Establishment of a Carbon Emission Balance Model and Analysis of Carbon Neutrality Pathways for Urban Reclaimed Water Plants

• • Indirect carbon emissions constitute 56.8% of total emissions, with electricity accounting for 33.4%, indicating that energy efficiency and chemical reduction are primary levers for decarbonization. • • Reclaimed water source heat pumps contribute 67.4% of total carbon reduction, achieving a balance ratio of 103.7%, making them the critical component for carbon neutrality. • • Coupling reclaimed water reuse with heat pumps requires carbon reduction shares of 34.82% and 65.18% respectively to reach a 100% balance ratio, offering a universally applicable strategy. • • The ratio of residual thermal energy to chemical energy carbon reduction is 8.76:1; extracting only 36% of residual heat alongside sludge anaerobic digestion-cogeneration achieves full carbon balance.