1

MEMORANDUM

TO: Hillary Ward, U.S. Environmental Protection Agency, OAQ PS/Sector Policies and

Programs Division, Fuels and Incineration Group

FROM: Eastern Research Group, Inc. (ERG)

DATE: July 2015

SUBJECT: Summary of Updated Landfill Dataset Used in the Cost and Emission Impacts Analysis of

Landfill Regulations

Introduction

The EPA is reviewing the new source performance standard s (NSPS) and emission guidelines (EG) for municipal solid waste (MSW) landfills (40 CFR part 60, subpar t WWW and 40 CFR part 60, subpart Cc, respectively). Currently, the regulations require landfil ls that are at least 2.5 million megagrams (Mg) and

2.5 million cubic meters in size and that have estimated nonmethane organic compounds (NMOC) emissions of at least 50 Mg per year to collect and contr ol or treat landfill gas (LFG). 1

As a first step in developing the estimated cost and emis sion impacts of various changes to the current regulatory requirements resulting from the ongoing review of the NSPS/EG, a dataset of existing (current) and future (projected) landfills was created (NSPS/EG dat aset) in July 2014. The purpose of this memorandum is to document changes made to the July 2014 datas et to reflect more recent and comprehensive data.

Using the updated NSPS/EG dataset as an input, a Microso ft ® Access database was developed to calculate the emission reductions and costs. The assumptions and calc ulations used in the database are detailed in the 2015 memorandum, Updated Methodology for Estimating Cost and Emission Impacts of MSW Land fill Regulations.

1. Landfill Data Sources

The landfill databases 2,3 used in the July 2014 NSPS proposal and ANPRM were updated usi ng data from the Greenhouse Gas Reporting Program (GHGRP), select web s earches, and input from EPA Regions and state and local regulatory agencies on landfills expec ted to undergo a modification in the next 5 years. Landfills that stopped accepting waste on or before Novembe r 8, 1987 are not affected by the EG. To accommodate this rule applicability criterion for the purposes of the dataset, any landfill closing before

1988 was removed from the consolidated dataset. After each d ata source was reviewed, data from the various sources were combined appropriately. The entire da taset was then reviewed to remove duplicate

1 The requirements for existing sources under the state and federal plans implementing the EG are similar to t hose for

new sources under the current NSPS.

2 ERG. 2014. Modeling Database Containing Inputs and Results of P roposed Revisions to MSW Landfill NSPS.

3 ERG. 2014. Modeling Database Containing Inputs and Preliminary I mpacts for Review of the MSW Landfill

Emission Guidelines.2

landfills across reporting years or between the various da ta sources. The sources for data updates are

described below.

1.1 GHGRP Data

GHGRP reporting year (RY) 2013 data are the primary data so urce for this updated dataset. Where landfills did not have data for RY2013, data from RY2012 were used. When bo th RY2012-RY2013 were missing, RY2011 data were used. RY2010 data were used only if no other rep orting data were available. The data tables in Appendix B of this memorandum show which reporting ye ar basis was used for various key data parameters. Information about the landfill itself, curren t and historical annual waste acceptance rates, as well as gas collection and control system (GCCS) data (as applicable) were incorporated into the database. These annual historical waste rate data serve as a signif icant improvement to the data input file used to generate emission estimates. 1,217 of 1,970 landfills in the dataset were from GHGRP Subpart HH data.

1.2 Website Research for Select LMOP Landfills

Several landfills in the July 2014 dataset did not report to GHGRP but had data available from EPA’s Landfill Methane Outreach Program (LMOP) to model emiss ions. These GHGRP non-reporters were reviewed further if the landfill had design capacities above 2 million Mg and had a calculated emission rate above 30 Mg/yr NMOC, which is approximately equivalent to t he reporting threshold of 25,000 mtCO 2 e threshold uses in GHGRP. After researching these landfills online, the data inputs at four LMOP landfills were adjusted and updated in the new dataset. The other LM OP landfills (744 of the 1,970 landfills) remained unchanged from the July 2014 dataset.

1.3 Modification Analysis

In fall 2014, EPA contacted EPA Regions and state agencie s to request information about modifications to existing landfills that were pending or occurred over the pas t 5 years. This voluntary outreach was conducted to identify landfills expected to increase their permitted design capacity after the July 2014 proposal, rendering them applicable to standards for new landf ills. EPA requested data on the characteristics of landfills undergoing a modification, such as timing of expans ion and permit approval, amount of waste capacity being added, and identification of landfills known to b e expanding. In addition, EPA performed online searches for permit modification information for state s expected to have landfills being modified where state regulatory authorities have shared this typ e of information.

As a result of these combined outreach efforts, 25 landfil ls were flagged in the NSPS/EG dataset as landfills anticipated to modify their design capacity in the next 5 years (2014-2018), and 18 of these 25 landfills were updated to include expansion data such as updated design capacity, updated estimated closure year, updated acreage, anticipated year of modification, or updatedannual waste acceptance rates. Appendix A1 summarizes the modification data collected for each EPA Region, by state/district/territory. If technical data parameters were updated as part of the modification, these landfills are denoted with a flag field of “Actual” in the ModFlag data field. If no technical dat a were updated, the landfill is denoted with a flag field of “Actual Flag only” in the ModFlag data field.

For states where modification information was unavailable, EPA estimated the landfills expected to modify based on significant changes in design capacity values. Fo r this analysis, significant change threshold was identified based on at least a 5 percent increase in cap acity when comparing GHGRP Subpart HH RY2013 data to each of the three prior years (RY2010-RY2012). A total of 108 landfills were flagged as anticipated to modify their design capacity in the next 5 years using Subpart HH data, and these landfills are shown in Appendix A-2. While these landfills likely modified prior to the July 17, 2014 applicability date of Subpart XXX, the number and characteristics of these mods were used to approximate the number and types of3

landfills undergoing modifications in the near future. These landfi lls are denoted as “Surrogate” in the ModFlag data field.

Collectively, from actual and surrogate modification in formation, a total of 133 landfills were identified as ones expected to modify their design capacity between 2014 and 2018. Cost and emissions impacts for

these 133 landfills will be transferred from the EG to the N SPS in the year the modification is anticipated to commence construction. It is important to note that la ndfills with a post-expansion permitted design capacity below 2.0 million Mg were excluded from the modification analysis because size thresholds below 2.0 million Mg were not considered in the impacts analysis for the proposed Emission Guidelines.

While conducting the research for landfills expected to m odify in the near future, five new landfills were

identified and added to the dataset. Some of these landfills opened or significantly modified recently or were permitted but not yet constructed. As such, open years were estimated for the purpose of generating LFG emission curves. These landfills are shown in Appendix A- 3.

2. Filling Data Gaps

For LMOP landfills, the basis of the fields in the data set and gap filling did not change since the July 2014 dataset except when corrections were made from more rec ent web research as noted above. 4 For GHGRP landfills, there were significant updates made to the datas et and sometimes reported and calculated parameters did not agree with one another, or there were m ultiple methods for filling a data gap. This section documents how the parameters were finalized for the datase t.

2.1 Design Capacity

Design capacity is reported to GHGRP HH Landfills Info data table. Generally the reported value was used in the regulatory database unless one of the two conditions below were met:

1. The calculated waste-in-place (WIP) in 2013 (based on the su m of all annual waste acceptance rates) exceeded the reported design capacity. This happened for 63 landfills.

2. The calculated future annual waste acceptance rates (AWA R) were +/- 10% different than the most recently reported AWAR when using the following equati on: AWAR = (Design Capacity - 2013 WIP)/(Estimated landfill closure y ear - 2013)

If either of these two criteria were met, the calculat ed WIP based on the reported estimated closure year of the landfill (if before year 2078) or the calculated WIP in ye ar 2078 (the maximum year included in the regulatory analysis) was entered in lieu of the design ca pacity.

As a final step, the capacity was converted from metric ton s to short tons to be consistent with how the other design capacities were stored in the database.

2.2 Current Area

The Landfill surface area containing waste is reported in the GHGRP HH Landfills Info data table and is

stored in the field Landfill Surface Area in the GHGRP Landfill Inventory table of the regulatory database.

If the area of the landfill with a GCCS (see Section 2.3) exceeded the area with waste, the current area was set equal to the GCCS area. If there were reported ar eas less than 40,000 m 2 or greater than 9,000,000 m 2

,

4 ERG 2014. Summary of Landfill Dataset Used in the Cost a nd Emission Impacts Analysis of Landfill Regulations.4

these areas were deemed outliers based on the area distribut ions of the remainder of the dataset and compared to LMOP acreage data. Five landfills were identi fied as outliers and reviewed against reported acreages in the LMOP database and in each of the five ca ses the acreage in GHGRP was replaced with the reported current acreage data in the LMOP database.

As a final step, the area was converted from m 2 to acres to be compatible with the costing equations.

2.3 GCCS Area

The acreage of a landfill with a GCCS installed was computed using surface area data reported in the
GHGRP HH_LNDFIL_WTH_GAS_CLCT_WST_DEP data table. The areas are reported with different surface type codes, with codes A2-A5 representing areas with a GCCS installed. The sum of these area types represents the total area with a GCCS installed . See the data field SumOfSurfaceArea-GCCSArea in the GHGRP Landfill Inventory table of the regulatory databa se.

If there were reported areas <40,000 m 2 (but not zero, which would represent no GCCS is installed) or >9,000,000 m

2

, these areas were deemed outliers based on the area distr ibutions of the remainder of the dataset. The data were reviewed and the reported well cou nt in the GHGRP
HH_GAS_COLLECTION_SYSTEM_DETLS data table were used to e stimate the GCCS area, assuming a well density of 1 well per acre.

There were also three landfills that had a calculated GCCS area greater than zero but had a GCCS indicator flag indicating no system was installed. These three l andfills were reviewed against LMOP data and one of the three landfills (Landfill ID# 528332) had its GCCS area c hanged to zero since the LMOP database indicated this project shutdown due to lack of gas.

As a final step, the area was converted from m 2 to acres to be compatible with the costing equations.

2.4 Design Area

The total design area of a landfill was computed by summing t he various types of surface areas reported
for landfills in the GHGRP HH_LNDFIL_WTH_GAS_CLCT_WST_DEP. The area types A1, A2, A3, A4, and A5 were summed to compute a design area in square mete rs. See the data field SumOfSurfaceAreaTotalDesignedArea in the Background Data: GHGRP Landfill Inventory table.

If the current area described in Section 2.2 exceeded the c alculated design area, the design area was set equal to the current area. If the current area was equal to the design area and the landfill was still open, the design area was flagged as suspect and was recalculated usi ng the equation below. Similarly, if there were calculated areas less than 40,000 m 2 or greater than 9,000,000 m 2 , these areas were deemed outliers based

on the area distributions of the remainder of the dataset an d the design area was recalculated using the equations below.

1. If ratio of 2013 WIP/Design Capacity <=1; Design area = cur rent area 5 /(WIP/DC).

2. If the above calculation was in the suspected outlier thre shold range of less than 40,000 m 2 or greater than 9,000,000 m 2

, the calculated value was compared to the reported design capacity in

the LMOP database, if available.

3. If the ratio of 2013 WIP/Design Capacity is >1, the reported design and current acreages in the
LMOP database were compared to the calculated design are a.

5 Current area, as corrected according to Section 2.2.5

As a final step, the area was converted from m 2 to acres to be compatible with the costing equations.

2.5 Depth

Waste depth data were reported in the GHGRP HH_LNDFIL_WT H_GAS_CLCT_WST_DEP data table for landfills with a GCCS installed. The average and maximum depths reported for each landfill in surface area types A2, A3, A4, and A5 were comput ed. Areas with zero depth were excluded from the averaging. These calculated data fields are stor ed in MaxOfWaste Depth and AvgOfWaste Depth in the Background Data: GHGRP Landfill Inventory tabl e.

The calculated maximum depth of waste was used in the co st analysis to be conservative.

For landfills without a GCCS, the designed depth of the landf ill was calculated using the following equation and an assumed waste density of 45 cubic feet per short ton

.

  = 
	   × 45  

 ÷ 35.315  

$  × 1.1 

 ÷ 
	%&	$ '

If there were reported or calculated depths less than 5 meters or greater than 300 meters, these depths were deemed outliers based on the waste depth distributions of the remainder of the dataset. The data were reviewed against the depths in the 2014 dataset and four of the values were changed to be consistent with the reported depths in the proposal dataset.

As a final step, the depth was converted from feet to mete rs to be compatible with the costing equations.

3. Model Landfills

In the July 2014 dataset, model landfills were based on the nu mber and characteristics of landfills opening between 2003 and 2010 to project new landfills. The data sources fo r the landfill inventory were considered complete through year 2010. Since the majority of revised dat a were based on GHGRP RY2013, the data were now considered complete through year 2012. As a result, l andfills opening between 2005 and 2012 in the GHGRP and LMOP databases were used to project new gre enfield landfills opening between 2013 and

2018.

Similar to the methods used in the July 2014 dataset, it wa s assumed that the sizes and locations of
landfills opening in the most recent complete 8 years of d ata (2005-2012) would be similar to landfills
opening in the future (2013-2018). Based on this analysis, five model landfills were created to represent
landfills opening in year 2013 and were assigned to the Emis sion Guidelines database with a prefix
identifier of “EG” (example: landfill ID EG1). All five of the EG greenfield model landfills has a design
capacity of at least 2.5 million Mg.

Eleven model landfills were created to represent landfills opening in 2014-2018 and these models were assigned to the NSPS database with a prefix identifier of “NSPS” (example: landfill ID NSPS1). Of the 11 model landfills, ten had a design capacity of at least 2. 5 million Mg.

4. Final Dataset

Considering models and actual landfills from the GHGRP, LMOP, and other data sources, there are 1,986 landfills in the dataset. Of these, 147 landfills are in the EG database and 1,839 are in the NSPS database.6

Appendix B provides a detailed listing of the background data sources, data tables, field names, and field descriptions (including units of measure) for the EG databa se. Appendix C provides a similar listing for the

data tables in the NSPS database. The contents of each dataset are available in a database format. 6,7

6 ERG. 2015. Modeling Database Containing Inputs and Results of S upplemental Proposal for MSW Landfill NSPS.

7 ERG. 2015. Modeling Database Containing Inputs and Results for Review of the MSW Landfill Emission

Guidelines.