Effect of the Type of Zeolite on Eliminating Nitrogen Load of Europhia Sediment Capping with Active Barrier System (ABS)

Abstract: The application of an active zeolite barrier was investigated to improvement of eutrophication in the ancient Canal. For this, four types of zeolites (diameter: 1～2 mm) were applied in order to investage effect of the type of zeolite on N removal. The dosage of the zeolites was 1.46 kg.m-2 and the ammonium concentrations in overlying water were 3.47 mg/L. It is found that the capacity of elimination total N of the four zeolites was significant and decreased with the following order: Haiyu zeolite F1 > Aolin zeolite F2 > Natural zeolite F3 > Calcium zeolite F4. In addition, the results show that zeolite F1 and F2 belong to N inhibiting type as TN concentration of overlying water quickly reduced to 2.53 mg/L, 3.7 mg/L, and the corresponding removal efficiency of TN is as high as 56% and 35.6% after covering zeolite F1 and F2. The results indicated that the consumption rates of ammonia nitrogen in this system is greater than or equal to release rates of ammonia from sediment. However, TN concentration of overlying water still rise to high level (1.57 times of initial TN) when covering zeolite F3 and F4 (N non-inhibited type). Therefore, it is considered that the Haiyu zeolite should be the best barrier materials to clean sediment of the ancient Canal.