Aryal R.,University of Technology, Sydney |
Vigneswaran S.,University of Technology, Sydney |
Kandasamy J.,University of Technology, Sydney |
Naidu R.,CRC CARE
Korean Journal of Chemical Engineering | Year: 2010
Stormwater runoff from urban and suburban areas generates numerous pollutants. The areas include residential areas, parks, commercial areas, industrial areas and road/highways. Land use and human activities largely determine the nature and level of pollutants. Among the various types of pollutants that can contribute to adverse water quality impact in receiving water bodies, of concern are suspended solids, heavy metals, polycyclic aromatic hydrocarbons and nutrients. This paper provides a critical review of the characteristics and sources of urban stormwater pollutants and the manner in which the pollution occurs. Treatment systems for urban stormwater runoff and for urban stormwater harvesting are discussed. © 2010 Korean Institute of Chemical Engineers, Seoul, Korea.
Chekli L.,University of Technology, Sydney |
Zhao Y.X.,University of Technology, Sydney |
Zhao Y.X.,Shandong University |
Tijing L.D.,University of Technology, Sydney |
And 6 more authors.
Journal of Hazardous Materials | Year: 2014
Adsorption of natural organic matter, aggregation and disaggregation have been identified as three of the main processes affecting the fate and behaviour of engineered nanoparticles (ENPs) in aquatic environments. However, although several methods have been developed to study the aggregation behaviour of ENPs in natural waters, there are only a few studies focusing on the fate of such aggregates and their potential disaggregation behaviour. In this study, we proposed and demonstrated a simple method for characterising the aggregation behaviour and aggregate structure of ENPs in different natural waters. Both the aggregate size of ENPs and their adsorption capacity for dissolved organic matter (DOM) were strongly related (R2>0.97, p<.05) to the combined effect of initial concentration of dissolved organic matter (DOM) and the ionic strength of the natural waters. The structure of the formed aggregates was strongly correlated (R2>0.95, p<.05) to the amount of DOM adsorbed by the ENPs during the aggregation process. Under high ionic strength conditions, aggregation is mainly governed by diffusion and the aggregates formed under these conditions showed the lowest stability and fractal dimension, forming linear, chain-like aggregates. In contrast, under low ionic strength conditions, the aggregate structure was more compact, most likely due to strong chemical binding with DOM and bridging mechanisms involving divalent cations formed during reaction-limited aggregation. © 2014 Elsevier B.V.
Zhou Y.-F.,University of Queensland |
Haynes R.J.,University of Queensland |
Naidu R.,CRC CARE
Environmental Science and Pollution Research | Year: 2012
Purpose: This study aims to examine whether addition of immobilising agents to a sandy, alkaline (pH = 8. 1) soil, which had been contaminated with Pb and Zn by airborne particles from a Pb/Zn smelter, would substantially reduce metal bioavailability. Methods: The effectiveness of five waste materials (blast furnace (BF) slag, alum water treatment (WT) sludge, red mud, sugar mill mud and green waste compost) as metal immobilising agents was evaluated by incubating them with a contaminated soil for a period of 12 months at rates of 5% and 10% (w/w), after which, Rhodes grass was grown in the soils in a greenhouse study. Results: Additions of WT sludge, BF slag and red mud reduced CaCl2, CH3COOH, HCl and EDTA-extractable Zn but compost and mill mud had no appreciable immobilising effects. Additions of all amendments reduced levels of CaCl2, CH3COOH and HCl-extractable Pb although concentrations of EDTA-extractable Pb remained unchanged. A sequential extraction procedure showed that additions of mill mud and compost increased the percentage of total Pb and Zn present in the oxidisable fraction whilst additions of the other materials increased the percentage present in the residual fraction. Rhodes grass yields were promoted greatly by additions of red mud, compost and particularly mill mud, and yields were negatively correlated with tissue Pb concentrations and extractable Pb. Conclusions: Red mud was the most effective material for lowering extractable Pb and Zn levels simultaneously while mill mud and compost were notably effective for Pb. A field evaluation in the study area is justified. © 2011 Springer-Verlag.
Chekli L.,University of Technology, Sydney |
Phuntsho S.,University of Technology, Sydney |
Roy M.,Australian National Measurement Institute |
Lombi E.,University of South Australia |
And 3 more authors.
Water Research | Year: 2013
Iron nanoparticles are becoming increasingly popular for the treatment of contaminated soil and groundwater; however, their mobility and reactivity in subsurface environments are significantly affected by their tendency to aggregate. Assessing their stability under environmental conditions is crucial for determining their environmental fate. A multi-method approach (including different size-measurement techniques and the DLVO theory) was used to thoroughly characterise the behaviour of iron oxide nanoparticles (Fe2O3NPs) under environmentally relevant conditions. Although recent studies have demonstrated the importance of using a multi-method approach when characterising nanoparticles, the majority of current studies continue to use a single-method approach.Under some soil conditions (i.e. pH 7, 10mM NaCl and 2mM CaCl2) and increasing particle concentration, Fe2O3NPs underwent extensive aggregation to form large aggregates (>1μm). Coating the nanoparticles with dissolved organic matter (DOM) was investigated as an alternative "green" solution to overcoming the aggregation issue instead of using the more commonly proposed polyelectrolytes. At high concentrations, DOM effectively covered the surface of the Fe2O3NPs, thereby conferring negative surface charge on the particles across a wide range of pH values. This provided electrostatic stabilisation and considerably reduced the particle aggregation effect. DOM-coated Fe2O3NPs also proved to be more stable under high ionic strength conditions. The presence of CaCl2, however, even at low concentrations, induced the aggregation of DOM-coated Fe2O3NPs, mainly via charge neutralisation and bridging. This has significant implications in regards to the reactivity and fate of these materials in the environment. © 2013 Elsevier Ltd.
Ma C.J.,Shaoguan University |
Ming H.,CRC CARE |
Li H.S.,South China Agricultural University
Advanced Materials Research | Year: 2013
Currently, the comprehensive utilization of red mud has been a worldwide challenge. Due to high alkaline level and a serious lack of nutrients, a great amount of red mud has been stocked in the open rather than covered by plantations, which showed harms to the atmosphere, water and soil environment. In order to explore a more effective phytoremediation approach of red mud and screen plants with strong tolerance, the research group applied Pennisetum hybridum as the experiment material for a long term, which is a new energy plant in the field of ecological environmental management and restoring. Through the addition of different types of addictives, his experiment conducted the plantation Pennisetum hybridum based on red mud improvement matrix. Besides, a systematic research of the improvement effects of different ameliorants on red mud was conducted. Concurrently, the growth of Pennisetum hybridum in different groups of the experiment was investigated. Their mutual effect on the improvement effect of red mud was analyzed systematically. Results demonstrated that effective raw materials of red mud improvement include phosphogypsum, wastes of polluted and edible mushrooms. These can significantly reduce the pH and conductivity of red mud. After the improvement, Pennisetum hybridum can grow vigorously in the mixture matrix of red mud, and significantly improve the red mud matrix. Concurrently, considerable biomasses were obtained. The experiment results demonstrated that the addition of necessary nutriments for the plant growth was very important for red mud. The research has laid a solid foundation for the identification of the great potentials of Pennisetum hybridum in red mud phytoremediation, the further exploration of its role of restoring of red mud and the extensive application and promotion in the future. © (2013) Trans Tech Publications, Switzerland.