市政污水厂典型A2O工艺低碳运行的系统性评估

在“碳达峰、碳中和”的目标下,系统评估典型A²O工艺运行的碳排放当量及其组成,对我国市政污水厂的低碳运行具有重要的指导意义.以焦作市第一污水厂2020年的运行资料为研究案例,基于相关指南,引入水温因素构建阿伦尼乌斯公式模型用于核算直接碳排放过程,从电能消耗、药剂投加和污泥运输这3个方面核算间接碳排放过程.结果表明,CH₄和N₂O日排放强度为(115±56)kg·d^-1和(30±18)kg·d^-1;生化处理工段的能耗和药剂间接碳排放占比分别达到48.4%和51.3%; 2020年污水厂总计碳排放当量(以CO₂eq计)为2.17×10⁴t,单位污水碳排放当量(0.63±0.07)kg·m^-3;不同碳排放占比的大小顺序为：污水能耗(36.5%)>污水药剂(26.6%)>N₂O直接(15.4%)>污泥药剂(9.6%)>污泥能耗(6.7%)>CH₄直...

Systematic Evaluation of Low-carbon Operation of Typical A2O Processes in Municipal Sewage Plant

Under the "Carbon Peak, Carbon Neutral" goal, the systematic evaluation of the carbon emission equivalent (CO₂eq) and its compositions of the typical A²O process has important guiding significance for the low-carbon operation of most municipal sewage plants in China. Based on the operational data on the first municipal sewage plant of Jiaozuo in 2020 and the methods presented in "2019 Refinement to the 2006 IPCC Guidelines for National Greenhouse Gas Inventories, " a systematic evaluation of the CO₂eq of the typical A²O process was established, including direct emissions that were built on the Arrhenius model introducing the water temperature factor and indirect emissions from the three aspects of electricity consumption, agent addition, and sludge transportation. The results showed that the daily emission intensities of CH₄ and N₂O were (115±56) kg·d^-1 and (30±18) kg·d^-1, respectively. Additionally, indirect carbon emissions from electricity consumption and agent addition accounted for 48.4% and 51.3% in the biochemical treatment section, respectively. In 2020, CO₂eq amounts of total research plant and per unit sewage were 2.17×10⁴ t and (0.63±0.07) kg·m^-3, respectively. The magnitude of the proportion of different carbon emission compositions was as follows:sewage electricity (36.5%)>sewage agent (26.6%)>N₂O direct (15.4%)>sludge agent (9.6%)>sludge electricity (6.7%)>CH₄ direct (4.9%)>sludge transportation (0.3%). System import/export fluxes of carbon and nitrogen elements were calculated, followed by the carbon to nitrogen mass ratio in the sewage plant. Direct carbon emission characteristics of CH₄ and N₂O and their influencing factors were discussed, respectively. Based on the balance theory of carbon and nitrogen elements in the system, it is proposed that the selective introduction of industrial wastewater may become an important reference measure for the low-carbon operation of municipal sewage plants in the future.