Removal of ethanolamine (ETA) and COD produced in a power plant wastewater by nano-ZVI (zerovalent iron) and hydrogen peroxide (H2O2)

Abstract

Ethanolamine (C2H7NO, ETA) is used in a power plant to prevent plumbing system from corrosion by maintaining pH at a certain level. Water flowing inside the plumbing system should periodically be cleaned using ion exchange resin. On the way of regeneration of the resin by sulfuric acid, ethanolamine wastewater is produced. Removal mechanism of ETA has not been well established because it is very much resistant material in biodegradability, and even in chemical degradation. In this research high concentration of ETA ranging 5,000 ∼ 9,000mg/l was successfully removed closely down to zero level using nano sized zerovalent iron powder (nZVI) and appropriate amount of hydrogen peroxide (H2O2). Organic material of high COD concentration (6,000 ∼ 13,500mg/l) was also contained in the wastewater along with high concentration of ETA. COD of the wastewater was simultaneously reduced down to 2,500 ∼ 6,000mg/l along with ETA when catalytic oxidation of nZVI with hydrogen peroxide takes place, which can be removed further in a biological system of the following process. Removal rate of ETA showed highest at pH 3. Wastewater produced in a power plant containing high concentrations of ETA and COD could be successfully treated up to the level, from which biological process can be applied for direct discharge to the natural water body.