PART 71 FEDERAL OPERATING PERMIT

 STATEMENT OF BASIS

Salt River Project Agricultural Improvement and Power District

Tri-Cities Landfill Energy Facility

Permit No. SR-ROP 15-01

I. Facility Information

A. Permittee

Salt River Project Agricultural Improvement and Power District

P.O. Box 52025, PAB 352

Phoenix, AZ 85072-2025

B. Facility location

11630 Beeline Highway

Scottsdale, AZ

On the reservation of Salt River Pima-Maricopa Indian Community

C. Contact information

Facility Contact: Barbara Sprungl, (602) 236-5374

Responsible Official: Larry Bottolfson, (602) 236-6230

D. Description of operations, products

This facility produces electricity by firing IC engines with landfill gas collected at 

the Tri-Cities Landfill and the Salt River Landfill.

E. Permitting and construction history

This action is a renewal of a Part 71 Operating Permit for Tri-Cities 

Landfill Energy Facility (“TCLEF”). EPA issued initial Part 71 Operating 

Permit, #SR-OP 00-02, for Tri-Cities Landfill Energy Facility (“TCLEF”) on 

September 21, 2000. The permittee applied for a renewal to the initial permit,

which EPA approved, that became effective on December 30, 2006, #SR-ROP 

05-03. This action is for the second renewal of the TCLEF operating permit. 

Since the last renewal, the following two administrative permit amendments were

made to the permittee’s permit and are incorporated in this renewal:
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1. Carbon monoxide monitoring, performance test notification, and compliance: 

on March 8, 2007, EPA corrected the concentration limits in conditions II.C.3, 

II.C.4 and II.C.6 at which the permittee must take action. The initial permit listed 

a CO concentration of 145 ppmv @15% O2 for both the engines and the thermal 

oxidizer. The permittee demonstrated that the calculation was incorrect and the 

limits were corrected to 265 ppmv @15% O2 for the three engines and 5 ppmv 

@15% O2 for the thermal oxidizer.

2. Fee payment address: on May 18, 2009, EPA updated the fee payment address, 

listed in condition IV.A.4. EPA changed the fee payment address and alerted the 

permittee to the update. 

 

The permittee has never been required to apply for an EPA-issued New Source 

Review (“NSR”) permit. The facility is currently in compliance, has not received 

any notices of violations and does not have any pending enforcement issues. 

F. Emission-generating units and activities

As per Permittee’s request, assigned emission unit identification numbers have 

been revised. The two IC engines venting to the thermal oxidizer, TO1, will now 

be identified as ENG4 and ENG5. The three engines venting to the atmosphere 

are ENG1, ENG2 and ENG3.

Table 1 – TCLEF Emission Units

Emission 

Unit I.D. 

No. Unit Description

Associated Control 

Equipment

ENG1 Caterpillar G3516 LE internal combustion 

engine (800 kW, 9.01 MMBtu/hr)

none

ENG2 Caterpillar G3516 LE internal combustion 

engine (800 kW, 9.01 MMBtu/hr)

none

ENG3 Caterpillar G3516 LE internal combustion 

engine (800 kW, 9.01 MMBtu/hr)

none

ENG4 Caterpillar G3516 LE internal combustion 

engine (800 kW, 9.01 MMBtu/hr)

unit TO1:

John Zinc ZTOF 

10x40 thermal 

oxidizer

ENG5 Caterpillar G3516 LE internal combustion 

engine (800 kW, 9.01 MMBtu/hr)
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G. Potential to emit (in tons/year)

Potential to emit (“PTE”) means the maximum capacity to emit any air pollutant 

(Clean Air Act criteria pollutants or hazardous air pollutants) under its physical 

and operational design. Any physical or operational limitation on the maximum 

capacity of TCLEF to emit an air pollutant, including air pollution control 

equipment and restrictions on hours of operation or on the type or amount of 

material combusted, stored, or processed, may be treated as part of its design if

the limitation is enforceable by EPA. PTE is meant to be a worst case emissions 

calculation and is used in many cases to determine the applicability of federal 

requirements. Actual emissions are typically lower than PTE. 

The Federal Clean Air Act (“CAA” or “Act”), 42 U.S.C. 7401-7671q, regulates 

emissions from major stationary sources of air pollution. Pursuant to Part C of 

the CAA, the prevention of significant deterioration (“PSD”) requirements 

promulgated at 40 C.F.R. 52.21 apply to major stationary sources emitting CAA 

pollutants for which the area is in attainment with the national ambient air quality 

standards (“NAAQS”). For power generation facilities like TCLEF, the major 

source PSD threshold of any pollutant is 250 tons per year (“tpy”). Pursuant to 

Part D of the CAA, the major source thresholds are lower for sources in 

nonattainment new source review (“NNSR”) areas where one or more of the 

certain criteria pollutants are not in attainment with the NAAQS. The area where 

the facility is located is in serious nonattainment for particulate matter (“PM-10”)

and marginal nonattainment for ozone. Under both the PSD or NNSR programs, 

in order to avoid major source status, a source can limit its emissions in a 

Federally enforceable permit such as a Title V permit to below the threshold 

levels. In the initial permit, the permittee requested EPA to limit its PTE of carbon 

monoxide (“CO”) emissions, thereby making the facility non-major under either 

PSD or NNSR for all CAA-regulated pollutants. This permit maintains the

Federally enforceable limit for annual CO emissions of 88.3 tpy established in the 

initial permit. This permit also maintains the short-term limit for CO as 20.2 

lbs/hour from all engines at the facility on a combined basis. However, we are 

updating our authority to limit the potential to emit of the source from the general 

requirements under 40 C.F.R 71.6(b) to 40 C.F.R 49.158(c)(2)(i) under the newly 

effective Tribal NSR rule, which applies to sources located on Tribal lands with 

existing synthetic minor limits established prior to August 30, 2011. Based on 

these permit limits and other information included in the permit application, the

PTE of each emission unit is presented in Table 2.
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Table 2 – Facility-wide Potential to Emit

Pollutant (tons/year)

Unit NOx VOC SO2 PM10 CO HAP

ENG1 13.19 6.59 0.98 3.65 24.18 0.02

ENG2 13.19 6.59 0.98 3.65 24.18 0.02

ENG3 13.19 6.59 0.98 3.65 24.18 0.02

TO1 (ENG4

and ENG5)

34.33 0.80 1.96 7.29 15.7 0.04

Total 73.90 20.58 4.90 18.23 88.3 0.09

II. Tribe Information

A. General

The reservation of the Salt River Pima-Maricopa Indian Community is located in 

Maricopa County and borders the cities of Mesa, Tempe, Scottsdale, Fountain 

Hills and metropolitan Phoenix. The Community consists of 52,600 acres, 

comprised mostly of agricultural lands. The Community is comprised of two 

Indian tribes, the Onk Akimel Au-Authm (Pima) and the Xalchidom Pii-pash 

(Maricopa). 

B. Local air quality and attainment status

This facility is located in the area of the Salt River Pima-Maricopa Indian 

Community which is currently designated as serious nonattainment for PM-10 

and marginal nonattainment for ozone, maintenance area for CO, and attainment 

or unclassifiable for PM-2.5, nitrogen dioxide (“NO2”), sulfur dioxide (“SO2”)

and lead.

III. Applicable Requirements

The permittee owns and operates five stationary spark ignition (SI) internal combustion 

engines (ICE) which are considered “existing” engines under 40 C.F.R Part 63, Subpart 

ZZZZ, National Emission Standards for Hazardous Air Pollutants for Stationary 

Reciprocating Internal Combustion Engines (NESHAP). The ICE engines are therefore 

subject to NESHAP ZZZZ. This renewal incorporates the applicable requirements under 

40 C.F.R Part 63 Subpart ZZZZ. 
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IV. Non-applicable Requirements

TCLEF is an electricity-generating facility which uses landfill gas from the Tri-Cities 

Landfill and Salt River Landfill as a fuel to run a series of engines. The initial Part 71 

permit issued to TCLEF by EPA Region 9 in 2000 contained applicable requirements 

from 40 C.F.R. Part 60, Subpart WWW. Specifically, the permit contained a nonmethane 

organic compound (“NMOC”) emission limit (“reduce NMOC by 98 weight percent or 

reduce the outlet NMOC concentration to less than 20 parts per million by volume”) set 

forth at 40 C.F.R. 60.752(b)(2)(iii)(B), including a requirement to perform the associated 

performance testing. The NMOC limit applied to engines and an enclosed flare (thermal 

oxidizer) at TCLEF that combusted landfill gas from the adjacent Tri-Cities Landfill, 

which is owned by the Salt River Pima-Maricopa Indian Community. At the time that 

TCLEF was permitted, the Tri-Cities landfill, which sends landfill gas or NMOC to 

TCLEF for flaring, had not yet applied to EPA Region 9 for a Part 71 permit.

EPA has determined that, in such cases where landfill gas is combusted for electricity 

generation by a separate stationary source, the landfill owners and/or operators are 

ultimately responsible for compliance with the requirements of Subpart WWW. This 

responsibility includes the emission control requirements along with the associated 

testing, monitoring, record-keeping, and reporting requirements set forth in the 

regulations. Therefore, EPA has deleted the NMOC limit and testing conditions, 

Conditions II.A.3, and II.C.3 through II.C.5, from the TCLEF renewal permits. To 

ensure compliance with the Subpart WWW requirements, the Part 71 permit EPA Region 

9 issued to the Tri-Cities Landfill on September 27, 2013 incorporated all applicable 

requirements from Subpart WWW, including the 98 percent weight NMOC reduction (or 

20 ppm outlet concentration) emission limit and associated performance testing that 

apply to the engines and thermal oxidizer at TCLEF. EPA anticipates that the 

owner/operator of Tri-Cities Landfill will coordinate with permittee to ensure compliance 

with all requirements of Subpart WWW. EPA also intends to incorporate Subpart WWW 

requirements in the Part 71 permit for Salt River Landfill, issued on February 1, 2008.

Stationary spark ignition internal combustion engines are also subject to 40 C.F.R Part 60 

Subpart JJJJ, Standards of Performance for Stationary Spark Ignition Internal 

Combustion Engines if the engines were constructed, reconstructed, or modified on or 

after June 12, 2006. The engines located at TCLEF are considered “existing” engines, 

constructed prior to June 16, 2006 and have not been modified or reconstructed since. 

The engines are therefore not subject to New Source Performance Standard JJJJ. 

Additionally, the engines located at TCLEF are SI engines and not compression ignition 

(CI) engines and therefore 40 C.F.R Part 60 Subpart IIII does not apply. 
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The permittee is not proposing any new construction or increase in emissions and is 

therefore not subject to the Prevention of Significant Deterioration (PSD) permitting 

program. 

V. Emission Unit Testing and Monitoring

A The applicant has demonstrated through performance testing that its CO 

emissions in the past five years have been consistently less than the CO emission 

limits included in the initial Part 71 permit by a significant margin. Therefore, the 

applicant requested a reduction in the frequency of its required annual testing. 

EPA Region 9 has reviewed the applicant’s request and test results from the first 

permit term, and agrees that such a change is justified. 

Therefore EPA has revised the testing frequency in the permit. TCLEF will be 

required to conduct CO performance tests on each of the three engines, ENG1, 

ENG2, and ENG3, venting to the atmosphere, and the thermal oxidizer, TO1, 

three times during the permit term, in the first, third and fifth years.

B In addition, in order to assure compliance with the CO emission limits for the IC 

engines and thermal oxidizer, the permit requires quarterly use of portable CO 

analyzers. The permit requires the applicant to take corrective action if individual 

exhaust CO concentrations of emission units ENG1, ENG2 and ENG3 exceed 265 

ppmv @ 15% O2 , or emission unit TO1 exceeds 5 ppmv @ 15% O2 (Since ENG4 

and ENG5 vent to TO1, it is not necessary to monitor CO concentrations at those 

emission units).

Table 3 summarizes the CO monitoring and testing requirements in the permit.

Table 3 – Monitoring Requirements

Requirement

Emission 

Limit 

Condition 

Monitoring Added to 

Part 71 Permit

Monitoring 

Condition 

CO: 20.2 lb/hr 

facility-wide

II.A.1 source test, 

three times

per permit 

term

265

ppmv,

for ENG1, 

ENG2 and 

ENG3; 

5 ppmv for 

T01, 

portable 

analyzer

II.C.1,2

CO: 88.3 tons/yr 

facility-wide

II.A.2 source test, 

three times 

per permit 

term

II.C.1,2
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VI. Use of All Credible Evidence

Determinations of deviations, continuous or intermittent compliance status, or violations 

of the permit are not limited to the testing or monitoring methods required by the 

underlying regulations or this permit; other credible evidence (including any evidence 

admissible under the Federal Rules of Evidence) must be considered by the source and 

EPA in such determinations. 

VII. EPA Authority

Title V of the CAA requires that EPA promulgate, administer, and enforce a Federal 

operating permits program when a State, local, or Tribal agency does not submit an 

approvable program within the time frame set by Title V or does not adequately 

administer and enforce its EPA-approved program. On July 1, 1996, EPA adopted 

regulations codified at 40 C.F.R. Part 71 setting forth the procedures and terms under 

which the Agency would administer a Federal operating permits program. See 61 Fed. 

Reg. 34202. These regulations were updated on February 19, 1999 to incorporate EPA's 

approach for issuing Federal operating permits to covered stationary sources in Indian 

country. See 64 Fed. Reg. 8247.

As described in 40 C.F.R. ' 71.4(a), EPA will implement a Part 71 program in areas 

where a State, local, or Tribal agency has not developed an approved Part 70 program. 

Unlike States, Indian Tribes are not required to develop operating permits programs, 

though EPA encourages Tribes to do so. See, e.g., Indian Tribes: Air Quality Planning 

and Management, 63 Fed. Reg. 7253 (Feb. 12, 1998) (also known as the Tribal Authority 

Rule). Therefore, within Indian country, it is appropriate that EPA administer and 

enforce a Part 71 Federal operating permits program for stationary sources until Tribes 

receive approval to administer their own operating permits programs. As the Salt River 

Pima-Maricopa Indian Community has not received approval from EPA to operate a Title 

V permits program, it is appropriate for EPA to issue this Part 71 permit.

VIII. Endangered Species Act

Pursuant to Section 7 of the Endangered Species Act (ESA), 16 U.S.C. § 1536, and its 

implementing regulations at 50 C.F.R. Part 402, EPA is required to ensure that any action 

authorized, funded, or carried out by EPA is not likely to jeopardize the continued 

existence of any Federally-listed endangered species or threatened species or result in the 

destruction or adverse modification of such species’ designated critical habitat. The Title 

V permit EPA is issuing to the permittee for the Tri-Cities Landfill Energy Facility does 

not authorize the construction of new emission units, or emission increases from existing 
8

units, nor does it otherwise authorize any other physical modifications to the facility or its 

operations. Therefore, EPA has concluded that the issuance of this permit will have no 

effect on listed species or their critical habitat.

IX. Public Participation

A. Public Notice

As described in 40 C.F.R. § 71.11(a)(5), all Part 71 draft operating permits shall 

be publicly noticed and made available for public comment. The public notice of 

permit actions and public comment period is described in 40 C.F.R. § 71(d).

There is a 30-day public comment period for actions pertaining to a draft permit. 

Public notice will be given for this draft permit by mailing a copy of the notice to 

the permit applicant, the Salt River Project Agricultural Improvement and Power 

District, the affected state (Arizona), local air pollution control agencies, 

emergency planning agencies, local government, land use agencies, federal and 

local land use agencies. A copy of the notice will also be provided to all persons 

who have submitted a written request to be included on the mailing list. Public 

notice will also be published in the Arizona Republic and the Au-Authm Action 

News.

B. Opportunity for Comment

Members of the public may review a copy of the draft permit prepared by EPA, 

this statement of basis for the draft permit, the application, and all supporting 

materials submitted by the source at the address listed in section IX.E, below. 

Copies of the draft permit and statement of basis can also be obtained from EPA’s 

website (http://www.epa.gov/region09/air/permit/r9-permits-issued.html), or by 

contacting Roberto Gutierrez at the EPA address or phone number listed in 

section IX.E, below. All documents will be available for review at the EPA 

Region IX office indicated in section IX.E, below, during regular business hours.

If you believe that any condition of the draft permit is inappropriate, you must 

raise all reasonably ascertainable issues and submit all arguments supporting your

position during the 30-day public comment period. Any supporting documents 

must be included in full and may not be incorporated by reference, unless they are 

already part of the administrative record for this permit or consist of tribal, state 

or federal statutes or regulations, or other generally available referenced materials.

All comments received during the public comment period and all comments made 

during any public hearing will be considered in arriving at a final decision on the 

permit. The final permit is a public record that can be obtained by request. A 

statement of reasons for changes made to the draft permits and responses to 
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comments received will be sent to all persons who commented on the draft 

permit.

C. Opportunity to Request a Hearing

A person may submit a written request for a public hearing to Roberto Gutierrez, 

at the address listed in section IX.E, below, by stating the nature of the issues to 

be raised at the public hearing. EPA shall hold a public hearing if EPA finds, on 

the basis of requests, a significant amount of public interest in this draft permit. If 

a public hearing is held, EPA will provide public notice of the hearing and any 

person may submit oral or written statements and data concerning the draft 

permit.

D. Mailing List

If you would like to be added to our mailing list to be informed of future actions 

on this or other Clean Air Act permits issued in Indian Country, please send your 

name and address to Roberto Gutierrez at the address listed below.

E. Contact Information

Roberto Gutierrez (AIR-3)

U.S. Environmental Protection Agency, Region IX

75 Hawthorne St.

San Francisco, CA 94105

Phone: (415) 947-4276

E-mail: Gutierrez.Roberto@epa.gov