### United States **Environmental Protection Agency** September 201 5



### Tri

**- Cities Landfill Energy Facility** 
**Title V Permit No.**  **SR**

**- R**  **OP 15** 

**- 0**  **1**

**Response to Public Comments on the Proposed Title V**  **Permit Renewal** 
**for the Tri** 

**- Cities Landfill Energy Facility** 2 

### 1. **Introduction**

**– S**  **ummary of the Formal Public Participation Process** 

On August 6 , 201 5 , t he 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 Tri

Cities Landfill Energy Facility (TCLEF or Project). TCLEF is owned a nd operated by the S alt River Project Agricultural Improvement and Power District (SRP AIP D ). The public comment period on
th is propos ed action (Proposed R enewal Permit) 1 closed on September 8 , 201 5

.

Region 9 announced the 201 5 public comment period through the public notice published in
both the Au

- Authm Action News and Arizona Republic Newspaper s on August 6 , 201 5

. Region 9 also distributed notices to the necessary parties

, including notices sent by mail and email on August 6

, 201 5 . 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 oth er means) from parties seeking notification regarding permit actions in Region 9, Arizon a, within
the Maricopa County Air Quality Department ( MC A Q D or District).

The administrative record for our Proposed Re newal 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 Re newal Permit and other supporting documents a vailable on Region 9’s
website

.



### 2. **Background Information**

The Salt River P roject 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

.

T he 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 Tri

Cities Landfill (TCL), how ever, TCL stopped accepting waste in 1993 and is now a closed landfill but still generates landfill gas. Captured vapors from both landfill s are either sent to an onsite candlestick flare for destruction or offsite to the TCLEF where the vapors are used t o fuel one of
five 80 0 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 124.6.3 

### 3. **Region 9 ’s Response to Public Comments** 

S ection 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 SRP AIPD c omments are addressed

. In some instances, the response of similar comments may be grouped under one consolidated EPA response

. D ocuments relevant to the permit are available through a link at our website, www.ep a.gov/region09/air/permit/r9

- permits

- issued.html#psd , or at www.regulations.gov ( Docket ID # EPA

- R09

- OAR

- 20 1 5

- 0 5 17 )

.

**3.1 Comments and Responses on**  **the Proposed**  **Title V Permit Renewal for Tri** 

**** **Cities 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 operat e 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 m ore than three IC engines are simultaneous operating and demonstrate s compliance with condition II.B.1.

No chang es were made in the P ermit or the S tatement of B asis

.

**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 . Conditions4 II.B.6 and II.B.8 have been retained, while condition II.B.4 h as 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 ma y 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 SRP AIPD sug gested 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.5 **SRP AIPD**  **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 t he Statement of Basis.



### 4. **Final Revised PSD Permit No**

**. S**  **R**

**- ROP 15** 

**- 0**  **1**

A fter 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 P art 7 1 permit renewal to SRPAIPD
for Tri

- Cities Landfill Energy Facility

.