• • Deep dewatering to 65% moisture reduces total process cost by 5.2% (from 2350 to 2277 CNY/t DS) and carbon emissions by 20.5% (from 892.5 to 709.1 kg CO2/t DS) compared to conventional dewatering to 76% moisture, despite higher dewatering costs (700 vs. 252 CNY/t DS operating cost).
• • Sludge with higher organic content (65%) and lower moisture (70%) achieves negative auxiliary energy consumption (-1.77 t steam/t DS) and lower unit processing cost (1134 CNY/t DS) versus lower organic content (50%) and higher moisture (80%) sludge requiring 1.85 t steam/t DS and costing 2001 CNY/t DS.
• • Transport cost is halved when sludge moisture decreases from 76% to 65% (313 vs. 229 CNY/t DS) due to reduced mass, directly impacting logistics economics.
• • Carbon emissions from sludge drying and incineration dominate the full-process footprint, with steam consumption contributing 343.8 kg CO2/t DS for conventional dewatering versus 290.1 kg CO2/t DS for deep dewatering, while electricity consumption is lower for deep dewatering (168.8 vs. 262.4 kg CO2/t DS).