Biofilters for the co-treatment of volatile organic compounds and odors in a domestic waste landfill site

Volatile organic compounds (VOCs) and odors are two important gaseous pollutants escaped from landfill, which are harmful to human health and the surrounding environment. In this study, biofilter was used to control VOCs and odors from an actual landfill. The operating efficiency and mechanism of biofilters on the sealing zone and leachate treatment zone were respectively analyzed and compared. The results found that components of gaseous pollutants from these two zones are different. Hydrogen sulfide (572.96 μg/m³), ammonia (479.28 μg/m³), and dimethyl sulfide (279.81 μg/m³) were mainly detected in sealing zone, and dichloromethane (3573.97 μg/m³), triethylamine (1818.21 μg/m³), benzene (1809.11 μg/m³), and chlorobenzene (1286.81 μg/m³) were main components of gaseous pollutants in leachate treatment zone. Although the types and concentrations of gaseous pollutants in these two zones were significantly different, the biofilters showed good removal efficiencies. The average removal rate of the total VOC (TVOC), sulfides, and amines in both biofilters exceeded 80%. The outlet concentrations meet the level-3 standard of the Emission standards for odor pollutants (GB 14544–93). This is mainly related to the evolution of bacterial population during the operation of biofilters. In the inoculums, the dominant bacterial genus is Brevibacillus (58.84%), and bacteria with Bacillus and Pseudomonas only occupied 2.67% and 1.77%. With the extension of operation time, the dominant bacteria of biofilter in the sealing zone gradually evolved into Mycobacterium (67.82%) and Bacillus (27.90%), while the dominant bacteria of biofilter in the leachate treatment zone evolved into Bacillus (72.69%) and Pseudomonas (21.59%). These results indicated that identification of gaseous pollutant components and design of appropriate treatment systems based on their components will further improve the operating efficiency of biofilters in the actual landfill.