Removal of synthetic and natural organic compounds during biological nitrification

Biological nitrification has been successfully used in Europe for many years to remove ammonia at an early stage of water treatment train. This research investigated the removal of two classes of organic compounds by nitrification filtration: (1) high molecular weight compounds, and (2) synthetic compounds which present, for most of them, a health hazard. Two laboratory-scale reactors were designed to simulate the conditions for nitrification kinetics of a full-scale water treatment process in France. One reactor was fed only with ammonia and the other with ammonia and 0,2 mg C/l of acetate to simulate the amount of biodegradable organic matter typically present in water. Two classes of high-molecular weight organic polymers were investigated: a polysaccharide (Dextran) and two proteins (Lactoglobuline and Lysozyme). Gel permeation analysis coupled with ¹⁴C detection showed that whereas protein were hydrolyzed and partially mineralized, Dextran was refractory to any biodegradation. Similar results were found in both pilots with and without acetate. As for the synthetic organic compounds, results show that phenol, mono- and dichlorobenzenes, and mono- and dichlorophenols were totally or partially biodegraded, while trichlophenol was not.