Innovative Cost-Effective Control Device for Wastewater VOC Emissions (As Required by NESHAPs [BWON, HON, MON, MACT] and Other Regulations) Dr. Carl E. Adams, Jr., PE, Senior Author 1 * Dr. Lial F. Tischler 2 Andrew W. Edwards, PE 3 1 ENVIRON International Corporation, Nashville, Tennessee 2 Tischler/Kocurek, Austin, Texas 3 ENVIRON International Corporation, Houston, Texas
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Innovative Cost-Effective Control Device for Wastewater VOC Emissions
(As Required by NESHAPs [BWON, HON, MON, MACT] and Other Regulations)
Dr. Carl E. Adams, Jr., PE, Senior Author1 *
Dr. Lial F. Tischler2
Andrew W. Edwards, PE3
1 ENVIRON International Corporation, Nashville, Tennessee2 Tischler/Kocurek, Austin, Texas3 ENVIRON International Corporation, Houston, Texas
VOC Emissions Regulatory Overview
USEPA NESHAP and State RACT typically require:
− Control of Hazardous Air Pollutants (HAP) or VOC off-gases from
storage vessels & sumps
process vents
wastewater equipment
− ≥ 95% removal of VOC or HAP (98% benzene removal for BWON)
Traditionally accepted Control Technologies Traditionally accepted Control Technologies
− Adsorption (e.g., carbon adsorbers)
− Enclosed combustion (oxidizers & fuel gas systems)
− Scrubbers
− Flares
Vapor Phase Adsorption: Granular Activated Carbon
Thermal Oxidizers: Flare or Gaseous Incinerator
Figure 1. Typical Acceptable Control Devices
ThermalOxidizers
Granular Activated Carbon Canisters
Alternative Control Technology Option Can Substantially Lower Cost
Traditional control disadvantages include
− High capital cost
− High operation and maintenance costs• Carbon regeneration/replacement
• Fuel consumption
• Nitrogen loss• Nitrogen loss
− Operational complexity
Regulations specifically allow for “alternative control technology”
− Must demonstrate equal or better emission reduction
− Must obtain approval of Administrative Authority (i.e., EPA and/or State); e.g., BWON requires demonstration of 98% benzene removal
− Must follow USEPA protocols for approval
What is VOC BioTreat?
VOC BioTreat is the process of qualifying an Alternative Control Device, other than Activated Carbon or Thermal Oxidation, for the biodestruction of regulated biodegradable VOC emissions.
The Alternative Control Device is cost-effectively an existing activated sludge process with emission sources in proximity to WWTP.
VOC BioTreat - an Approved Alternative Control Device
The authors have developed new and improved demonstration methods (protocols):
− Bench-scale BOX Test and Core Column Simulation full-scale confirmation
− Provides more realistic and reliable VOC biodegradation rates than the EPA default methodsthe EPA default methods
− Allows for EPA and/or State approval of VOC BioTreat as equivalent treatment technology
Has been approved as BWON alternative control device
− USEPA has accepted improved BOX Test and Full Scale confirmation methods
− State of Louisiana has issued written approval of approach and Alternative Control status
− All states are expected to “sign off” on USEPA-approved protocols
Figure 2. Basic Overview of Alternative Control Device for a Refinery
A Cost-Effective Solution for the Biodestruction of VOC Emissions
Incorporates protocols presented herein to demonstrate an Alternative Control Device
Confirms the use of existing biological wastewater treatment facilities.
Follows exact EPA requirements and protocols for approval
A Cost-effective Solution for the Biodestruction of VOC Emissions
Conclusively demonstrates co-treatment of gaseous emissions or VOCs and aqueous soluble organics in existing wastewater treatment facilities.
Using these protocols, most activated sludge biotreatment systems can be qualified as an Alternative Control Device to treat biodegradable VOCs.biodegradable VOCs.
It is transferable to other VOC/HAP and other regulations.
Approach: High-Level Assessment
Existing WWTP amenable to the technology?
− Diffused aeration system
− Deep tanks
− Existing blowers have adequate air flow treatment capacity (modification may be necessary)
− Compounds have sufficient solubility (relatively low Henry’s Law constants)
− VOC air volume compatible with WWTP diffused air treatment capacity
Favorable economics?
− Reasonable proximity of VOC sources to WWTP
− Current system O&M costs
− Minimal modifications required to adapt WWTP to technology
VOC BioTreat - The Process
Step 1: High Level Feasibility Evaluation
Step 2: Develop preliminary facility-specific model with assumed biodegradation rate to gauge benzene removal performance requirements and obtain initial Agency concurrence for approach
Step 3: Conduct BOX testing to determine site-specific VOC biodegradation rate and maximize VOC BioTreat effectivenessbiodegradation rate and maximize VOC BioTreat effectiveness
Step 5: Obtain final Agency approval of Alternative Control Device
Step 6: Prepare detailed engineering plan and implement Alternative Control Device solution
Step 1 & 2 must be concluded and favorable before proceeding with the rest of the program.
TOXCHEM+ Is Model of Choice TOXCHEM+ is used on all VOC BioTreat projects
TOXCHEM+ Proprietary model - Hydromantis, Inc.
Approved by EPA for wastewater unit emissions estimates (V.4 is current)
Must input and use EPA (WATER9) physical and chemical properties for VOCs being modeled (TOXCHEM+ has its own database but allows entry of modified chemical properties)allows entry of modified chemical properties)
Advantages− Easy to use interface
− Assumes non-equilibrium for rising air bubbles
− Allows modeling of contaminated gases
Disadvantages− Poor simulation of surface aerator emissions
− Must input WATER9 chemical characteristics to use for inventories, compliance
− May incorporate a questionable KG / KL
Case History
Marathon Petroleum Company Garyville Refinery (MPC)
Garyville, Louisiana
Figure 3. Current/Proposed Benzene Control Devices
MPC requested that ENVIRON develop the protocols to qualify the existing activated sludge system (AIS) as an Alternative Control Device.
Table 1. Economic Impacts for VOC Control Devices MPC-Garyville Refinery WWTP
Process Technology
Cost-Effective Impact
Capital cost ($) Annual Operating Cost ($)
Thermal Oxidizer 600,000 340,000
Granular Activated Carbon (6 carbon canisters on each of two API separators,22 change-outs/yr per API) + Maintenance of a N2 blanket
240,000 500,000
Biological (piping, fans and connection to blowers)
Design Inlet Benzene Concentration to Bioreactor (after mixing with inlet air) = 14 ppbv
Conclusions The information provided herein achieved required benzene removal
goals under maximum stress conditions at the MAP-Garyville site.
The methodology developed and employed have been approved by the state and federal agencies. The methods and results confirm compliance with 40 CFR § 61.340:
These methods delineate more realistic and reliable benzene biodegradation rates (fbio) than the EPA default rates.
The biorates, thus determined, are more representative of full-scale conditions than the typical USEPA approach.
It is premised that any properly configured activated sludge system can be qualified as an Alternative Control Device when qualified with the protocols herein.
Conclusions (cont’d)
The approach, presented herein, is an environmental-friendly, sustainable VOC Control Device
− Negligible additional energy usage
− Minimal carbon footprint
The site-specific benzene biodegradation rate for MPC at Garyville, LA is 29.3 L / g VSS-hr @ 26 oC (22.6 L/gm-hr, corrected to 20 oC).
This value compares to the USEPA default rate of 1.4 L/gm-hr.
The activated sludge system herein provides excellent configuration and flexibility to achieve benzene removals >99+% even under benzene loadings >16 times projected design levels.