Synthetic effect of zero-valent iron and granular activated carbon omethane production from pentachlorophenol wastewater

Abstract

The main aim of this study was to investigate the effects and mechanisms of zero-valent iron (ZVI) and granular activated carbon (GAC) on biological degradation of pentachlorophenol (PCP) for methane production. In the bath tests, the optimal dosage of ZVI was determined to be 200 mg/L under the combined action of GAC. Combination addition of ZVI and GAC (ZVI/GAC) was more conducive to PCP degradation and chemical oxygen demand removal than that of single ZVI addition, corresponding removal efficiencies were 79.58% and 31.38%, respectively. The kinetic study was showed that ZVI/GAC addition could enhance PCP degradation rate in anaerobic reac-tor. Furthermore, continuous flow experiments were also conducted in three two-phase anaerobic reactors. The results indicated that the operating performances including operational stability and methane production of PCP wastewater were enhanced by ZVI or ZVI/GAC, and the average methane production reached 1241.5 mL and 1482.3 mL, respectively. Degradation pathway analysis demonstrated that the PCP was successively reduced to be lower chlorinated organic substances, and the total CPs decreased under the action of ZVI/GAC.