Treatment of Wet FGD Wastewater by a Modified Chemical Precipitation Method Using a Solid Powder Reagent

Abstract

This research focused on developing a modified chemical precipitation (MCP) method for treating wet flue gas desulfurization (FGD) waste water by adding a solid powder reagent directly. Simulated wet FGD wastewater was treated by MCP method in simulation experiments. Optimization experiments were carried out with the help of response surface methodology (RSM) and central composite design (CCD) to evaluate the effects and the interactions of experimental variables, including reagent dosage, temperature and pH value. The optimal reagent dosage, temperature and pH value were 3018.0 mg/L, 40.5 °C and 5.7, respectively. The RSM was demonstrated as an appropriate approach for the optimization of wet FGD wastewater treatment with the MCP method. A comparative study between the MCP method and the traditional chemical precipitation (TCP) method on raw wet FGD wastewater treatment was conducted. Results indicate that the MCP had less reagent dosage and variety than the TCP method had. Thus, the MCP method had a lower cost.

Keywords

Wet FGD wastewater / Modified chemical precipitation / RSM / CCD

References

[1] Srivastava RK, Jozewicz W. Flue gas desulfurization: the state of the art. J Air Waste Manag Assoc, 2001, 51(12): 1676-1688.

[2] Gutiérrez Ortiz FJ. A simple realistic modeling of full-scale wet limestone FGD units. Chem Eng J, 2010, 165(2): 426-439.

[3] Borgwardt RH. Combined flue gas desulfurization and water treatment in coal-fired power plants. Environ Sci Technol, 1980, 14(3): 294-298.

[4] Lefers J, Van Den Broeke W, Venderbosch H, et al. Heavy metal removal from waste water from wet lime (stone): gypsum flue gas desulfurization plants. Water Res, 1987, 21(11): 1345-1354.

[5] Vendrup M, Sund C. Treatment of wastewater from flue gas cleaning. Water Sci Technol, 1994, 29(9): 307-312.

[6] Andalib M, Arabi S, Dold P, et al. Mathematical modeling of biological selenium removal from flue gas desulfurization (FGD) wastewater treatment. Proc Water Environ Fed, 2016, 11: 228-248.

[7] Sonstegard J,Pickett T, Harwood J et al (2008) Full scale operation of GE ABMet^® biological technology for the removal of selenium from FGD wastewaters. The international water conference. Orlando

[8] Mooney FD, Murray-Gulde C. Constructed treatment wetlands for flue gas desulfurization waters: full-scale design, construction issues, and performance. Environ Geosci, 2008, 15(3): 131-141.

[9] Sundberg-Jones SE, Hassan SM. Macrophyte sorption and bioconcentration of elements in a pilot constructed wetland for flue gas desulfurization wastewater treatment. Water Air Soil Pollut, 2007, 183(1–4): 187-200.

[10] Shaw WA. Benefits of evaporating FGD purge water. Power, 2008, 152(3): 59-63.

[11] Marlett JM (2012) Flue gas desulfurization (FGD) evaporator operation report, ENEL Brindisi. The international water conference. San Antonio

[12] Nielsen P, Christensen T, Vendrup M. Continuous removal of heavy metals from FGD wastewater in a fluidised bed without sludge generation. Water Sci Technol, 1997, 36(2): 391-397.

[13] Enoch G, van den Broeke W, Spiering W. Removal of heavy metals and suspended solids from wastewater from wet lime (stone): gypson flue gas desulphurization plants by means of hydrophobic and hydrophilic crossflow microfiltration membranes. J Membr Sci, 1994, 87(1): 191-198.

[14] Enoch GD, Spiering W, Tigchelaar P, et al. Treatment of waste water from wet lime (stone): flue gas desulfurization plants with aid of crossflow microfiltration. Sep Sci Technol, 1990, 25(13–15): 1587-1605.

[15] Huang YH, Peddi PK, Tang C, et al. Hybrid zero-valent iron process for removing heavy metals and nitrate from flue-gas-desulfurization wastewater. Sep Purif Technol, 2013, 118: 690-698.

[16] Huang YH, Peddi PK, Zeng H, et al. Pilot-scale demonstration of the hybrid zero-valent iron process for treating flue-gas-desulfurization wastewater: part I[J]. Water Sci Technol, 2013, 67(1): 16-23.

[17] Huang YH, Peddi PK, Zeng H, et al. Pilot-scale demonstration of the hybrid zero-valent iron process for treating flue-gas-desulfurization wastewater: part II. Water Sci Technol, 2013, 67(2): 239-246.

[18] Seigworth A, Ludlum R, Reahl E. Case study: integrating membrane processes with evaporation to achieve economical zero liquid discharge at the Doswell Combined Cycle Facility. Desalination, 1995, 102(1): 81-86.

[19] Bezerra MA, Santelli RE, Oliveira EP, et al. Response surface methodology (RSM) as a tool for optimization in analytical chemistry. Talanta, 2008, 76(5): 965-977.

[20] Del Castillo E, Montgomery DC, McCarville DR. Modified desirability functions for multiple response optimization. J Qual Technol, 1996, 28: 337-345.

[21] Kang Y, Lu J, Guo J. Experimental study on effects of FGD wastewater treatment by “one-step” process. Thermal Power Gener, 2015, 44(6): 58-62.

[22] Sakhare N, Lunge S, Rayalu S, et al. Defluoridation of water using calcium aluminate material. Chem Eng J, 2012, 203: 406-414.

[23] Kumar E, Bhatnagar A, Hogland W, et al. Interaction of anionic pollutants with Al-based adsorbents in aqueous media: a review. Chem Eng J, 2014, 241: 443-456.

[24] Freundlich H. Adsorption in solution. Z Phys Chem, 1906, 57: 384-470 (in German)