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A process for the determination of anaerobic-oxic biologically treated perfluoroalkyl substances (PFASs) in leachates from a landfill in Beijing, China, is provided. The applicability of electrocoagulation (EC) with aluminum electrodes for the remediation of PFASs in landfill leachates is investigated in detailed. With reaction time of 45 min, plate distance of 1 cm, current density of 35 mA/cm 2 and plate amounts of four pairs, the EC reactor achieved the optimal removal efficiencies for chemical oxygen demand and PFASs. Perfluorooctane sulfonate was not detected in the treated leachates after the EC treatment. The average removal efficiencies of perfluorohexanoic acid, perfluoroheptanoic acid, perfluorooctanoate acid, perfluorononanoic acid and perfluorodecanoic acid were 65.1, 58.5, 75.2, and 33.8%, respectively. However, perfluoroundecanoic acid and perfluorododecanoic acid concentration increased by about 20.2 and 18.6% after the EC treatment process.

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A B S T R A C TThe performance of electrocoagulation (EC) process in the treatment of geothermal water with high fluoride content was studied. The effect of applied current density, electrode plate number, electrode plate distance, and the temperature of geothermal water was investigated. The results show that EC can effectively reduce fluoride content to a low level, which can supply sanitary standard for drinking water in China (GB 5749-2006(GB 5749- , 2006. With the increase in current density and electrode plate area, the removal efficiency of fluoride in geothermal water was also increased. However, with electrode plate distance increased from 0.5 to 2.0 cm, the fluoride removal efficiency decreased accordingly. The fluoride removal efficiency was improved when geothermal water temperature was increased from 18 to 38˚C, while the fluoride removal efficiency changed little with geothermal water temperature from 38 to 62˚C.