Memorandum 

20 February 2007 

Page 1 

TO: Airport Deicing Administrative Record

FROM: Mary Willett and Mark Briggs, ERG

DATE: August 2010

SUBJECT: Estimated Capital and O&M Costs for Anaerobic Fluid Bed Treatment of 

ADF Contaminated Stormwater 

EPA and ERG collected both influent and effluent samples from the anaerobic fluid bed (AFB) treatment 

system installed at the Albany International Airport in Albany, New York. The actual sampling data is 

provided in the Albany Sampling Episode Report. Based on the removal efficiency of the AFB for many of 

the pollutants of concern (POCs) and its demonstrated performance at two airports (Albany and Akron), 

EPA and ERG believe the AFB is one of the viable treatment alternatives for stormwater contaminated with 

aircraft deicing fluid (ADF). This memorandum presents the methodology that will be used to estimate 

costs for airports to install and operate ABF reactors to treat stormwater contaminated with ADF. 

AFB Technology Description

The AFB treatment system uses a vertical, cylindrical tank in which the ADF contaminated stormwater is 

pumped upwards through a bed of granular activated carbon -- small pieces with irregular surfaces -- at a 

velocity sufficient to fluidize, or suspend, the media. Treatment of organic carbon in the ADF contaminated 

stormwater comes via a thin film of microorganisms that grows and coats each granular activated carbon 

particle, providing a vast surface area for biological growth. The anaerobic microorganisms occur naturally 

in sediment, peat bogs, cattle intestines, and even brewer's yeast. Breakdown products from the AFB 

treatment system include methane, carbon dioxide and new biomass. Effluent from the AFB can be 

discharged to a local POTW or, in most cases, directly to surface water. 

The range of influent soluble COD concentrations that can be efficiently treated by an AFB system is 

approximately 2,000 to 128,000 mg/L. For both the low concentration threshold and high concentration 

threshold, the AFB system can manage brief excursions outside the 2,000 to 128,000 mg/L range. 

However, the treatment for high concentrations can not be sustained for long. EPA understands this 

concentration range should be used as a guide for selecting an appropriate treatment technology for ADF 

contaminated runoff. For example, for concentrations greater than 128,000 mg/L COD (approximately 8% 

propylene glycol), recycling technologies such as evaporation would be a more appropriate choice1

. 

AFB treatment reactors are designed to operate at a near constant influent COD load. Operation at a near 

constant COD load results in a more stable bacterial population, improving the treatment efficiency and 

increasing the predictability of the effluent quality. Operating AFB systems to treat collected deicer runoff 

in an aviation setting, as opposed to other industrial settings, requires additional control measures to achieve 

near constant COD load because of the wide fluctuation in COD influent concentration. Simple storagebased equalization, although important in the design of the overall treatment system, may not provide a 

 

1

 Airport Council International – North America comments on EPA’s Proposed Rule for Effluent Guidelines for the 

Airport Deicing Category. 
Memorandum 

August 2010 

Page 2 

sufficient dampening of concentrations to allow steady-state operation. Therefore, added controls are 

required that are designed so that influent COD concentrations are measured on an ongoing basis and the 

influent flow rates to the AFB are adjusted to achieve the desired COD loading. 

Treating wastes using an anaerobic biological system as compared to an aerobic system offers several 

advantages. The anaerobic system requires much less energy since aeration is not required and the 

anaerobic system produces less than 50 percent of the sludge of an aerobic process. In addition, because the 

biological process is contained in a sealed reactor, odors are eliminated. Figure 1 is a diagram showing the 

major components of a typical AFB treatment system2

. 

Figure 1. Typical Anaerobic Fluid Bed Treatment System for Treatment of Stormwater 

Contaminated by ADF

Figure 2 is a process flow diagram showing how an AFB treatment system has been integrated into an 

existing airport for treatment of ADF contaminated storm water3

. For this airport, ADF contaminated 

stormwater was collected at the deicing pads and delivered to mixed equalization tanks which dampen flow 

 

2

 US Department of Defense, ESTCP, Mineralization of TNT, RDX, and By-Products in an Anaerobic Granular 

Activated Carbon Fluidized Bed Reactor, April 2003. 3

 Rick McQueen and Tim Arendt, Development of a Dicer Management System for Akron-Canton Airport 
Memorandum 

August 2010 

Page 3 

and concentration excursions. ADF contaminated stormwater is then pumped from the equalization tanks 

to the AFB reactors for removal of COD. Although Figure 2 shows two mixed equalization tanks, airports 

have the flexibility to install any combination of tanks or stormwater ponds to provide adequate 

equalization prior to AFB treatment. In addition, the AFB reactor treatment system consists of two AFB 

reactors and two media-solids separation units. The paring of AFB reactors and media-solids separation 

units allows the system to be operated in either parallel or series modes to support treatment requirements 

under different conditions. The use of two reactors is also important to achieve redundancy. The size and 

cost of the reactors and separators have the most direct relationship to COD load removed of the various 

system components4

. Other cost components included with the overall cost of the AFB treatment reactor 

system include activated carbon media, interior support systems, treatment building, and exterior treatment 

support systems. 

Figure 2. Deicer Management Process Block Diagram 

Available Capital Cost Data

Two airports have provided installed capital and operating costs for AFBs to treat ADF contaminated 

stormwater; Albany International Airport (Albany) and the Akron-Canton Airport (Akron) in Canton, 

Ohio. According to Albany, the installed cost for their deicing stormwater treatment system is 

approximately $8.1 million dollars (2006 $)5

. This cost does not include equalization tanks or ponds prior 

to the AFB, additional storm water piping to transfer ADF impacted stormwater from areas of generation to 

the storage tanks or ponds, or purchase of additional land to accommodate the AFB treatment reactors. 

These additional costs (see memorandums on tank costs and piping costs), must also be added to the total 

 

4

 Airport Council International – North America comments on EPA’s Proposed Rule for Effluent Guidelines for the 

Airport Deicing Category. 

5

 Installed cost for treatment system were verbally provided by Mark Sobel during the Albany Sampling Episode. 

Costs were escalated by 18.07 percent to adjust costs from 1999 dollars to 2006 dollars using Bank of Canada 

Consumer Price Index Calculator (http://www.bankofcanada.ca/en/rates/inflation_calc.html). 

North 

Deicing 

Pad 

South 

Deicing 

Pad 

BOD Monitoring/

Flow Diversion 

Storage 

Tank 

Storage

Tank 

Anaerobic Fluidized 

Bed Reactor Treatment 

System 

To Stream 
Memorandum 

August 2010 

Page 4 

cost for a complete AFB treatment system. The Albany treatment system is designed to treat approximately 

5,200 lbs/day of chemical oxygen demand (COD) at an average influent concentration of 5,000 mg/L. The 

Akron AFB reactors are designed to treat approximately 3,400 lbs/day of COD at an average influent 

concentration of 19,000 mg/L. Based on the design COD loading and average influent concentration, the 

Akron AFB treatment system can process approximately 21,600 gal/day (15 gal/min) of ADF contaminated 

stormwater. Installed capital costs for the AFB treatment system at Akron is estimated to be approximately 

$3.3 million (2006 $), and does not include collection and storage costs. Table 1 shows the design 

information for both the Albany and Akron AFB treatment systems6

. The information provided in Table 1 

shows the Akron-Canton AFB system is designed for a lower COD loading than Albany, but a higher COD 

and propylene glycol concentration. Design loading rates (lbs COD/ft3

 media) for Akron are also lower 

than the actual loading rates at Albany. 

Table 1. Akron-Canton Airport Treatment System Design Basis Versus Albany AFB6

Parameter Akron-Canton AFB Design Albany International Airport 

Performance Data 

Load 3,400 lbs COD/day 

2,000 lbs PG/day 

5,200 lbs/day COD 

3,100 lbs/day PG/day 

Flow Rate 15 gpm 100 gpm 

Influent Concentrations 19,000 mg/L COD 

11,120 mg/L PG 

5,000 mg/L COD 

3,000 mg/L PG 

Effluent Concentrations <340 mg/L COD 

< 1 mg/L PG 

500 mg/L TSS (from reactors) 

50 mg/L TSS (after solids removal) 

<340 mg/L COD 

<1 mg/L PG 

200 mg/L TSS 

Number of Reactors 2 2 

Reactor Dimensions 10 feet diameter x 32 feet high 14 feet diameter x 32 feet high 

Volume Per Reactor 2,515 cubic feet 3,425 cubic feet 

Methane Production Rate 6.1 cubic feet/lb COD removed @ 

80o

F 

6.75 cubic feet/lb COD removed @ 

80oF 

PG: Propylene Glycol 

Anaerobic Fluid Bed Capital Cost Methodology

As indicated in industry comments to the proposed rule, the capital cost approach which uses a linear 

relationship between ADF use and ADF percent capture to predict costs does not consider minimum capital 

costs for small systems or the economy of scale for larger systems. All AFB treatment systems, regardless 

of size, will require basic components such as chemical dosing systems, gas handling systems, sludge 

handling systems, storage tanks, in-line monitoring equipment, and process control systems. For many of 

these components, cost is independent of treatment system size7

. 

 

6

 Rick McQueen and Tim Arendt, Development of a Dicer Management System for Akron-Canton Airport 

7

 Airline Transport Association of America, Inc. comments on EPA’s Proposed Rule for Effluent Guidelines for the 

Airport Deicing Category. 
Memorandum 

August 2010 

Page 5 

To assist EPA with developing costs for small AFB treatment reactors, industry developed a cost curve that 

shows a more appropriate general relationship between cost and COD load for Primary Treatment 

Components for systems designed to treat between 500 and 7,000 lbs/day of COD. As shown in the figure 

below that was provided in industry comments8

 (Figure 1), the cost per pound of COD removal increases 

rapidly for smaller load removal systems because of the economy of scale with the reactor and separator 

system, and the cost for support buildings and facilities is relatively constant and not tied to COD loading. 

Figure 1. AFB Reactor Capital Cost for Treating 

ADF Contaminated Stormwater 

y = 275101x-0.6279

0

1000

2000

3000

4000

5000

6000

7000

0 2000 4000 6000 8000

COD Loading (lbs/day)

Capital Cost ($/l

b

COD/day)

Using the equation in Figure 1, EPA can roughly predict the installed capital cost for an AFB reactor 

(excluding storage, collection, and possible land costs) if the COD loading is known. The example below 

shows how the cost model will estimate costs for an AFB treatment system. 

Installed Capital Cost Example:

Applied ADF (Type 1 propylene glycol): 417,000 gallons/season9

ADF/COD Conversion Factor: 14.28 lbs COD/gal Type I ADF 

Estimated ADF Capture Efficiency for Block and Pump System: 40 percent 

Treatment System Operating Period: 194 days/yr10

Avg. COD Loading = 417,000 gal/season x 14.38 lbs COD/gal x 0.40 x 1/194 days = 12,363 lbs COD/day 

Cost for COD Removal: 275,101 x (12,363)-0.6279 = $741/lb COD/day 

Installed Capital Cost for AFB: 12,363 lbs COD/day x $741/lb COD/day = $9.2 million 

 

8

 Airport Council International – North America comments on EPA’s Proposed Rule for Effluent Guidelines for the 

Airport Deicing Category. 

9

 Average annual applied ADF from all airports reporting to questionnaire 10 Average operating days per year provided by Albany International Airport from 1998 to 2006 
Memorandum 

August 2010 

Page 6 

For the airport costing model, the amount and type of ADF applied, and the deicing season operating period 

will be obtained from the survey database. The estimated ADF capture efficiency will vary depending of 

the type of collection method. For example, airports that utilize centralized deicing pads have an estimated 

capture efficiency of approximately 60 percent11. If the airport uses a storm sewer block-and-pump type 

system and glycol collection vehicles (GCVs), the estimated capture efficiency will be approximately 40 

percent12. If an airport only uses GCVs, the estimated capture efficiency will be approximately 20 percent. 

Annual Operating and Maintenance Costs

Annual operating and maintenance (O&M) costs were provided for both the Akron and Albany treatment 

reactors. According to Albany, their annual O&M cost is approximately $510,000/year to operate the AFB. 

Akron has recently constructed their AFB and does not have actual operating data. Akron provided 

estimated annual O&M costs to be $195,000/year. Since annual operating costs for the AFB are directly 

related to the annual amount of ADF use and the capture percentage, ERG decided to normalize annual 

AFB reactor annual operating costs to these two factors. Table 3 shows the AFB reactor annual O&M costs 

normalized to annual ADF usage for Albany and Akron. 

Table 3. Normalized Annual O&M Costs for the Anaerobic Fluid Bed Reactors 

Annual 

ADF 

Use 

(gal/yr) 

Estimated 

Percent 

Capture1

Annual ADF 

Captured 

Annual O&M 

Cost 

(2006 $/yr)1

Normalized 

Annual 

O&M Cost 

($/gal ADF 

recovered) 

Albany 125,775 92 115,713 $510,000 $4.40 

Akron 60,264 60 36,200 $195,000 $5.39 

Average: $4.90 

 1. Airport deicing loadings database 

To estimate annual costs, the annual ADF use will be multiplied by the percent capture and the average 

annual O&M cost as shown below. 

Annual AFB Treatment Reactor O&M: ADF Use (gal/yr) x Percent Capture x $4.90 

Annual O&M Cost Example:

Applied ADF (Type 1 propylene glycol): 417,000 gallons/season13

Estimated ADF Capture Efficiency for Block and Pump System: 40 percent 

Annual O&M Cost: 417,000 gal x 0.4 x 4.90 = $816,000/year 

 

11 Average capture efficiency for Albany, Denver and Pittsburgh airports having centralized deicing. 12 General Mitchell International Airport WPDES Permit Requirement. 

13 Average annual applied ADF from all airports reporting to questionnaire 
Memorandum 

August 2010 

Page 7 

The annual O&M costs in the above example do not include costs for collection, transfer or storage of the 

ADF contaminated stormwater. 

Cost Methodology Limitations

EPA recognizes that using the number of operating days in the equation to calculate COD load to the AFB 

and ultimately estimate costs is simplistic. The size of the actual treatment system at any specific airport 

will depend on a variety of factors such as method of stormwater collection and frequency, duration and 

intensity of deicing events, and general airport operations. Depending on these factors, the AFB treatment 

system design engineers and airport management will need to make trade-offs between the size of treatment 

and storage. EPA is not attempting to design an AFB treatment system for any specific airport, but is 

instead using limited information such as annual ADF usage to predict estimated capital and operating costs 

to within + 30% of actual costs. EPA recognizes that specific airport constraints may underestimate or 

overestimate costs for AFB treatment systems, but when taken as a whole for the entire industry, costs 

should be within + 30% of actual costs.