摘要
Although phosphorus(P)recovery and management from sewage sludge are practiced in North America and Europe,such practices are not yet to be implemented in China.Here,we evaluated the environmental sustainability opportunity and socio-economic costs of recovering P from sewage sludge by replacing the current-day treatments(CT;sludge treatment and landfill)and P chemical fertilizer application(CF)in China using life cycle assessment and life cycle costing methods.Three potential P recovery scenarios(PR1‒PR3:struvite,vivianite,and treated sludge)and corresponding current-day scenarios(CT1‒CT3 and CF)were considered.Results indicated that PR1 and PR2 have smaller environmental impacts than the current-day scenarios,whereas PR3 has larger impacts in most categories.PR3 has the lowest net costs(sum of internal costs and benefits,39.1-54.7 CNY per kg P),whereas PR2 has the lowest external costs(366.8 CNY per kg P).Societal costs for production and land use of 1 kg P by P recovery from sewage sludge(e.g.,∼527 CNY for PR1)are much higher than those of P chemical fertilizers(∼20 CNY for CF).However,considering the costs in the current-day treatments(e.g.,∼524 CNY for CT1),societal costs of P recovery scenarios are close to or slightly lower than those of current-day scenarios.Among the three P recovery scenarios,we found that recovering struvite as P fertilizer has the highest societal feasibility.This study will provide valuable information for improved sewage sludge management and will help promote the sustainable supply of P in China.
基金
This study was funded by the National Key R&D Program of China(2018YFE0106400)
the National Natural Science Foundation of China(42122059 and 41977324)
the Natural Science Foundation of Tianjin(20JCYBJC01080).The support from Aalborg University was also acknowledged.