In-building heat recovery mitigates adverse temperature effects on biological wastewater treatment: A network-scale analysis of thermal-hydraulics in sewers

Heat recovery from wastewater is a robust and straightforward strategy to reduce water-related energy consumption. Its implementation, though, requires careful assessment of its impacts across the entire system as adverse effects on water resource facility competition among heat strategies may arise. A model-based therefore implies extending modeling spatial scope, with aim enabling thermal-hydraulic simulations household tap along flow path down facility. With this in mind, we propose new framework interfacing (i) households, (ii) private lateral connections, (iii) main public sewer network. Applying analyze fate budgets Swiss catchment, find that losses connections are large cannot be overlooked any analysis, due high-temperature, low-flow characteristics maximizing environment. Further, implementing shower drain devices 50% catchment's households lower temperature at significantly less – only 0.3 K than centralized in-sewer recovery, significant thermal damping effect induced by secondary lines. In-building technologies thus likely adversely affect biological treatment processes. The proposed open-source can applied other catchment. We thereby hope enable more efficient strategies, harvesting while minimising treatment.