北京市沥青搅拌站VOCs排放清单研究

定量化的排放清单是环境管理和研究工作的重要抓手,由于行业规模小、活动水平数据匮乏、测试难度大,沥青混合料生产过程的VOCs排放研究国内文献报导极少.本文构建了一套沥青混凝土搅拌站VOCs排放量核算方法,依据排放特点分环节分别核算VOCs排放量,分析排放量的时空分布特征,定量分析排放清单的不确定性,并基于目前的污染控制水平和未来行业管控规划,预估2030年北京市沥青混合料生产行业的VOCs排放量,以期为北京市VOCs总量减排和精细化管理提供依据.结果表明：2017年北京市沥青搅拌站VOCs总排放量为25.9 t,不确定度为25.6%,其中,沥青储罐的排放量最大,占总排放量的87.2%;顺义、昌平、通州3个区的排放量位居前三,分别占行业总排放量的16.2%、14.4%和14.1%;在时间分布上,5—7月沥青混合料产量最高、VOCs排放量最大;通过情景分析,本研究认为通过出台行业标准和绿色生产技术指南,可大幅削减沥青混合料生产行业的VOCs排放量.     

Environmental impacts of different food waste resource technologies and the effects of energy mix

The environmental impacts of food waste management strategies and the effects of energy mix were evaluated using a life cycle assessment model, EASEWASTE. Three different strategies involving landfill, composting and combined digestion and composting as core technologies were investigated. The results indicate that the landfilling of food waste has an obvious impact on global warming, although the power recovery from landfill gas counteracts some of this. Food waste composting causes serious acidification (68.0 PE) and nutrient enrichment (76.9 PE) because of NH₃ and SO₂ emissions during decomposition. Using compost on farmland, which can marginally reduce global warming (−1.7 PE), acidification (−0.8 PE), and ecotoxicity and human toxicity through fertilizer substitution, also leads to nutrient enrichment as neutralization of emissions from N loss (27.6 PE) and substitution (−12.8 PE). A combined digestion and composting technology lessens the effects of acidification (−12.2 PE), nutrient enrichment (−5.7 PE), and global warming (−7.9 PE) mainly because energy is recovered efficiently, which decreases emissions including SO₂, Hg, NO_x, and fossil CO₂ during normal energy production. The change of energy mix by introducing more clean energy, which has marginal effects on the performance of composting strategy, results in apparently more loading to acidification and nutrient enrichment in the other two strategies. These are mainly because the recovered energy can avoid fewer emissions than before due to the lower background values in power generation. These results provide quantitative evidence for technical selection and pollution control in food waste management.