基于Calpuff模型的生活垃圾填埋场恶臭气体影响范围评估

Assessment of influence range of landfill odorous gas based on Calpuff model

为了研究以氨气对代表的恶臭物质扩散对周边环境造成的影响,利用Calpuff模型评估了苏州某山谷型填埋场作业面上的气体释放,分析了大气温度、气压、风速和气体释放通量等参数的变化对下风向、距离填埋场1.7 km位置10 m高度处空气中氨气浓度的影响;计算了氨气在不同风速和不同单位时间释放质量下的最大影响距离,并对单位时间释放质量及最大影响距离关系进行了拟合;依据现有国家标准,对拟合公式与现有国标计算公式进行了比较.结果表明:风速与气体释放通量是主要的扩散影响因素;国标的计算公式中以5年平均风速作为主要依据选取参数存在缺陷,基于场地实际条件得到的拟合公式可以对国标公式计算结果进行修正,以保证填埋场周边群众避免受到恶臭问题的干扰.

The Calpuff model was adopted to analyze the impact of odorous substance dispersion, such as ammonia, emitted from the working surface of a valley type landfill in Suzhou and surround- ings. The effects of the parameters were analyzed by the model, including ambient temperature, pressure, wind velocity, and gas flux variations on the ammonia aerial concentration of the place 10 m in height and 1.7 km away from the landfill downwind analyzed. The maximum influence dis- tance of the ammonia, with different wind velocities and release qualities per unit time was calculated. A formula was proposed for fitting the relation between the release quality per unit time and maximum influence distance. The fitting formula was compared with the existing formula specified in the national standard. The result indicates that the wind velocity and gas flux variations are critical factors to affect dispersion and the calculation formula specified by national standard has its limitation since the five-year average wind speed is chosen as the main basis for selecting parameters. The fit- ting formula, based on the actual site conditions, can modify the national standard formula to ensure the residents around the landfill away from the odor pollution.