Study On Odor Dispersion And Distribution Characteristics And Control In Sludge Dewatering Room

Being one of the world seven typical public hazards, Odor has gained widespread attention. Urban wastewater treatment plant is an important odor pollution source, of which the sludge dewatering room is one of the most serious odor pollution treatment sectors. Odor in the room can cause bad effect on workers'health, and affect odor control to meet the state standard for wastewater treatment plant. Based on this background, this paper studied on odor dispersion and distribution characteristics in sludge dewatering room, which will provide theory support and guideline to dewatering room design and its odor control.At the beginning, odor classification, resource, hazard, evaluation and related legislation and standard were introduced and summarized. Then, the odor characteristics of wastewater treatment plant were researched, especially the odor in sludge dewatering room was analyzed in detail. After comprehensive understanding for odor, the paper took a study on the odor dispersion and distribution characteristics in sludge dewatering room and odor control measures were presented. In this paper, H2S was viewed as representative of odor and was applied to study odor dispersion and distribution characteristics. In order to study the characteristics, numerical simulation based on computational fluid dynamics (CFD) was applied and here simulation software FLUENT was used. Air distribution is a significant factor for odor dispersion and distribution. This paper analyzed odor dispersion and distribution under the present ventilation design in three meteorological scenes in sequence, as follows: the hottest month in summer under the most common wind direction, the coldest month in winter under the most common wind direction, the hottest month in summer under the annual most common wind direction. Still the fourth scene with different ventilation design but with same meteorological condition in scene one was simulated. Through analyzing the simulation results, it suggested that odor pollution effects vary from one scene to another, and pollution in scene three was the most serious, while the best was scene four with nice air distribution and relatively lower H2S concentration. When design dewatering room, the designer can simulate the odor distribution in precede to help improve design, so that workers'exposure to odor can be reduced. The results also showed that sludge dewatering machines should be placed the downwind of the most common wind direction in summer and should be near the exhausted outlet to drive out odor with the shortest path quickly. With numerical simulation air velocity field and odor concentration field were obtained, which can guide odor control method, natural vegetable extracted juice, that spray positions can be places around dewatering machine, airflow upstream, low velocity area and eddy current area. And numerical simulation can be useful for air collecting system design. Through simulation the optimal air distribution can be acquired, then when applied in engineering odorants would be gathered as most as possible. The study on odor control measures revealed that odor-free treatment technology is the development trend for odor control techniques. As for the dewatering room odor control in this paper, biological filter is the top priority in the long run.