Heavy-Metal Accumulation in Low-Sludge Wastewater Treatment Technique: Sonication-Cryptic Growth
Publication: Journal of Environmental Engineering
Volume 138, Issue 3
Abstract
This paper used a sonication-cryptic growth technique in sequencing batch reactor (SBR) to reduce sludge yield and then analyzed the accumulation of eight typical heavy metals in sludge, namely, Hg, Cr, Ni, Cu, Zn, As, Cd, and Pd. SBR-1 was blank, SBR-2 used sonication, SBR-3 was dosed with heavy metals, and SBR-4 had both sonication and heavy metals. Artificial wastewater dosed with heavy metals was used for SBR-3 and SBR-4. Results showed that the addition of heavy metals in influent caused the latter to accumulate in sludge and that each metal exhibits different behavior. Heavy-metal addition dropped sludge bioactivity by 53% and decreased the effluent chemical oxygen demand (COD) (SBR-3 versus SBR-1). Application of sonication (each day, 15% sludge was treated for 15 min by ultrasound) decreased the excess sludgy by almost half; however, it increased sludge heavy-metal concentration only by 3.5% (SBR-4 versus SBR-3). Furthermore, sonication benefited sludge bioactivity and thus improved the effluent COD quality. It also significantly changed the individual accumulation patterns of eight heavy metals.
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Acknowledgments
The authors thank financial support from the Ministry of Science and Technology of the People’s Republic of China (China-Israel Joint Research Program) and the National Natural Science Foundation of China (NSFC50978088, NNSFC51039001).
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Information & Authors
Information
Published In
Journal of Environmental Engineering
Volume 138 • Issue 3 • March 2012
Pages: 248 - 251
Copyright
© 2012 American Society of Civil Engineers.
History
Received: Oct 13, 2010
Accepted: Apr 28, 2011
Published online: Apr 30, 2011
Published in print: Mar 1, 2012
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