www.all4inc.com | philadelphia | atlanta | houston | washington dc so 2 data requirements rule – a...
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www.all4inc.com | Philadelphia | Atlanta | Houston | Washington DC
SO2 Data Requirements Rule – A Proactive
Compliance Approach
Mark Wenclawiak, CCM | [email protected] | 678-460-0324 August 19, 2015
Presented to A&WMA Southern Section Annual Meeting
2 Your environmental compliance is clearly our business.
Agenda SO2 Data Requirements Rule (DRR) Overview Process to Characterize Ambient Air Quality
• Air Dispersion Modeling • Ambient Air Monitoring• Technical Assistance Documents (TADs)
Implications of Upcoming Modeling and Regulatory Policies• Proposed Appendix W changes
Case Study Questions and Open Discussions
4 Your environmental compliance is clearly our business.
Final rule issued August 11, 2015 (40 CFR Part 51, Subpart BB)
Applies to facilities that:1. Emitted 2,000 tons per year (tpy) of actual
emissions during most recent calendar year2. Not located in a nonattainment area3. Discretion to include additional sources
Affected facilities will model or conduct monitoring to characterize ambient air
Who is Subject?
5 Your environmental compliance is clearly our business.
Agencies notify U.S. EPA regional offices on list of SO2 sources by January 15, 2016
Agencies specify whether each source will use monitoring or modeling by July 1, 2016
Air dispersion modeling protocols due by July 1, 2016; analysis due January 13, 2017
Ambient monitoring plans are due by July 1, 2016; monitors operational by January 1, 2017
NOW is the time to react!
When is This Happening?
7 Your environmental compliance is clearly our business.
SO2 Modeling TAD Representative
meteorological data for most recent 3 years
Receptors placed only where an ambient monitor could actually be located
Comparison to Regulatory Modeling
Regulatory Modeling Representative
meteorological data for 5 years
Receptors placed anywhere deemed as ambient air
Rule of Thumb: Maximum ground-level concentration at a distance approximately 10 times stack height in flat terrain
10 Your environmental compliance is clearly our business.
SO2 Modeling TAD Actual emission rates
from past 3 years Characteristics can be
varied on an hourly basis
Use of actual (i.e., current) stack heights only
Comparison to Regulatory Modeling
Regulatory Modeling Potential to emit Can vary emissions
rates – but typically not varied hourly (and could result in permit limits)
Use of GEP, not current stack height
11 Your environmental compliance is clearly our business.
Varying emissions data is intensive and time consuming
Intermittent sources (i.e., emergency generators) only evaluated if operated enough to contribute to 99th percentile
Actual emissions can be an improvement over allowable emissions
June – December 2013: 246 monitors across the U.S. did not collect 1-minute meteorological data due to a lack of funding.
Considerations for DRR Modeled Emission Rates
12 Your environmental compliance is clearly our business.
Pros: • Less costly • Can be less time consuming
Cons: • Determining actual emissions can be challenging • Ongoing compliance demonstrations built into the rule• Facility may not be able to demonstrate compliance
with the NAAQS
Pros and Cons of Modeling
14 Your environmental compliance is clearly our business.
A facility may use a combination of the following:1. Perform dispersion modeling to identify location(s)
of maximum SO2 concentrations• Normalized emissions rate• Rank each receptor for concentration and number of days
when that receptor is the highest for the day for all receptors
2. Install temporary ambient monitors at several locations to identify the location(s) of maximum SO2 concentrations
Steps to Determining Ambient Monitoring Locations
15 Your environmental compliance is clearly our business.
Pros: • More realistic view of ambient SO2 emissions• Future compliance requirements may diminish
Cons: • Capital costs (installation and upkeep) • Time consuming• Noncompliance could mean ongoing monitoring
obligations and more stringent future air permitting obligations
Pros and Cons of Monitoring
17 Your environmental compliance is clearly our business.
Constant maximum emission rate overly conservative• Compounded by combining with observed
monitoring concentrations as background Higher concentrations during periods of SSM
• May 22, 2015 SIP call rule Emission Variability Processor (EMVAP)
• Incorporate varying emissions with Monte Carlo statistical technique; 50th percentile monitored concentration as background
Appendix W proposed changes
Importance of Variable Emissions
18 Your environmental compliance is clearly our business.
What 1-hour background concentration do you add to modeled concentration? • Highest hourly modeled concentration paired with
highest hourly monitored concentration• 3-year average of 99th percentile of maximum daily
(p=0.0001; 1 exceedance every 10,000 days!)• EMVAP and 50th percentile background concentration
Probability of exceedance 0.005; equivalent to 99.5th percentile, compared to 99th percentile form of the standard
Selection of Ambient Air
20 Your environmental compliance is clearly our business.
Chemical plant in the southeast Modeling not previously conducted CEMS data for largest SO2 emitting source, limited
emissions data for other sources Relatively flat terrain in rural setting Next door neighbor is utility power plant
Background
21 Your environmental compliance is clearly our business.
2 tasks• Modeling-based evaluation
Cumulative concentration of plant’s sources relative to the NAAQS
• Monitoring-based evaluation Rank normalized modeling results
Project
22 Your environmental compliance is clearly our business.
Recommendations for mitigating elevated concentrations• Balance with future expansion plans with facility,
particularly PSD projects If not possible, recommend ambient monitoring
locations Outcome
• Modeling shows concentrations below NAAQS*• Expanded scope to include other criteria pollutants
and PTE rates in anticipation of future modeling needs such as a PSD project
Compliance Approach
www.all4inc.com | Philadelphia | Atlanta | Houston | Washington DC
Questions & Open Discussions
Mark Wenclawiak, CCM | [email protected] | 678-460-0324 August 19, 2015