Kinetic Analysis on Phosphorus Adsorption, Phosphorus Desorption, Nitrification, and Denitrification by Using Mineralized Refuse

Possessing good particle size distribution, the mineralized refuse has high contents of Fe, Al, and Ca, which might be the phosphorus pool. The absorption and desorption of phosphorus, nitrification, and denitrification in the mineralized refuse and clay were investigated by using batch incubation respectively. The variation of phosphorous adsorption in the mineralized refuse and clay is fitted the Langmuir isotherm equation. The maximum phosphorus adsorption capacity of the mineralized refuse is 2914 mg kg-1. Both the maximum adsorption capacity and adsorption rate of phosphorus in the mineralized refuse are 3 times higher than that of the clay. The desorption rate of phosphorus in the mineralized refuse is only about 30%. The NH4+-N content in the mineralized refuse samples falls from 129 mg N kg-1 to 83.0 mg N kg-1 within the first 24 hours during the nitrification process. Accordingly, the NO3--N content in the mineralized is increased from 137 mg N kg-1 to 170 mg N kg-1. While the decrease of NH4+-N content and the increase of NO3--N content in the clay is only 1/2 and 1/6 as large as that in the mineralized refuse respectively. During the denitrification process, the K-value of the fitted zero-order kinetics for NO3--N denitrification in the mineralized refuse is 7.5 times higher than that in the clay.