城市物质代谢的生态效率——以深圳市为例

城市可持续发展研究的关键是城市物质代谢通量及其效率研究,但物质代谢通量仅能反映代谢速率,而其生态效率则能反映支持社会经济发展的物质代谢能力。从工业、生活的源头循环(减少原生资源的消耗)和末端循环(减少污染物的产生)角度,构建城市物质代谢生态效率的度量模型,并依据中国城市化发展进程,选定深圳市作为研究区,核算城市水、能量和废物代谢通量以及代谢的生态效率。结果表明:随着深圳市社会经济的快速发展,水、能源和废物代谢通量呈现出增长势头,但代谢的生态效率不断提高。1998～2004年间,GDP增长2.7倍,城市水和电的代谢通量分别增长1.5倍和3.0倍;工业增加值增长3.7倍,工业水、电、能源和废物的代谢通量分别增长1.9、3.5、2.7倍和2.0倍;常住人口增长1.5倍,居民水和电的代谢通量分别增长1.8倍和1.7倍;资源效率提高1.8倍,环境效率提高3.7倍,生态效率提高2.3倍。虽然深圳市物质代谢的生态效率在提高,但是随着物质资源的日益稀缺,物质代谢的生态效率仍需进一步提高,而提高城市物质代谢生态效率的关键是资源效率和环境效率的协同发展,以及逐步构建废物资源化的循环链条。

Eco-efficiency of urban material metabolism: a case study of Shenzhen

The keys of studying urban sustainable development are material metabolism flux and efficiency.Metabolism flux of urban materials can only reflect the metabolism velocity,while its eco-efficiency can determine the metabolism capacity to support socio-economic development.The general model and the measure model of eco-efficiency were set up,based on the source recycle(decreasing the consumption of crude resources)and terminal recycle(decreasing the discharge of pollutants)of production and life.These models were employed to study material metabolism flux and efficiency in Shenzhen.Results showed water,energy and waste metabolism fluxes have increased since 1998 with constant socio-economic development,and their eco-efficiencies have also increased rapidly.When GDP rose by 2.7 times,the metabolism fluxes of urban water and electricity rose by 1.5 and 3.0 times,respectively.When added value of industry rose by 3.7 times,the metabolism fluxes of industrial water,electricity,energy,and waste rose by 1.9,3.5,2.7,and 2.0 times,respectively.When population rose by 1.5 times,the metabolism fluxes of residential water and electricity rose by 1.8 and 1.7 times,respectively.During the period,the resource efficiency,environmental efficiency,and eco-efficiency rose by 1.8,3.7,and 2.3 times,respectively.Whereas the efficiency of material metabolism has been improved in Shenzhen,the scarciuy of material resources has become more and more serious.Therefore,it is necessary to further improve the efficiency of material metabolism.The keys of improving the Eco-efficiency of urban material metabolism are the increasing of resources,and environmental efficiencies,and the establishment of recycling chain of the re-utilization of waste resources.