Enhanced Copper Removal from Activated Sludge Using Bioferric Selectors

• Published in: Journal of environmental engineering (New York, N.Y.) Vol. 125; no. 5; pp. 470 - 478
• Main Authors: McCormick, Mark W, Cannon, Fred S
• Format: Journal Article
• Language: English
• Published: Reston, VA American Society of Civil Engineers 01.05.1999
• Subjects: Applied sciences; Biological and medical sciences; Biological treatment of waters; Biotechnology; Environment and pollution; Exact sciences and technology; Fundamental and applied biological sciences. Psychology; Industrial applications and implications. Economical aspects; Other wastewaters; Pollution; TECHNICAL PAPERS; Wastewaters; Water treatment and pollution; Activated sludge; Bioreactor; Iron III; Batchwise; Flocculation; Urban waste water; Copper; Waste water purification; Optimization; Biological purification; Heavy metal
• ISSN: 0733-9372; 1943-7870
• DOI: 10.1061/(ASCE)0733-9372(1999)125:5(470)

Effluent copper concentrations from a pilot-scale conventional activated-sludge system (control) were compared with those from a conventional pilot treatment process that also integrated bioferric selector units. The bioferric selector units employed iron coagulation within the activated-sludge basin and also provided storage of activated sludge in a nonaerated selector for a period of 18-24 h. During pseudo-steady-state operation over a 30-day period, the systems employing the bioferric selector treatment consistently yielded lower effluent copper concentrations than did the controls. Although influent copper concentration ranged from 126 to 723 ppb (228 ppb average), the two bioferric selector units achieved an average effluent copper concentration of 22 ppb, whereas the two conventional controls achieved an average of 40 ppb. The difference in copper concentrations between the bioferric selector units and the controls was statistically significant to the 99.5% confidence level when comparing effluent copper concentrations as a function of mixed-liquor volatile suspended solids (MLVSS). For both conditions, lower effluent copper corresponded to higher MLVSS, and for equal levels of MLVSS, the bioferric selector units statistically achieved lower effluent copper concentrations than did the controls. Likewise, Freundlich isotherm plots indicated that the MLVSS (or MLSS) that had undergone the bioferric selector treatment achieved statistically greater capture of copper than did their control counterparts.