River Water Treatment Using Electrocoagulation for Removal of Natural Organic Matter and Pharmaceutical Compounds

Abstract

Water pollution can seriously impact aquatic systems health which can reduce the availability of clean freshwater. Hence, it is vital to develop efficient technologies for treating water. Present study focused on the removal of two emerging pollutants acetaminophen (ACP), tetracycline (TCL) and a conventional pollutant natural organic matter (NOM) from river water using electrocoagulation (EC). EC process was optimized in batch mode and based on the results continuous mode experiments were conducted. Batch mode EC assessed various operating conditions such as reaction time, electrode materials (Al, Fe, SS), inter-electrode distance (2, 3 and 4 cm), voltage (6, 9, 12, 18 V) and drug concentration. In continuous mode, hydraulic retention time (HRT) and drug concentration were tested. Optimized conditions were then used to carry out EC augmented with aeration. Maximum removal of ACP and NOM in batch mode EC occurred at 60 min reaction time, using Al-Al, 2 cm inter-electrode distance, and 9 V. Initial ACP concentration was varied as 1, 2, 5, 10, and 20 mg/L and the results showed as the concentration increased treatment efficiency decreased. XRD and FTIR spectrum showed that as H bonding with Al(OH)3 flocs was the main mechanism for removal of ACP. Pseudo-second-order kinetics model showed a good fit on data for ACP removal. Single factor ANOVA showed statistically significant variance between treatments for ACP removal (F2.76 = 136, P = lt 0.001). Linear correlation was significant between UV254 absorbance and ACP removal at different concentrations. Preliminary analyses suggested that EC cost for river water treatment will be US$ 0.22/m3. newlineContinuous mode EC for ACP removal was carried out with Al-Al as electrodes, 9 V, natural pH, and electrical conductivity of river water. Results revealed that HRT of 40 min and 0.5 mg/L ACP exhibited best removal efficiency for NOM (55.9%) and ACP (53.4%) removal. EC generated sludge (floating and settled) was analysed using XRD, FTIR, FESEM-EDS. XRD spectrum revealed the signific