Research On Deodorization Ventilation Of Sludge Dewatering Workshop

With the rapid urbanization of China,the distance between the municipal sewage treatment plant and the urban area is getting shorter and shorter,and the resulting odor hazard is becoming more and more serious.According to the statistics of the national environmental reporting network management platform,the odor hazard has become the second largest environmental problem after noise in China.In the sewage treatment process,the odorous substances that are not timely removed will leak into the surrounding area through the doors,windows or gaps,and affecting a larger area.In recent years,the introduction of various national environmental policies has also put forward higher requirements for exhaust gas emissions in the sewage treatment industry.How to effectively design and optimize the deodorization ventilation system of sewage treatment facilities has become an urgent problem for the sewage treatment enterprises at this stage.For such problems,there are many empirical engineering design cases based on the air change rate in the existing research,and the operation effects are generally not ideal.Due to the lack of detailed prediction and evaluation of the air distribution,it is impossible to accurately grasp the distribution of contaminant concentration field and pressure field in sewage treatment facilities under different deodorization ventilation engineering design elements(such as: air distribution).So it is difficult to optimize the design of deodorization ventilation schemes.Based on the field test of a sludge dewatering workshop in Shenzhen,using ammonia and hydrogen sulfide as typical pollutants for research,this study verified the rationality of the Realizable k-? model for simulating the deodorization and ventilation in sewage treatment facilities by STAR-CCM+.The results show that the error between the simulated value of the spatial average pollutant concentration and the measured value is less than 10%.Then based on the field investigation results of the sludge dewatering workshop in Shenzhen,the typical ventilation modes of the sewage treatment facilities which includes mechanical ventilation and hybrid ventilation were discussed.And,based on the verified CFD method and uniform experimental design theory,the influence of air distribution and air change rate on the contaminant concentration field distribution of sewage treatment facilities under the typical ventilation modes is further analyzed.Among them,the hybrid ventilation additionally analyzes the influence of air distribution,air change rate and air inlet size on the pressure field.The results show that the exclusion rate of pollutants in the breathing zone can reflect the advantages and disadvantages of air distribution.The concentration distribution of pollutants in the typical ventilation modes is mainly affected by the air exchange times and air distribution.The average space pressure in the hybrid ventilation mode is mainly affected by the air exchange times and the size of the air inlet.Then,combined with numerical experimental simulation results and stepwise regression method,based on the quadratic polynomial,the contaminant concentration field simplified prediction models of mechanical ventilation and hybrid ventilation and the pressure field simplified prediction models of hybrid ventilation for the selected sewage treatment facility were constructed.Subsequently,with reference to domestic and foreign literature standards,the deodorization ventilation scheme evaluation indicators for the working environment sanitation,the odor leakage possibility,the air distribution and the ventilation system energy efficiency were defined,and a comprehensive evaluation system for the deodorization ventilation scheme of sewage treatment facilities was constructed.Finally,based on the above research,a software for deodorizing ventilation project evaluation of sewage treatment facilities was developed.The results of the case application show that the developed software can better reflect the current situation of the design and improvement needs.