title: Pilot-scale demonstration of the hybrid zero-valent iron process for treating flue-gas-desulfurization wastewater: part I.
abstract: The hybrid zero-valent-iron (hZVI) process is a novel chemical treatment process that has shown great potential in previous laboratory and field bench-top scale tests for removing selenium, mercury and nutrients from various 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 five months. Results show that the hZVI process could simultaneously reduce selenate-Se from 1 to 3 mg/L to below 10 μg/L and mercury from over 100 μg/L to below 10 ng/L in compliance with the new stringent effluent discharge limits planned by the U.S. EPA for Se and Hg. A three-stage hZVI system with a combined hydraulic retention time of 12 h is sufficient for Se treatment, while a single-stage system can meet Hg treatment requirement. The successful pilot study demonstrated that the hZVI process is scalable and could be a reliable, low-cost, high-performance treatment platform with many application potentials, particularly, 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: D007220:Industrial Waste; D007501:Iron / Q000737:chemistry*; D008628:Mercury / Q000737:chemistry; D010865:Pilot Projects; D012643:Selenium / Q000737:chemistry; D013455:Sulfur / Q000737:chemistry*; D013997:Time Factors; D014865:Waste Disposal, Fluid / Q000379:methods*; D014867:Water / Q000737:chemistry; D014874:Water Pollutants, Chemical / Q000737:chemistry*
chemical_list: D007220:Industrial Waste; D014874:Water Pollutants, Chemical; D014867:Water; D013455:Sulfur; D007501:Iron; D008628:Mercury; D012643:Selenium