Regeneration of saturated activated carbon by low-voltage arcing method: Insight from nature water treatment

Abstract

Low-voltage arcing method enables low energy consumption, wide applicability, reduced carbon loss (<5 %), and equipment miniaturization for saturated activated carbon (SAC) regeneration. For a comprehensive evaluation the regeneration effect of low-voltage arcing method, we regenerated the granular activated carbon replaced after two years of service in water treatment, and compared the performance of regenerated activated carbon (RAC) with new activated carbon (NAC) in water treatment by replicating the same production process employed by tap water plants. At an optimal regeneration temperature of 800 ℃ for SAC, the results from the 8-month water treatment indicated that NAC only slightly outperformed (0.8 %) RAC in terms of reducing chemical oxygen demand due to its particle size and integral structure. RAC has certain advantages in reducing the turbidity of water, and has less influence on the pH value than NAC. The effect of both RAC and NAC on conductivity is minimal, and the conductivity change gradually decreases over time as adsorption capacity declines and biofilms form. Overall, there is no significant difference in the effect of RAC and NAC in such long-term water treatment experiment.