Project overview
The wastewater treatment works in Lancashire have had new chemical dosing infrastructure installed. The changes will reduce the phosphorus level of effluent and in turn improve the water quality of nearby watercourses. bWGM has delivered the design and engineering on the two United-Utilities-owned sites.
The background
Infrastructure investment by United Utilities focused on reducing phosphorus levels in effluent water. This was a priority area owing to the impact of phosphorus levels on waterbodies.
In high concentrations, phosphorus can cause algal blooms, which clog water flow and remove oxygen from the water. These factors have a negative impact on the ecological health of a catchment and can impact aquatic life. Ferric is commonly used to address this, as it helps to remove phosphorus in the wastewater. During the process, ferric naturally causes the pH level of the wastewater to lower, so to counteract this, caustic is also used to bring the pH back to the optimal range.
bWGM began work on the project in October 2025, completing the work in March 2026.
Multidisciplinary approach/strategy
bWGM is a joint venture between Binnies and fellow RSK Group company WGM Engineering. An in-house team of civil, mechanical, electrical, process and commissioning engineers delivered the design and construction of the new dosing infrastructure to both sites.
Challenges
Access to the sites was via narrow rural roads, which presented logistical challenges for the movement of plant, materials and personnel. In addition to this, all construction work was done on live wastewater treatment works, where available working space was limited and the full function of the plant needed to be maintained.
Solutions
To develop the solutions, bWGM utilised Building Information Modelling (BIM) on both projects. The fully integrated 3D model enabled the team to visualise the new treatment infrastructure within the tight site boundaries, identify conflicts early and eliminate clashes before works began, leading to a well-coordinated and predictable build programme.
To maximise safe usable space, the project team began by removing redundant treatment infrastructure. This gave the opportunity to repurpose parts of the footprint to accommodate the new dosing assets. Creating safe space in this way also enabled the plant to continue its normal operations uninterrupted. The new chemical dosing kiosks installed at the sites were manufactured and tested off-site, which enabled a much quicker installation process. To counter the narrow site access, a specialist lifting contractor was brought in to install the kiosks using specialist lifting equipment.
The designs for the upgrades include a bespoke manhole that acts like a typical manhole during normal operations but can be isolated during chemical filling. This means that should there be a chemical spill, the manhole would collect the spillage, ensuring no chemicals reach the ground or nearby watercourses.
Impact
On completion, the project ensured the continued operation of the plant in accordance with environmental regulations. Ensuring the nearby catchments receive treated wastewater at the consented limit for phosphorus (4 mg per litre) annual average from the site will protect the ecological health of the waterbodies and support aquatic life to continue to thrive.