Ethanol Plant Emissions

Modern ethanol plants have been designed to incorporate a variety of emission control equipment to make the plants safe, efficient, and to control potential pollutants. It is important for project developers, and regulatory officials, to be familiar with the regulated pollutants.

Plant emissions may vary depending on process, design, plant type and feedstock. The typical ethanol production process includes feedstock delivery to the plant, feedstock handling and milling. During this process, tiny particles (particulate matter less than 10 microns in diameter, called PM10) are released into the air. PM10 is also emitted during the drying process. During fermentation, distillation and drying, volatile organic compounds (VOCs) are released. Some VOCs are known as hazardous air pollutants (HAPs). These include some or all of the following: acetaldehyde, acrolein, ethanol, formaldehyde, 2-furaldehyde, methanol, acetic acid and lactic acid. Potential emissions of these compounds must be measured and appropriate controls included in plant design regardless of the biofuel technology being considered. Carbon monoxide, nitrogen oxides, and sulfur oxides are also generated from combustion in the boilers at the plant. Carbon monoxide may also be generated in the drying process if such a process is included in the plant design. Modern emissions control equipment is included in most plant designs. However, potential emissions must be calculated and appropriate control strategies included in permit applications.

Other emissions may result from activities not associated with the production process. These may include: hydrogen sulfide and VOCs released from the wastewater treatment process; PM10 from the cooling towers; fugitive PM10 and VOC emissions from haul road traffic and equipment leaks, respectively; PM10, NOx, SOx, CO and VOCs from emergency equipment; and potential VOC evaporative loss emissions from the wet distillers grains solid storage piles if dryers are not in use at the plant.

Air Quality Permits
Virtually every state has enacted air quality regulations that require facilities with the potential to emit air pollutants above specified levels to obtain construction and/or operating permits. State regulations may vary in terms of permit requirements and the time-frame for authorizing and issuing permits. The project development team should confirm that the engineering firm or permit consultant with whom they may contract for these services is properly licensed in the state. The project development team should also review applicable work of the prospective firm(s) to determine relevant experience in these important areas. The project team should maintain an awareness of permit conditions and requirements that may affect plant operations initially, and in the future if plant expansion is contemplated.

Construction Permits
Before a new plant is built or an existing facility expands or modifies its plant, an air quality construction permit may be required. There are two types of construction permits: state and federal, known as Prevention of Significant Deterioration (PSD) permits. The type of construction permit needed will depend on the air pollutants that could be released from the new plant or expansion project.

Purpose
First and foremost, air quality construction permits are needed to protect the ambient air quality. Ambient air is the air outside of buildings that the general public has access to. The U.S. Environmental Protection Agency (EPA) has developed national ambient air quality standards (NAAQS) to protect the public health, welfare, and the environment. Predictive computer modeling is conducted prior to issuing construction permits to evaluate the potential impact the plant will have on the ambient air quality. A construction permit cannot be issued if the plant will cause or significantly contribute to violations of the ambient air quality standards. Construction permits also impose federally enforceable requirements that are recognized by the EPA.
Construction permits include emission and/or production limits that ensure air quality protection. The permits contain recordkeeping, reporting, monitoring, and testing requirements to ensure the plant is able to demonstrate that the permitted limits are met. The public is given notice that a construction permit may be issued and is given an opportunity to comment on activities that affect their environment. The public notice also provides an opportunity for communities to be educated about the environmental impacts of plants locating in their area.

State Construction Permits
Many states have had air quality construction permits in place since 1972 or earlier. In recent years, state permit requirements have been modified to reflect changes in the Clean Air Act Amendments of 1990. Facilities are typically required to obtain a construction permit before they construct, reconstruct or modify any air contaminant source or emission unit where there is a net increase in the potential-to-emit above prescribed quantities. Potential-to-emit (PTE) means the maximum emissions that would result from operating the source at full capacity 24 hours a day, 7 days a week, 52 weeks a year taking into consideration federally enforceable requirements.

Federal Construction Permits
EPA developed the federal construction permit program, known as the New Source Review Program, in 1977. Many states have incorporated the federal program into the state regulations and thereby maintain the authority to implement and enforce these rules. This program assures the following:

• economic growth will occur in harmony with the preservation of existing clean air resources;
• public health and welfare will be protected from adverse affects which might occur even at pollution levels below the ambient standards; and
• air quality in areas of special natural recreation, scenic, or historic value, such as national parks and wildlife areas, will be preserved, protected and enhanced.
  

Under the New Source Review program there are two types of preconstruction permits. In areas that have pollution levels below the NAAQS, referred to as attainment areas, sources that meet the appropriate criteria will obtain a Prevention of Significant Deterioration (PSD) permit. In areas that have pollution levels above the NAAQS, referred to as nonattainment areas, sources meeting the appropriate criteria will obtain a nonattainment New Source Review permit.

In order for a facility to trigger the emission levels that require a PSD or New Source Review construction permit, they must meet both of the following criteria:

1) The facility must have the PTE of: 100 tons per year (tpy) of any criteria pollutant (PM10, NOx, CO, VOCs (used as an alternative to ozone), and Pb) if the source is one of 28 specific source categories listed in the PSD rules (40 Code of Federal Regulations (CFR) §52.21 (b)) OR 250 tpy of any criteria pollutant for sources not specifically listed in the PSD rules, and
2) Have net emissions increases of: 15 tons per year (tpy) of PM10, 40 tpy of SO2 or SO3 or any combination thereof, 40 tpy of NOx (calculated as NO2), 40 tpy VOC, 100 tpy CO, or 0.6 tpy Pb (lead).

Other pollutants with significant thresholds include total suspended particulate (TSP), fluorides, sulfuric acid mist, hydrogen sulfide (H2S), total reduced sulfur (TRS), and reduced sulfur compounds.

Chemical process plants are considered a major stationary source. It has been determined that ethanol plants are chemical process plants, so they are subject to the major stationary source requirements and the 100 ton per year threshold. A determination regarding production of other biofuels should be made during consultation with state permitting authorities. If a plant must obtain a construction permit under the PSD program, it must conduct a control device review and install BACT based on that review. The plant must also conduct an air quality review using computer modeling to assure that they will not exceed the NAAQS or impact areas of special natural recreation, scenic, or historical significance. As part of the air quality review, an increment analysis must also be performed. Increment is the portion of the ambient air that a facility is allowed to impact. This ensures each facility doesn’t excessively pollute the air and
affect future growth in the area. PSD permits may be subject to review by EPA, federal land managers, bordering states, and tribal organizations.

Operating Permits
An ethanol plant or any other type of biofuels plant may also need to obtain an air quality operating permit. There are two types of operating permits: major source (federal program) and minor source (state program). Again, the potential emissions from the plant will determine whether a facility must obtain a major or minor operating permit.

Purpose
The federal operating permit program, known as the Title V program, was created by the Clean Air Act Amendments of 1990 and was designed to create a "one stop" permit. The Title V operating permit compiles all of the applicable state and federal regulatory requirements, existing construction permit provisions, and recordkeeping, reporting, testing, and monitoring requirements into one permit. The intention behind listing everything in one permit is to assist facilities with maintaining compliance. Often times, a facility will have several construction permits for several pieces of equipment and it is difficult to keep track of all of the requirements in each permit. One permit with all of the facility’s requirements is intended to make it easier to track the requirements.

Public notification is also an important aspect of the operating permit program. The public is notified when an operating permit is proposed and is given the opportunity to comment during the 30-day public notice period. This gives the public the opportunity to become educated about the impacts that the facility may have on their environment. Many states have implemented comprehensive operating permit programs for facilities emitting certain air pollutants. Several states have taken the operating permit program one step further than the federal Title V operating permit program. The federal program only regulates larger facilities (or major sources) of air pollution while some state operating permit programs regulate both larger and smaller facilities (or minor sources) of air pollution.

Unlike a construction permit that must typically be obtained prior to construction and is generally valid for the life of the emission unit, an operating permit must usually be applied for within some period, often 2 months, after the facility begins operation. The operating permit may be issued for a specific period of time rather than the life of the operating unit. Project developers should contact state regulatory officials to determine specific permit requirements for the proposed project.

Permit Process
Project developers should take steps to understand the time requirements of the various permits required by federal, state and local authorities. Permits dictate the pace of project development, and permit conditions may affect the operating parameters of the plant. Permits are typically filed on behalf of the ethanol project development group by an environmental consulting firm. As noted previously, project developers should understand the time commitment for permit applications and the process that governs the review and content requirements of the applications. The best source of information is typically the regulatory agency staff. Staff members can provide details about specific information required for the proposed project.

General information about which the project developers should be aware is listed below.

• Is it a new source or modification of an existing source?
• If it is a modification, has the applicant provided information regarding the existing source?
• Are all of the applicable forms complete with the appropriate information?
• Have emission points been identified, described, and consistently named?
• Does the plant diagram show heights and locations of all buildings, delineations of ambient air (e.g. property boundaries), and emission points?

Emissions Information

• Are fuel types, fuel use, raw production materials, consumption, production rates, and operating schedules provided?
• Have both actual and potential emissions of regulated air pollutants been provided?
• Have the assumptions and calculations of the actual and potential emissions been included?
• Are citations of emission factors included?
• Can a major or minor source determination be made?
• Is the project subject to Prevention of Significant Deterioration (PSD) review?
  

Control Methodology and Equipment

• Has emission control equipment been identified and described?
• Is supporting information on control equipment efficiencies included?
• Did the facility propose limits on plant operation or work practices that may affect emissions?
• If it is a PSD project, has a Best Available Control Technology (BACT) analysis been provided?
  

Monitoring, Recordkeeping, and Reporting

• Have compliance monitoring devices or activities been identified and described?
• Has the facility proposed testing of any emission units?
• Did the facility provide information on existing or proposed recordkeeping practices?
  

Modeling

• Is the project subject to modeling?
• If yes, has a modeling protocol been submitted and approved?
• Have the modeling inputs, assumptions, etc. been provided to the state regulatory agency on CD or diskette?
• Was the modeling conducted in accordance with the approved protocol?
• If it is a PSD project, have the ambient standards, PSD increment, and other impacts analyses been provided?
  

After a draft permit is filed, reviewed and approved, it is prepared for public notice. The public notice period generally includes an opportunity for public comments or public hearings. Project developers are advised to be attentive to potential sources of dissent and to take steps to mitigate concerns and questions about the project prior to the comment period. The permit process can be a lengthy period during which technical and community issues are discussed with project developers, technical consultants, regulatory officials and community representatives.

Permit Application Tips
State regulatory officials understand there is a significant volume of information required in construction and operating permit applications. In addition, wastewater treatment and drinking water permits will likely be required. Several tips that may make the process go more smoothly include:

• Start early. Recognize the permit requirements and the time frame for permit issuance by federal, state and local authorities.
• Talk with the regulatory agency staff. Communication is a key to a successful permitting process.
• Make sure the permit application is complete and accurate. If plans change after you have submitted permit applications, you have an obligation to submit updated information, or face the risk of delays.
• Address confidentiality issues appropriately, if such issues are important.
• Include calculations and citations with your permit application. This information will assist the regulatory staff during permit review.
• Research. Generally, ethanol plants are subject to various federal standards as well as state regulations. Federal requirements could influence your decisions regarding plant equipment. The issue of dryers at the plant is a recent example of permit issues influencing equipment choices.
• Be aware of current regulatory issues. As the ethanol industry continues to expand throughout the nation and more emissions data is gathered, state agencies face new and often times challenging issues. Many of these issues are best dealt with during the early planning stages of the project.
• Again, communication with state regulatory officials will help the project development group address these issues.
• Get help. Although not required, state regulatory officials generally suggest that plant developers consult with people or companies that are familiar with the specific state requirements for permitting an ethanol plant. A qualified consultant that is familiar with the process and professional staff can help minimize the cost and time required for successful completion of the permit process. Familiarity and professional relationships can help move the permit process toward a successful completion in a timely fashion.
  

Permit Content
Construction permits and operating permits generally consist of the same basic elements. Each permit will contain general and specific conditions. Project developers should be generally familiar with the content and conditions of the permit. Working with and communicating with a qualified consultant is essential to this process. State regulatory officials can provide precise information about permit requirements.

Other Permitting and Compliance Issues
State regulatory officials monitor compliance of ethanol plants and other biofuel production facilities but compliance responsibilities ultimately rest with the plant owners and operators. Compliance issues can arise when the plant is constructed or operated in a fashion that differs from the conditions in the construction permit or operating permit. Common violations include failure to perform emissions testing, testing late, exceeding emissions or production limits, failure to keep adequate records, failure to submit required reports on time, and failure to conduct and keep records of control equipment maintenance. Following are a few tips that can help a facility maintain compliance, and reduce the potential for adverse economic consequences that may impact the plant owners.

Compliance Tips

• Read and reread permit on a routine basis.
• Understand permit requirements.
• Keep records in one place and in a logical order.
• Properly operate and maintain control equipment.
• Designate an "environmental manager" and train a backup.
• Ask state regulatory officials questions in order to get necessary information and to avoid misunderstandings and mistakes.
• Plan ahead!
• As noted, state and local regulatory agencies are the best source of information that is specifically applicable to an ethanol plant in the area. Information about federal permit requirements can be obtained from regional EPA offices and by visiting the EPA web site located at: http://www.epa.gov/.

From "A Guide for Evaluating the Requirements of Ethanol Plants", Developed by the Clean Fuels Development Coalition, the Nebraska Ethanol Board, and the U.S. Department of Agriculture, summer 2006.