Emission characteristics, treatment status and mitigation countermeasures of volatile organic compounds from typical solvent sources in Shenzhen City

In order to strengthen the comprehensive regulation of industrial volatile organic compounds (VOCs), Shenzhen City, a developed industrial and economic area, was selected as the research area. Through field investigation and field testing, the VOCs emission characteristics and end-of-pipe (EOP) treatment status of typical solvent sources such as rubber and plastic products industry, printing industry, surface coating industry and electronic components manufacturing industry were discussed. At the same time, some specific measures of emission reduction for source substitution and terminal management were made. The results showed that: The average emission of VOCs from typical solvent sources in Shenzhen City was in the order of surface coating (51.8 t/a) > electronic components (36.5 t/a) > printing (21.0 t/a) > rubber and plastic (17.4 t/a). Rubber enterprises and printing enterprises of different emission scales contributed more evenly to their respective industries, while painting enterprises and electronic enterprises with emissions higher than 300 t/a contributed 63.9% and 44.9% to their respective industries, respectively. Under the influence of control policies such as the substitution of water-based raw materials and the promotion of EOP treatment facilities, OVOCs were the main VOCs components of the four industries' fixed emission sources, with a mass proportion ranging from 76.8% to 97.0%. Besides, the characteristic pollutants were formaldehyde and acetaldehyde. The EOP process types of the four industries were mainly the inefficient combination of UV photolysis, water spraying and activated carbon adsorption, accounting for about 51.4%-69.6%. The evaluation results showed that 78% of the tested typical combined processes had an average treatment efficiency of lower than 35%. The lack of pertinence of treatment schemes and the lack of standardization of operation management were the main factors causing the low EOP reduction rate of VOCs from the sources of solvent use. Therefore, in order to control the emission of VOCs from the sources of solvent use in the future, the source control should be promoted from "baseline constraint" to "advanced driven". The EOP treatment should comprehensively consider the technical feasibility and management effectiveness to ensure the efficient reduction of the total amount of VOCs emissions in the industries.