To achieve net-zero targets globally, industrial decarbonisation is a major priority. This paper examines lost energy resources in a wastewater treatment plant (WWTP) and the deployment of novel wastewater heat recovery (WWHR) technology in the food and beverage processing industry. Four industrial WWTPs were monitored in Ireland to quantify the available embedded energy. Post monitoring, WWHR technology was developed to be integrated within existing infrastructure without compromising the primary function, and evaluated in real operating conditions. On average, 1.11–2.55 GWh/a of embedded energy was measured within the wastewater. The direct WWHR pilot plant resulted in a projected recovery rate of 10.89 MWh/a, leading to substantial economic savings and emission reductions. Incorporating a water-to-water heat pump incurred energy savings of 13.5 MWh/a. Nationally, the energy recovery potential was assessed to be 82.1 GWh/a in Ireland and 476.9 GWh/a in the UK. A large proportion of the energy embedded in this wastewater remains to be recovered and, based on the monitoring campaign, could amount to 118.5 TWh/a and 20.4 TWh/a for the UK and Ireland, respectively. WWHR could serve a prominent role in increasing operational energy efficiency of manufacturing processes by enacting energy, economic and emission savings, thus leading to industrial decarbonisation.