Foundries face stricter air quality, pollution monitoring.

For years foundries, like other heavy industries, have worked to eliminate or minimize air pollution by utilizing dust collectors systems, scrubbers, precipitators and a host of devices to capture a broad range of airborne contaminants. By and large, these efforts were successful, but now new air quality regulations have stiffened the requirements on effluents, exhaust gases, fumes, impurities and other waste materials.

The American Foundrymen's Society Air Quality committee has been working to assist foundries in clarifying local, state and federal regulations related to pollution control and suggesting ways to comply with these increasingly stringent pollution control rules.

Fugitive Emissions

Fugitive emissions particulate, fumes and gases) are contaminants not emitted directly from a process stack or duct. Examples might include emissions from:

* material that escapes capture by process equipment exhaust hoods;

* material transfer, inside or outside a facility;

* buildings accommodating material processing or handling equipment;

* uncontrolled process equipment;

* waste piles and roadways.

Fugitive emissions are subject to the same Prevention of Significant Deterioration (PSD) air impact assessment and control requirements that would apply to stack emissions. Certain operations also should be counted as fugitive emissions when calculating the applicability of the off-set limits of a source or modification.

Fugitive emissions are an environmental concern of the foundry industry. Suggested methods for reducing fugitive emissions include the use of water, chemicals, asphalt or concrete roadways, paved parking lots or storage areas; installation of hoods, fans and fabric filters to enclose dusty materials; covering trucks in transport; cleanup of dusty areas; and effective maintenance and good housekeeping.

Air Pollution Modeling

Air pollution modeling is essential for some facilities to determine compliance status with clean air regulations. It may include major contamination sources subject to PSD requirements and in future air toxic regulations. It also may be required in permit applications for new sources review.

Computer models are used for diverse purposes including predicting the effect of point and nonpoint area sources on geographic air zones and the impact of facility emissions on ambient air quality prior to issuing operating permits. Many models, available from EPA or through private consulting firms, provide information on specific situations with different combinations of pollutants. Generally programmed for a mainframe computer, they are accessible without cost on the EPA bulletin board (919/541-1325).

Some models for personal computers are available, mostly from air pollution consulting firms. Current models include "PTDIS," PTAREA," ICES" and "CRSTERS." They accept input of a variety of parameters including emission rates, stack gas temperatures and concentrations, stack height and exit velocities and prediction of downwind impact concentrations.

Computer model predictions can be valuable for estimating impact prior to applying for permits, and for estimating emission changes resulting from planned modifications to the facility.

Air Toxics

The Clean Air Act will be expanded and strengthened during this session of Congress. It is being driven by the frustration with Superfund, OSHA and public pressure caused by the release of SARA Title III emission data. The proposed legislation concerns smog, acid rain and toxic air pollutants. On April 3 the Senate passed its revision to the Clean Air Act, with the House expected to schedule floor debate on their version sometime after April 15. The basic differences between the Senate and House versions will be how much and how soon.

For many years, foundries have been concerned with "criteria pollutants" such as particulates and sulfur dioxide. Emphasis now centers on "noncriteria pollutants" (more than 150 in the Senate version of the Clean Air Act) that may be released from basic foundry operations. Depending on the specific chemical, controls may now be required for very small emission levels.

The air toxics process could begin with a request from the appropriate federal or state agency for a plant to perform an inventory of toxic substances. These agencies determine which chemicals are regulated and how to perform a chemical inventory. The plant will be notified that it is in compliance if emissions are exempt or below required levels, or, if not, computer modelling may be recommended for nonexempt substances. Should emissions exceed a specified level, additional regulatory screening may be required.

Odor Emissions

Historically, most laws and standards relating to emission and air quality included the control of particulates, oxides of nitrogen and sulfur and hydrocarbons, but did not involve odors. As most foundries have complied with air emission standards, now odors are likely to initiate a community reaction. Laws exist to force the abatement of many chemical odors and it is probable that all such odors will have to be controlled eventually.

Odor problems are seldom created by a single compound. Many chemicals have a very low odor threshold, making them difficult and expensive to control. There are many sources for odors in the foundry, including phenol, sulfur dioxide, hydrogen sulfide, formaldehyde, ammonia, mineral spirits and various hydrocarbons. Systems well within the control limits for particulate and gaseous emissions may still allow the escape of odors to the community.

One of the frustrating issues concerning odor is its elusive nature. Perceptions of odor are individualistic and difficult to quantify, Basically, three characteristics help define odor sensation:

* the quantity of substance must be sufficient to cause a sensation;

* the identification of the odor by the individual depends on his/her experience and other physiological and psychological details;

* the force with which odor impinges on the nasal membranes.

Some odors may not be experienced with normal breathing rates but become evident when carried by winds or inhaled during higher rates of breathing.

To better quantify their limits, test panels have been formed to evaluate the odors. Many methods, including gas chromatography, give more reliable data, but odors are measured in odor units. An odors are measured in odor units. An odor un it is defined as the quantity of any odor or mixture of odors that, when dispersed in one cubic foot of air, produces a median threshold odor detection response.

Foundry odor abatement presents several possible control methods, including process changes or modifications, dilution with clean air, adsorption, combustion, chemical absorption, condensation, oxidation and incineration.

The first choice, process modification, would alleviate the need for control devices and their operating and maintenance costs. Other methods are dependent on the sources and concentration, and each compound must be treated individually. There are many in-plant resources for the treatment of odors.

When faced with an odor abatement problem, a foundry must evaluate all plant odor sources, reviewing each for potential regulatory limits. These limits are determined by state and local regulation, and each source must be researched individually.

After the potential odor sources are identified, a program to determine the possibility of process changes and/or method of abatement must be investigated. The compliance agency may be involved in the process, depending on the nature and seriousness of the problem. As with most foundry issues, a proactive program to address the problem is more successful than reacting to community complaints.

The American Foundrymen's Society has published a manual on "Odor Pollution Control" as part of its Environmental Series. Written by G. S. Cole, it is a reference for the direction and solution of foundry odor problems.

SARA, Title III

The Emergency Planning and Community Right-to-Know Act of 1986 details what chemical manufacturers, processors and users are required to report annually concerning their releases of listed toxic chemicals.

These reporting requirements, outlined in Section 313 of Title Ill of Superfund Amendments and Reauthorization Act of 1986 (SARA), specify that both routine and accidental releases be reported. The regulations describe the applicability in detail. A foundry is subject to the reporting requirements if all of the following apply:

* it has ten or more full-time employees;

* it conducts manufacturing operations;

* it manufactures, processes or in any other way uses any of the listed toxic chemicals in amounts greater than the threshold quantities.

A foundry is included in these reporting requirements if it is included in the Standard Industrial Classification Codes 20 through 39. The threshold quantity for manufacturers and processors in 1989 and thereafter is 25,000 lb of toxic chemicals used during the preceding calendar year.

Data To Be Reported 

The EPA Form R, Toxic Chemical Release Inventory Reporting, requires that the following releases of a chemical be reported in pounds per year): to air from fugitive or nonpoint sources;

to air from stack or point sources;

* to water directly discharged to a receiving stream;

* in wastes that are injected underground;

* to land on site (including landfills, surface impoundments or landspreading);

* to water discharged to a publicly-owned treatment works (POTW);

* in other wastes transferred offsite for treatment or disposal.

One approach to this mandatory reporting requirement might be to review raw and other ancillary materials purchases (metals and melt additives) to determine if purchases totalled 25,000 lb or more in 1989.

The chemicals to be reported are listed in several EPA publications, including: Form R, noted above; Toxic Chemical Release Inventory Questions and Answers; Section 313 Final Rule (40 CFR Part 372, 53 FR 4500) reprint; Title III List of Lists; and Estimating Releases and Waste Treatment Efficiencies for the Toxic Chemical Release Inventory Form, EPA 56014-88-002. These references can be obtained from EPA.

It is absolutely imperative that a foundry know its processes, raw materials and the ultimate disposition of its waste materials. Each department should record in detail all data necessary to prove regulatory compliance, since a fine of up to $25,000 a day can be levied for proven noncompliance.

Reference to Final EPA PSD Regulations, August 7, 1980, 40 CFR 51.21 and 51.24 is suggested for information dealing with specific fugitive emissions regulations.

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