污水的内含能及污水处理过程的耗能与节能

污水处理是一个高能耗、低能效的复杂过程。改变传统认知，将污染物当作能量物质加以资源化，回用于水处理过程或者产品化，可改变污水处理的能耗。以城市污水与焦化废水为例，分析了水质中污染物具有的内含能形式，并探讨了两种计算方法，指出内含能利用的两类可能途径和最大限度。基于热力学基本定律与污水水质特征，辅以适当的当量假设，分析了污水处理过程中的不同形式能量消耗及其原因，运用能流图表达了两个具体案例的能量转化与分布规律。比较了污水处理两类节能评价方法的优异性，提出了未来水处理可能的节能新途径。在加深污水内含能认识的基础上，结合相关产业与工艺技术，分离回收有价值成分，如营养物（氮、磷）、重金属等，并获得水资源的再利用，以间接补偿处理过程的能耗，从而实现节能目标。

Embodied energy of wastewater and energy consumption and saving in its treatment processes

Wastewater treatment is a complex process with high energy consumption and low efficiency. Different from the traditional concept of wastewater treatment, the pollutants contained of wastewater can be regarded as energy materials or as the raw materials of other products to be havested to reduce the energy consumption. The forms of the pollutants'' embodied energy in wastewater were examined by employing two calculation methods and taking sewage and coking wastewater as examples. Moreover, two possible path ways for the utilization and maximization of the recovery of embodied energy during the wastewater treatment were discussed. The different forms of energy consumption and their causes in wastewater treatment process were analyzed based on thermodynamic laws and quality characteristics of the wastewater, with reasonable assumptions. The laws of energy transfer and distribution of two specific cases are expressed by the energy flow diagram. Some possible energy-saving approaches and wastewater treatment methods in the future are predicted by comparing different energy saving technologies. Based on in-depth understanding of the embodied energy in wastewaters, valuable elements such as nutrients (nitrogen, phosphorus) and heavy metals can be separated and recovered, and water resources can be reused by combining with related industries and technologies. Therefore, the goal of energy saving can be achieved by the indirect compensation of energy consumption in the wastewater treatment process.