## A Comparison of Monitoring Results
For California Landfills under the
New Source Performance Standards

a nd the California Landfill Methane Rule

Pre pared by:

S C S E N G I N E E R S 3900 Kilroy Airport Way, Suite 100 Long Beach, California ( 562 ) 426

- 9544

October 2014

Offices Nationwide www.scsengineers.comN S P S a n d C A L M R C o m p a r a t i v e D a t a



## A Comparison of Monitoring Results
for California Landfills under the
New Source Performance Standards

a nd the California Landfill Methane Rule

Pre pared by :

S C S E N G I N E E R S 3900 Kilroy Airport Way, Suite 100 Long Beach, California ( 562 ) 426

- 9544

October 2014N S P S a n d C A L M R C o m p a r a t i v e D a t a

i T a b l e o f C o n t e n t s

Section Page

1.0 INTRODUCTION & PURPOSE

................................ ................................ ................................ .............. 1

2.0 BACKGROUND

................................ ................................ ................................ ................................ ...... 1

2.1 NSPS Monit oring Requirements

................................ ................................ ................................ . 1

2.2 California Landfill Methane Rule Monitoring Requirements

................................ ................ 2
2.2.1 Instantaneous SEM

................................ ................................ ................................ .. 2
2.2.2 Integrated SEM

................................ ................................ ................................ ....... 3

2.3 Side

- By

- Side Comparison of Monitoring Requirements

................................ ....................... 4

3.0 SUMMARY OF THE DATA SET USED FOR COMPARATIVE ANALYSIS

................................ ......... 6

4.0 RESULTS

................................ ................................ ................................ ................................ ................... 7

4.1 NSPS Results P rior to Implementing CA LMR

................................ ................................ .......... 7

4.2 CA LMR Results for NSPS and LMR

- Only Sites

................................ ................................ ....... 8
4.2.1 Instantaneous SEM Results

................................ ................................ ..................... 8
4.2.2 Integrated SEM Results

................................ ................................ .......................... 9

4.3 CA LMR Results for NSPS Sites Only

................................ ................................ ..................... 10
4.3.1 Instantaneous SEM Results for NSPS sites

................................ ....................... 10
4.3.2 Integrated SEM Results

................................ ................................ ...................... 11

4.4 CA LMR Results for LMR

- Only Sites

................................ ................................ ....................... 12

4.4.1 Instantaneous SEM Results

................................ ................................ .................. 12
4.4.2 Integrated SEM Results

................................ ................................ ....................... 12

5.0 COMPARATIVE COST OF NSPS AND LMR MONITORING

................................ ......................... 13

6.0 CONCLUSIONS

................................ ................................ ................................ ................................ .... 14

6.1 NSPS Landfills Subject to CA LMR

................................ ................................ ......................... 14
6.1.1 Instantaneous SEM

................................ ................................ ............................... 14

Surface Traverse

................................ ................................ ................................ . 14
Cover Penetrations

................................ ................................ ............................. 15 Exceedances Requiring GCCS Expansion

................................ ...................... 15
6.1.2 Integrated SEM

................................ ................................ ................................ .... 16

6.2 New Landfills Subject to CA LMR

................................ ................................ ........................... 17N S P S a n d C A L M R C o m p a r a t i v e D a t a

i i L i s t o f T a b l e s

No.

1 Comparison of NSPS and CA LMR Monitoring Requirements

2 Landfills Categorized by Applicable Regulation
3 Landfills Categorized by Climate Type
4 Landfills Categorized by Operational Status

5 Landfills Categorized by Type of Ownership
6 Landfills Categorized by Waste

- In

- Place

7 NSPS Instantaneous SEM Results
8 CA LMR Instantaneous SEM Results
9 CA LMR Integrated SEM Results
10 CA LMR SEM Results for the 42 NSPS sites

11 CA LMR SEM Results for the 30 LMR

- only Sites

12 Comparison of Instantaneous SEM Results under NSPS and CA LMR RequirementsN S P S a n d C A L M R C o m p a r a t i v e D a t a

1



## 1.0 INTRODUCTION & PURPOSE

SCS Engineers (SCS) conducted a comparative analysis of the results of Surface Emissions Monitoring (SEM) conducted to comply with the requirements of the California Landfill Methane Rule ( CA LMR) under §95460 to 95476 of Title 17, California Code of Regulations (CCR), and the federal monitoring requirements in 40 Code of Federal Regulations (CFR) Part 60, Subpart WWW (“New Source Performance Standards” or “ NSPS ” ) for municipal solid waste (MSW) landfills. Th is paper reviews data from California landfills that have implemented the requirements of NSPS, LMR or both regulations , and summarizes the monitoring re sults and level of effort required for their implementation.



## 2.0 BACKGROUND

2.1 NS P S M ONI T OR I N G R EQ U I R EM EN TS

T he NSPS requires I nstantaneous S urface Emissions M onitoring ( Instant aneous SEM ) on a quarterly basis to ensure that the landfill gas (LFG) collection and control system is operating properly and that the methane concentration is less than 500 parts per million (ppmv) above background at the surface of the landfill. On a q uarterly basis, t he regulation requires the landfill
owner or operator to monitor surface concentrations of methane along the entire perimeter of the
collection area

, along a pattern that traverses the landfill at 30 meter (98 foot) spacing intervals between the walking paths for each LFG collection area

. Additionally, the landfill owner must monitor penetrations of the landfill cover where visual observations indicate elevated
concentrations of LFG , such as distressed vegetation

, cracks

, or seeps in t he cover. The SEM monitoring equipment (FID meter) is designed to continuously read methane concentrations and record readings at or above 500 p p m v as monitoring personnel traverse the path throughout the
collection area. Instantaneous SEM is only requir ed for landfill areas required to have gas collection and control under the NSPS. The owner or operator may establish an alternative traversing pattern that ensures equivalent coverage. Each landfill must develop a surface monitoring design plan that inc ludes a topographical map marked with the monitoring route and provide an explanation for any site

- specific deviations from the 30

- meter intervals. Areas with steep slopes or other dangerous areas (e.g., w h ere heavy equipment is operating) may be
excluded from the surface testing to protect personnel safety

.

Any reading of 500 ppm v or more at a location is recorded as an exceedance. Typically, c over maintenance or adjustments to the collection system a re undertaken to remediate the exceedance

, and the location re

- monitored within 10 calendar days of the initial measurement

. If re

monitoring shows a second exceedance, additional corrective action is undertaken

, and the
location is monitored again within 10 days of the second measurement . If re

- moni toring shows a
third exceedance for the same location in the same quarter , a new well or other collection device

must be inst alled within 120 calendar days of the initial exceedance. The United States
Environmental Protection Agency (EPA), or its delegate d state agency , may also approve an alternative timeline for remediation or an alternative remedy , such as upgrading the blower, header pipes or control device, after receiving a request for approval. L ocation s that initially
show an exceedance

, but ha ve measured methane concentration s of less than 500 ppm v methaneN S P S a n d C A L M R C o m p a r a t i v e D a t a

2

at the first or second 10

- day re

- monitoring event must be re

- monitored one month after the initial
exceedance was detected to ensure the remedy was successful

.

A c losed or inactive MSW landfill that ha s no exceedances after four consecutive monitoring periods may be monitor ed annually . If an exceedance is detected during an annual event , the landfill must return to quarterly monitoring

.

The results of the quarterly (or annual) Instantaneous S EM events are reported to the EPA
Administrator on a semi

- annual basis.



### 2.2 C A LI FOR NI A LA N D F I L L M E TH A NE R U L E M O NI TOR I NG

R EQ U I R EM EN TS

The CA LMR monitoring approach is similar to the NSPS in many respects, but has additional requirements . As discussed below, t he Instantaneous SEM monitoring requires the technician to
follow a tighter

, more prescriptive walking pattern. The CA LMR also requires Integrated
Surface Emissions Monitoring (Integrated SEM ) , which is not required under the NSPS.

2 . 2 . 1 I n s t a n t a n e o u s S E M

As with the NSPS, the C A LMR requires sites to conduct I nstantaneous SEM of the entire
landfill surface on a quarterly basis

. This requirement, as well as several other requirements of
the CA LMR

, are more stringent, however. T he CA LMR requires each la ndfill owner/operator

to divide t he entire landfill surface , regardless of age of waste, i nto 50,000 square foot grids ( slightly larger than one acre) a nd establish a walking pattern that traverses each grid with no more than a 25

- foot (7.6 meter) spacing interval between the walking paths

. As with the NSPS monitoring regime, the handheld monitoring device continuously reads methane concentrations
and

, for the CA LMR

, records readings at 200 ppmv and above. Moreover, all cover penetrations of the landfill surface must be monitored , whether or not they exhibit indications of
elevated concentrations of LFG

. Also , s urface testing cannot be performed when the average wind speed exceeds five miles per hour (mph)

, the instantaneous wind speed exceeds 10 mph

, or if there has been measurable precipitation in the preceding 72 hours. In these situations, monitoring must be delayed

, unless the owner or operator requests and receives approval from the California Air Resources Board ( CARB ) (or delegated air district) for an alternative approach. A ny reading greater than 500 ppm v methane is considered an exceedance and must be
recorded. In addition, I nstantaneous SEM readings between 200 and 500 ppmv, while not considered exceedances, must also be recorded. The locati on of each exceedance must be recorded and marked on a map, and the following data reported:

 Location (or affected grid)

 Concentration in ppm v

 Date and time of measurement

 Corrective action taken to repair the exceedance

 Date of repair

 Results of any required re

- monitoring

 Wind speed during surface samplingN S P S a n d C A L M R C o m p a r a t i v e D a t a

3

Similar to the NSPS, if an exceedance is detected, the owner/operator must undertake corrective action (e.g., cover maintenance/repair or well vacuum adjustments)

, and the location must be re

monito red within 10 calendar days of the initial measurement . If re

- monitoring shows an exceedance, additional corrective action must be taken, and the location must be re

- monitored no later than 10 calendar days after the second measurement . If re

- monitoring shows a third exceedance within the same quarter, a new or replacement well must be installed and compliance with the 500 ppmv limit achieved within 120 calendar days. However unlike the NSPS, there is no requirement for monthly follow

- up monitoring once an exceedance has been corrected.

Closed or inactive MSW landfills, as well as closed or inactive areas on an active MSW landfill, that have no exceedances after four consecutive monitoring periods may transition to annual monitoring. However, any exceeda nces during annual monitoring that cannot be remediated within 10 calendar days must return to quarterly monitoring.

The results of the quarterly (or annual) monitoring events are reported to the Executive Officer
for CARB (or delegated air district) on an annual basis.

2 . 2 . 2 I n t e g r a t e d S E M

Under th e CA LMR

, Integrated SEM is required in addition to I nstantaneous SEM

. Under Integrated SEM

, all methane readings within each 50,000 square foot grid are averaged

. A n

a veraged reading of 25 ppmv or grea ter within a grid is considered an exceedance and must be
remediated

. T he same grids used to conduct I nstantaneous SEM are used for Integrated SEM

, and the walking pattern must be no more than a 25

- foot spacing (7.6 meter) interval within each grid. A s with the I nst antaneous SEM, wind and precipitation limitations apply

, and the owner/operator must record the location of the grid o n a map.

If an Integrated SEM exceedance is recorded for a grid , c orrective action must be taken (e.g., cover maintenance or repair, or well vacuum adjustments )

, and the grid must be re

- monitored within 10 calendar days of the initial measurement . If re

- monitoring shows a second exceedance, additional corrective action must be taken

, and the grid must be re

- monitored again
no later than 1 0 calendar days after the second measurement . If the re

- monitoring shows a third exceedance, a new or replacement well must be installed and compliance with the integrated
limit achieved within 120 calendar days of the third measurement

.

The owner or oper ator must report the following information for any Integrated SEM
exceedance:

 The affected grid

 Average concentration in ppm v

 Date and time of measurement

 Corrective action taken to remediate the exceedance

 Date of the corrective action

 Results of any requ ired re

- monitoring

 Wind speed during re

- monitoring

Any closed or inactive MSW landfill, as well as any closed or inactive areas on an active MSW
landfill

, that has no exceedances after four consecutive monitoring periods may monitorN S P S a n d C A L M R C o m p a r a t i v e D a t a

4

annually. Any exceeda nces during the annual monitoring that cannot be remediate d within 10 calendar days will result in a return to quarterly monitoring.

The results of the quarterly (or annual) monitoring events are reported to the Executive O fficer of CARB (or delegated air district) on an annual basis.

Sites that do not have any exceedances under both I nstantaneous or Integrated SEM for four consecutive quarters can increase the grid walking pattern spacing to a 100

- foot interval. However, similar to the trigger for lower frequency of monitoring , any exceedance that cannot be corrected within 10 days will result in a return to 25

- foot spacing.



### 2.3 S I D E

- B Y

- S I D E C O MP A R I S O N O F M O NI TOR I N G

R EQ U I R EM EN TS

Table 1 below compares key elements of the NSPS and C A LMR SEM requirements.N S P S a n d C A L M R C o m p a r a t i v e D a t a

5 Table 1. Comparison of NSPS and CA LMR Monitoring R equirements

SEM Requirement NSPS CA LMR Instantaneous SEM Area of landfill subject to
Instantaneous SEM Areas where LFG collection system

is required to be installed Entire landfill surface, except working face

P ath R equirements 98

- foot spacing (30 meters) 25

- foot spacing (7.6 meters)

D ata R ecorded Any reading 500 ppmv methane or

greater above background Any reading 200 ppmv or greater above background

E xceedance
Threshold Any methane reading ≥ 500 ppmv A ny methane reading > 500

ppmv *

Exceedance
Corrective Action Requirements Following exceedance detection

,

perform correction action and re

monitor within 10 days; if a second exceedance is detected, perform
additional corrective action and re

monitor within 10 days of the 2 nd
event; if a 3 rd exceedance is detected, expand the GCCS or implement an approved alternative remedy Same as NSPS

Integrated SEM N/A Collect methane readings continuously within 50,000

square

- foot grids. Average of readings within a grid ≥ 25 ppmv trigger corrective action.

Cover Penetration Monitoring Monitor penetrations quarterly where

visual observation indicates elevated concentrations of landfill gas (i.e., distressed vegetation) Monitor all penetrations quarterly

Weather C onditions (wind, precipitation) Perform during typical meteorological cond itions Wind : Cease SEM if average wind speed exceeds 5 mph or instantaneous exceeds 10 mph.

Preci pitation : Cease SEM if any measurable precipitation within
last 72 hours.

*Due to similarities in thresholds, some air districts have been enforcing the CA LMR >500 ppmv threshold using
the NSPS ≥500 ppmv threshold

.N S P S a n d C A L M R C o m p a r a t i v e D a t a

6



## 3.0 SUMMARY OF THE DATA SET USED FOR
COMPARATIVE ANALYSIS

SCS analyzed data from 7 2 California landfills regulated under the CA LMR, which took effect

in mid

- 2011. Because CA LMR requirements are more stringent than the NSPS, after mid

2011, the NSPS landfills in the dataset implemented LMR requirements and reported the relevant data to the State of California and EPA, as appropriate. SCS obtained the aggre gate NSPS monitoring results through review of quarterly monitoring reports developed from up to two

years ( 8 quarters) prior to implementation of the CA LMR ( 3 rd quarter 2009 through mid

- 2011).

T he CA LMR dataset was compiled from monitoring reports beg inning with the date of implementation (mid

- 2011) through the end of 2013. Thus, a ggregate CA LMR monitoring
results from NSPS sites and CA LMR only sites ( i. e.., sites never subject to the NSPS) were obtained from quarterly monitoring reports developed during from July 2011 through December

2013

.

Table 2 through Table 6 provide additional descriptive information on the landfills in the dataset.

Table 2

. Landfills C ategorized by A pplicable R egulat ion

No. of Landfills NSPS & CA LMR CA LMR Only

42 30

Table 3

. Landfills C ategorized by Climate Type

No. of Landfills Arid *

(< 25 inches precipitation/year) Non

- Arid * (>25 inches precipitation/year)

6 0 12

*Definition of “arid” taken from CA LMR and 40 CFR Part 98

Table 4

. Landfills C ategorized by Operational Status

No. of Landfills Closed Active

2 7 4 5

Table 5

. Landfills C ategorized by Type of Ownership

No. of Landfills Public Private

4 1 31

Table 6

. Landfills C ategori zed by Waste

- In

- Place

No. of Landfills 0

- 450,000 tons 450,000

- 2.5 million

tons >2.5 million tons

0 26 4 6N S P S a n d C A L M R C o m p a r a t i v e D a t a

7

Each quarter of available monitoring data was assessed individually. The data w ere then aggregated to develop summary statistics. SCS collected and compiled the following data for each landfill, as available :

 Report type (NSPS/CA LMR), area (acreage/grids) monitored, total number of penetrations monitored;

 Number of I nstantaneous SEM exceedances identified following the NSPS and/or the CA LMR monitoring requirements ;

 Number of I nstantaneous SEM excee dances from penetrations following the NSPS and CA LMR requirements ;

 Number of Instantaneous SEM exceedances triggering the 120

- day period for expansion
of the GCCS

, or an approved alternative remedy ;

 Number of I ntegrated SEM exceedances (grids with averag e methane readings > 25 ppmv) for the landfills regulated under the CA LMR ;

 Number of Integrated SEM exceedances triggering the 120

- day period for expansion of
the GCCS or an approved alternative remedy ; and

 Comparison of the location s of I nstantaneous ve rsus Integrated SEM exceedances

.



## 4.0 RESULTS

This section summarizes the results of the assessment of monitoring conducted under the NSPS
and CA LMR rules. The discussion is presented in four parts: (1) NSPS monitoring results for 42 landfills prior to im plementation of the CA LMR; (2) CA LMR monitoring results for 72 landfills, including both the 42 NSPS landfills, and 30 “LMR

- only” landfills; (3) comparative NSPS and CA LMR monitoring results for the 42 NSPS landfills; (4) CA LMR monitoring
results for the “LMR

- only” landfills

.



### 4.1 NS P S R ES U L TS P R I OR TO I MP L EM E N TI N G C A L MR

SCS reviewed 212 reports of monitoring conducted using the NSPS regime at 4 2 California landfills subject to the NSPS requirements. A total of 1,147 exceedances (instantaneous SEM readings of 500 ppmv methane or greater ) were recorded . O f the total, 446 ( 38.9 %) were detected by traversing the specified serpentine path , and the remaining 701 ( 61.1 %) were detected at penetrations in the landfill surface with visible indicators of elevated concentrations
of LF G (e.g., distressed vegetation, or cracks or seeps in cover)

.

 Exceedances detected traversing the prescribed path : A total of 27,140 acres were monitored . E xceedances were detected at 1. 6 % of the acres monitored

.

 Exceedances detected at targeted penetrations: A total of 26,231 penetrations were
monitored following the NSPS requirement to target penetrations with visible signs of
elevated LFG concentrations. E xceedances were detected at 2.7 % of the penetrations
monitored

.

 Exceedances triggering 120

- Day GCCS Expansion: O nly 1. 2 % of all exceedances
were unable to be remedied by simple cover repair or collection system adjustments within the first 20 days , thus triggering the 120

- day GCCS expansion requirement

. AllN S P S a n d C A L M R C o m p a r a t i v e D a t a

8

of these exceedances occurred at one landfill

. None of the remaining 41 NSPS landfills in the dataset trigger ed GCCS expansion as a result of instantaneous SEM exceedances

.

Table 7 provides a summary of the NSPS instantaneous SEM results

.

Table 7 . NSPS Instantaneous SEM Monitoring Results

Traversing the Prescribed Path (500 ppmv threshold) NSPS

Landfills

Exceedances as a percentage of acres monitored 1. 6 %

Targeted Penetration Monitoring

Exceedances as a percentage of penetrations monitored 2. 7 %

Total

Percentage of exceedances which resulted in GCCS expansion 1. 2 %



### 4.2 C A LMR R ES U LTS FOR NS P S A ND LMR

- O N LY S I TE S

4 . 2 . 1 I n s t a n t a n e o u s S E M R e s u l t s

SCS reviewed 521 monitoring reports for 7 2 California landfills subject to the CA LMR

, including the 4 2 NSPS described previously

. As the rule requires, each landfill was divided into 50,000

- square

- foot grids, for a total of 49,790 grids (equivalent to 57,151 acres) subject to

Instantaneous SEM monitoring across the 7 2 sites

. 1 The monitoring reports identified a total of 3,211 recorded exceedances (e.g., methane reading s higher than 500 ppmv ) . Of these, 2,141 exceedances ( 66.7 %) were detected by traversing the specified serpentine path , and the remaining 1,070 ( 33.3 %) occurred at penetrations in the landfill surface

.

 Exceed ances Detected Traversing the Prescribed Path : Of the 57, 151 acres monitored, e xceedance s were detected at 3.7 % of the acres monitored

.

 Exceedances D etected at P enetration s : A total of 70,529 penetrations were monitored
at the landfills in the dataset

, following the requirements of the CA LMR to monitor every penetration during every monitoring event

. E xceedances were detected at 1.5 % of all penetrations monitored

.

 Exceedances T riggering GCCS Expansion: Under the CA LMR, 4.7 % of all
exceedances triggered the 120

- day requirement for GCCS expansion

. These exceedances
occurred at five of the 7 2 landfills in the dataset

, two of which obtained an approved alternative remedy other than expanding the GCCS

. The remaining three landfills were required t o undertake a GCCS expansion. It should be noted that the two sites with the
alternative remedies each had only one exceedance. Sixty

- seven (67) of the sites in the dataset did not trigger GCCS expansion as a result of Instantaneous SEM exceedances.

1 For comparative purposes, CA LMR monitoring grids have been converted to acres in order to normalize for comparison t o NSPS. Each 50,000

- square

- foot

- grid is equivalent to 1.148 acres.N S P S a n d C A L M R C o m p a r a t i v e D a t a

9

 R equests for Monitoring Variances: The CA LMR includes specific wind and precipitation limits for conducting SEM monitoring . Review of the data set indicates that these requirements can be difficult to meet. Of the 7 2 sites evaluated, 53 (or 72.6 %) required a permanent alternative for wind speed due to conditions at the site

.

Table 8 summar izes the Instantaneous SEM monitoring results under CA LMR

.

Table 8

. CA LMR Instantaneous SEM Monitoring Results

Travers ing the Prescribed Path (500 ppmv threshold) LMR

Landfills

Exceedances as a percentage of acres monitored 3.7 %

Penetration Monitoring

Exceedances as a percentage of penetrations monitored 1.5 %

Total

Percentage of exceedances which resulted in GCCS expansion 4.7 %

4 . 2 . 2 I n t e g r a t e d S E M R e s u l t s

The monitoring reports reviewed by SCS also provided the results of the Integrated SEM for the

7 2 sites. As with Instantaneous SEM, e ach landfill was divided into 50,000

- square

- foot grids

, for a total of 41,363 grids subject to Integrated SEM monitoring (equivalent to 47,479 acres)

. 2
Integrated SEM exceedance s ( e.g., an integrated grid reading greater than 25 ppmv methane ) were detected in 1.8% of the grids (or 1.5% of the acres monitored)

.

Only 0. 5 % of all grids monitored had exceedances which triggered the 120

- day requirement to expand the GCCS. These exceedances occurred at six of the 72 landfills in the dataset, one of which obtained an approved alternative remedy other than expanding the GCCS . The remaining
five landf ills , representing 0.4% of the grids, were required to undertake a GCCS expansion. Sixty

- six (66) sites in the dataset did not trigger GCCS expansion as a result of Integrated SEM
exceedances.

Three of the five landfills (60%) that trigger ed GCCS expans ion due to Integrated SEM results also triggered GCCS expansion due to Instantaneous SEM results

.

Table 9 provides a summary of the Integrated SEM results

.

2 The number of Integrated grids monitored is different than the number of instantaneous grids monitored due to allowance under CA LMR for a reduction of monitoring frequency.N S P S a n d C A L M R C o m p a r a t i v e D a t a

1 0 Table 9

. CA LMR Integrated SEM Results

Monitoring Grid s (>25 ppmv threshold) LMR

Landfills

Exceedances detected as a percentage of grids monitored (>25 ppmv) 1.8%

Percentage of exceedances per grid s monitored triggering 120

- day expansion 0.5%

Percentage of exceedances per grid monitored which resulted in GCCS expansion 0. 4 %



### 4.3 C A LMR R ES U LTS FOR NS P S S I TE S O NLY

This section describes the CA LMR monitoring results for the 42 landfills previously implementing the NSPS monitoring regime

. Focusing only on the NSPS landfills in this section enables us to highlight differences in the two monitorin g regimes (NSPS vs. LMR) as applied to
the same landfills. This “apples to apples” comparison provides more conservative results than including landfills never subject to the NSPS and only newly subject to any monitoring regime. Comparing the results of the 42 NSPS landfills to the entire data set would result in even small er percentage exceedances in all aspects, thus further decreasing cost

- effectiveness.

4 . 3 . 1 I n s t a n t a n e o u s S E M R e s u l t s f o r N S P S s i t e s

NSPS sites represented 58% of the landfills in the data set, 68% of the monitoring reports, 78% of the acres monitored, and over 90% of the instantaneous exceedances detected.

Exceedance s D etected W alking the P rescribed P ath

The tighter walking pattern of the CA LMR monitoring re gime resulted in detection of more
exceedances while traversing the monitoring path. NSPS monitoring reports for the “before LMR” period documented exceedances at 1.6% of the acres monitored, while the “after LMR”

results of the same NSPS landfills recorded ex ceedances at 4.4% of the acres monitored. However, the analysis also found that the vast majority of identified exceedances were easily remedied with repairs to cover materials and did not require installation or expansion of GCCS.
Under both the NSPS an d the CA LMR, the requirement and timing to expand the GCCS system (or obtain approval for an alternative remedy) is the same. In the two years “before LMR,” one landfill triggered the 120

- day expansion requirement and subsequently expanded its GCCS. In 30 months of CA LMR monitoring at these same NSPS landfills, five landfills triggered the 120

- day expansion , although only three of them were required to expand the GCCS. The exceedances that resulted in GCCS expansions at the three landfills represent 0 .3% of the total
acres monitored

.

The analysis does not indicate whether these exceedances would have also been identified under the NSPS procedures, or whether the CA LMR regime was solely responsible for their identification. Furthermore, we do not kno w if the fundamental decision to expand the GCCS was driven by the CA LMR, or whether the GCCS expansions were planned or required by
NSPS timelines. While CARB promulgated the rule believing that it would result in more frequent and earlier LFG collectio n system installations and expansions

, the analysis does notN S P S a n d C A L M R C o m p a r a t i v e D a t a

1 1

support this conclusion. Even with a much more intensive (and costly) walking pattern, only

two additional NSPS landfills were required to expand their GCCS under the CA LMR.

Exceedances Detected by Penetration Monitoring

NSPS landfills implementing the Federal NSPS monitoring regime monitored penetrations using the standard industry practice of sampling penetrations with visual or other signs indicative of
elevated concentrations of LFG. The LMR, by contrast, explicitly requires monitoring of every penetration to the landfill cover.

Following the NSPS approach, NSPS landfills monitored 26,231 penetrations and detected exceedances at 2.7% of penetrations monitored. Under the LMR, the number of penetrations monitored increased by 84% , but the percentage of exceedances detected declined to 2.0%. This result occurred because exceedances were only detected at 1.1% of the additional pe netration s monitored

. Thus, it a ppears that the effort expended to monitor every penetration at a landfill is less effective in finding exceedances than the more targeted NSPS approach of monitoring penetrations when there is an indication of a n actual problem.

4 . 3 . 2 I n t e g r a t e d S E M R e s u l t s

Because the current NSPS/EG does not require integrated monitoring, it is not possible to
conduct a before

- and after

- LMR implementation comparison. However, available data for the
42 NSPS sites indicate that integrated exceedances were detected in 2.1% of the grids monitored,
and GCCS expansion was required for 0. 5 % of grids monitored. In all, six landfills triggered
the 120

- day expansion requirement, and five of these landfills expanded. Three of these five landfills had previously been identified through instantaneous monitoring, which implies that the
incremen tal benefit of integrated monitoring may have been the identified need for GCCS expansion at two additional landfills. We c ould not determine from the reports reviewed

w hether the fundamental reason for expansion was solely the CA LMR integrated monitorin g results, or whether the landfills already planned for GCCS expansions.

Table 10 presents a summary of the results for the 42 NSPS sites subject to CA LMR.N S P S a n d C A L M R C o m p a r a t i v e D a t a

1 2 Table 10. CA LMR SEM Results for 42 NSPS sites

Instantaneous exceedances detected via surface traverse per CA LMR requirement s , as a percentage of acres monitored 4.4 %

E xceedances detected via surface traverse which resulted in GCCS
expansion , as a percentage of acres monitored 0.3 %

E xceedances detected at penetrations monitored per CA LMR requirements , as a percentage of penetrations monitored 2. 0 %

Percentage increase in number of penetrations monitored under

the LMR 84%

Percentage of exceedances detected at the additional penetrations monitored under the LMR 3 1.1 %

Integrated Exceedances detected as a percentage of grids

monitored (>25 ppmv) 2.1%

Percentage of integrated exceedances per grid s monitored which resulted in GCCS expansion 0. 5 %



### 4.4 C A LMR R ES U LTS FOR L MR

- O N LY S I T ES

Thirty landfills in the dataset subject to the CA LMR are exempt from the NSPS or EG due to their age, design capacity and/or NMOC emissions potential. This section evaluates the results of monitoring these “LMR

- only” landfills.

4 . 4 . 1 I n s t a n t a n e o u s S E M R e s u l t s

Under the CA LMR, all regulated landfill s must follow the requirements for instantaneous and integrated surface emissions monitoring. Our review of the instantaneous monitoring results for
“LMR

- only” landfills found that these 30 landfills (42% of the landfills in the dataset), were responsibl e for less than 10% of the exceedances recorded. Approximately 59 % of exceedances
were detected via traversing the monitoring path , and the remaining 41% were detected through penetration monitoring. Exceedances were detected via surface traverse in 1 .4 % of the acres monitored, and at 0.6 % of the penetrations monitored.

A ll of these exceedances were remediated within 20 days with cover repair and/or GCCS adjustments. Over the first 30 months of CA LMR implementation, not a single LMR

- only (non

- NSPS) landfill in the dataset had an exceedance that triggered the LMR requirement to expand the GCCS. This result is particularly significant because it is the GCCS expansions that are primarily responsible for the methane and NMOC reductions associated with this rule.

4 . 4 . 2 I n t e g r a t e d S E M R e s u l t s

The integrated monitoring results for the 30 landfills in the dataset found that there were no exceedances (>25 ppmv) detected in any grid during the first 30

- months of LMR

3 Calculated as the incremental increase in exceedances between the NSPS and CA LMR monitoring (for NSPS landfills) divided by the incremental difference in the number of penetrations monitored under both cases.N S P S a n d C A L M R C o m p a r a t i v e D a t a

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implementation. As a result, none of these landfills was required to expand its GCCS due to integrated monitoring results.

Table 11 presents a summary of the results for the 30 non

- NSPS sites subject to CA LMR.

Table 11. CA LMR SEM Results for 30 LMR

- O nly S ites

I nstantaneous exceedances detected via surface traverse as a percentage of acres monitored 1.4%

Percentage of instantaneous exceedances detected via surface

traverse which resulted in GCCS expansion 0%

Instantaneous exceedances detected as a percentage of penetrations monitored 0.6%

Integrated Exceedances detected as a percentage of grids

monitored (>25 ppmv) 0%

Percentage of integrated exceedances per grid s monitored which resulted in GCCS expansion 0%



## 5.0 COMPARATIVE COST OF NSPS AND LMR
MONITORING

While b oth the CA LMR and the NSPS require personnel to travel to regulated landfill sites and
walk the surface of the landfill , there are important differences in the requirements and burden of the two approaches . The CA LMR monitoring pat h ha s much tighter spacing intervals than the

NSPS (7.6 vs. 30 meters, or 25 vs. 98 feet), which translates directly into more personnel time required in the field and higher implementation costs . In addition, the CA LMR requires monitoring of every cover penetration on the landfill, whereas the NSPS requires monitoring where there is evidence of a potential surface emission issue . Finally, the CA LMR requires

I ntegrated SEM monitoring in addition to instantaneous monitoring, which results in additional
time and costs , even when performed along with the Instantaneous SEM monitoring.

Instantaneous Monitoring: C onducting i nstantaneous SEM under the CA LMR is significantly
more labor

- intensive and costly than the monitoring required under the NSPS. Availab le cost data indicate that monitoring at a 25

- foot interval and within defined grids greatly increases staff hours required to complete the work. This additional cost is driven primarily by the tighter walking pattern, which takes proportionately more tim e to complete. In many cases, the LMR requirement to work within a grid creates additional inefficiencies. Overall, this review indicates that the time required to perform the CA LMR monitoring is 4 to 5 times great er than that for the NSPS, reflecting t he need for 4 times more walking due to the spacing decrease and the additional inefficiencies resulting from the use of grids

. This labor time does not include compilation and review of the monitoring data, mobilization to/from the site or delay in
monit oring due to meterological conditions. It also does not include labor time associated with cover repair and re

- monitoring.

Penetration Monitoring: T he CA LMR requirement to monitor all cover penetrations increase s labor time because walking to and moni toring additional penetrations takes time. TheN S P S a n d C A L M R C o m p a r a t i v e D a t a

1 4

comparison of NSPS and CA LMR requirements for 42 NSPS landfills (described in section 4.3.2) found the CA LMR requirement to monitor every penetration resulted in an 84% increase in the number of penetratio ns monitored. Because labor costs are the primary driver of penetration monitoring costs, this finding implies that the costs of penetration monitoring increased by a similar percentage.

Integrated Monitoring: T he Integrated SEM requirements under the CA LMR are estimated to
increase field time by 25% to 75% , depending on whether the landfill does separate or combined
Instantaneous and Integrated SEM

, and t he methodology used to develop the integrated
emissions estimate. L andfill s that conduct Instantaneous and Integrated SEM separately must
undertake two separate traverses of the entire landfill, which doubles the time required to conduct the monitoring. Moreover, even at the landfills that perform both requirements at the

same time, additional time is required to conduct the monitoring.

EPA’s cost analysis (see Table 5, 79 Fed. Reg. 41823) indicates that adopting the CA LMR approach in the proposed NSPS would increase monitoring costs by more than seven times (from
a total an nual cost of $ 42

, 3 00 to $362,900)

. However, the results of this analysis found that the
additional effort and resources only detected exceedances at an additional 1.3 % of grids monitored, while increasing gas collection at only one of 72 landfill s

.



## 6.0 CONCLUSIONS

This section summarizes conclusions drawn from the analysis described in this report. The conclusions are presented in two sections. The first compares results of surface emissions monitoring of NSPS landfills under the NSPS requirements (bef ore the CA LMR) and the CA LMR requirements (beginning in mid

- 2011). The second focuses on the results of surface monitoring conduted as required by the CA LMR at non

- NSPS landfills (e.g., not previously regulated under the NSPS).



### 6.1 NS P S LA ND F I L LS S U B JE C T T O C A L MR

In sights gained by this analysis are provided for both instantaneous and integrated surface emissions monitoring.

6 . 1 . 1 I n s t a n t a n e o u s S E M

Surface Traverse

The key difference between t he NSPS and the CA LMR I nstantaneous SEM regime s is the
increased intensity of site

- level monitoring

. The density of the CA LMR walking path is approximately 4 times greater than that of the NSPS regime (spacing of 25 vs. 98 feet, respectively

, between walking paths ). A review of monitoring results under both programs
indicates that the CA LMR regime result s in the detection of additional exceedances as compared to NSPS monitoring , but not at a level commensurate with the additional burden and cost

.

Under the NSPS requirements, exceedance s were detected at 1.6% of the total acres monitored

. Under the CA LMR requirements, such exceedance s were detected at 3.7% of the acres
monitored . Thus, the CA LMR requirements resulted in the detection of exceedances at anN S P S a n d C A L M R C o m p a r a t i v e D a t a

1 5

additional 2.1% of acres monitored

. This slight increase in additional exceedances detected
suggest s that the CA LMR requirements are not cost

- effective as they increase costs by more than seven times (according to EPA’s cost analysis).

Cover Penetrations

Under the CA LMR monitoring regime, the number of penetr ations monitored was 84% higher than under the NSPS requirements. U nder the NSPS program

, which directs monitoring at penetrations exhibiting some obvious sign of elevated methane , exceedances were identified at
2. 7 % of total penetrations monitored. By co mparison, under the CA LMR regime

, exceedances
were identified at 2.0 % of total penetrations monitored at the 42 NSPS sites . This suggests that
the targeted monitoring approach under the NSPS r ule is far more cost

- effective in identifying penetration leak s.

The increased benefit of the CA LMR is even lower, however, because all of the exceedances detected under the NSPS requirements were also detected by the CA LMR. In fact, for those penetrations monitored solely due to the CA LMR, the percent age differ ence in the detection of
exceedance s is 1. 1 %, which is less than half that of the NSPS program

.

As with surface traverse monitoring, cover penetrations are monitored by field personnel walking to the penetration at the landfill. By significantly increasing the number of penetrations monitored, the CA LMR increases labor co sts by nearly a factor of two, while detecting a much smaller percentage of exceedances.

Exceedance s R equiring GCCS Expansion

Under both the NSPS and CA LMR monitoring progra ms , t he percentage of exceedances that could not be quickly remedied with cover repairs or GCCS adjustments was low : only 1. 2 % for
the NSPS and 5.2 % for the CA LMR

. This finding indicates that , a preponderance of the
exceedances identified using insta ntaneous monitoring (98% for NSPS and 93 % for CA LMR) can be remedied quickly with cover repairs or minor adjustments to the gas collection system.

In addition, u nder both rules, only a few landfills were required to expand their GCCS

. Under
the NSPS m onitoring regime, e xceedances requiring expansion occurred at one landfill ( 0.1% of
acres monitored of the NSPS sites in the data set ) , and t hree landfills ( 0.3% of acres monitored of the NSPS sites) were required to expand under the CA LMR monitoring approach

. Th us, the additional intensity of the CA LMR monitoring regime result ed in GCCS expansion at two additional NSPS landfills out of the 4 2 NSPS in the database (or 0.2 % of acres monitored at the NSPS landfills in the data set)

.

Instantaneous sur face monitoring under the CA LMR is significantly more expensive than the NSPS requirement, and the results of this more intensive monitoring do not justify the increased monitoring cost. The vast majority of the exceedances detected under both programs were easily remedied, and the CA LMR did not identify a significant number of landfills with problems severe enough to require expansion of the GCCS system, which is the main way to establish that methane emissions are being reduced.

Table 1 2 presents a su mmary of the information for NSPS Landfills subject to the CA LMR.N S P S a n d C A L M R C o m p a r a t i v e D a t a

1 6 Table 1 2

. Comparison of Instantaneous SEM Results under NSPS and CA LMR Requirements

Surface Traverse Under

NSPS Under

CA L MR

E xceedances detected as percentage of acre s monitored 1.6% 3.7%

Incremental exceedances detected under the CA LMR as a percentage of acres monitored -- 2.1%

Number of Landfills required to e xpand GCCS based on surface

traverse monitoring 1 3

Penetration Monitoring

Exceedances detected as a percentage of penetrations monitored 2.7% 1.5%

Total
Exceedances that required GCCS expansion, as a percentage of

acres monitored 0.1% 0.3%

6 . 1 . 2 I n t e g r a t e d S E M

Integrated SEM monitoring detected exceedances in 2.1% of the grids monitored at NSPS landfills following the CA LMR requirements. Only 0.5% of these grids, located at five landfills, resulted in GCCS expansion.

In addition, comparison of grid

- level monitoring results under the Instantaneous and Integrated SEM approaches indicates that 29% of the grids detected using integrated m onitoring were also detected by instantaneous monitoring. Similarly, three of the five landfills that triggered GCCS expansion for integrated monitoring also triggered the expansion requirement due to instantaneous monitoring results. Thus, only two landfills were required to expand the GCCS due to integrated monitoring.

Integrated monitoring can require significant additional effort and cos t, depending on whether a landfill does separate or combined Instantaneous and Integrated SEM. Landfills that conduct Instantaneous and Integrated SEM separately must undertake two separate traverses of the entire landfill, which doubles the time required to conduct monitoring . L andfills that undertake combined monitoring also face increased costs because of the additional time to perform both SEM approaches during a single pass of the landfill . Additional costs are also incurred depending on the method used to develop the integrated emissions estimates.

The result of the integrated monitoring was to identify two additional landfills for GCCS expansion, out of 72 landfills in the data set. Given the significant overlap in monitoring results
and the add itional cost associated with integrated monitoring, integrated monitoring does not
appear cost

- effective.

As discussed in Section 4. 2.2 , the majority of the landfill s that w ere required to expand the GCCS due to Instantaneous SEM monitoring were also identified under the Integrated SEM monitoring

. T his finding indicates that the I nstantaneous SEM requirements are effectively detecting landfills with collection system problems and potential compliance iss ues.N S P S a n d C A L M R C o m p a r a t i v e D a t a

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### 6.2 N E W LA ND FI L LS S U B JEC T T O C A L MR

As discussed in section 3.0, 30 of the 72 landfills in the CA LMR data set (41% of landfills)
were not NSPS sites prior to implementation of the CA LMR . These landfills were brought into
the CA LMR under either the capacity requirement of greater than 450,0 00 tons in place (for active landfills), or the h eat r ate i nput c apacity requirement of 3.0 million British Thermal Units per hour (mmBtu/hr) for closed landfills with both a GCCS that operated after January 1, 1977 and more than 450,000 tons of waste in p lace.

For these landfills, Instantaneous SEM data indicate that the intensive monitoring required under
the CA LMR resulted in detection of a lower percentage of exceedances per acre monitored than was found for NSPS landfills monitoring under NSPS require ments prior to implementation of
the CA LMR. Instantaneous SEM exceedances were detected at only 1.4% of acres monitored

at non

- NSPS landfills under the CA LMR, which is comparable to the detection of exceedances
at 1.6% of acres monitored at NSPS sites following the NSPS requirements. This is a surprising finding, given that the CA LMR require s monitor ing of the surface of the landfill on a 25

- foot
pattern, while the NSPS arequires a less

- intensive 98

- foot pattern.

The effectiveness of penetration moni toring at LMR

- only landfills was also much lower. Exceedances were detected at only 0.6% of the non

- NSPS landfills monitored under the CA LMR. This result is significantly lower than exceedance percentages for NSPS landfills under the NSPS requirements (2.7% of penetrations) or the CA LMR regime (1.5% of penetrations).

In addition, none of the Instantaneous SEM exceedances triggered either the 120

- day expansion requirement or the GCCS expansion requirement

. Further, none of the non

- NSPS landfills covered under the CA LMR detected any i ntegrated SEM exceedances. As a result, not a single

non

- LMR landfills in the data set was required to undertake GCCS expansion.

These monitoring results demonstrate that non

- NSPS landfills are t o o small and/or too old to

warrant intensive monitoring or regulation

. Despite monitoring four times more intensively, these landfills detected a smaller percentage of exceedances. With no evidence of significant
LFG control issue s, the cost of this level of monitoring is too high and the impact of monitoring
on methane emission levels minimal

.