Project Title:  AUTOMATION OF DISPOSAL OF WASTE DEICING FLUIDS

Technical Contact:   L. Robert Kimball and Associates
Contact Person:   Richard Holes, PE

Corporate Sponsor:   University Park Airport
Contact Person:   Bryan Rodgers

Team Name:    Cheetah Engineering
Team Members:   Chad Verbano, Kevin Yontosh, Shawn Warren, Steve Young, Spencer Shih
 

PROJECT SUMMARY:

The University Park Airport, which is owned and operated by The Pennsylvania State University, provides air service to customers throughout the Centre Region. During the deicing period, approximately October 15 through April 15, the Airport provides deicing services to the airline carriers to prevent in-air and on-ground ice buildup that could detrimentally affect aircraft performance.

The aircraft deicing process uses either propylene or ethylene glycol. Each material is considered to be industrial waste and The Pennsylvania Department of Environmental Protection mandates that the glycol be collected and disposed of properly to prevent damage to the nearby environment.

The image to the left represents the underground storage tanks.

The airport has a separate apron where each aircraft taxis to be deiced. This apron is surrounded on the downstream side by a concrete channel that collects the runoff and diverts it to a single inlet. During the deicing season, the runoff is directed into two 10,000 gallon underground storage tanks. The inlet to the tanks is controlled by a valve which must be manually operated from the tank’s location.
 
 
 
 
 

The image to the left represents the above ground storage tank.

Once the fluid is in the storage tanks, it is pumped into a 500 gallon above ground storage tank by two submersible pumps located at the bottom of one of the tanks. The pumps force the fluid into a 4” force main located next to the aboveground storage tank. The aboveground storage tank is located in the rear of the ARFF building. The pump must be manually controlled and the controls are located on the ARFF building. Airport personnel must stand at the control panel and time the amount of time the pump is running to insure that the aboveground storage tank is not overflowed.

The airport has two options for disposing of the spent deicing fluid. First, the airport can load the material directly from the 4” force main into a truck and then deliver it to the Bellefonte sewage plant. Second, since the Airport is allowed to dispose of material into the sanitary sewage system, the airport attaches a hose from the standpipe to the aboveground storage tank. The material is then slowly metered into the sewage system at a rate of 250 gallons every 24 hours through the opening of a spigot.

The problems with the current setup are as follows:
 

1.  The current process must be run manually and requires 4 man-hours a week      which is not desirable.

2.  The hose from the standpipe to the aboveground storage tank is not desirable.

3.  The aboveground storage tank is not desirable.

4.  The open sewer clean out is not desirable.

5.  The valve that allows spent glycol to enter the underground storage tanks must be      manually controlled from outdoors which is not desirable.

The goal of this project is to automate the process that the airport uses to collect the spent deicing fluid. As part of this project, design drawings showing the layout of the new system will be prepared using AutoCAD. In addition, the technical specifications for any new equipment will be provided.

SPECIFICATIONS:

Critical Design Issues:

1. Dispose of approximately a total of 15,000 gallons of waste deicing fluid from the underground
    storage tanks to the sewer drainage system during the winter season.

2. The airport is only allowed to input 500 gallons of waste deicing fluid over a 48-hour period.

    a. The sewage treatment plant set this rate and the fluid must be metered into the plant
        at a constant rate.
    b. Deicing fluid has a high Biological Oxygen Demand (BOD), even in a diluted state.
        Thus the fluid must be metered in a at a continuous rate to avoid using all of the oxygen
        in the plant and killing bacteria that make the plant run properly.

3. Underground space below current above-ground storage tank is not available.

    a. Due to the amount of piping and wiring currently located in the region adjacent to the
        sewage drain inlet, an underground-storage tank is not an option.

PROPOSED SOLUTION:

Automate Existing System With Pressure Sensors and an Automatic Flow Meter Valve

Design Aspects and Requirements
 

1.  The current above ground storage tank will be replaced with a 1000-gallon concrete      double-walled tank. The tank will be wound with heating coils to prevent the fluids from freezing.

2.  There will be 3 main pressure sensors installed to automate the system.

3.  A pressure sensor will be installed at the bottom of the aboveground storage tank to activate      the pump.

4.  A pressure sensor will be installed at the top of the aboveground storage tank to deactivate the pump.

5.  A third pressure sensor will be installed in the underground storage tank as a safety alarm      to prevent the pump from running when the fluid level is too low.

6.  Additional alarms will be included as necessary.

7.  An automatic flow meter valve will be installed at the outlet of the aboveground storage      tank to meter fluid into the sewer drainage system at the rate of 10 gal/hr.

8.  A backup pump will be installed in the underground storage tanks.

9.  Controls for the system will be located in the General Aviation terminal.

This solution was considered the best because it utilizes the current system at the airport, which will minimize the cost of the project for the airport.