Abstract: A device for determining a height of soil above a structure buried below a soil bed includes a sensor assembly comprising a total stress pressure sensor for transmitting a first signal indicating a total pressure, a pore water pressure sensor located proximate to the total stress pressure sensor, the pore water pressure sensor for transmitting a second signal indicating a fluid pressure, a sensor module configured to receive the first and the second signals, determine a difference between the first signal and the second signal, based on the difference between the first signal and the second signal, determine a height of soil above the sensor assembly, and transmit a third signal indicating the height of soil to an external device.

Abstract: A device for determining a height of soil above a structure buried below a soil bed includes a sensor assembly comprising a total stress pressure sensor for transmitting a first signal indicating a total pressure, a pore water pressure sensor located proximate to the total stress pressure sensor, the pore water pressure sensor for transmitting a second signal indicating a fluid pressure, a sensor module configured to receive the first and the second signals, determine a difference between the first signal and the second signal, based on the difference between the first signal and the second signal, determine a height of soil above the sensor assembly, and transmit a third signal indicating the height of soil to an external device.

Abstract: A fluidized bed reactor for removing phosphorus and nitrogen from wastewater has a column comprising a number of sections. The diameter of the column changes stepwise between the sections. A flow velocity in excess of 100 cm/min is maintained in a lowermost one of the sections and lower flow velocities are maintained in subsequent sections. A struvite supersaturation ratio is controlled in part by recycling wastewater from an outlet of the column. Struvite pellets are removed periodically from the bottom of the column.

Abstract: A fluidized bed reactor for removing phosphorus and nitrogen from wastewater has a column comprising a number of sections. The diameter of the column changes stepwise between the sections. A flow velocity in excess of 100 cm/min is maintained in a lowermost one of the sections and lower flow velocities are maintained in subsequent sections. A struvite supersaturation ratio is controlled in part by recycling wastewater from an outlet of the column. Struvite pellets are removed periodically from the bottom of the column.

Abstract: A fluidized bed reactor (14) for removing phosphorus and nitrogen from wastewater has a column comprising a number of sections. (15A, 15B, 15C, 15D) The diameter of the column changes stepwise between the sections. A flow velocity in excess of 100 cm/min is maintained in a lowermost one of the sections and lower flow velocities are maintained in subsequent sections. A struvite supersaturation ratio is controlled in part by recycling wastewater from an outlet of the column. Struvite pellets are removed periodically from the bottom of the column.

Abstract: A fluidized bed reactor (14) for removing phosphorus and nitrogen from wastewater has a column comprising a number of sections. (15A, 15B, 15C, 15D) The diameter of the column changes stepwise between the sections. A flow velocity in excess of 100 cm/min is maintained in a lowermost one of the sections and lower flow velocities are maintained in subsequent sections. A struvite supersaturation ratio is controlled in part by recycling wastewater from an outlet of the column. Struvite pellets are removed periodically from the bottom of the column.