.

Maximum use has been made of precast concrete, resulting in reduced health and safety risks, significant time savings and more than £1 million of cost savings. Other innovations include a high efficiency aeration system, which reduces the power required to operate the works and therefore the plant’s carbon footprint.

Andy Fielding, Innovation Champion for Liverpool GCA JV, said: “Liverpool is United Utilities’ flagship project with many challenges, yet it is rewarding in many ways. Right from the outset the difficulties were apparent but the team has worked to overcome these issues, and by striving to use the best of existing technologies through an innovative approach, the project is well on its way to becoming a great success.”