Pollution profiles, removal performance and health risk reduction of malodorous volatile organic compounds emitted from municipal leachate treating process

Abstract

The potential adverse effects of malodorous volatile organic compounds (VOCs) from municipal waste management on ecosystems and human health have caused general public concern. Therefore, an integrated technique of spray tower (ST) with biotrickling filter (BTF) was designed for attenuation of VOCs from the municipal leachate treating process in this study. A total of 60 kinds of VOCs with total concentrations ranging from 3.54 to 26.42 ppm were accurately identified using proton transfer reaction time-of-flight mass spectrometry (PTR-TOF-MS) and gas chromatography-mass spectrometer (GC-MS). Among them, the levels of aromatic hydrocarbons (AHs) especially benzene (1.31–7.90 ppm) and toluene (0.93–5.71 ppm) were highest, occupying 77.66% of total volatile organic compounds (TVOCs). Average removal efficiencies of AHs, nitrogen-and-oxygen-containing compounds (NAOCCs), aliphatic hydrocarbons (AIHs), halogenated hydrocarbons (HHs), and volatile sulfur organic compounds (VOSCs) by ST-BTF were 60.75%, 79.55%, 75.01%, 81.71%, and 54.32%, respectively. Moreover, the odorous flavor, the ozone formation potential (OFP), and the health risks of the studied VOCs were dramatically diminished after the ST-BTF purification. More abundant and stabler bacterial communities in the BTF were developed to resist the impact of VOC shock loading as compared with fungi. The conspicuously increased abundance of Bacteroidetes, Verrucomicrobia and Epsilonbacteraeotal played significant roles in the degradation of HHs. Moreover, the dominant Pseudomonadaceae and Pseudomonas belonging to Proteobacteria significantly metabolized xenobiotics, as predicted by PICRUSt. These results indicated that the ST-BTF is an efficient technique for attenuation of ecological and human health risk under moderate and shock loading of VOCs.