



MEMORANDUM

TO:	Karen Marsh, U.S. EPA/OAQPS/SPPD  -  EPA Office of Air Quality Planning and Standards

FROM:	Eastern Research Group, Inc.
		
DATE:	October 2, 2017

SUBJECT:	CAA section 112(d)(6) Technology Review for the Publicly Owned Treatment Works Source Category
	

This memorandum summarizes the results of an analysis to identify developments in practices, processes, and control technologies that have occurred since the National Emission Standards for Hazardous Air Pollutants (NESHAP) was promulgated for the Publicly Owned Treatment Works (POTW) source category. This analysis is part of the U.S. Environmental Protection Agency's (EPA) review efforts in accordance with section 112(d)(6) of the Clean Air Act (CAA). This memorandum is organized as follows:

      1.0	Introduction
      2.0	Background for the POTW Source Category
      3.0	Sources of Available Control Technology Information
      4.0	Developments in Practices, Processes, and Control Technologies
      5.0	Cost and Environmental Impacts
      6.0	Conclusions
      7.0	References

INTRODUCTION

Section 112 of the CAA requires EPA to establish technology-based standards for listed source categories referred to as NESHAP. These technology-based standards are often referred to as maximum achievable control technology (MACT) standards. Section 112 also contains provisions requiring EPA to periodically revisit these standards. Specifically, paragraph 112(d)(6) states:

      (6) REVIEW AND REVISION.  -  The Administrator shall review, and revise as necessary (taking into account developments in practices, processes, and control technologies), emissions standards promulgated under this section no less often than every 8 years.

To comply with this CAA requirement, EPA conducted a technology review for the POTW MACT standards for major sources. For the purposes of reviewing a MACT standard, EPA considers a "development" in practices, processes, and control technologies to be:

          Any add-on control technology or other equipment that was not identified and considered during development of the original MACT standards.
          Any improvements in add-on control technology or other equipment (that were identified and considered during development of the original MACT standards) that could result in additional emissions reduction.
          Any work practice or operational procedure that was not identified or considered during development of the original MACT standards.
          Any process changes or pollution prevention alternative that could be broadly applied to the industry and that was not identified or considered during development of the original MACT standards.
          Any significant changes in the cost (including cost effectiveness) of applying controls (including controls EPA considered during the development of the original MACT standards).

BACKGROUND FOR THE POTW SOURCE CATEGORY

POTW Description

POTWs receive wastewater streams from a variety of upstream industrial, commercial, and other sources and treat the wastewater prior to discharge to the receiving water body (e.g., river or lake). The HAP emitted at POTW originate in these other facilities. In some instances, the POTW or the facilities that send their wastewater to the POTW for treatment may be subject to pretreatment standards as required in the Clean Water Act (CWA) (40 CFR parts 400 - 471). HAPs emitted from POTW include, but are not limited to, acetaldehyde, benzene, formaldehyde, methanol, methylene chloride, toluene, and xylenes. 

Emissions from wastewater handling and treatment may occur in the wastewater collection and conveyance systems prior to reaching the POTW, during primary treatment operations such as screening or primary clarification, or during secondary or tertiary treatment processes including activated sludge, aeration basins, or disinfection. HAP present in wastewater entering POTW can biodegrade, adhere to sewage sludge, volatilize to the air, or remain in the effluent from the plant discharge to receiving waters. HAP emissions at these facilities occur from kinetic stripping caused by turbulent wastewater flow, aeration stripping caused by the addition of air to wastewater, or evaporation. Emissions occur at treatment units with both turbulent flow and exposure to the atmosphere such as influent waste stream conveyance channels, bar screens, grit chambers, grinders, pump stations, aerated feeder channels, primary clarifiers, primary effluent channels, and primary screen stations.

POTW typically have other sources of emissions on site such as boilers, engines, sewage sludge incinerators, emergency generators, and flares. This equipment contributes a large portion of the total HAP emissions from a POTW, and when combined with the emissions from the wastewater treatment operations may result in the POTW becoming a major HAP source.

POTW Regulatory History

The current POTW MACT standards (40 CFR part 63, subpart VVV) were promulgated on October 26, 1999 and apply to certain POTW that receive industrial wastewater for treatment. A POTW is subject to the POTW MACT standards if all of the following are true: [§63.1580(a)(1-3)]



 You own or operate a publicly owned treatment works (POTW) that includes an affected source (§63.1595);

      (2)	The affected source is located at a POTW which is a major source of HAP emissions, or at any industrial POTW regardless of whether or not it is a major source of HAP; and 

      (3)	Your POTW is required to develop and implement a pretreatment program as defined by 40 CFR 403.8 (for a POTW owned or operated by a municipality, State, or inter municipal or interstate agency), or your POTW would meet the general criteria for development and implementation of a pretreatment program (for a POTW owned or operated by a department, agency, or instrumentality of the Federal government).

In developing the subpart VVV standards, the EPA established two POTW subcategories  -  industrial and non-industrial. An industrial POTW is a POTW that accepts a waste stream regulated by another NESHAP and provides treatment and controls as an agent for the industrial discharger. For instance, an industrial discharger subject to the benzene waste operations NESHAP (40 CFR part 61, subpart FF) complies by using the treatment and controls located at the industrial POTW. A non-industrial POTW is any POTW that is designed to provide treatment (including recycling and reclamation) of municipal sewage and industrial wastewater, is a major HAP source, but that does not meet the definition of an industrial POTW. 

A new, reconstructed, or existing industrial POTW is subject to the control requirements under subpart VVV if it includes an affected source and is required to develop and implement a pretreatment program as defined by 40 CFR 403.8, regardless of whether the POTW is a major source of HAP emissions. A non-industrial POTW is subject to subpart VVV if it is a major source of HAP emissions, includes an affected source, and is required to develop and implement a pretreatment program as defined by 40 CFR 403.8. New and reconstructed non-industrial POTWs have control requirements under subpart VVV, but existing non-industrial POTW have no control requirements. 

There are currently thirteen existing major source POTWs subject to subpart VVV. Six of these facilities were identified prior to rule proposal. These are: Gulf Coast Waste Disposal Authority (GCWDA)'s Bayport Facility, the City of Hopewell, Virginia's Hopewell Regional Wastewater Treatment Facility, the New York City Department of Environmental Protection (NYC-DEP)'s Coney Island Wastewater Treatment Plant and North River Wastewater Treatment Plant, and the Milwaukee Metropolitan Sewerage District (MMSD)'s Jones Island Water Reclamation Facility and South Shore Water Reclamation Facility. The GCWDA Bayport Facility and the Hopewell Regional Wastewater Treatment Facility are considered existing, industrial POTW and the remainder of the POTWs are classified as existing, non-industrial POTW. These existing, non-industrial POTW do not currently have any requirements under the rule. As a result of comments received on the proposed rule, EPA identified an additional seven existing facilities subject to the rule. These are: the GCWDA's 40-Acre and Washburn Tunnel facilities, the City of Omaha's Papillion Creek Wastewater Treatment Plant, the American Bottoms Regional Wastewater Treatment Facility in Sauget, IL, the City of Albuquerque's Southside Water Reclamation Plant, and the Orange County Sanitation District's Huntington Beach and Fountain Valley wastewater treatment plants. These seven facilities are also existing, non-industrial POTW that do not currently have any requirements under the rule.

The emission point types subject to the air emission controls under subpart VVV include but are not limited to: influent waste stream conveyance channels, bar screens, grit chambers, grinders, pump stations, aerated feeder channels, primary clarifiers, primary effluent channels, and primary screen stations, (i.e., all treatment units up to but not including the secondary treatment units). These emission point types are required under subpart VVV to be covered, and, except for the primary clarifier, must vent the air in the headspace to a control device in accordance with the standards for closed-vent systems and control devices in 40 CFR 63.693 (subpart DD). The control system may be either a carbon adsorption system, a condenser, a vapor incinerator, a boiler, a process heater, or a flare achieving 95% destruction efficiency of the HAP. 

The POTW MACT standards include equipment standards as described above and an alternative performance standard for affected emissions points. Under the alternative standard in 40 CFR 63.1586(b), facilities may also comply with the MACT standard by limiting HAP emissions to 0.014 fraction emitted, effectively requiring 98.6% control of incoming HAP. This alternative standard allows the POTW to determine the best method (e.g., pretreatment, covers, or variation in wastewater treatment units), or combination of methods, that will achieve compliance with the HAP fraction emission limit.

Various practices, processes, and control technologies were considered in the development of the POTW MACT standards, including:

          Covers 
          Covers vented to control devices (carbon adsorbers, scrubbers, condensers, thermal oxidizers)
          Pretreatment

SOURCES OF AVAILABLE CONTROL TECHNOLOGY INFORMATION 

To identify developments in practices, processes and control technologies since the current POTW MACT standards were developed in 1999, the following sources of data were consulted:

          RACT/BACT/LAER Clearinghouse
          Subsequent regulatory development efforts
          Section 114 request data provided by POTWs 
          Title V permits
          Minor and synthetic minor permits
          Literature search and review
          Pretreatment Program 

RACT/BACT/LAER Clearinghouse

Under EPA's New Source Review (NSR) program, if a company is planning to build a new plant or modify an existing plant such that criteria air pollution emissions will increase by a certain amount, then the company must obtain an NSR permit. The NSR permit is a construction permit, which generally requires the company to minimize air pollution emissions by changing the process to prevent air pollution and/or installing air pollution control equipment. The terms "BACT," and "LAER" are acronyms for different program requirements relevant to the NSR program. BACT, or Best Available Control Technology, is required on new or modified major sources in areas meeting the national ambient air quality standards (attainment areas). LAER, or Lowest Achievable Emission Rate, is required on new or modified major sources in non-attainment areas. RACT, or Reasonably Available Control Technology, is required on sources in areas that are not meeting national ambient air quality standards (non-attainment areas). BACT and LAER (and sometimes RACT) are determined on a case-by-case basis, usually by State or local permitting agencies.

The EPA established the RACT/BACT/LAER Clearinghouse, or RBLC, to provide a central database of air pollution control technology information (including past BACT and LAER decisions contained in NSR permits) to promote the sharing of information among permitting agencies and to aid in future case-by-case determinations. However, data in the RBLC are not limited to sources subject to RACT, BACT, and LAER requirements. Noteworthy prevention and control technology decisions and information may be included even if they are not related to past RACT, BACT, or LAER decisions. 

The RBLC contains over 5,000 air pollution control permit determinations that can help identify appropriate technologies to mitigate most air pollutant emission streams. It was designed to help permit applicants and reviewers make pollution prevention and control technology decisions for stationary air pollution sources, and includes data submitted by several U.S. territories and all 50 States on over 200 different air pollutants and 1,000 industrial processes.

The RBLC provides several options for searching the permit database on-line to locate applicable control technologies. Our search of the RBLC specified processes in the Waste Combustion and Waste Disposal categories, including: Contaminated Ground Water Treatment, Industrial Wastewater Treatment, Publicly Owned Treatment Works, and Other Waste Water Treatment Processes, with permits dating back to 1990. Our search of the RBLC also specified SIC Code 4952 (Sewage Systems). The search results included the following data fields:

          RBLC ID;
          Facility Name, and State;
          Permit Date;
          Process name;
          Throughput;
          Pollutant;
          Control technology; and
          Percent efficiency of control.

Based on the searches conducted for facilities in the Waste Disposal category and SIC Code 4952, the facilities and processes of interest for the POTW MACT were determined. The relevant results of the search are presented in table 1. Table 1 excludes results for internal combustion engines, boilers, sewage sludge incinerators, and other combustion devices that are not used exclusively for control of emissions from the processes regulated under subpart VVV. Table 1 does include scrubbers, which are typically used for removal of reduced sulfur compounds (most notably hydrogen sulfide (H2S)) from primary and secondary treatment equipment at POTWs for purposes of odor control.


                             Table 1. RBLC Review
                                 Facility Name
                                    RBLC ID
                                  Permit Date
                                    Process
                             Control Technologies
                                 Permit Limits
STORA ENSO North America  -  Water Quality Center
WI-0229
7/29/2004
Industrial wastewater treatment
None specified.
VOC: 78.4 lb/hr
Consolidated Papers Inc.  -  Water Quality Center
WI-0115
10/03/2000
Industrial wastewater treatment (paper manufacturing)
Use of pollution prevention practices that minimize and/or abate spills, escape and/or the emission of VOC'S.
None
North of River Sanitary District (NORSD) NO. 1
CA-0509
5/29/1992
POTW (6 MGD)
Covers for preliminary raw sewage processing.
Incinerator for digester gas.
H2S scrubber, 96% control.

ADM Corn Processing  -  Cedar Rapids
IA-0088
6/29/2007
Industrial wastewater treatment
Enclosed flare, limit H2S concentration of biogas produced to 200 ppmv.
VOC: 98% reduction
SO2: 0.023 lb/MMBtu
SCA Tissue (Menasha)
WI-0215
6/10/2004
Industrial wastewater treatment (fiber prep paper manufacturing)
Techniques and operating practices which promote lowest possible VOC emissions.
VOC: 0.096 lb/ton
STORA ENSO North America  -  Whiting Mill
WI-0205
12/19/2003
Industrial wastewater treatment (paper mill)
Operate using good management practices (no numerical limit).
None
Tyson Fresh Meats
NE-0028
7/02/2003
Industrial wastewater treatment (meat packing) 
Packed bed scrubber and flare.
SO2: 40 tpy
EXCEL Corporation  -  Ft. Morgan
CO-0046
4/27/2000
Industrial wastewater treatment (meat packing)
Sulfur recovery system, low sulfur content water.
SO2: 98% reduction
OSCO Treatment Systems, Inc.
TN-0039
6/12/1990
Industrial wastewater treatment (0.325 MGD)
Incoming storage and treatment tanks covered and vented to a control system consisting of a thermal incinerator (99%) followed by a caustic scrubber (95%).
VOC: 4.3 lb/hr
Hilton Davis Co.
OH-0153
12/18/2001
Wastewater tank at an industrial wastewater treatment plant
Tank must be covered, route vapors to thermal incinerator (95%).
VOC: 17.8 tpy
Southerly Wastewater Treatment
OH-0053
12/18/2001
POTW (400 MGD)
Two packed tower scrubbers.
Control VOC by 85%.
Control H2S by 90%.
VOC: 85% reduction
H2S: 90% reduction
MGD = million gallons per day
lb/day = pounds per day
lb/hr = pounds per hour
lb/MMBtu = pounds per million BTU
tpy = tons per year

Most of the POTWs found in the search of the RBLC database have control technologies and requirements that are less stringent or equivalent to the control requirements in the POTW NESHAP. Many of the control technologies are focused on reducing H2S emissions to control odors, as well as reducing SO2 emissions generated from combusting H2S in control devices such as flares or thermal oxidizers.

Two industrial wastewater treatment plants required more stringent controls than are required in the POTW NESHAP. These facilities (ADM Corn Processing - Cedar Rapids and OSCO Treatment Systems, Inc.) require 98% and 99% control of VOC emissions, respectively. The PSD-BACT requirements for the ADM Corn Processing - Cedar Rapids facility specify that the VOC emissions from the anaerobic digester in the wastewater treatment plant be controlled by 98%. In the case of OSCO Treatment Systems, Inc., the information in the RBLC database indicates that incoming storage and treatment tanks are covered and vented to a control system consisting of a thermal incinerator with a VOC control efficiency of 99%. While the required reductions found in the PSD-BACT requirements for these facilities are more stringent than the requirements of the POTW NESHAP, the control technology is consistent with the cover and control option for new sources under the current rule.

Subsequent Regulatory Development Efforts 

The POTW MACT standards were promulgated in 1999. Since that time, EPA has developed air toxics regulations for additional source categories that emit organic hazardous air pollutants (HAP) from the same types of emission sources that are present in the POTW source category. In subsequent air toxic regulatory actions, EPA consistently evaluated any new practices, processes and control technologies. A review of these subsequent air toxics regulations, including supporting documentation used in the rulemakings, was conducted to determine if any practices, processes or control technologies could be applied to the POTW source category. A description of the standards reviewed, and their requirements, follows.

National Emission Standard for Benzene Waste Operations (40 CFR part 61 subpart FF). This rule was finalized in 1990 and revised in 2000. This NESHAP applies to sources with uncontrolled benzene emissions greater than 10 tons per year (tpy). The rule requires that tanks, containers, drain systems, oil-water separators, and surface impoundments be covered and vented through a closed-vent system to a control device that reduces organic emissions by 95 weight-percent or to a concentration of 20 parts per million by volume. If a vapor recovery system (e.g., a carbon adsorption system or a condenser) is used, it shall recover or control the organic emissions vented to it with an efficiency of 95 weight-percent or greater, or shall recover or control the benzene emissions vented to it with an efficiency of 98 weight-percent or greater. Liquid waste streams must be treated to reduce benzene concentration to 10 parts per million by volume (ppmv) or remove benzene by 99 percent or more on a mass basis.

NESHAP for Synthetic Organic Chemical Manufacturing Industry (SOCMI) sources (HON) (40 CFR part 63, subparts F, G, H, and I). These rules were originally proposed in 1994 and finalized in 2006. These NESHAPs require that process vents, storage vessels, transfer operations, process wastewater streams and equipment at major sources of HAP control any HAP emissions vented from these emission units. Sources must use fixed roofs, covers, and vent piping as appropriate and then route the emissions to a recovery or control device that reduces emissions of total HAP by 98 weight-percent or to a concentration of 20 ppmv, whichever is less stringent. A recovery or control device may include, but is not limited to, absorbers, carbon adsorbers, condensers, incinerators, flares, boilers, and process heaters. 

NESHAP for Off-Site Waste and Recovery Operations (40 CFR part 63 subpart DD). This rule was originally promulgated in 1996 and revised in 2015. This rule applies to major sources of HAPs that are a waste management operation that receive off-site materials or wastewater. The rule requires that tanks, containers, oil-water separators, and surface impoundments be covered and vented through a closed-vent system to a control device. Transfer systems, drain systems, and process vents must be vented through a closed-vent system to a control device. The closed-vent system must be operated either with no detectable emissions, or below atmospheric pressure. Any carbon adsorption system or condenser must recover 95 percent or more by weight of the total HAP in the vent stream. Any vapor incinerator, boiler, or process heater must destroy the total organic compounds (TOC) in the vent stream by 95 weight-percent, or to a concentration of 20 ppmv. 

NESHAP for Pharmaceuticals Production (40 CFR part 63 subpart GGG). This rule was promulgated in 1998 and revised in 2014. The rule requires that storage tanks, wastewater tanks, wastewater impoundments, containers, drain systems, and oil-water separators be covered and vented via a closed-vent system to a control device. The control device must reduce inlet emissions of HAP by 95 weight-percent or greater, or to outlet concentrations less than or equal to 20 ppmv as TOC. An open biological treatment unit treating wastewater with less than 50 ppmv HAP is exempt from these cover and control requirements, but a closed biological treatment system is subject to the control requirements.

NESHAP for Group IV Polymers and Resins (40 CFR part 63 subpart JJJ), NESHAP for Pesticide Active Ingredient Production (40 CFR part 63 subpart MMM), and NESHAP for Polyether Polyols Production (40 CFR part 63 subpart PPP). These three rules were promulgated in 2014, 2002, and 2014, respectively. These NESHAPs require that, for any wastewater stream, the owner or operator of each affected source shall comply with the HON wastewater requirements in 40 CFR 63.132 through 63.147 (40 CFR part 63 subpart G) for each process wastewater stream originating at an affected source.

NESHAP for the Pulp and Paper Industry (40 CFR part 63 subpart S). This rule was originally proposed in 1993, finalized in 1998, and revised in 2000 and 2012. This NESHAP established emission limits and work practice standards for facilities engaged in the production of pulp, paper, or paperboard located at major sources of HAP. This NESHAP requires that affected processes collect and control any HAP vented from these processes. The rule requires the operator to maintain negative pressure at each enclosure or hood opening and that the closed vent system be operated with no detectable leaks. The control device must reduce total HAP emissions by 98 weight-percent or to a concentration of 20 ppmv or less. 

NESHAP for Plywood and Composite Wood Manufacturing (40 CFR part 63 subpart DDDD). This rule was originally proposed in 2003, finalized in 2004, and revised in 2005, 2006, and 2007. This NESHAP established emission limits and work practice standards for facilities engaged in the manufacture of plywood and/or composite wood products located at major sources of HAP. The rule requires that, if a wet control device is used to capture organic HAP in the wastewater from a process, the operator must insure that the HAP is contained or destroyed to minimize re-release to the atmosphere such that the desired emissions reductions are obtained. HAP must be reduced by 90 weight-percent or to 20 ppmv.

NESHAP for the Miscellaneous Organic Chemical Manufacturing (MON) sources (40 CFR part 63 subpart FFFF). This rule was originally proposed in 2002 and finalized in 2006. This NESHAP established emission limits and work practice standards for new and existing MON process units, wastewater treatment and conveyance systems, transfer operations, and associated ancillary equipment located at major sources of HAP. This NESHAP requires that affected equipment control any HAP vented from these sources by routing the vapors to a control device that reduces emissions of total HAPs by 98 weight-percent or to a concentration of 20 ppmv. A control device may include, but is not limited to, absorbers, carbon adsorbers, condensers, incinerators, flares, boilers, and process heaters.

NESHAP for Chemical Manufacturing Area Sources (40 CFR part 63 subpart VVVVVV). This rule was promulgated in 2009 and applies to chemical manufacturing process units located at a new or existing area source of HAP. The standards and compliance requirements for wastewater systems, specified in 40 CFR 63.11495-11498, require that: each process vessel must be equipped with a cover or lid that must be closed at all times, any transfer of liquids to tank cars or railcars must be done with submerged loading, vapor balance, or vented through a closed-vent system to a control device. HAP emissions from process vents must be reduced by at least 95 weight-percent or to less than or equal to 20 ppmv by routing through a closed vent system to any combination of control devices. Any wastewater stream containing partially soluble HAP at a concentration greater than or equal to 10,000 ppmw must be separated into organic and water phases using a decanter, steam stripper, thin film evaporator, or distillation unit to separate the water phase from the organic phase(s). The water phase must be discharged to onsite or offsite wastewater treatment or hazardous waste treatment; and the organic phase(s) must be recycled to a process, used as fuel, or disposed as hazardous waste either onsite or offsite.

National Uniform Emission Standards for Storage Vessels and Transfer Operations, Equipment Leaks, and Closed Vent Systems and Control Devices ("Uniform Standards") (40 CFR part 65, subparts H, I, J and M). These standards were proposed on March 26, 2012. Although the technology review analyses are not based directly on operations in the POTW source category, they are based on chemical manufacturing and refinery processes with similar types of equipment and emissions sources. Thus, it is expected that emissions control and compliance demonstration methods that have been determined to be cost effective for control of one of these emission points would generally be cost effective for similar emission points at POTW facilities. The proposed rule would apply to source categories currently subject to a NESHAP under subparts in 40 CFR part 61 or 40 CFR part 63 or an NSPS under subparts in 40 CFR part 60 that are specifically referenced to part 65 from future rulemakings. The proposed rule would require that all emission vapors be routed through a closed-vent system to a control device that reduces regulated material emissions by at least 98 percent or to an outlet concentration less than 20 ppmv.

A review of the NESHAP standards promulgated after subpart VVV indicate that, the current subpart VVV control requirements are comparable to the requirements in other NESHAPs that apply to major sources of HAP. For existing industrial facilities relying on the POTW to meet their NESHAP standards, the POTW must meet all the requirements of the subject NESHAP. Therefore, if the subject NESHAP were updated, then the POTW would be subject to the updated NESHAP if the POTW is used to comply with the industrial user's NESHAP requirements. New or reconstructed POTWs are required to meet the NESHAP requirements of the industrial facility such as those described above, or the control requirements in subpart VVV §63.1586, whichever is more stringent. 40 CFR 63.1586 requires covers on influent waste stream conveyance channels, bar screens, grit chambers, grinders, pump stations, aerated feeder channels, primary clarifiers, primary effluent channels, and primary screen stations and that the air in the headspace be vented to a control device.

Section 114 Request Data Provided by POTWs 

As part of this technology review, EPA issued an Information Collection Request (ICR), pursuant to CAA section 114, to collect information from POTWs. Available information was requested regarding process equipment, control technologies, point and fugitive emissions, and other aspects of facility operations. POTWs completed the surveys for their individual wastewater treatment plants and submitted responses (and follow-up responses) to EPA.

Major Source POTWs

Ten POTWs that are major sources of HAP responded to EPA's ICR and provided information on their facilities. Three of these major-source facilities indicated the use of air pollution control equipment on the wastewater treatment operations for control of HAP emissions. One facility indicated the use of caustic scrubbers and carbon adsorbers for odor control, but did not claim any control of HAP emissions using these devices.

The GCWDA Bayport Facility (Bayport) is an industrial POTW and subject to NESHAP subpart VVV because it treats wastewater subject to 40 CFR part 63, subpart G (HON). The industrial wastewater is piped to the Bayport facility via the 2.4 mile-long Biosan Pipeline. The Biosan pipeline does not contain junction boxes or manholes along the system. As an industrial POTW subject to NESHAP subparts VVV and G, Bayport is required to reduce the HAPs in the wastewater using either biological processes or control devices. Bayport complies with the requirements of the rules by covering their main lift station (the only primary treatment unit) and routing the emissions vented from the headspace to the second stage aeration basins as feed air for biological treatment. Emissions from certain secondary and tertiary treatment units are controlled using a regenerative thermal oxidizer (RTO).

GCWDA's 40-Acre Facility is an existing non-industrial POTW that is a major source of HAP. This facility provides wastewater treatment for four industrial users. Pretreated wastewater from two industrial users is piped directly to the oxygen activated sludge unit via a closed pipeline system with no openings to the atmosphere. This facility is subject to subpart VVV. Aerial photography shows that these wastewater treatment units are uncovered.
The GCWDA's Washburn Tunnel is an existing non-industrial POTW that is a major source of HAP. This WWTP receives wastewater from several significant industrial users. This facility is subject to subpart VVV. Aerial photography shows that these wastewater treatment units are uncovered.
The Hopewell Regional Wastewater Treatment Facility (Hopewell) is an industrial POTW and subject to NESHAP subparts VVV and S because it treats wastewater from West Rock's (aka Rock-Tenn) pulp and paper mill subject to 40 CFR part 63, subpart S. To comply with 40 CFR 63 subpart VVV and subpart S, a direct pipeline was installed in 2001 for direct discharge of regulated wastewater from West Rock's pulp and paper mill into Hopewell's UNOX System for biological treatment in closed high-purity oxygen aeration basins. The West Rock wastewater stream bypasses the preliminary and primary treatment units and is introduced directly into the UNOX System, which degrades the HAP. The Hopewell permit requires that the UNOX system be operated to reduce and to destroy the affected HAPs present in the regulated wastewater by at least 92 weight-percent. The Hopewell permit also requires that the three grit chambers and Parshall flume be covered and vented to control VOC.
The NYC-DEP's Coney Island Wastewater Treatment Plant (Coney Island) and North River Wastewater Treatment Plant (North River) are existing non-industrial POTWs that are major sources of HAP. Coney Island receives wastewater from one significant industrial user. The January 22, 2016 Title V permit for Coney Island does not contain any control requirements for HAP under subpart VVV. The permit does indicate that odors from all primary treatment processes are controlled by scrubbers or scrubbers followed by carbon absorption. An aerial photo of the site shows that all processes are covered. North River receives wastewater from ninety significant industrial users. The December 20, 2012 Title V permit for North River does not contain any control requirements for HAP under subpart VVV. The permit does indicate that the plant has three (3) two-stage odor control systems. Odors from all primary treatment processes are controlled by wet scrubbers followed by carbon adsorbers. Although an aerial view of this site shows no detail of the treatment plant, it is likely that all processes are covered. 

The MMSD's Jones Island Water Reclamation Facility (Jones Island) and South Shore Water Reclamation Facility (South Shore) are existing non-industrial POTWs that are major sources of HAP. The December 5, 2011 Title V permit for Jones Island does not contain any control requirements for HAP under NESHAP subpart VVV. The April, 2011 Title V permit for South Shore does not contain any control requirements for HAP under NESHAP subpart VVV. Aerial photos of both sites show that all processes are uncovered.

The Orange County Sanitation District's Plant 1 (Fountain Valley) is an existing non-industrial POTW that is a major source of HAP. This WWTP receives wastewater from 147 significant industrial users. There are biofilters, carbon adsorbers, and chemical scrubbers in use on the primary treatment facilities, but these are not used for control of HAP. This facility is subject to subpart VVV as a major HAP source. Aerial photography shows that the primary treatment facilities are covered.
The Orange County Sanitation District's Plant 2 (Huntington Beach) is an existing non-industrial POTW that is a major source of HAP. This WWTP receives wastewater from 104 significant industrial users. There are chemical scrubbers and carbon adsorbers in use on the primary treatment facilities, but these are not used for control of HAP. This facility is subject to subpart VVV as a major HAP source. Aerial photography shows that the primary treatment facilities are covered.

A review of the Section 114 responses from Major Source POTWs did not identify any new developments in practices, processes, or control technologies for reducing emissions of HAP since the rule was originally promulgated in 1999.

Minor Source POTWs

Six POTWs that are minor sources of HAP responded to EPA's ICR and provided information on their facilities. Three of these minor-source facilities indicated the use of air pollution control equipment on the wastewater treatment operations for control of HAP emissions, and three other facilities indicated the use of caustic scrubbers and carbon adsorbers for odor control, but did not claim any control of HAP emissions using these devices.

The St. Louis MSD's Bissell Point Plant (Bissell Point) is an existing non-industrial POTW. Bissell Point receives wastewater from 51 significant industrial users. Although the current Title V permit for this source issued in 2002 indicates that Bissell Point is a major source of HAP and subject to NESHAP subpart VVV, a detailed potential to emit analysis done by the source in 2006-2007 indicates that Bissell Point is a minor source of HAP. The December 26, 2002 Title V permit for this facility does not contain any control requirements for VOC or HAP under subpart VVV or other rules for the primary wastewater treatment facilities. The source indicated in a 2007 letter that there are covers over the trickling filters and primary tank effluent weirs.

The Great Lakes Water Authority's Detroit WWTP is an existing non-industrial POTW that is currently considered a minor source of HAP. This WWTP receives wastewater from numerous significant industrial users. This facility is not subject to subpart VVV. Aerial photography shows that the primary treatment facilities are covered.
The City of San Diego's North City Water Reclamation Plant is an existing non-industrial POTW that is a minor source of HAP. This WWTP receives wastewater from numerous significant industrial users. The ICR response indicates the use of caustic scrubbers and carbon adsorbers to control HAP emissions from headworks, grit removal, and the primary sedimentation and aeration basins. This facility is not subject to subpart VVV. Aerial photography shows that the primary treatment facilities are covered. 

The City of San Diego's Point Loma Wastewater Treatment Plant is an existing non-industrial POTW that is a minor source of HAP. This WWTP receives wastewater from 53 significant industrial users. The ICR response indicates the use of caustic scrubbers and carbon adsorbers to control HAP emissions from headworks, grit removal, and the primary sedimentation basins. This facility is not subject to subpart VVV. Aerial photography shows that the primary treatment facilities are covered. 

The City of San Diego's South Bay Water Reclamation Plant is an existing non-industrial POTW that is a minor source of HAP. This WWTP receives wastewater from 12 significant industrial users. The ICR response indicates the use of caustic scrubbers and carbon adsorbers to control HAP emissions from headworks, grit removal, and the primary sedimentation and aeration basins. This facility is not subject to subpart VVV. Aerial photography shows that the primary treatment facilities are covered. 

The Great Lakes Water Authority's Warren Wastewater Treatment Plant (WWTP) is an existing non-industrial POTW that is a minor source of HAP. This WWTP receives wastewater from 15 significant industrial users. Odorous emissions from the wet well are routed to a chemical scrubber. Odorous emissions from the grit chambers and primary splitter box are routed to a carbon adsorption unit. Aerial photography shows that the headworks, grit chambers, and primary clarifiers are covered.

A review of the Section 114 responses from Minor Source POTWs did not identify any new developments in practices, processes, or control technologies for reducing emissions of HAP since the rule was originally promulgated in 1999.

For more information regarding the responses received from the section 114 requests and how this data was used to conduct risk assessments for the POTW category, please refer to the memorandum entitled "Inputs to the Publicly Owned Treatment Works March 2016 Residual Risk Modeling".

Title V Permits

State and federal websites were searched for major source air permits issued to POTWs. The operating permits were examined for any operating restrictions, emission limits, or control requirements on the wastewater treatment equipment, such as conveyance channels, bar screens, grit chambers, grinders, pump stations, aerated feeder channels, primary clarifiers, primary effluent channels, and primary screen stations. POTWs typically have boilers, process heaters, engines, and emergency generators onsite. Restrictions and limits on these sources were not considered, except in cases where the boilers, process heaters, or engines serve as the control device for any organic vapors vented from processes at the site. Information from the Title V permits are shown in table 2.

A review of available Title V permits for POTW facilities shows that control requirements vary widely across both minor and major sources of HAP. In many permits, there are no control requirements for the wastewater treatment facilities. Six facilities require covers or control of VOC from the wastewater treatment facilities, and these six wastewater treatment plants are all located in urban areas. Only one of the permits (GCWDA Bayport Facility) has specific limits on VOC control efficiencies or has VOC/HAP limits on the wastewater treatment facilities. Several of the Title V facilities use carbon bed adsorbers or scrubbers to control VOC emissions. Nearly all the Title V facilities are using scrubbers to control H2S emissions. 

In summary, the most stringent control requirements found in a review of existing Title V permits issued to POTW facilities are those required by NESHAP subpart VVV.

Minor and Synthetic Minor Permits

State and federal websites were searched for minor source permits issued to POTWs. Since these sources are minor sources of HAP, they are not subject to requirements under NESHAP subpart VVV unless they are an industrial POTW required to develop and implement a pretreatment program as defined by 40 CFR 403.8 (for a POTW owned or operated by a municipality, State, or inter municipal or interstate agency), or if the POTW would meet the general criteria for development and implementation of a pretreatment program (for a POTW owned or operated by a department, agency, or instrumentality of the Federal government). Information from the minor source permits is shown in table 3.




                        Table 2. Title V Permit Review
                            Facility Name and State
                                  Permit Date
                            Subject to Subpart VVV 
                   Wastewater Treatment Processes in Permit
                             Control Technologies
                                 Permit Limits
GCWDA Bayport Facility 
Texas
12/11/2015
Yes. 
Existing, Industrial POTW 
Biosan pipeline (BSPIPE), aeration tanks (GRPPOBTU), and 
main lift station (MLS)
Wastewater treatment units are subject to subparts G and VVV. There are no details on control technologies used.
Limits for wastewater treatment units specified in subparts G and VVV.
Hopewell Regional WWTF
Virginia

10/2/2014
Yes. 
Existing, Industrial POTW
Screening, grit removal, channels, primary clarifiers, aeration (UNOX), secondary clarifiers, and sludge handling.
Grit chamber effluent channels and Parshall flume are covered and vented per a 1996 RACT requirement.
The UNOX system (a closed aeration system) is subject to subpart S, and must decrease HAPs by 92% or more.
Operate UNOX system to decrease HAP in any wastewater containing pulping process condensates (subject to subpart S) by 92%.
St. Louis MSD Bissell Point Plant
Missouri
12/26/2002
No. This is a minor source of HAP.  
Grit removal tanks, grinders, primary settling tanks, sludge holding tanks, ash settling basins, trickling filter pump station, influent pump station, effluent pump station, trickling filters, aeration tanks, and final clarifiers
No control requirements for wastewater treatment units or equipment are listed in the permit. 
No limits for VOC or HAP from wastewater treatment units.

NYC-DEP Coney Island WWTP
New York
1/22/2016
Yes. 
Existing, Non-industrial POTW
Screens, wet well, grit removal tanks, primary settling tanks, primary settling tanks, influent channels, mixed liquor channels, aeration, final settling, and sludge handling.
The water treatment units are controlled by 22 wet scrubbers and 13 carbon adsorbers. The wet scrubbers are used to remove H2S. Two flares burn digester gas. 
Annual VOC and HAP emissions from wastewater treatment processes are estimated using the TOXCHEM+ model.
NYC-DEP North River WWTP
New York
12/20/2012
Yes. 
Existing, Non-industrial POTW
Screens, wet well, grit removal tanks, primary settling tanks, primary settling tanks, influent channels, mixed liquor channels, aeration, final settling, and sludge handling.
The wastewater treatment units are covered and controlled by wet chemical scrubbers and activated carbon absorbers. The wet scrubbers are used to remove H2S. A flare burns excess digester gas.
Annual VOC and HAP emissions from wastewater treatment processes are estimated using the TOXCHEM+ model.
Milwaukee MSD - Jones Island Water Reclamation Facility
Wisconsin
8/26/2013
Yes. 
Existing, Non-industrial POTW
Screening, grit removal, primary treatment, secondary treatment, disinfection, and sludge handling.
No control requirements for wastewater treatment units or equipment were listed in the permit. 
Annual VOC and HAPs emissions from wastewater treatment processes are estimated using the TOXCHEM+ model.
Milwaukee MSD - South Shore Water Reclamation Facility
Wisconsin

8/26/2013
Yes. 
Existing, Non-industrial POTW
Screening, grit removal, primary treatment, secondary treatment,
and disinfection.
No control requirements for wastewater treatment units or equipment were listed in permit. Two flares burn excess digester gas.
Annual VOC and HAPs emissions from wastewater treatment processes are estimated using the TOXCHEM+ model.
City of Warren Wastewater Treatment Plant 
Michigan 
6/15/2016
No. This is a minor source of HAP.
Wet well, grit chamber, primary splitter box, and sludge press.
Wet well is controlled with a scrubber for odor control. Grit chamber and primary splitter box are controlled with carbon adsorption.
No limits for VOC or HAP emissions from wastewater treatment units.
Cedar Rapids WPCF
Iowa
1/1/2014
No. This is a minor source of HAP.
Wastewater treatment plant equipment is not listed, but emission points are listed.
Packed bed scrubbers and carbon scrubbers are used to control H2S emissions from belt filter press and sludge handling. A packed tower chemical scrubber is also used to control H2S emissions.
Two bio-scrubbers are used to control H2S emissions.
Packed bed scrubbers: H2S: 9.4 tpy
Carbon scrubbers: H2S: 9.4 tpy
BioScrubber #1:
H2S: 9.4 tpy
BioScrubber #2:
H2S: 9.4 tpy
Indianola Water Pollution Control
Iowa
5/23/2013
No. This is a minor source of HAP.
Wastewater treatment plant equipment is not listed, but significant emission points are listed.
A digester gas flare controls excess gas from the anaerobic digester.
No limits for VOC or HAP from wastewater treatment units.

Metropolitan WWTP
Minnesota
3/13/2001
No. This is a minor source of HAP.
Screening, grit removal, channels, primary clarifiers, aeration, secondary clarifiers, and sludge handling.
No control requirements for wastewater treatment units or equipment were listed in the permit. 
No limits for VOC or HAP from wastewater treatment units.

Chesapeake-Elizabeth WWTP
Virginia
4/11/2011
No. This is a minor source of HAP.
Screening, grit removal, aeration, clarification, and sludge handling.
Packed tower scrubber controls odors. No control requirements for VOC or HAP emissions from wastewater treatment units or equipment were listed in the permit. 
No limits for VOC or HAP from wastewater treatment units.

Hartford Water Pollution Control Facility
Connecticut
4/1/2013
No. This is a minor source of HAP.
Screening, grit removal, aeration, clarification, and sludge handling.
No control requirements for wastewater treatment units or equipment were listed in the permit.
No limits for VOC or HAP from wastewater treatment units.

Central Contra Costa Sanitary District
California
3/12/2015
No. This is a minor source of HAP.
Screening, grit removal, grinders, settling tanks, aeration, clarification, filtration, disinfection, and sludge handling.
Preliminary and primary treatment units are each controlled with an odor control scrubber.
The sludge blending tanks are controlled with 2 packed tower scrubbers and a biofilter odor control system.
No limits for VOC or HAP from wastewater treatment units.

Union Sanitary District
California
7/29/2004
No. This is a minor source of HAP.
Screening, grit removal, aeration, clarification, and sludge handling.
No control requirements for wastewater treatment units or equipment were listed in the permit.
VOC: 15 lb/day
East Bay Municipal Utility District
California
12/19/2012
No. This is a minor source of HAP.
Headworks, influent pump station, bar screens, grit removal, channels, sedimentation tanks, aeration, secondary clarifiers, activated sludge units, anaerobic digesters, and sludge handling.
Two carbon bed scrubbers control emissions from the headworks, influent pump station and bar screens. Atomized mist scrubber controls odors from sludge handling. Three co-generation engines burn gas from the anaerobic digesters. Four digester gas flares control excess gas from the anaerobic digesters.
Digester flares: VOC: 15 lb/day for each flare
City of Santa Rosa Wastewater Treatment
California
5/20/2013
No. This is a minor source of HAP.
Aeration, sedimentation, clarification, secondary clarification, anaerobic digesters, and sludge handling.
Four engines burn gas from the anaerobic digester. A digester gas flare controls excess gas from the anaerobic digesters.
No limits for VOC or HAP from wastewater treatment units.

Williamsburg WWTP
Virginia
4/11/2011
No. This is a minor source of HAP.
Headworks, influent pump station, bar screens, grit removal, channels, sedimentation tanks, aeration, secondary clarifiers, activated sludge units, anaerobic digesters, and sludge handling.
Packed tower scrubber controls odors. No control requirements for VOC or HAP emissions from wastewater treatment units or equipment were listed in the permit.
No limits for VOC or HAP from wastewater treatment units.
Upper Blackstone Water Pollution Abatement District
Massachusetts
12/7/2009
No. This is a minor source of HAP.
Screening, grit channels, primary
settling tank, influent channel, effluent weirs, and sludge handling tanks.
The wastewater treatment units are controlled with a biofilter. 
The sludge tank is controlled with a carbon filter.
Sludge dewatering is controlled with a biofilter.
Wastewater treatment: H2S: 99% removal
Sludge tank:
H2S: 95% removal
Sludge dewatering: H2S: <0.5 ppmv



                      Table 3. Minor Source Permit Review
Facility Name and State
Permit Date
Process
Control Technologies
Permit Limits
GCWDA - 40-Acre Facility
Texas
3/19/2010
Influent splitter, aeration basins, 2 stabilization basins, equalization basins and 2 facultative basins.
No control requirements for wastewater treatment units or equipment were listed in the permit.
NSR permit limits included for VOC and HAP.
GCWDA Washburn Tunnel Facility
Texas
8/28/2015
Coarse screening, grit removal, clarification, activated sludge treatment system, clarification, skimmer.
No control requirements for wastewater treatment units or equipment were listed in permit. Iron salts are added to prevent release of H2S from the belt filter press.
NSR permit limits included for VOC and HAP.
Detroit Wastewater Treatment Plant
Michigan

1/31/2014
The wastewater treatment process facilities are not listed in the air permit.
No control requirements for wastewater treatment units or equipment were listed in the permit.
No limits for VOC or HAP from wastewater treatment units.
South Milwaukee Wastewater Treatment Facility
Wisconsin
12/21/2012
The wastewater treatment units are not listed in the Registration.
No specific control requirements for wastewater treatment units or equipment were listed in the Registration.
VOCs are limited to less than 25 tpy in this Registration.
Buffalo Waste Water Treatment Plant
Minnesota
9/24/2007
The wastewater treatment units are not listed in the permit.
No control requirements for wastewater treatment units or equipment were listed in the permit.
No limits for VOC or HAP emissions from wastewater treatment units. 

A review of available minor source permits for POTW shows that these plants are generally not required to control VOC. 

Literature Search and Review

Scientific literature was reviewed for control technologies in use at WWTPs and similar sources to control VOC and HAP air emissions. The types of controls and control strategies identified include:

          Cover and control
          Biological treatment
          Other strategies

Cover and Control

Subpart VVV currently allows the use of covers and closed-vent systems that route emissions to a control device as one control option to reduce HAP emissions. Control devices that could be used include flares, thermal oxidizers, carbon adsorbers, or biological treatment, which is discussed in more detail in section 3.6.2. The reviewed literature confirmed this strategy remains viable.

In one study, researchers in Taiwan evaluated various control options, including cover and control as well as the use of activated sludge to treat collected air from oil separators at a refinery. The researchers concluded that the cover and control strategy was optimum for treating the high VOC concentrations (exceeding 10,000 ppmv as CH4) found at primary treatment units such as oil separators, and for the lower VOC concentrations (less than 1,000 ppmv as CH4) found at secondary treatment units, collecting and injecting the exhaust stream into an activated sludge system was recommended.  The Taiwanese Environmental Protection Administration updated their regulations governing VOC emissions in September 2005, legally mandating a seal cover system with the captured stream vented to a control device for primary treatment units at petrochemical WWTPs.

As described in sections 3.1 (RBLC Review), 3.3 (section 114 Responses), 3.4 (Title V Permits), and 3.5 (Minor and Synthetic Minor Permits) of this memo, POTWs commonly cover their processes and route the gas stream to scrubbers, carbon adsorbers, or incinerators/flares. These control trains are primarily used for odor control and to reduce H2S emissions, but in some cases, there are specific requirements for VOC control such as in the case of the RBLC findings for OSCO Treatment Systems, Inc., and the Southerly Wastewater Treatment Plant in Cleveland.

Biological Treatment 

Biological treatment may be used to reduce HAP emissions through the use of covers and a closed-vent system that vents the emissions back into a biological treatment unit. The use of biological treatment in this fashion is similar to the use of conventional control devices (such as discussed in section 3.6.1), but is discussed separately here as a non-conventional control measure unique to wastewater treatment facilities.

There are two main types of biological treatment units for air emissions: those based on using activated sludge/aeration basins to remove VOC and HAP from the foul air vent stream, and those employing biofilters or biotowers (biotrickling filters) to remove VOC and HAP from the foul air vent stream. The former utilizes the air to be treated as feed air into activated sludge tanks or aeration basins, while the latter passes the air to be treated through a filter media such as compost (biofilter) or through a specially designed vessel such as a packed bed where biological microorganisms degrade the VOC and HAP (biotower). 

Activated Sludge: In addition to the Taiwanese study discussed above that indicated the use of activated sludge to control lower VOC concentration streams, other literature identified activated sludge systems as an option for controlling HAP. For example, the Marathon Petroleum Corporation (MPC) refinery in Garyville, Louisiana uses a proprietary activated sludge system to treat benzene emissions to meet the control requirements of the benzene waste NESHAP.  Similarly, researchers in Taiwan studied the use of an activated sludge system to control VOC emissions and observed VOC removal efficiencies of greater than 85% under certain conditions.  One current subpart VVV facility, the Bayport facility in Texas, uses a similar process and complies with the requirements of 40 CFR subpart G (HON) by venting the air in their headspace collection system to the second stage aeration basins as feed air for biological treatment. The Hopewell facility, also subject to subpart VVV, also utilizes a biotreatment application by employing an aeration basin as part of the design of their UNOX system.

Biofilters: Researchers have also investigated biofilters and biotowers (biotrickling filters) as a control technology for air emissions at POTWs. As air passes through the biofilter or biotower, odorous and organic compounds are removed and then oxidized by microbes growing on the filter media. Many of the studies indicated that the use of biofilters or biotowers over chemical scrubbers for odor control has the side benefit of partial VOC control, but that VOC control was not the primary goal in these applications. Biological treatment using biofilters and biotowers has typically focused on odor (H2S) control, resulting in a high level of control for H2S (>95 percent) and relatively lower removals of VOC and HAP (40  -  83 percent).

One group of researchers converted an existing chemical scrubber to a biotrickling filter to control H2S, and noted that "Significant removal of reduced sulfur compounds, ammonia, and volatile organic compounds present in traces in the air was also observed." but did not provide a specific reduction estimate for VOC.   A pilot-scale biofilter constructed at the Hyperion wastewater treatment facility in Los Angeles employed a 2-stage biofilter to remove H2S in the first stage and VOC and HAP in the second stage.   Removal efficiencies utilizing this system resulted in consistently high removal rates for H2S, and varying removal rates for VOCs with some HAPs reduced by 99% under certain conditions.

A study conducted for the Office of Naval Research that involved the construction of a full-scale biotrickling filter to control VOC and odorous air emissions from wastewater load equalization and treatment tanks at the Industrial Water Treatment Plant (IWTP) and the Oil Recovery Plant (ORP) at Naval Air Station North Island in San Diego, California showed H2S removal efficiencies of greater than 99%, and total VOC removal efficiencies of 50%. 

Other Strategies

Several articles reviewed described experimental or unique applications that may be used to control emissions from POTWs. These include the use of non-thermal plasmas (NTP), where researchers used a dielectric barrier discharge applied to two different VOC mixtures resulting in VOC removal between 95 and 100 percent.  Another researcher evaluated the use of titania-based photocatalysis for the destruction of VOC in both the aqueous and air phase. 

The literature search and review did not identify any new developments in practices, processes, or control technologies for reducing emissions of HAP since the rule was originally promulgated in 1999.

Attachment A lists the articles evaluated under this literature search and review.

Pretreatment Program
 
 EPA developed a National Pretreatment Program under the CWA (40 CFR Part 403) to regulate indirect wastewater discharges to POTWs from industries that send their waste streams to the POTW for final treatment prior to direct discharge to a receiving body of water. The National Pretreatment Program requires these industrial users (IUs), to obtain permits to limit certain parameters (pollutant concentration, temperature, pH, etc.) in their effluent prior to discharge of their wastewater to the POTW. Such a permit may specify the effluent quality that necessitates that an IU pretreat or otherwise control pollutants in its wastewater before discharging it to a POTW.
 
 Section 403.8(a) of the CWA's General Pretreatment Regulations provides that any POTW (or combination of treatment plants operated by the same authority) with a total design flow greater than 5 MGD and smaller POTWs in defined circumstances must establish a pretreatment program. Under the Pretreatment Program, POTW subject to the requirement to develop a pretreatment program must identify their industrial users and control, through permits, orders, or other means, the contribution of pollutants to the POTW in order to ensure compliance with all national pretreatment standards and requirements. The industrial discharger must comply with the general requirements and specific prohibitions of EPA's regulations at 40 CFR part 403.5, categorical pretreatment standards spelled out for industrial categories at 40 CFR Subchapter N  -  Effluent Guidelines and Standards, and specific local limits that must be developed in defined circumstances. The specific prohibitions address characteristics of the wastewater streams and include specifications such as flashpoint, pH, solids size (to avoid obstructions), flowrates, and temperature of the wastewater. The specific prohibitions also prohibit "Pollutants which result in the presence of toxic gases, vapors, or fumes within the POTW in a quantity that may cause acute worker health and safety problems." (40 CFR 403.5(b)(7).) The categorical pretreatment standards are specific standards established by the EPA for certain industries. These standards vary in format and can be concentration-based limits, mass limits, production-based limits, best management practices, discharge prohibitions, or a combination of these formats. There are 35 different industries with established categorical pretreatment standards. The third component in the pretreatment requirements consists of the local limits that must be established by the POTW in the circumstances spelled out in the regulations. Local limits may need to be developed to address specific concerns of the POTW, related to the general and specific prohibitions. In addition to ensuring that industrial users' discharges to the POTW do not pass through the POTW and result in the violation of the POTW's discharge permit, such limits may be necessary in the following circumstances: to protect the POTW operations, maintain the POTW's discharge levels, avoid sludge contamination, and ensure worker health and safety. The local limits may be expressed as case-by-case discharge limits, management practices, or specific prohibitions.

While the National Pretreatment Program is not implemented under the CAA, it may effectively limit emissions from POTWs by reducing the initial pollutant load into the POTW. These reductions are reflected throughout the entirety of the POTW, from the collection system to the primary treatment units to any secondary treatment units and finally at any waste (sludge) handling operations.

DEVELOPMENTS IN PRACTICES, PROCESSES, AND CONTROL TECHNOLOGIES

After review of the RBLC, recent regulatory determinations, responses to the section 114 request, air permits for POTWs, relevant literature, and the National Pretreatment Program, pretreatment and covers with controls were identified as technically feasible control technologies for reducing HAP emissions from POTWs.

These control technologies were both considered during development of subpart VVV when it was initially promulgated in 1999; however, the current extent and way these technologies are being used was investigated in this analysis.

A discussion of the current rule requirements for each type of POTW (Non-Industrial and Industrial) and any work practice or operational procedure that was not identified or considered during development of the original MACT standards; or any developments in new practices, processes, or control technologies that were identified during this review follows.

Non-Industrial POTWs 

Existing Non-Industrial POTWs
Summary of Existing MACT Level of Control for Existing Non-Industrial POTWs 

The MACT floor for existing, non-industrial POTW is no control.
Developments in Practices, Processes, and Control Technology for Existing Non-Industrial POTWs 

The use of pretreatment, and covers and control, were investigated with respect to the current practices at existing non-industrial POTWs.

Pretreatment. The National Pretreatment Program was considered when subpart VVV was initially promulgated in 1999; however, it was included in the rule as part of the applicability of the NESHAP and not considered part of the standard. In this analysis, pretreatment was evaluated as a potential component of the standard and not as part of the applicability. 

In the 2015 ICR for the POTW NESHAP, the EPA requested data related to any pretreatment programs the POTW had developed and implemented. All 17 of the POTW that responded to the ICR included information about their specific pretreatment programs, and all six of the sources subject to the POTW NESHAP have pretreatment requirements established for all industrial wastewaters they receive. The pretreatment requirements established by the POTW are based on the National Pretreatment Program, which was developed under the CWA to prevent pollutants from being introduced into a POTW that could interfere with the operation of the POTW, or could be passed through the treatment process and impact the use or disposal of sludge or be discharged to surface waters (40 CFR 403.5).

Because the pretreatment program has the overall goal to reduce "...the presence of toxic gases..." and the specific categorical limits and local limits specifically can reduce certain toxic gases in the wastewater streams, pretreatment will reduce HAP emissions from both the collection systems and the POTW treatment plant operations (including both primary and secondary treatment) by limiting the quantity of HAP in the wastewater before it is even discharged to the collection system or arrives at the POTW treatment plant.

No new practices, processes, or control technologies were identified with respect to the use of pretreatment for the reduction of HAP emissions. 

Covers and Controls. The use of covers and controls has increased since the initial development of the POTW NESHAP. For example, in the original review for the 1999 promulgation of the rule, there was only one POTW that had covers on all primary treatment units. No other covers were identified during the initial development of the rule. During the 2016 review, two POTWs subject to the POTW NESHAP that cover all treatment units to address odor concerns were found, see table 2 and section 3.3. Also, more POTW now have at least some treatment units covered (see table 2 and section 3.3). However, there are two POTW subject to this rule that do not have covers on any treatment units. 

When vented to an add-on control device, the exhaust stream from under a cover may be routed to a caustic scrubber, a carbon adsorber, or to a secondary wastewater treatment unit such as an aeration basin where the exhaust stream is used as feed air for biological treatment. Add-on control devices such as caustic scrubbers and carbon adsorbers are typically used at POTW treatment plants to control odors. While caustic scrubbers are not expected to be effective in controlling volatile HAP, properly designed and operated carbon adsorbers are commonly used in other industries to control volatile organic compounds (VOC) and HAP emissions. However, as installed at POTW to assist in odor control, carbon adsorbers are not typically designed or operated to provide HAP emission reduction.

With respect to cover and control requirements, no new practices, processes, or control technologies were identified during this review.

New or Reconstructed Non-Industrial POTWs
Summary of Existing MACT Level of Control for New or Reconstructed Non-Industrial POTWs

The POTW MACT standard (subpart VVV) promulgated in 1999 requires new or reconstructed non-industrial POTWs to control emissions using one of the following control options: 

          Cover and control - requires covers on the emission points up to, but not including, the secondary influent pumping station or the secondary treatment units. These emission points are treatment units that include, but are not limited to, influent waste stream conveyance channels, bar screens, grit chambers, grinders, pump stations, aerated feeder channels, primary clarifiers, primary effluent channels, and primary screening stations. In addition, all covered units, except primary clarifiers, must have the air in the headspace ducted to a control device in accordance with the standards for closed-vent systems and control devices in §63.693 of subpart DD.
          HAP fraction emission limit  -  requires that the fraction of HAP emitted from all units up to the secondary influent pumping station or the secondary treatment units does not exceed 0.014 of the mass loading of HAP to the POTW.

For purposes of compliance with the HAP fraction emission limit, a POTW may use any combination of pretreatment, wastewater treatment plant modifications, and control devices to satisfy the limit. Therefore, facilities utilizing this option can take credit for HAP reductions achieved through pretreatment programs, biotreatment options such as biotowers or biotrickling filters, for HAP reductions associated with the use of scrubbers or carbon adsorbers used for odor control, or any combination of these options.
Developments in Practices, Processes, and Control Technology for New or Reconstructed Non-Industrial POTWs

No new practices, processes, or control technologies were identified with respect to the use of pretreatment for the reduction of HAP emissions. See sections 3.7 and 4.1.1.2 for more details on pretreatment programs. 

With respect to cover and control requirements, no new practices, processes, or control technologies were identified during this review.

Industrial POTWs

Existing Industrial POTWs
Summary of Existing MACT Level of Control for Existing Industrial POTWs

Existing, industrial POTWs are required to comply with the NESHAP for which the POTW is relied upon to meet the wastewater control requirements of the industrial user (e.g. an industrial user subject to 40 CFR part 61, subpart FF).
Developments in Practices, Processes, and Control Technology for Existing Industrial POTWs

No new practices, processes, or control technologies were identified with respect to the use of pretreatment for the reduction of HAP emissions. See sections 3.7 and 4.1.1.2 for more details on pretreatment programs. 

With respect to cover and control requirements, no new practices, processes, or control technologies were identified during this review. However, the analysis found that processes and practices are being applied differently than anticipated under the current standard. 

Section 63.1585(a) requires that an affected facility comply with the applicable other NESHAP(s), but does not provide for subpart VVV standards to apply to primary treatment units, when those primary treatment units are not affected facilities under the other NESHAP. 

A detailed review of the section 114 responses indicated that the two existing, industrial POTW treatment plants can comply with the other NESHAPs (40 CFR part 63, subparts G and S) without controlling or limiting HAP emissions within the primary treatment units. One POTW complies with HON (subpart G) by covering the main lift station and routing the vented air to the second-stage aeration basins where biological activity consumes HAPs in the wastewater. The other POTW complies with the Pulp and Paper NESHAP (subpart S) by hard piping the pulp and paper wastewater directly to the UNOX basin where biological activity reduces the concentration of HAP in the wastewater. The primary treatment units at this POTW are subject to no standards because compliance with subpart S takes place within secondary treatment units at the POTW.

Although the primary units at the two industrial POTWs were not subject to VVV, the data from their responses to the ICR indicate that one POTW has covers in place over primary treatment the units that meet the standards in 63.1586(a), and the other utilizes a pretreatment program which reduces emissions sufficient to meet 63.1586(b). 

Reviewing the data provided through the ICR, it was recognized that subparts VVV and another applicable NESHAP may not cover the same emission points. Where another NESHAP does not address emission points covered by subpart VVV, subpart VVV would be considered the more stringent regulation.

New or Reconstructed Industrial POTWs
Summary of Existing MACT Level of Control for New or Reconstructed Industrial POTWs

New or reconstructed industrial POTWs are required to comply with the NESHAP for which the POTW is relied upon to meet the wastewater control requirements of the industrial user (e.g. an industrial user subject to 40 CFR part 61, subpart FF), OR the requirements under subpart VVV for new or reconstructed non-industrial POTWs as described above (cover and control or HAP fraction limit), whichever is more stringent.
Developments in Practices, Processes, and Control Technology for New or Reconstructed Industrial POTWs

No new practices, processes, or control technologies were identified with respect to the use of pretreatment for the reduction of HAP emissions. See sections 3.7 and 4.1.1.2 for more details on pretreatment programs. 

With respect to cover and control requirements, no new practices, processes, or control technologies were identified during this review. However, as with existing Industrial POTWs, subparts VVV and another applicable NESHAP may not cover the same emission points. Where another NESHAP does not address emission points covered by subpart VVV, subpart VVV would be considered the more stringent regulation. 

Cost and Environmental Impacts

As discussed in section 4, pretreatment and cover and control were identified as technically feasible for reducing HAP emissions from POTWs but were not considered to be developments in the practices, processes, or control technologies under this review.

The control costs for pretreatment and cover and control are provided in section 5.1. Costs for specifically using biological treatment as the control device when a cover and control system is used is discussed in section 5.1.3. Cost impacts are also described in section 5.2. 

Control Option Costs

Pretreatment

While each POTW currently affected by the rule has a pretreatment program in place, several commenters indicated that they would have to redesign the program at great cost in order to reduce HAP emissions since the National Pretreatment Program does not target HAP. While the EPA recognizes there are certain monitoring and recordkeeping requirements for the POTW under the pretreatment program, such requirements might overlap with requirements through the CWA (40 CFR Part 403). The EPA was unable to determine the additional costs for additional HAP requirements through pretreatment during this review.

Cover and Control

Control costs and cost effectiveness were determined for the cover and control option based on information provided to EPA by POTWs in response to the section 114 request and using established control cost estimation procedures as presented in EPA's Control Cost Manual.  Control options selected for this analysis include a flare, a regenerative thermal oxidizer (RTO), and a carbon adsorber.

To determine control costs and cost effectiveness, the following information was needed:

          HAP emission rate;
          Exhaust stream flow rate;
          Exhaust stream gas composition;
          Area to be covered; and
          Cover costs.

A summary of the data used to derive these key parameter values needed to conduct the cost calculations follows.

HAP emission rate - Based on responses received to the section 114 request, the average HAP emissions from the six respondents was 2.55 tpy. 

Exhaust stream flow rate - Based on responses received to the section 114 request, the number and size of air pollution control devices (scrubbers, biotrickling filters, carbon adsorbers) used at POTWs can vary. Facilities were found to use from one to five devices, with reported air flowrates to each of the devices ranging from 2,800 cubic feet per minute (cfm) to nearly 250,000 cfm. Other than the two large scrubbers controlling the North River WWTP in New York City (which underlies a city park adjacent to the Hudson River), all other control devices have flow rates of 45,400 cfm or less. For purposes of cost estimation, it was assumed that compliance could be achieved for an affected unit with a single control device with a flow rate of 45,000 cfm. This is the size of the San Diego Point Loma wet scrubber controlling "Headworks, Primary Treatment". The headworks and primary treatment facilities are the POTW processes with control requirements in the rule.

Exhaust stream gas composition - A study conducted in California on controlling emissions from the headworks of a POTW indicated "Total VOC concentrations in POTW exhaust air is usually below 10 ppm".  Therefore, the exhaust stream to be controlled was assumed to contain HAPs at a concentration of 10 ppm. The HAP profile for the exhaust stream was assumed to include equal parts methanol, acetaldehyde, chloroform, xylene, toluene, and methylene chloride, which are typical components of POTW waste air as found in the literature. Based on the section 114 responses, methanol, xylene, and acetaldehyde are the highest emitted HAPs at POTWs and constitute over 75% of the total HAP emissions.

Area to be covered - Based on responses received for the section 114 request and analysis of satellite imagery of the six POTWs currently subject to the rule, it is estimated that the average area of the primary treatment units at these facilities is 200,000 square feet. Primary settling tanks and clarifiers comprise the majority of the area needing to be covered.

Cover costs - An engineering course offered at Colorado State University's Engineering Department focuses on the design of municipal wastewater treatment plants and includes information on cover costs. A cost estimating guide is available for the course project, which is to design and estimate costs for the construction and operation of an actual full scale water treatment facility. This cost estimating guide presents a range of fixed cover costs from $12 to $26 per square foot. A value of $26 per square foot has been used in this cost analysis.

Costs for new sources

Table 4 presents a summary of the capital and annual costs and cost effectiveness of covering all primary treatment units and routing collected gases to a control device. Appendix B contains detailed calculations used to derive the control costs and cost effectiveness determinations.

                       Table 4. Control and Cover Costs
                           Cover and Control Device
                                  TCI[a] ($)
                                 TAC[b] ($/yr)
                           Emission Reduction (tpy)
                          Cost Effectiveness ($/ton)
Primary Treatment Units Covered and Flare
                                  $12,800,000
                                  $22,900,000
                                     2.55
                                  $8,960,000
Primary Treatment Units Covered and RTO
                                  $12,200,000
                                  $2,020,000
                                     2.55
                                   $790,000
Primary Treatment Units Covered and Carbon Adsorber
                                  $11,700,000
                                  $2,350,000
                                     2.55
                                   $921,000
  [a] Total Capital Investment
  [b] Total Annual Costs

Costs for existing sources

As discussed in section 4.2.1.2, a cover installed at one facility (on a primary treatment unit that was not subject to requirements under the other applicable MACT or the POTW MACT for primary treatment) with emissions routed to biological treatment reduced emissions from the primary treatment unit. By using this cover and control, the facility demonstrates compliance with the control standard in 63.1586(a) at no additional cost. 

Biological Treatment

Control costs were investigated for biological treatment units used as control devices for gas streams collected under covers. Estimated costs associated with biological treatment is dependent on site-specific considerations and the type and design of the biological treatment unit (activated sludge/aeration basins or biofilters/biotowers). 

Cost for new sources

POTWs typically have biological treatment units to treat wastewater streams. These same biological treatment units can be used to treat gas streams collected under treatment unit covers in certain instances, as the GCWDA Bayport Facility does and as described in section 3.3.1 of this memorandum. The cost for using biological treatment as a control device in this fashion would include the necessary piping and collection equipment needed to route gas streams from where they are collected to the biological treatment, and the cost of covers, which could be as high as 80% of the costs shown in table 4 (see Appendix B).

Although it is anticipated that a new POTW, planning to use biological treatment to treat gas streams, would design their plant to use the same biological treatment unit used for wastewater streams, the costs for installing a biological treatment unit used only to treat gas streams was investigated. 

A review of the literature on cost data associated with biological treatment for VOC control found four studies that considered costs of biotrickling filters. One study in Taiwan estimated control costs to treat VOC emissions from an oil/water separator at a refinery wastewater treatment plant ranging from nearly $3,000/ton using an incinerator to less than $1,000/ton using a deep activated sludge aeration system.  

Three additional studies provided cost data for biotreatment, but did not include sufficient information on emissions to estimate cost effectiveness in terms of $/ton. In one 2000 study, Marc Deshusses and Todd Webster published a paper detailing the construction and operation costs of a full-scale biotrickling filter for VOC control at a wastewater treatment plant. This study demonstrated that, "for an empty bed contact time of 90 seconds, the overall treatment costs (including capital charges) were as low as $8.7/1,000 m[3] air in the case where a nonchlorinated volatile organic compound (VOC) was treated, and $14/1,000 m[3] air for chlorinated compounds such as CH2Cl2."  This study compared the construction and operation costs of biotrickling filters to the costs of conventional thermal oxidation and regenerative carbon adsorption, and concluded that, while costs total treatment costs using regenerative activated carbon was higher than a biotrickling filter, the treatment costs of thermal oxidation and biotrickling filters were similar. The authors also cited another study comparing the costs of biotrickling filters with the costs of a regenerative catalytic oxidizer treating high flow rate waste streams ranging from 10,000 to 60,000 m[3]/hr and concluded that "the competitiveness of biotrickling filtration greatly increases with increasing waste air flow rate and with increasing reactor size."  Finally, an unpublished study examined the costs of using a biotrickling filter as control. The system treated 5,226 m[3]/hr of air and had a control efficiency of 99%. The study estimated the capital and annual operating costs of the biotrickling filter at $150,000 and $185,972, respectively. 

It should be noted that the studies on biotrickling filters estimated their effectiveness and cost for a VOC waste stream. Although the studies were insightful, not all VOC are considered HAP under the CAA. This limited the use of the studies for to determining the cost-effectiveness of a biotrickling filter for control of HAP only. Also, note that these costs do not include the cost for covering the treatment units, which constitute as much as 80% of the costs shown in Table 4 (see Appendix B). These covers would be necessary to capture the gases sent to the biological treatment unit.

Cost for existing sources

POTWs typically have biological treatment units to treat wastewater streams that can be used to treat gas streams collected under treatment unit covers, as described in section 3.3.1 of this memorandum. 
The cost for using biological treatment as a control device in this fashion would include the necessary piping and collection equipment needed to route gas streams from where they are collected to the biological treatment, and the cost of covers, which could be as high as 80% of the costs shown in table 4 (see Appendix B). However, existing POTWs are already meeting the existing and proposed standards; therefore, no additional controls are necessary for existing POTWs; and therefore, no additional costs would apply.

Cost Impacts

As shown in sections 5.1.2 and 5.1.3, costs associated with the installation of a cover and control system to comply with the control requirements for a new or modified source in the rule vary. Cover and control costs are calculated for typical air pollution control devices (Flare, RTO, Carbon Adsorber), with the lowest cost option estimated at $789,524 per ton of pollutant removed annually. The costs of biological treatment are difficult to determine; however, this review did determine that design features and operational practices allow each of the industrial POTW facilities flexibility to show compliance with a fraction emitted standard without proscribing specific control systems.
Conclusions

This memorandum summarizes the results of an analysis to identify developments in practices, processes, and control technologies that have occurred since the NESHAP was promulgated for the POTW source category. This analysis is part of the EPA's review efforts in accordance with section 112(d)(6) of the Clean Air Act (CAA).

Pretreatment 

This analysis found that pretreatment programs are an important practice that have the potential to reduce HAP emissions from both the collection systems and the POTW treatment plant operations (including both primary and secondary treatment) when limits are placed on the quantity of HAP in the wastewater before it is discharged to the collection system or arrives at the POTW treatment plant. Pretreatment has been incorporated into the POTW rule since originally promulgated and no new developments in practices, processes, or control technologies were identified as part of this technology review.

Existing POTWs

The analysis found that while not considered a new development in practices, processes, or control technologies, the use of covers and controls has increased at existing industrial and non-industrial POTWs since the original MACT standards were developed, though not specifically for the control of HAP emissions. When used, covers and controls are typically in place to control odors. Therefore, no new developments in practices, processes, or control technologies were identified for existing industrial and non-industrial POTWs in this review.
Industrial POTWs

The analysis found that for industrial POTWs, compliance with the POTW rule was being achieved by complying with the other applicable NESHAP as described in Section 4.2. The reductions achieved by complying with the other applicable NESHAP could exceed the current level of control required in 63.1585(a), because industrial POTWs must select the most stringent requirements between the other applicable NESHAP and subpart VVV. The analysis found that the POTWs can, and do, comply with both the other applicable NESHAP and subpart VVV and that no new developments in practices, processes, or control technologies were identified for industrial POTWs. 

New POTWs

The analysis found no new add-on controls or practices that indicates that the existing requirements (cover and control or meet the HAP fraction emitted limit) for new POTWs should be revised or that any new requirements should be added.

REFERENCES

Adams, C.E., L.F. Tischler, and A.W. Edwards. 2011. Innovative Cost-Effective Control Device for Wastewater VOC Emissions (As Required by NESHAPs [BWON, HON, MON, MACT] and Other Regulations). Proceedings of the Water Environment Federation. WEFTEC 2011: Session 31 through Session 40, pp. 1679-1700(22)04.

Catton 2016. Cost Estimating, Wastewater Treatment Facility Design - CIVE 437, Colorado State University Engineering Department. Available online at: http://www.colorado.edu/engineering/civil/CVEN4434/resources/costs.html 

Cheng, W., and Fang Y. 2012. Abatement of Gaseous VOCs Using Activated Sludge Systems: Technology Feasibility and Cost Analysis. Sustainable Environmental Research, 22:295-303.

Chou, M., and H. Chang. 2005. Bio-oxidation of Airborne Volatile Organic Compounds in an Activated Sludge Aeration Tank. Journal of the Air & Waste Management Association, 55:5, 604-611.

Chou, M., and W. Cheng. 2005. Gaseous Emissions and Control in Wastewater Treatment Plants. Environmental Engineering Science. 22:591-600.

Converse, B.M., E.D. Schroeder, R. Iranpour, H.H.J. Cox, and M.A. Deshusses. 2003. Odor and VOC Removal from Wastewater Treatment Plant Headworks Ventilation Air Using a Biofilter. Water Environment Research (accepted paper).

Deshusses, M.A. and T.S. Webster. 2000. Construction and Economics of a Pilot/Full-Scale Biological Trickling Filter Reactor for the Removal of Volatile Organic Compounds from Polluted Air. Journal of the Air & Waste Management Association 50:1947-1956.

Easter, C., C. Quigley, P. Burrowes, J. Witherspoon, and D. Apgar. 2005. Odor and Air Emissions Control Using Biotechnology for Both Collection and Wastewater Treatment Systems. Chemical Engineering Journal 113:93-104.

Gabriel, D., and M.A. Deshusses. 2003. Retrofitting Existing Chemical Scrubbers to Biotrickling Filters for H2S Emission Control. Proceedings of the National Academy of Sciences 100:6308-6312.

J.M. Hermann, 2010. Environmental Photocatalysis: Perspectives for China. Science China: Chemistry Vol 53: 1831-1843.

Schiavon M., M. Scapinello, P. Tosi, M. Ragazzi, V. Torretta, and E.C. Rada. 2015. Potential of Non-Thermal Plasmas for Helping the Biodegradation of Volatile Organic Compounds (VOCs) Released by Waste Management Plants. Journal of Cleaner Production 104:211-219.

U.S. EPA, 2016a. 2016. RACT/BACT/LAER Clearinghouse. Available at: http://cfpub.epa.gov/RBLC/.

U.S. EPA. 2016b. Emissions Control for Wastewater Treatment Plant - Final Report, Research Triangle Park, NC.

U.S. EPA, 2002. EPA Air Pollution Control Cost Manual, Sixth Edition. EPA/452/B-02-001. Available at: https://www3.epa.gov/ttncatc1/dir1/c_allchs.pdf

Webster, T.S., and A.P. Togna. 2001. Development of Biotrickling Filters to Treat Sulfur and VOC Emissions. Office of Naval Research, Arlington, VA.


                                       

                        Appendix A - Literature Review
Title
Publication Date
Summary
Relevance
Abatement of gaseous VOCs using activated sludge systems:
Technology feasibility and cost analysis
Sustainable Environmental Research, Volume 22, No. 5. 2012
This study assessed the air exhaustion control of corrugated plate interceptor (CPI) oil separators in
a refinery wastewater treatment plant for biodegradation of volatile organic compounds (VOCs) by deep activated sludge aeration systems. Based on field sampling and laboratory analysis, lipophilic alkanes (900-1,200 ppm as total hydrocarbons (THCs)) were removed by the activated sludge system and only 0.40-0.60 ppm THC VOCs were emitted, and VOC emission factors were 0.055-0.548 g m-3 wastewater using the different calculation approaches.
Use of activated sludge to control petroleum refinery wastewater air emissions.
Bio-oxidation of Airborne Volatile Organic Compounds in an Activated Sludge Aeration Tank
Journal of the Air & Waste
Management Association, 55:5, 604-611 (2005).
This study used an activated sludge aeration tank to treat gas-borne volatile organic compounds.
Use of activated sludge to control VOC emissions.
Construction and Economics of a Pilot/Full-Scale Biological Trickling Filter Reactor for the Removal of Volatile Organic Compounds from Polluted Air
Air & Waste Management Assoc. 50: November 2000
With interest in biological techniques for air pollution control increasing, the costs associated with the construction and operation of biological trickling filters are a fundamental criterion to evaluate the competitiveness of biotrickling filtration over more conventional air pollution control technologies. The present paper compares costs that were evaluated from a conceptual scaleup with data from the construction and operation of a pilot/full-scale biotrickling filter. The results are placed in a general perspective for the deployment of large biotrickling filters.
Use of a biological trickling filter to control chlorinated and nonchlorinated VOC air emissions.
Co-treatment of H2S and Toluene on a Biotrickling Filter
Chemical Engineering Journal May 2002
This paper examined biological treatment of VOC and H2S in wastewater using two identical biotrickling filters, one operated at pH 4.5 and the other one was operated at pH 7.0. Microbial counting and activity measurements indicated the development of different microbial populations in the reactors. Overall, the results presented indicated that effective co-treatment of H2S and VOCs can be obtained in a single-stage biotrickling filter.
Use of a biotrickling filter to control H2S and VOC emissions.

                        Appendix A - Literature Review
Title
Publication Date
Summary
Relevance
Development of Biotrickling Filters to Treat Sulfur and VOC Emissions
Office of Naval Research January 2001
The objective of this Phase II Option Small Business Innovation Research project was to design, construct, install, and measure the effectiveness of a full-scale biotrickling filter (BTF) to treat volatile organic compounds (VOCs) and odorous (sulfur) air emissions from wastewater load equalization and treatment tanks. H2S removal is 99% and VOC removal is 50%.
Use of biotrickling filters to control H2S and VOC emissions.
Developments in odour control and waste gas treatment biotechnology; a review
Biotechnology Advances 19 (2001)
Waste and wastewater treatment processes produce odors. Waste gases from industry have traditionally been treated using physicochemical processes, such as scrubbing, adsorption, condensation, and oxidation, however, biological treatment of waste gases has gained support as an effective and economical option in the past few decades. One emergent technique for biological waste gas treatment is the use of existing activated sludge plants as bioscrubbers, with no requirement for additional units or for interruption of wastewater treatment.
Use of existing activated sludge system to control odors (sulphurous and organic compounds).
Environmental Photocatalysis: Perspectives for China
Science China: Chemistry Vol 53, No. 9. September 2010
This paper examines the use of photocatalysis in water treatment facilities for the degradation of organic and inorganic compounds, as well as pathogenic organisms. Photocatalysis induces mild oxidations in the absence of water by generating active neutral atomic O* species. Air pollutants can also be destroyed, especially all the VOC's (volatile organic compounds), providing certain air humidity enabling titania to produce cracking OH:: radicals.
Other strategy using titania-based photocatalysis to control VOC emissions.


                        Appendix A - Literature Review
Title
Publication Date
Summary
Relevance
Gaseous Emissions and Control in Wastewater Treatment Plants
Environmental Engineering Science, Vol. 22, No. 5, 2005
Gaseous emissions at 14 wastewater treatment plants (WWTPs) were sampled for various manufacturing processes in Taiwan. The current control methods for gaseous emissions from WWTPs were thoroughly evaluated in this study, and resulted in the recommended use of a system of sealed covers, connected by suction to a purification facility, as the optimal technology for controlling VOC emission from WWTPs. This study also recommended collecting emissions with wide-ranging concentrations (100 - 1,000 ppmv as CH4) from the neutralization and biotreatment stages and then injecting them into the activated sludge basins via blowers.
Use of a system of sealed covers, connected by suction to a purification facility (i.e. an incinerator), as the optimal technology for controlling primary treatment VOC emission from WWTPs. Also mentions covering secondary treatment units and routing to the activated sludge basin.
Gaseous Emissions from Wastewater Facilities
Water Environment Research, 2010 Literature Review
A review of the literature published in 2009 on topics related to gaseous emissions from wastewater facilities is presented. This review is divided into the following sections: odorant emissions from wastewater treatment plants (WWTPs); greenhouse gas (GHG) emissions from WWTPs; emissions from collection systems; physicochemical emission control methods; biological odor control methods; odor monitoring; and odor impacts.
Use of biofilters to control odor (H2S and organics).
In-Situ Oxygenation System for Volatile Compound Emission Control
NYSERDA February 2002
This project's objectives were to build and test a new oxygenation system (In-Situ Oxygenation System- ISO) that limits the emission of volatile organic compounds to the atmosphere and provides energy efficient aeration. Based on the aeration requirements of a 2mgd wastewater treatment plant, the ISO system would save $201,000 as compared to a surface aeration system and $310,000 as compared to diffused bubble aerators. The ISO system reduced MEK emissions by 99.5%. 98% of the oxygen introduced into the wastewater was consumed or remained in the effluent.
In-Situ Oxygenation System to control VOC and HAP emissions.


                        Appendix A - Literature Review
Title
Publication Date
Summary
Relevance
Innovative Cost-Effective Control Device for Wastewater VOC Emissions (As Required by NESHAPs [BWON, HON, MON, MACT] and Other Regulations)
Proceedings of the Water Environment Federation, WEFTEC 2011: Session 31 through Session 40, pp. 1679-1700(22) http://la-awma.org/files/2009_3-3.pdf
This presentation discusses biological methods for removing VOC from wastewater. The method treats gaseous VOC emissions and aqueous soluble VOC in the water by using an activated sludge biotreatment. Discusses the economic Impacts for VOC control devices for the MPC-Garyville Refinery WWTP to biodegrade benzene.
Use of bioreactor to control VOC emissions.
Literature Review of Air Pollution Control Biofilters and Biotrickling Filters for Odor and Volatile Organic Compound Removal
Environmental Progress (Vol. 24, No. 3) October 2005
A literature study was conducted to compare the feasibility of biofilters and biotrickling filters for the treatment of complex odorous waste air containing hydrogen sulfide (H2S), organic reduced sulfur compounds, and chlorinated and nonchlorinated volatile organic compounds (VOCs). About 40 pilot-plant studies and full-scale applications at wastewater treatment plants and other facilities were reviewed. Reactor design and pollutant removal efficiencies were summarized in tables for easy reference and for a perspective on the current state of the art, and to allow comparison between different projects. The survey indicated that both biofilters and biotrickling filters are capable of combining a high H2S and odor removal efficiency with VOC removal. 
Use of biofilters and biotrickling filters to control H2S and VOC emissions.
Odor and air emissions control using biotechnology for both
collection and wastewater treatment systems
Chemical Engineering Journal 113 (2005)
This paper reviewed data collected on biotechnology-based odor and air emissions control performance over the last 4 years to track performance of various biofilters and biotowers. The data show that, while control of other air emissions such as overall VOC and HAP is feasible, typically removal efficiencies of VOC and HAP are lower than those observed for typical odorous compounds such as H2S.
Use of biofiltration to control H2S, VOC, and HAP emissions.

                        Appendix A - Literature Review
Title
Publication Date
Summary
Relevance
Odor and VOC Removal From Wastewater Treatment Plant Headworks Ventilation Air Using a Biofilter
Water Environment Research 2003
Laboratory scale experiments and field studies were performed to evaluate the feasibility of biofilters for sequential removal of H2S and VOCs from wastewater treatment plant waste air. The biofilter was designed for spatially separated removal of pollutants in order to mitigate effects of acid production resulting from H2S oxidation. In field studies performed at the City of Los Angeles' Hyperion Treatment Plant, excellent removal of H2S, moderate removal of non-chlorinated VOCs such as toluene and benzene, and poor removal of chlorinated VOCs were observed in treating the headworks waste air. Biofilters offer a distinctive advantage over chemical scrubbers currently employed at publicly owned treatment works; they not only remove odor and H2S efficiently at low cost, but also reduce overall toxicity by partially removing VOCs.
Use of biofilters to control H2S and VOC emissions.
Potential Control Strategies to Reduce Emissions from Refinery Wastewater Collection and Treatment Systems
California Air Resources Board May 2004
This is an initial assessment of the wastewater systems for the (California) Bay Area refineries. This assessment was conducted to determine whether there are significant potential emission reductions from control of uncontrolled components of refinery wastewater collection systems. The assessment examined the wastewater system for the refineries to identify the potential for further VOC emission reductions from drains and junction box vents.
Use of water seals on drains to control VOC and HAP emissions from collection systems at refineries.


                        Appendix A - Literature Review
Title
Publication Date
Summary
Relevance
Potential of non-thermal plasmas for helping the biodegradation of volatile organic compounds (VOCs) released by waste management plants
Journal of Cleaner Production 104 (2015)
This paper investigates the feasibility of exploiting a non-thermal plasma (NTP) to treat the gaseous effluents released by the mechanical-biological treatments (MBTs) of waste and overcome the typical disadvantages of biofilters, whose removal efficiency is limited during acclimatization of bacteria, peaks of pollutant concentration or unstable airflow rates. The study concluded that NTPs can be considered as a promising technology to help the biodegradation of VOCs in facilities where biofilters are used as APC systems.
Other strategy using non-thermal plasma to control VOC emissions.
Retrofitting existing chemical scrubbers to biotrickling filters for H2S emission control
Proceedings of the National Academy of Sciences 2003, 100. May 2003
This study converted an existing full-scale chemical scrubber to a biological trickling filter and showed that effective treatment of hydrogen sulfide (H2S) in the converted scrubber was possible even at gas contact times as low as 1.6 s. That is 8 - 20 times shorter than previous biotrickling filtration reports and comparable to usual contact times in chemical scrubbers. Significant removal of reduced sulfur compounds, ammonia, and volatile organic compounds present in traces in the air was also observed. This study demonstrates that biotrickling filters can replace chemical scrubbers and be a safer, more economical technique for odor control.
Converting an existing chemical scrubber into a biotrickling filter to control VOC and HAP emissions.

                        Appendix A - Literature Review
Title
Publication Date
Summary
Relevance
Technical and economical analysis of the conversion of a full-scale scrubber to a biotrickling filter for odor control
Water Science and Technology Vol 50 No 4. 
2004
This study evaluated the technical and economical feasibility of converting wet chemical scrubbers to biotrickling filters for H2S control at the Orange County Sanitation District (OCSD), California. The reactor was operated at a gas contact time of 1.6 to 2.2 seconds reaching H2S elimination capacities up to 105-110 g H2S m - 3 h - 1, consistently maintaining outlet concentrations well below the regulatory limits (24 h average of 1 ppmv) and demonstrating to be very robust against temporary changes. Also, a cost-benefit analysis of the conversion was performed. Savings from chemicals, energy and water usage compared to a chemical scrubber operated in parallel to the biotrickling filter throughout the project indicated that the payback time of the conversion was about 1.3 years. The cost analysis suggests that there is a significant benefit of converting chemical scrubbers to biotrickling filters over a wide range of operating conditions.
Converting an existing chemical scrubber into a biotrickling filter to control H2S emissions.
The effects of a lower irrigation system on pollutant removal and on the microflora of a biofilter
Environmental Technology
Vol. 30, No. 6, 
May 2009
Moisture control is one the most important parameters in biofilters for air pollution control. Overall, this study demonstrates enhanced pollutant removal in biofilters equipped with a lower irrigation system through a better control of moisture.
Use of biofilter to control HAP (toluene) emissions.
Wastewater VOC Emissions
AWE International
September 2013
This article outlines new wastewater emissions protocols that are providing a cost effective approach with reduced environmental impact.
Use of activated sludge to control VOC and HAP emissions.



                                       
Appendix B  -  Control Cost Workbook ("POTW Technology Review Memo Cost.xlsx")
