title: Pilot-scale demonstration of the hybrid zero-valent iron process for treating flue-gas-desulfurization wastewater: part II.
abstract: The hybrid zero-valent-iron (hZVI) process is a novel chemical treatment process that has shown promise for removing heavy metals and nutrients from industrial wastewaters. In this study, a pilot-scale demonstration was conducted to continuously treat 3.8-7.6 L/min (1-2 gpm) of the flue-gas-desulfurization (FGD) wastewater at a coal-fired power plant for 5 months. In this paper, a spike test was conducted to evaluate performance of the hZVI process for removing selected toxic metals at artificially elevated concentrations. The results showed that a multiple-stage hZVI process could decrease selenate-Se from 22 mg/L to ~10 μg/L and dissolved Hg(2+) from 1.15 mg/L to ~10 ng/L. In addition, the process simultaneously removed a broad spectrum of heavy metals such as As(III), As(V), Cr(VI), Cd(II), Pb(II) and Cu(II) from mg/L to near or sub-ppb (μg/L) level after a single-stage treatment. The process consumed about 0.3 kg ZVI per 1 m(3) FGD wastewater treated at a cost of about US$0.6/m(3). Solid waste production and energy consumption were reasonably low. The successful pilot study demonstrated that the hZVI technology can be a low-cost, high-performance treatment platform for solving some of the toughest heavy metal water problems.
authors.affiliation: Department of Biological and Agricultural Engineering, Texas A&M University, TAMU 2117, College Station, TX 77843, USA. yhuang@tamu.edu
authors.forename: Yong H
authors.initials: YH
authors.lastname: Huang
authors.forename: Phani K
authors.initials: PK
authors.lastname: Peddi
authors.forename: Hui
authors.initials: H
authors.lastname: Zeng
authors.forename: Ci-Lai
authors.initials: CL
authors.lastname: Tang
authors.forename: Xinjun
authors.initials: X
authors.lastname: Teng
mesh_terms: D004560:Electricity; D005740:Gases / Q000737:chemistry*; D007220:Industrial Waste / Q000032:analysis*; D007501:Iron / Q000737:chemistry*; D019216:Metals, Heavy / Q000302:isolation & purification; D008855:Microscopy, Electron, Scanning; D009566:Nitrates / Q000302:isolation & purification; D010865:Pilot Projects; D012822:Silicon Dioxide / Q000302:isolation & purification; D012995:Solubility; D013455:Sulfur / Q000302:isolation & purification*; D062065:Wastewater / Q000737:chemistry*; D014874:Water Pollutants, Chemical / Q000302:isolation & purification / Q000633:toxicity; D018508:Water Purification / Q000379:methods*; D014961:X-Ray Diffraction
chemical_list: D005740:Gases; D007220:Industrial Waste; D007501:Iron; D019216:Metals, Heavy; D009566:Nitrates; D012822:Silicon Dioxide; D013455:Sulfur; D062065:Wastewater; D014874:Water Pollutants, Chemical