A novel adsorption-anaerobiosis column for the removal of persistent organics from contaminated water

A novel adsorption-anaerobiosis column (AAC) system was used to treat persistent organics, namely neopentanoic acid (NPA, at 0.5 g l−1) and 2-ethylhexanoic acid (EHA, at 1.0 g l−1), in contaminated water. The fire-expanded clay pellets that were used to pack the column served as an adsorbent for organic contaminants and as a carrier for anaerobic biofilm immobilization. The AAC system could remove 75% of the NPA and 98% of the EHA at a hydraulic retention time (HRT) of 2 days. The system could recover from a shock load equivalent to a 150% increase in hydraulic and organic loads, caused by a sudden decrease of HRT from 5 to 2 days.