Chromium Distribution, Leachability and Speciation in a Chrome Plating Site

Hexavalent chromium (Cr(VI)) waste produced by chrome plating activities pollutes the surrounding environment and harms human health. However, information about the chromium (Cr) pollution characteristics of actual electroplating sites is still lacking. In this study, the concentration, leachability and speciation of Cr in soils from a typical chrome plating site were analyzed. Our results showed that this site was severely contaminated by Cr (7.2 to 7735.2 mg/kg) and Cr(VI) reached the mean concentration of 138.7 mg/kg. The spatial distribution of Cr(VI) was related to the plating processes. Chrome plating and sewage treatment areas could be considered as the hot spots of contaminated sites. The vertical distribution of Cr(VI) was mainly affected by soil properties, where the loam layer retained and reduced a large amount of Cr(VI) due to its high content of iron minerals and finer particle fractions. Additionally, the chemical extraction results showed that Cr was mainly in non-residual fractions and the existence of Cr(VI) led to a high leaching toxicity based on the toxicity characteristic leaching procedure (TCLP) results. Moreover, X-ray photoelectron spectroscopy (XPS) results revealed the speciation of Cr in the long-term contaminated soils. A large amount of Cr(VI) was reduced into Cr(III) and mainly existed as Cr(OH)3 and Cr2O3. Furthermore, Cr(VI) tended to precipitate as CaCrO4 and persisted in soils. Therefore, it is necessary to find appropriate strategies to remediate these contaminated soils. Overall, these findings strengthen our understanding of Cr(VI) behaviors and lay a foundation for the future pollution investigation, ecological remediation and risk assessment of sites contaminated by electroplating.

Evaluating Cultural Landscape Remediation Design Based on VR Technology

Due to the recent excessive pursuit of rapid economic development in China, the cultural heritage resources have been gradually destroyed. This paper proposes cultural recovery and ecological remediation patterns, and adopts virtual reality (VR) technology to evaluate the visual aesthetic effect of the restored landscape. The results show that: (1) the average vegetation coverage increased, providing data support for remediation design evaluation; and (2) the fixation counts and average saccade counts of the subjects increased after the remediation design, indicating that the restored cultural landscape reduced visual fatigue and provided a better visual aesthetic experience. Furthermore, the comparative analysis of the quality of the water environment shows that the remediation design project improved the ecological environment quality of the relics area. The results of this study will contribute to rural revitalization in minority areas in southwest China.

Regenerating dross : a campus for sustainable energy systems

The following thesis began as an investigation into post-industrial urban waste and the ecological remediation potential that such landscapes embody. It looks at the forces behind waste landscapes or drosscapes and examines the theories associated with the ever-growing amount of waste landscapes throughout our cities. This thesis is largely centered on using Landscape Urbanism as a means of regenerating post-industrial waste sites. The Landscape Urbanists have proposed the use of landscape, rather than architecture, to transform urban waste and reconnect it back to the urban fabric. Where does architecture exist within this context? How can architecture act as a catalyst throughout this transformation? This thesis will examine how architecture and landscape can operate in unison throughout post-industrial site remediation and it will explore how built form can become an integral part of a continuous landscape.

Regenerating dross : a campus for sustainable energy systems

The following thesis began as an investigation into post-industrial urban waste and the ecological remediation potential that such landscapes embody. It looks at the forces behind waste landscapes or drosscapes and examines the theories associated with the ever-growing amount of waste landscapes throughout our cities. This thesis is largely centered on using Landscape Urbanism as a means of regenerating post-industrial waste sites. The Landscape Urbanists have proposed the use of landscape, rather than architecture, to transform urban waste and reconnect it back to the urban fabric. Where does architecture exist within this context? How can architecture act as a catalyst throughout this transformation? This thesis will examine how architecture and landscape can operate in unison throughout post-industrial site remediation and it will explore how built form can become an integral part of a continuous landscape.

The Potential Application of Giant Reed (Arundo donax) in Ecological Remediation

Giant reed is known as one of the most important energy plants as a consequence of its huge dry biomass production. It can be used for bioenergy or biopolymer production. Thus, it can replace maize and reduce the production cost of biomass and electricity. Giant reed and its products have different uses in industry. The use of giant reed as a raw material to obtain cellulose past for the production of rayon viscose and paper. Thanks to the flexible and strong of the material, giant reed can be used in the manufacture of fishing rods, brass musical instruments, canes and construction supplies. One of the most important characteristics of giant reed is that it shows strong growth capability in different soils with wide ranges of pH, salinity and high heavy metal contents and can be used for ecological remediation. Giant reed was able not only to decontaminate polluted soils with heavy metals, but also to purify the wastewater and decrease the pH and make red mud safer. Here, we review the available evidence regarding the utilization of giant reed in the field of phytoremediation and discuss the potential application of giant reed combined with advanced remediation technologies in ecological remediation.

Biostimulation-phytoremediation of petroleum hydrocarbon contaminated soil: Response surface methodology (RSM)

In view of the analysis and remediation of petroleum hydrocarbon contaminated soil, the study on ecological technology of oilfield well site was carried out. The response surface was used to optimize the single-factor biological stimulation experiment of moisture content, the leavening agent content and the compound fertilizer content, and get the best experimental plan of biological stimulation. The artificial stimulation-plant combined remediation experiment was designed. Through screening 20 kinds of plant seeds suitable for growth, selected 5 plants with high tolerance to petroleum hydrocarbons. The artificial biostimulation-phytoremediation combined degradation experiment of petroleum hydrocarbons in contaminated soil was designed, and the degradation rate of petroleum hydrocarbons in soil under the optimal ecological remediation scheme was obtained. It was found that petroleum hydrocarbons degradation rate in soil after 70 days artificial stimulation experiment was 28.6%. Through the screening of 20 plants, peanut had the highest tolerance to petroleum hydrocarbons in soil, and the degradation rate in 70 days soil reached 31.1%. After 70 days of biostimulation-phytoremediation, the degradation rate in soil reached 38.9%.