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Unsuccessful Urban Governance of Brownfield Land Redevelopment: A Lesson from the Toxic Soil Event in Changzhou, China

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A public health crisis in the process of brownfield land redevelopment (BLR) has frequently appeared in the context of promoting industrial upgrading and de-industrialization in China. Recent discussions on the

A public health crisis in the process of brownfield land redevelopment (BLR) has frequently appeared in the context of promoting industrial upgrading and de-industrialization in China. Recent discussions on the reasons for this problem centered on the lack of laws, standards, and policies needed to secure the process of BLR. However, we argue that an urban governance approach to BLR can identify the sources of the problem. This paper discusses a case study of a toxic soil event in Changzhou, China, based on the theoretical framework—the Institutional Industry Complex (IIC). Under the pressure of fiscal distress as well as the requirements of economic growth and urbanization, local governments in China are bound with fiscal revenue from land development and land urbanization and have formed a pro-growth alliance with enterprises, property developers, and even the public. The alliance is defined as the pro-growth IIC of land finance regime in this paper. Due to the path-dependence of the IIC, the conventional pro-growth IIC of land finance regime in China has been circulated, and then transformed into a pro-growth IIC of BLR. As a result, the goal of the pro-growth IIC of BLR is maximizing profit in the process of land development, a goal that is the same as the pro-growth IIC of land finance regime Thus, as the pivotal stockholders of the pro-growth IIC of BLR, local governments, enterprises, and property developers hesitate to pursue a prudent and secure BLR process, which effectively attenuates a series of serious environmental issues and public health crises. That is the root cause of the problem. This study suggests a positive interaction between central and local government, as well as between enterprise and the public to create a sustainable IIC of BLR in future.

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Date Created
  • 2017-05-15

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Synergistic reductive dechlorination of 1,1,1-trichloroethane and trichloroethene and aerobic degradation of 1,4-dioxane

Description

Widespread use of chlorinated solvents for commercial and industrial purposes makes co-occurring contamination by 1,1,1-trichloroethane (TCA), trichloroethene (TCE), and 1,4-dioxane (1,4-D) a serious problem for groundwater. TCE and TCA

Widespread use of chlorinated solvents for commercial and industrial purposes makes co-occurring contamination by 1,1,1-trichloroethane (TCA), trichloroethene (TCE), and 1,4-dioxane (1,4-D) a serious problem for groundwater. TCE and TCA often are treated by reductive dechlorination, while 1,4-D resists reductive treatment. Aerobic bacteria are able to oxidize 1,4-D, but the biological oxidation of 1,4-D could be inhibited TCA, TCE, and their reductive transformation products. To overcome the challenges from co-occurring contamination, I propose a two-stage synergistic system. First, anaerobic reduction of the chlorinated hydrocarbons takes place in a H2-based hollow-fiber “X-film” (biofilm or catalyst-coated film) reactor (MXfR), where “X-film” can be a “bio-film” (MBfR) or an abiotic “palladium-film” (MPfR). Then, aerobic removal of 1,4-D and other organic compounds takes place in an O2-based MBfR. For the reductive part, I tested reductive bio-dechlorination of TCA and TCE simultaneously in an MBfR. I found that the community of anaerobic bacteria can rapidly reduce TCE to cis-dichloroethene (cis-DCE), but further reductions of cis-DCE to vinyl chloride (VC) and VC to ethene were inhibited by TCA. Also, it took months to grow a strong biofilm that could reduce TCA and TCE. Another problem with reductive dechlorination in the MBfR is that mono-chloroethane (MCA) was not reduced to ethane. In contrast, a film of palladium nano-particles (PdNPs), i.e., an MPfR, could the simultaneous reductions of TCA and TCE to mainly ethane, with only small amounts of intermediates: 1,1-dichloroethane (DCA) (~3% of total influent TCA and TCE) and MCA (~1%) in continuous operation. For aerobic oxidation, I enriched an ethanotrophic culture that could oxidize 1,4-D with ethane as the primary electron donor. An O2-based MBfR, inoculated with the enriched ethanotrophic culture, achieved over 99% 1,4-D removal with ethane as the primary electron donor in continuous operation. Finally, I evaluated two-stage treatment with a H2-based MPfR followed by an O2-MBfR. The two-stage system gave complete removal of TCA, TCE, and 1,4-D in continuous operation.

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Date Created
  • 2018

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The versatile roles of sulfate-reducing bacteria for uranium bioremediation

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Uranium (U) contamination has been attracting public concern, and many researchers are investigating principles and applications of U remediation. The overall goal of my research is to understand the versatile

Uranium (U) contamination has been attracting public concern, and many researchers are investigating principles and applications of U remediation. The overall goal of my research is to understand the versatile roles of sulfate-reducing bacteria (SRB) in uranium bioremediation, including direct involvement (reducing U) and indirect involvement (protecting U reoxidation). I pursue this goal by studying Desulfovibro vuglaris, a representative SRB. For direct involvement, I performed experiments on uranium bioreduction and uraninite (UO2) production in batch tests and in a H2-based membrane biofilm reactor (MBfR) inoculated with D. vuglaris. In summary, D. vuglaris was able to immobilize soluble U(VI) by enzymatically reducing it to insoluble U(IV), and the nanocrystallinte UO2 was associated with the biomass. In the MBfR system, although D. vuglaris failed to form a biofilm, other microbial groups capable of U(VI) reduction formed a biofilm, and up to 95% U removal was achieved during a long-term operation. For the indirect involvement, I studied the production and characterization of and biogenic iron sulfide (FeS) in batch tests. In summary, D. vuglaris produced nanocrystalline FeS, a potential redox buffer to protect UO2 from remobilization by O2. My results demonstrate that a variety of controllable environmental parameters, including pH, free sulfide, and types of Fe sources and electron donors, significantly determined the characteristics of both biogenic solids, and those characteristics should affect U-sequestrating performance by SRB. Overall, my results provide a baseline for exploiting effective and sustainable approaches to U bioremediation, including the application of the novel MBfR technology to U sequestration from groundwater and biogenic FeS for protecting remobilization of sequestrated U, as well as the microbe-relevant tools to optimize U sequestration applicable in reality.

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Date Created
  • 2014