A New Technique for Improving Sediment-water Quality by Means of Re-suspension - Fukuyama Method

Title: A New Technique for Improving Sediment-water Quality by Means of Re-suspension - Fukuyama Method
Author(s): Masaharu FUKUE, Kouji UEHARA, Hidenori KOUGE, Yoshio SATO, Toru HARADA, Mahiro YAMANA, Catherine N. MULLIGAN
Paper category : conference
Book title: 2nd International Conference on Waste Engineering and Management - ICWEM 2010
Editor(s): J.Zh. Xiao, Y. Zhang, M.S. Cheung and Reuben P. K. Chu
Print-ISBN: 978-2-35158-102-5
e-ISBN: 978-2-35158-103-2
Publisher: RILEM Publications SARL
Publication year: 2010
Pages: 812 - 817
Total Pages: 6
Nb references: 1
Language: English

Abstract: Heavy eutrophication in enclosed or semi-enclosed water areas causes and/or results in adverse effects to sediment and water quality. By continuous loading of organic matter to a canal located in the central part of Fukuyama City, the sediments contain an ignition loss of 30 percent. The COD of sediment reached 15 percent, which is half of the ignition loss. As a result, hydrogen sulfide production often occurred, mostly from spring to autumn. Therefore, Fukuyama city decided to investigate the possibility of cleaning up the bottom of the canal. The pre-investigation of the quality of sediment and water showed that the sediments were under a heavily anaerobic condition and the dissolved oxygen was almost zero. Dredging and sand capping was initially considered. However, considering cost performance, time savings, effectiveness of the methods, etc., a new technology was required to be developed. Finally, the re-suspension method developed by Fukue et al. was selected based on pilot tests, and the potential for scale-up to full scale for a variety of applications.
The re-suspension method consists of (1) dispersion of the sediment by air-water jets, (2) pumping of the suspension (small particles and organic matter), (3) settlement in a tank, (4) filtration and (5) disposal of solids (followed by incineration for this case). The pilot test was performed to clean up an area of 3000 m2. The dispersed depth of the bottom was approximately 50 cm. The time spent for the work was two weeks. The wet amount of re-suspended solid removed from the bottom was about 8 tonnes in dry mass. Since the solids contain high concentrations of COD, T-P and T-N, the remaining sediment was considerably improved. The ORP of the surface sediments was approximately -150 mV. The ORP of the re-deposited sediments increased to above +70 mV.

Online publication: 2011-01-25
Publication type : full_text
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