Effects of dicyandiamide and surfactant on nitrogen form dynamics in digested slurry

The aim of the present study was to explore the effects of dicyandiamide(DCD)and surfactant on the form and content of nitrogen in digested slurry, using a laboratory simulation experiment with different combinations of application of the treatments. Six treatments were used:single application of digested slurry, digested slurry+8%DCD, digested slurry+16%DCD, digested slurry+surfactant, digested slurry+8%DCD+surfactant, and digested slurry+16%DCD+sufactant. The total nitrogen(TN), total Kjeldahl nitrogen(TKN), ammonium nitrogen(NH4+-N), and nitrate nitrogen(NO3--N)content of digested slurry were measured at 10, 30 min, and 1, 3, 10, 24, 48 h. The results revealed that, in the digested slurry+8%DCD and digested slurry+16%DCD treatments, the concentrations of NH4+-N, TKN, and NO3--N increased by 0.74%~8.96%, 24.67~59.70 mg·L-1, 13.42~145.88 times, respectively, and the concentrations of all three increased with the quantity of DCD. The addition of surfactant had little effect on the form and concentration of nitrogen in digested slurry.