The effects of different electron donors on anaerobic nitrogen transformations and denitrification processes in Lake Taihu sediments

Nitrogen transformations in anaerobic sediments and leachate in Lake Taihu were simulated in the laboratory. Ammonium, nitrate and nitrite were analyzed after incubation under anaerobic conditions. Different reductive states and pH values were obtained by using different electron donors, such as glucose, sucrose, potato starch and sodium acetate. Chemical nitrogen transformation mechanisms were discussed relative to physico-chemical properties of lake sediment. Results demonstrated that nitrogen transformations in anaerobic conditions supplemented with different electron donors varied, and supplementation with certain electron donors may enhance nitrogen removal from anaerobic sediments. Among the four electron donors studied, higher nitrogen removal efficiencies were observed with acetate and starch. Saccharides, such as glucose, sucrose and starch, stimulate nitrate reduction to nitrite, while acetate stimulates nitrate reduction to ammonium.