Use of Shallow Reservoir and Flooded Organic Soil Systems for Waste Water Treatment: Nitrogen and Phosphorus Transformations1
- K. R. Reddy and
- D. A. Graetz2
Use of a shallow reservoir (with a marly clay loam bottom) and flooded organic soil (Histosol) for inorganic N and PO4-P removal from waste water (agricultural drainage effluent) was evaluated under simulated conditions. The results show that the shallow reservoirs and flooded organic soils could be effectively used for NH4-N and NO3-N removal from the waste waters. Aerating the floodwater resulted in rapid removal of NH4-N as a result of nitrification and NH3 volatilization. Creating an anaerobic condition in the water column resulted in slower removal of NH4-N due to volatilization. Nitrate N removal was more rapid under anoxic water column conditions than with aerobic water column conditions. Rapid nitrification resulted in the initial increase in NO3-N levels in the water column. Aerating the water column with CO2 free air resulted in rapid losses of NH4-N through volatilization. Aerating the water column with the air containing CO2 resulted in a greater loss of NH4-N through nitrification than volatilization. A shorter residence time (1–6 days) of waste water over a soil column was required for effective removal of NH4-N, and a longer residence time of 12–24 days was required for effective removal of NO3-N from the water. For reservoir soil, about 70 and 76% of the floodwater P was removed under aerobic and anaerobic water column conditions, respectively. For flooded organic soil, 51% of the aerobic floodwater P was removed after 2 days of incubation, followed by an increase in soluble P concentration of the overlying water, whereas about 64% of the anaerobic floodwater P was removed during a 29-day incubation.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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