ABSTRACT
Presently, volatile organic compounds (VOCs) pollution control in China has entered the deep-water zone, facing difficult challenges. The cost-effectiveness of VOCs abatement alternatives will determine the final environmental benefits. Screening of abatement alternatives with good cost-effectiveness and performance is important to form a sound basis for VOCs emission abatement work to create sustainable and stable alternatives. In this study, 12 typical emission scenarios are set up based on the emission characteristics of pollution sources, such as emission concentration, airflow volume, continuous or intermittent emissions, and fluctuations in concentration. Based on these typical scenarios, the operation costs of current mainstream emission abatement alternatives is estimated, and a cost-effectiveness comparison is made using the unit abatement cost (UAC, yuan·kg-1, VOCs) as the index. The results obtained can provide a reference for choosing appropriate VOCs abatement alternatives according to the characteristics of VOCs emission. Results show that for low concentration VOCs, the UAC of emission abatement is normally more than 8 yuan·kg-1. The concentration in the process plays an important role in reducing UAC. Therefore, the reasonable collection of VOCs gas, resulting in smaller emission volume and higher concentration, has a significant impact on the subsequent emission abatement cost-effectiveness. Enhancing the classification collection of VOCs to improve resource attributes of the recovered VOCs liquid is also an effective way to improve the cost effectiveness of VOCs abatement.
ABSTRACT
While wastewater and polybrominated diphenyl ethers (PBDEs) are commonly both discharged into aquatic ecosystems, little information is known about how wastewaters with different nutrient levels impact on microbial degradation of PBDEs. In this study, we used an anaerobic microcosm experiment to examine how the removal rates of 2,2',4,4'-tetrabromodiphenyl ether (BDE-47) from contaminated sediment varied when exposed to three wastewaters with different nutrient properties, namely livestock wastewater (LS), municipal sewage (MS), and shrimp pond wastewater (SP), and to determine the microbial controls on removal processes. We found that BDE-47 degraded relatively rapidly in MS, which had low carbon and nitrogen concentrations, but degraded much more slowly in LS and SP, which had relatively high nutrient concentrations. The variations in BDE-47 removal in different wastewater were related to iron reduction rates and the abundances of organohalide-respiring bacteria (OHRB). The community compositions of both total bacteria and OHRB from the family Dehalococcoidaceae differed significantly among the wastewater treatments. Compared with other treatments, some bacterial groups with PBDE degradation abilities were more abundant in MS where the PBDE-degradation efficiencies were higher. Our results should help support evaluations of the bioremediation potential of sites that are contaminated with both halogenated organic compounds and nutrient-rich wastewater.
