Optimizing pig manure management chain: environmental and economic co-benefits of integrated packages

CONTEXT China, the global largest pork producer and consumer, faces severe environmental pressures from inadequate manure management, yet comprehensive empirical analyses of environment-economy trade-offs remain scarce. OBJECTIVE This study provides a comprehensive comparative assessment of manure treatment modes in pig production across multiple environmental footprints and economic benefits, and optimizes stage-specific technologies into integrated packages that reconcile mitigation with profitability across the manure management chain. METHODS This study integrates farm survey data ( n = 162), life cycle assessment, and linear and multi-objective optimization to assess co-benefits or trade-offs of technology combinations under various objectives. RESULTS AND CONCLUSIONS Anaerobic digestion (AD) mode minimizes greenhouse gas (GHG) emissions and phosphorus (P) losses, while combining composting with AD mode minimizes reactive nitrogen (Nr) emissions. Single-objective optimization reveals acute trade-offs, profit maximization exacerbates emissions, whereas environmental minimization depresses net returns by up to 48%. Multi-objective optimization shows these trade-offs are surmountable. Whole-chain packages integrating source reduction, process control, and end-of-pipe measures reduce Nr by 41–44%, GHG by 15–16%, and P by 22–48%, while limiting profit reductions to 12–22%. Notably, these co-benefit packages increase net ecosystem economic benefits (NEEB) by 85–99% relative to the baseline, as the societal value of emission reductions outweighs the pig farm profit losses. For advanced modes, further environmental mitigation gains are smaller (Nr 30–35%) and costlier, indicating diminishing returns. SIGNIFICANCE Our study demonstrates that systematic technology integration can reconcile environmental sustainability with economic viability while generating net societal benefits in livestock production.