Prof. CHUA Hong

Prof. CHUA Hong |Clyto Access

Professor Environmental Engineering, THEi, Hong Kong

Keynote Speaker
Organizing Committee Member

Expertise: Environment Protection And Management


Ir Professor CHUA Hong PhD in Environmental Engineering, National University of Singapore (on NUS Research Scholarship and Glaxochem Industrial Scholarship) Certificate in Environmental Technology, King Mongkut's University of Technology, Jointly hosted by Asian Institute of Technology, Thailand (on UNESCO Asia Pacific Scholarship) BEng (Hons) in Chemical Engineering, National University of Singapore Ir Professor Chua is the Dean of Faculty of Science and Technology, Technological and Higher Education Institute of Hong Kong (THEi), a member institute of the Vocational Training Council (VTC) of Hong Kong. Before joining THEi in 2012, Ir Professor Chua had worked in the Hong Kong Polytechnic University, where he was Professor of the Department of Civil and Structural Engineering from 1992 to 2012, and Director of the Water and Waste Research and Development Centre in PolyU Shenzhen Technology Park since 2010.In the past ten years, Ir Professor Chua has been responsible for numerous industrial and commercial environmental-engineering, F&B, and biotechnology-related consultancy,product-development and technology transfer projects for such clients as Government Departments, industrial and commercial companies in Hong Kong, China, Japan, Singapore,Taiwan, Vietnam, the Philippines and Malaysia. He has attracted a total of over HK$19,000,000 worth of high-level consultancy projects, and has won the PolyU Outstanding Consultant Award for 1999, 2000, 2001, 2002, 2004 and 2006. Ir Professor Chua has received numerous research and development grants from the Hong Kong Research Grants Council, Hong Kong Industrial Department Innovative Technology Funds and Industrial Collaborative Funds, The total awarded funds amounting to above HK$56M in the past ten years. He has published over 200 papers in reputable (SCI-listed) international journals and refereed conference proceedings, and is now serving as Vice Chairman for Hong Kong Association for Advancement of Science and Technology, International reviewer for Journal of Applied Biochemistry and Biotechnology (SCI listed), International reviewer for Symposium Series on Biotechnology for Chemicals and Fuels, USA, International advisory board for Journal of Asian Water (Singapore based), and International technical advisor for Journal of Asian Water(Chinese Edition).


Title: Metal Redistribution and Bioavailability Enhancement in River Sediment after In-situ Ca(NO3)2 and CaO2 Treatments


Contaminated river sediment has been subject to urban, industrial, agricultural and various anthropogenic discharges. High concentration of nutrients and organic chemicals are often found in the sediment. The contaminated sediment can be treated by different physiochemical ex-situ remediation methods. However, the treated sediment may still be disposed of at landfills if the contamination level of the sediment does not fulfill stringent standards for recycle purposes. On the contrary, in-situ biogeochemical remediation is considered a waste-free treatment method with less disruption to the ecosystem. Yet, it has been reported that in-situ sediment remediation mobilized metals from sediment and may enhance the toxicity upon aquatic life. In such regard, contaminated river sediment was treated in this study by the addition of Ca(NO3)2 or CaO2 as to mimic the in-situ odor mitigation, and acid volatile sulfide (AVS) and organic pollutant removal. The effect of Ca(NO3)2 or CaO2 on the bioavailability, bioaccessibility, and redistribution of metals in sediment was evaluated. After applying Ca(NO3)2 or CaO2, the metal concentrations in the sediments reduced insignificantly. However, as indicated by the assessments of [SEMtot-AVS]/fOC (SEM and fOC refer to simultaneously extracted metals and the fraction of organic carbon in sediment, respectively) and the bovine serum albumin leaching test, both bioavailability and bioaccessibility of metals (Cu, Zn, and Ni) to benthic organisms were enhanced after 35 days of remediation. Metal redistribution from relatively stable fractions (oxidizable and residual fractions) to weakly bound fractions (exchangeable and reducible fractions) was found in Ca(NO3)2- and CaO2-treated sediments, and corresponded well with the results of enhanced metal bioavailability. Upon purposeful assessment and investigation, this study provides scientific findings for determining the appropriate strategy for in situ sediment remediation.


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