青藏高原生态屏障区生活垃圾治理生态环境风险及应对路径——以青海省为例

Risk assessment and optimization of domestic waste treatment in the Qinghai-Tibet Plateau ecological barrier zone:A case study of Qinghai Province

生活垃圾治理失效导致的污染胁迫已成为青藏高原生态安全屏障建设面临的突出威胁,精准评估城乡生活垃圾治理的生态环境风险并科学制定应对路径,对改善人居环境品质、筑牢生态安全屏障具有重要意义。以青海省4306个居民点为研究对象,在定量测度城乡各类生活垃圾的产生量及其治理水平基础上,从生活垃圾治理体系的收集、转运与处理全过程视角,综合考虑危险度、暴露度、脆弱度因子构建生态环境风险评价指标体系,应用基于主客观综合赋权的TOPSIS方法和风险管控障碍度评价方法,多尺度评价生活垃圾治理生态环境风险并识别管控阻滞因子。结果显示:青海省城乡生活垃圾产生呈整体分散、局部组团式集中分布特征,全省生活垃圾集中治理率仅62.33%;全省生活垃圾治理的生态环境风险总体处于中风险等级,属于中高风险及高风险等级的居民点占36.90%,且河湟谷地区向柴达木盆地区、环青海湖及祁连山地区和青南高原地区呈风险递增;现行生活垃圾治理体系在镇级转运环节的生态环境风险最高,在祁连山脉、昆仑山脉东段以及青南高原峡谷地带转运风险突出;自然地理环境高寒性、分散式垃圾处理技术滞后性是风险管控的主要阻滞因子。建议以生活垃圾全处置和生态环境零胁迫为导向,采取补齐生活垃圾治理的软硬件短板、建立高效收集与处理的奖补政策机制、强化城镇与农牧居民环境伦理教育等举措,综合提升生态屏障区生活垃圾治理效能;基于青藏高原城乡聚落与生活垃圾产污分散性,充分顾及其治理全过程的生态环境风险,将生活垃圾治理体系配置的基本单元由县域下沉至镇域尺度,因地制宜实施城乡一体化治理、乡镇集中治理、村分散治理等镇域片区治理模式。

Qinghai-Tibet Plateau is a significantly ecological security barrier in China and even Asia.However,the improper treatment of domestic waste has become a prominent threat to the ecological security of Qinghai-Tibet Plateau ecological barrier zone.Hence,the scientific risk assessment and management strategies for domestic waste treatment in urban and rural settlements are fundamental to improving the living environment and stability of the ecological barrier zone.Based on the quantitative measurement of the generation and treatment level of domestic waste in 4306 settlements of Qinghai Province,this study constructed a framework of eco-environmental risk assessment by considering the hazard,vulnerability,and exposure factors,from the perspective of the whole process of the collection,transportation,and disposal of domestic waste treatment system.The TOPSIS and obstacle degree model were applied to comprehensively assess the eco-environmental risk and control obstacles of waste treatment.The results show that the distribution of domestic waste was characterized by an overall pattern of“globally dispersed,locally agglomerated”in Qinghai Province,and the rate of the centralized domestic waste treatment was relatively low at 62.33%.The eco-environmental risk of domestic waste treatment in Qinghai Province was at a medium risk level in general,with 36.90%of the settlements at an upper medium or high level.Furthermore,the eco-environmental risk showed a pattern of increase from the valley of the Yellow River and Huangshui River to the Qaidam Basin,the Qinghai Lake region,the Qilian Mountains region,and the highland alpine in southern Qinghai.Moreover,the eco-environmental risk of waste transportation was the highest in the domestic waste treatment system,with the Qilian Mountains,the eastern section of the Kunlun Mountains,and the valley of the highland alpine in southern Qinghai being notable.The analysis of obstacle degrees indicated that the alpine natural environment and the lag in decentralized waste disposal technology were main obstacles to risk control in Qinghai Province.Aiming at the complete disposal of domestic waste and near-zero stress to the eco-environment in the Qinghai-Tibet Plateau ecological barrier zone,greater efforts are needed to bridge the gap between hardware and software infrastructures for domestic waste management,carry out the policy of giving rewards and subsidies for effective waste treatment,and reinforce the environmental ethics education for urban residents,farmers,and herdsmen.Taking into account the eco-environmental risk of the whole process of the domestic waste treatment system,it is wise to adjust the basic unit of the domestic waste treatment system from the county scale to the town scale and implement three models of treatment:urban-rural integration treatment,centralized treatment in the town,and decentralized treatment in the villages based on the dispersion of urban and rural settlements and domestic waste generation on Qinghai-Tibet Plateau.