Ringsend WwTP SBR Retrofit Hybrid Package 1 Contract

Increasing treatment capacity at Ringsend WwTP

Since 2018 Irish Water has been undertaking a process of upgrading the existing Wastewater Treatment Plant at Ringsend, the largest WWTP in Ireland. The overall scope of the Ringsend Upgrade Project  is to increase the treatment capacity at the plant from 1.64m PE to 2.4m PE and to upgrade the treatment processes to achieve full compliance with the 2010 Urban Wastewater Treatment Directive.

In October 2020 Celtic Anglian Water, together with partners TES Technology and Farrans Construction (the FaCT3 Consortium), was awarded the Ringsend WwTP SBR Retrofit Hybrid Package I Contract as part of a multi-stage phased upgrade of the Ringsend Wastewater Treatment Plant (WwTP) to increase the treatment capacity of the plant from 1.64mPE to 2.4mPE.

The project was successfully completed in November 2021 and was delivered on time and within budget. In addition to the successful delivery the Hybrid Package 1 Contract, Celtic Anglian Water is the Operation & Maintenance Contractor at the Ringsend WwTP and assumed responsibility for the operation and maintenance of Hybrid Package I retrofitted Nereda® Technology Reactors in November 2021.

Project Scope

The Hybrid Package 1 Contract was one of four SBR Retrofit Contracts through which all 24 existing SBR Cells at the Ringsend WwTP would be retrofitted enabling them to be operated either as Nereda® Technology Reactors, or as Hybrid Nereda® Reactors, thus increasing the treatment capacity of the WwTP whilst ensuring the plant remained fully operational.

Under the scope of the Hybrid Package I Contract the Nereda® technology was retrofitted into 15 of the existing 24 SBR Cells, executed at the following locations on a Cell by Cell basis:

• Block 1 (comprising Cells 1A, 1B, 1C & 1D);
• Block 4 (comprising Cells 4A, 4B, 4C & 4D);
• Block 5 (comprising Cells 5A, 5B, 5C & 5D);
• Block 6 (comprising Cells 6A, 6C & 6D with Cell 6B limited scope as it has already been partly retrofitted)

Project Delivery

As part of the FaCT3 Consortium, Celtic Anglian Water was an integral part of the design, build, supply, installation and commissioning delivery team. We undertook key roles, amongst other roles, of the Project Supervisor Design Phase (PSDP) and Project Supervisor Construction Stage (PSCS).

To facilitate the implementation of the Hybrid Nereda® treatment process in the existing 15 SBR Cells, of Blocks 1, 4, 5, 6 sampling, process control and monitoring instrumentation was installed within each of the SBR cells together with the raising of the level of the sludge extraction pipework. The Scope of the Hybrid Package I Contract included:

• Supply and Installation of Nereda® Reactor process monitoring and control instrumentation into each of the Block 1,4, 5 & 6 Reactor Cells
• Supply and Installation of Multi-Channel Instrument Controllers for each Reactor Cell in Block 1, 4, 5, and 6
• Installation of 1 No. permanent effluent automatic sampler at drop pocket for effluent from block 1 & 4
• Provision of 2 No. portable effluent automatic samplers
• Installation of 16No. DN15 AISI 316L stainless steel tubes in the mid drop pocket of each Hybrid Nereda reactor
• Provision of Poly Aluminium Chloride Chemical Storage and Dosing to each Reactor Cell in Block 1, 4, 5, and 6
• Modifications to existing SAS Discharge pipework in each Reactor Cell
• Modification of SAGS pipework from Reactor Cell 3B to the Surge box on Block 6;
• Associated Electrical Works including Control and Automation
• Provision of a new PLC/ Server Kiosk to house all (Hybrid) Nereda® Controllers and associated Block PLC’s associated with the upgrade of all 6 of the existing SBR Blocks

In addition extensive Automation and Control works were also provided including the supply and installation of:

• Control System hardware and software
• Hybrid Nereda® Controller integration
• Server cabinet(s)
• PLC cabinet(s)
• Automation network
• Control network
• Fieldbus networks
• Instrumentation and Data Installation
• Modifications to existing Main MCC Panel feeding new SBR MCC Panels, communication for the Process Automation.

Innovations in approach

In order to allow the WwTP to remain fully operational during the upgrade innovative solutions were designed to ensure treatment capacity was maintained, as only two SBR Cells could be out of service at any one time.  In addition to this new and creative approaches were used to:

• Designing and applying a unique hoisting mechanism through the use of marine buoyancy float aids to raise the level of the 50m x 450mm diameter Stainless Steel SAS Discharge pipework by 1.5m in each Reactor Cell.
• Designing and using a floating pontoon to enable the installation team to fix the PAC Dosing pipework along the structural support columns into each SBR Cell whilst the Cell remained operational.