Assessment Of Phosphorus Recovery From Wastewater Of Feces And Urine Source Separation In China Based On The Whole Life Cycle

As a kind of life necessary but a non renewable resource,phosphorus has a stable cycle chain without human activities.However,due to the development of the commodity economy and the acceleration of the urbanization process,the limitation of the distance between waste production and recycling land,and the lack of recycling economy market,the phosphorus cycle is broken.Phosphorus recovery from waste is an effective means of pollution control and resource protection.As a kind of human waste,domestic sewage has the characteristics of small volume proportion of urine and feces,the high proportion of pollutants such as nitrogen,phosphorus,organic matter,etc.,so it is highly efficient and targeted to separate the source of manure and grey water and treat and recover them separately.However,the feasibility of using the sewage treatment system of manure and urine source separation in the environment and economy needs to be further studied.In this project,three application scenarios of rural single household treatment mode,joint household treatment mode and city are selected for life cycle environmental impact assessment.Each scenario includes a traditional sewage treatment system and sewage treatment system with separation of manure and urine sources.The system boundary includes the construction stage,operation stage and expansion system representing recycled products to avoid fertilizer production.In this paper,11 environmental impact indicators,including eutrophication potential and global warming,are compared in each scenario.Based on the data quality indicators,the uncertainty of the results is analyzed by the Monte Carlo simulation method.Finally,the life cycle cost of each scenario is analyzed.The results show that,in terms of environment,the impact of the construction stage of rural single household governance mode is higher than that of the operation stage,about 90%-100% of the total impact;the environmental impact of the operation stage of rural joint household governance mode and city is dominant,about 70%-80% of the total impact.However,the production of integrated polyethylene septic tank in the construction stage of rural joint household governance still contributes 10%-20% to the environmental impact.In terms of economy,the cost in the construction stage of rural single household governance mode is higher than that in the operation stage,accounting for about 80% of the total cost;the cost in the urban operation stage is dominant,accounting for about 60%-80% of the total cost;and the rural joint household governance mode is between the two.After the uncertainty analysis of the scheme,there is no significant change in the results of environmental impact: the fossil energy consumption potential and eutrophication potential of the scheme of manure source separation in rural single household governance mode are about 90% lower than those of the traditional scheme,but the global warming potential of the traditional scheme is about 70% higher than that of the manure source separation system;the fossil energy consumption potential and global warming potential of the rural joint household governance mode Compared with the traditional schemes,they are about 90% and 60% lower,but there is no significant difference in eutrophication potential;the leading environmental impact results of the two urban schemes are similar.According to the comprehensive environmental impact assessment and cost analysis,the rural manure and urine source separation schemes all show different degrees of advantages.However,the environmental impact of the traditional urban scheme and the manure and urine source separation scheme is similar,only at the economic level to support the application of the manure and urine source separation system.Therefore,in practical application,we can think that it is feasible in environment and economy to apply the separation system of the source of manure and urine in rural areas,but whether the city is suitable for the application of the separation system of the source of manure and urine needs to be analyzed according to the actual situation in order to make a correct decision.