Comprehensive Competitiveness Assessment of Four Typical Municipal Sludge Treatment Routes in China Based on Environmental and Techno-Economic Analysis

To find a sustainable and effective municipal sludge treatment route requires a systematic assessment of the comprehensive competitiveness of diverse sludge treatment routes. Four typical treatment routes in China including co-incineration in coal power plants (CIN), mono-incineration (IN), anaerobic digestion (AD) and pyrolysis (PY) were selected in this study. A novel assessment model integrating life cycle assessment (LCA), techno-economic analysis (TEA) with analytic hierarchy process (AHP)-Entropy method was established, and comprehensive competitiveness indicated by comprehensive index (CI) of the four routes was deeply evaluated. Results displayed CIN route (CI = 0.758) showed the best comprehensive performance for its best environmental and economic performance. This was followed by PY route (CI = 0.691) and AD route (CI = 0.570), indicating the enormous potential of sludge PY technology. IN route showed the worst comprehensive performance (CI = 0.186) owing to its high environmental impact and lowest economic benefit. It was noted that greenhouse gas emissions and severe toxic potential were the main environmental challenges faced by sludge treatment. Besides, result of sensitivity analysis revealed that the comprehensive competitiveness of diverse sludge treatment routes was improved with the increase of sludge organic content and sludge reception fee.