Uisce Éireann are responsible for the operation of the Wastewater Treatment Plants at Drogheda and Dundalk, both of which included aged Anaerobic Digestion Assets. As part of a Capital Maintenance Programme the Sludge Treatment Centres including the AD Systems are being upgraded and designed to include • Pre Digestion Sludge Preparation, with sludge balancing tanks, sludge screening, controlled aeration, sludge thickening and hydrolysis. • Pump fed and pump discharged Primary and Secondary Digestion to eliminate sludge bypass and methane emissions, followed by Pasteurisation, to eliminate liming, heat recovery and digested sludge storage with tank mounted double membrane biogas holders. • The digested sludge will be batch aerated prior to dewatering providing o a guaranteed retention period for aeration/degassing the sludge, therefore inhibiting the production of biogas and stripping any dissolved methane from the sludge to ensure any off gases are below the Lower Explosive Limit. o a homogenous sludge pumped to the dewatering centrifuges. • The biogas produced will be utilised by new Combined Heat and Power Units (CHP) – the intention being to provide all the heat for the AD and Pasteurisation process eliminating the use of fossil fuels. The proposed flowsheet is in-line with Uisce Éireann’s Sustainability Strategy and can play an important role in the roadmap for UÉ’ to be net zero carbon by 2040.