• MWH UK Ltd. (operating in CiM6 alliance)

    Netheridge STW

    Gloucester, Gloucestershire, United Kingdom

Project Summary

Due to a lack of control over the digestion stream over the years, Netheridge Sewage Treatment Works (STW) in Gloucester, England has incurred large fluctuations in gas production, made worse by the range of trade wastes that are accepted into the site. The Netheridge STW currently serves approximately 198,000 residents in Gloucester; however, the population is estimated to rise to nearly 219,000 by 2034. CiM6, a partnership between Costain and MWH UK Ltd. for AMP6, was retained to assess the existing digestion process and propose a design solution that allows for more operator control and maximizes gas production. The project objective was to have a consistent and controllable sludge feed to the digestion plant to increase sustainable biogas production.

To bolster biogas production and improve trade waste reception facilities, a new sludge imports facility for imported sludge from remote sites, and a trade waste reception and blending facility was necessary. MWH’s design team created an intelligent 3D model of the site to ensure that the spatial requirements of the design optimized construction. CiM6 worked collaboratively with Severn Trent Water to provide a detailed design of a new sludge and trade waste imports facility that offered supplementary buffer tank storage and a control system to smooth flow and load into the digestion stream. Additionally, the new design revamped the indigenous sludge route to enable proper thickening. The 3D model was used to create construction materials and plan the phased construction and operational activities.

Bentley applications optimized the design workflow and management. The common data environment capability in ProjectWise allowed the design team to collaborate on models submitted by suppliers as well as in-house design models. A site composite model was prepared and exported as a single iModel for virtual reviews spanning multiple disciplines over various locations. This streamlined design check and review process via Navigator eliminated rework and saved time. Additionally, OpenPlant Modeler’s efficient method of modifying pipework material and alignment drastically reduced editing time, as pipework generation typically takes significant time to amend.

Modelers in India were collaborating with engineers in the United Kingdom through ProjectWise’s connected data environment, reviewing iModels and marking up designs in Navigator. Once the 3D models were 90 percent complete, the 2D drawing sheet files were generated. The project team used OpenPlant Modeler for mechanical piping and equipment, AECOsim Building Designer for structural components, Navigator for design reviews, and MicroStation for 2D deliverables.

Project Playbook: AECOsim Building Designer, MicroStation, Navigator, OpenPlant, ProjectWise

  • The Netheridge STW accepts sludge deliveries from more than 100 regional sewage treatment works and accepts trade waste from regional and national traders; it is also the Sludge Treatment Center for Severn Trent Water.
  • MWH’s design solution included 2D sludge and trade waste screens, sludge and trade waste above ground tanks with pumped mixing for buffer storage, progressive cavity transfer pumping stations, primary sludge gravity belt thickeners, powder polymer makeup system, wash-water filters, and an odor control plant.
  • Design checks and reviews were done with composite iModels, eliminating rework.
  • Bentley’s efficient applications saved MWH UK Ltd. significant time in the editing and collaborative review phases of the design process.
  • “Bentley Navigator provided the capability to visualize the site as well as help the design engineers, the construction team, and the site operators to give comments and mark-ups, ensuring that the finished model was suitable for efficient construction and also safe to operate once complete.”

    Andrew Collett Design Manager MWH UK Ltd.