United States Environmental Protection Agency

September 2015

 

Tri-Cities Landfill Energy Facility

Title V Permit No. SR-ROP 15-01

Response to Public Comments on the Proposed Title V Permit Renewal 

for the Tri-Cities Landfill Energy Facility
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1. Introduction – Summary of the Formal Public Participation Process

On August 6, 2015, the U.S. Environmental Protection Agency (EPA), Region 9 (Region 9) 

provided notice of, and requested public comment on the Title V Permit Renewal for the TriCities Landfill Energy Facility (TCLEF or Project). TCLEF is owned and operated by the Salt River

Project Agricultural Improvement and Power District (SRPAIPD). The public comment period on 

this proposed action (Proposed Renewal Permit)1 closed on September 8, 2015. 

Region 9 announced the 2015 public comment period through the public notice published in 

both the Au-Authm Action News and Arizona Republic Newspapers on August 6, 2015. Region 9

also distributed notices to the necessary parties, including notices sent by mail and email on 

August 6, 2015. Parties notified by Region 9 included agencies, organizations, and public 

members for whom contact information was obtained through a number of different methods, 

including requests made directly to Region 9 through Region 9’s website (or through other 

means) from parties seeking notification regarding permit actions in Region 9, Arizona, within 

the Maricopa County Air Quality Department (MCAQD or District).

The administrative record for our Proposed Renewal Permit was made available at EPA Region 

9’s office in San Francisco, California and copies of the draft documents were available at the 

offices of the Salt River Pima-Maricopa Indian Community in Scottsdale, Arizona. Region 9 also 

made the Proposed Renewal Permit and other supporting documents available on Region 9’s 

website.

2. Background Information

The Salt River Project Agricultural Improvement and Power District owns and operates TCLEF, a 

4 megawatt, landfill gas to energy facility. In collaboration with the Salt River Pima-Maricopa 

Indian Community, which owns Tri-Cities Landfill and Salt River Landfill, landfill gas from both 

the landfills are captured, collected, and used as fuel for TCLEF’s five internal combustion 

engines for the purpose of generating electricity. 

The Salt River Pima-Maricopa Indian community owns and operates the Salt River Landfill (SRL), 

an active landfill with a gas collection and control system. SRPMIC also owns and operates TriCities Landfill (TCL), however, TCL stopped accepting waste in 1993 and is now a closed landfill 

but still generates landfill gas. Captured vapors from both landfills are either sent to an onsite 

candlestick flare for destruction or offsite to the TCLEF where the vapors are used to fuel one of 

five 800 kW engines to produce electricity. 

Both landfills and TCLEF have existing title V operating permits, issued by EPA Region 9, which 

cover their respective operations.

 1 We note that EPA’s permitting regulations at 40 CFR Part 124 refer to proposed permits as “draft permits.” See 

40 CFR 124.6.
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3. Region 9’s Response to Public Comments

Section 3.2 of this Response to Comments document summarizes the public comments 

received by EPA during the 30-day public comment period. This document also provides our 

responses to all significant public comments made during the public comment period, including 

an explanation of what changes have been made, if any, in the Final Permit as a result of those 

comments. Region 9 only received comments from SRPAIPD during the public comment period. 

Individual SRPAIPD comments are addressed. In some instances, the response of similar 

comments may be grouped under one consolidated EPA response. Documents relevant to the 

permit are available through a link at our website, www.epa.gov/region09/air/permit/r9-

permits-issued.html#psd, or at www.regulations.gov (Docket ID # EPA-R09-OAR-2015-0517).

3.1 Comments and Responses on the Proposed Title V Permit Renewal for TriCities Landfill Energy Facility

SRPAIPD Comment #1

Permit Conditions II.B.1 and II.D.5 require that TO1 continuously operate at all times when more 

than three engines are in simultaneous operation. This requirement may be redundant since 

ENGS4 and ENG5 are programmed to operate only if TO1 is operating.

EPA Response #1:

Condition II.B.1 requires that TO1 continuously operate at all times when more than three 

engines are simultaneously operating. While your control system, in practice, is programed to 

operate ENGS4 and ENGS5 only if TO1 is operating, that practice is not required as an 

enforceable permit condition. Without a condition ensuring this requirement the programing 

could change resulting in more than three engines operating without the TO1 operating. 

Condition II.D.5 requires the permittee maintain operational logs of all IC engines and thermal 

oxidizer. This condition documents operation of TO1 when more than three IC engines are 

simultaneous operating and demonstrates compliance with condition II.B.1.

No changes were made in the Permit or the Statement of Basis.

SRPAIPD Comment #2:

The requirements of Permit Conditions II.B.4, II.B.7 and II.B.8 are already included in II.B.5, II.B.3 

and II.B.6, respectively.

EPA Response #2:

EPA agrees. Condition II.B.3 and II.B.7 are duplicates and therefore II.B.3 has been removed 

from the permit. Condition II.B.4 is similar to conditions II.B.6 and II.B.8 combined. Conditions 
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II.B.6 and II.B.8 have been retained, while condition II.B.4 has been removed from the permit. 

The numbering of the conditions in the permit have also been updated appropriately. 

SRPAIPD Comment #3:

SRP is requesting that EPA allow for some flexibility in testing engines that have not operated for 

period of time. Due to economic or other factors, SRP may not operate a particular engine or the 

whole facility for months at a time and would like the flexibility to conduct testing upon re-start 

of an engine, rather than starting the engine for the sole reason of conducting a performance 

test. SRP has suggested some language in the attached “redlined” draft. Additionally, SRP 

believes the language in paragraph a. indicating that subsequent tests will be conducted during 

the third and fifth years of permit term may cause confusion when permit renewals not issued 

past the fifth year. Requiring a test every 16 to 24 months ensures that testing continues even if 

EPA’s issuance of a renewal is delayed for years. Paragraph b. of permit condition II.C.6 seems 

redundant since the previous section of the permit requires testing of the engines and TO1 every 

16 to 24 months, regardless of whether there were any exceedances.

EPA Response #3:

EPA understands that some of the engines at TCLEF may not operate consistently and may go 

long periods of time without operating, for various reasons. EPA agrees that TCLEF should have 

some flexibility on conducting performance testing on engines that have been shut down for an 

extended period of time. EPA is accepting the SRPAIPD suggested language with one minor 

change. If a unit has been shut down for more than 90 days, as opposed to the 3 months 

suggested by the SRPAIPD, then the permittee may choose to postpone a performance test 

until no later than 30 days after re-start of the unit. 

Additionally, EPA agrees that the language in condition II.C.6.a requiring performance testing 

“during the third and fifth years of the permit term” could be confusing if there is a delay in 

issuing a renewal permit. The permit already contains language requiring performance testing 

shall be conducted between 16 and 24 months, which serves the purpose of requiring 

performance testing on an appropriate timeline.

Finally, EPA disagrees that condition II.C.6.b is redundant with condition II.C.6.a. For some 

sources it may be appropriate to require a performance test on a unit if it was shut down due to 

excess emissions. Condition II.C.6.b provides the permittee the flexibility to keep a unit on the 

16 to 24 month performance testing cycle, even if the unit was shut down due to exceeding the 

CO emissions reading.

EPA has updated the language in the permit accordingly.
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SRPAIPD Comment #4:

SRP already maintains records of the hours of operation of each engine. The permit does not 

limit the amount or duration of startups or shutdowns, and maintaining records of these seems 

overly burdensome and unnecessary.

EPA Response #4:

While the permit does not limit the amount of startups or shutdowns, 40 C.F.R. 63.6625(h) does 

limit the engines’ time spent at idle during startup and limit the startup time to 30 mins or less. 

The permittee must document this information in order demonstrate compliance with 40 C.F.R. 

63.6625(h), which is the basis for condition II.B.5.

No changes were made in the Permit or the Statement of Basis.

4. Final Revised PSD Permit No. SR-ROP 15-01

After careful review of the comments submitted by the Salt River Pima-Maricopa Agricultural 

Improvement and Power District and the pertinent Federal statutes and regulations, Region 9 is 

issuing a decision pursuant to 40 CFR 52.21 to issue a final Part 71 permit renewal to SRPAIPD

for Tri-Cities Landfill Energy Facility.