以3座北京市某区代表性区级污水处理厂为研究对象,综合《城镇水务系统碳核算与减排路径技术指南》、《污水处理厂低碳运行评价技术规范》和《IPCC 2006 年国家温室气体清单指南 2019 修订版》碳排放核算方法,采用定量统计、相关性分析及敏感性分析等手段对污水处理厂正常运行状态下碳排放核算和影响因素进行特征分析和规律识别,并提出针对性减排路径建议。结果表明:C厂C-TECH工艺的吨水碳排放强度为三厂最低1.35 kg CO2eq·m−3,处于我国较低水平,接近“双碳”目标要求;而B厂改良SBR工艺的单位污染去除碳排放强度较小,其COD碳排放强度为3.16 t CO2eq·t−1,TN碳排放强度为36.44 t CO2eq)·t−1,TP碳排放强度为176.69 t CO2eq·t−1,处于我国中上水平,从效能角度更接近“双碳”目标要求。不同工艺产生的温室气体、进水水质波动及用电消耗导致三厂碳排放强度上存在差异,但各工艺的主排碳因子均为间接碳排放 (A厂、B厂和C厂中分别占73%、59%和59%) ,间接碳排放的主贡献因子为电力消耗 (A厂、B厂和C厂中分别占33%、40%和40%) 。相关性分析发现,各水厂碳排放强度还与N2O造成的直接碳排放有较大相关性,3座水厂年排放N2O 2.48×104 t CO2eq,A厂、B厂和C厂中相关性系数值分别达到0.68、0.87、0.66。敏感性分析表明,整体碳排放强度对电力消耗、N2O排放和药耗的变化更为敏感,药耗中葡萄糖溶液和多效高分子除磷剂对碳排放强度影响较大。以上结果表明,北京区级污水处理厂应从优化曝气系统、水泵效能等节电措施和调整水厂加药模式等节药措施上实现减排。 相似文献
The aim of this paper was to explore the implications of planned obsolescence (PO) and the associated product lifetime on the environmental impact of products. To achieve this task, a literature review was performed to assess both the historical context and recent situation of planned obsolescence. A search in scholarly journals was performed to evaluate to what extent product lifetime and PO have been discussed in the recent literature. Based on the findings, selected cases of PO are discussed and trends in the practice of limiting product lifetime are identified. Factors considered to have a significant influence on product lifetime have been identified and discussed. The discussion of case studies made it possible to establish the links between product design, manufacturing and associated impacts of lifetime. The role of the actors along the value chain is also considered to propose a business scheme, where the influences of consumer behaviour and design choices are crucial. Finally, strategies to facilitate the definition of different scenarios are given. These strategies may serve to increase the reliability of environmental assessment throughout a product life cycle. 相似文献
Objective: The objective of this study is to develop a novel algorithm on a mobile system that can warn drivers about the possibility of a collision with a pedestrian. The constraints of the algorithm are near-real-time detection speed and a good detection rate.
Method: Histogram of gradients (HOG)-based detection is widely used in pedestrian safety applications; however, it has low detection speed for real-time systems. Hence, it has no direct usage for mobile systems. In order to achieve near-real-time detection speed, partial Haar transform predetections are applied to an image before HOG detection. The partial and HOG detections are merged and a score-based confidence level is defined for the final detection phase. In this way, the outcome is prioritized and different warning levels can be issued to warn the driver before a possible pedestrian collision.
Results: The proposed algorithm provides an increase in detection speed (from 46 to 76 fps) and detection rate (from 80 to 91%) with respect to HOG-based pedestrian detection. It also improves confidence of the results by multidetection merging and score assignment to detections.
Conclusions: Performance improvement of the algorithm is compared with respect to state-of-the-art detectors/algorithms. Based on the detection rate and detection speed performance, it can be concluded that the proposed algorithm is suitable to be used for mobile systems to warn drivers about the possibility of collision with a pedestrian. 相似文献