Bag Leak Detection Blog

Many may feel that modifying or renewing an air permit can be a time consuming task, a new permit provides an opportunity to incorporate new monitoring technology that has other benefits. For instance, some may ask whether they should continue using opacity monitoring for their CAM requirements or if can they eliminate much of their manual monitoring by taking the opportunity to review their current practices.

First Emissions Monitoring Methods

Best Reasonable Solution for Emissions Monitoring

Many plants continue to use EPA Method 9 visual observations as their primary dust collector monitoring methodology. Even as newer plants have already moved on to modern monitoring technologies, such as triboelectric dust monitoring, these plants continue to hold fast to their Method 9 CAM plans. Does triboelectric dust emissions monitoring really provide a realistic alternative to visual observation? In many cases, visual observations were the most accurate and feasible solution at the time the air permit was written. And many are still following this method today. But technology has advanced significantly and today visual observation is less reliable, less accurate and substantially more labor intensive compared to electronic instruments.

From Opacity Hassles to Operational Value

With such a disjointed set of strategies and devices used for environmental compliance today many wonder how things ended up like this. Let's explore the history of environmental compliance monitoring technologies and see how we ended up where we are today. 

And then, given today's capabilities, explore how some companies turn the traditional regulatory headache into an opportunity for legitimate operational value creation.

Early Days - Visual Observations 

For many, differential pressure has been the only operation data they have ever monitored on their dust collection system. For decades, DP  has been the go to for monitoring performance, used as an indicator of total emissions and for diagnosing maintenance issues. Even though monitoring technology has advanced significantly since the 1970s when these regulations were first put forth, many plants continue operating under their older requirements.  "That's what we've always done," and "That's what my permit calls for us to do," usually lead the way.  Even today where superior monitoring methods are available, it is common to find plants that feel there is no need to monitor anything more than their DP to achieve compliance. 

New solutions for air permit monitoring

For generations opacity monitoring was essentially the only monitoring option for dust collector operators across all industries. Many plants continue to operate that way, allowing older air permits to just renew without any changes if possible. Because of this, opacity monitoring still forms a key part of their compliance monitoring, even though there may be better methods of monitoring available.  But when it comes to opacity monitoring what kind of options are available? 

Stack Monitoring for Air Permits

The basic idea of a stack observation of opacity is to try to quantify how much particulate is emitted from the stack by determining how much light it blocks from passing through the plume. This measurement of the plumes light blocking power is called opacity. The more dust in the air the more light is scattered/blocked. Prior to 1974 all emissions monitoring was based on the Ringelmann system first developed in the late 19 century to monitoring coal emissions. This system outlined a set of procedures on how an observer could take a visual reading of opacity by viewing the emission source (e.g. stack) from a distance during daytime.  In 1974, the EPA revised the test into the current EPA opacity observation standard methods in an attempt to make the test more reliable and less prone to observer bias. These methods or instructions for conducting the test are known as EPA Methods 9 and 22. 

A Hassle, but an opportunity

Many air permits are outdated. Sure, they're still approved and "compliant" but they were written around technology that was available at the time. Typically that is much less accurate than what's available today, and often relies on systems which require frequent calibration, have significant labor requirements, fail to provide early warning of impending issues and involves data management and reporting burdens. But often when an air permit renewal date approaches, it's just one more hassle - and many permits are simply resubmitted with the same language time after time.

But for many plants, their compliance assurance monitoring plans (CAM Plans) are seriously out of date. 

Variability in writing and enforcing air permits

Contrary to what you might think, there is little uniformity in air emissions permits from plant to plant. While many look to the Federal Government’s standards for PM emissions (i.e. MACT and other regulations), even these are not always applied uniformly across all applications. The job of actually enforcing most regulations often falls to the State authorities, who then may even distribute the responsibility further to other smaller air control boards that serve specific regions (such as in California). State regulations must be at least as strict as the Federal regulations when there is overlap - but the states have broad discretion on their own enforcement requirements. Even then the exact requirements for each plant can be further modified depending on factors such as the exact location of the plant, the surrounding area’s pollution levels, number of employees, and process conditions among others. 

That means there is a wide variety of language and terminology used on permit documentation.

For this reason, dust collector OEMs and filter manufacturers may not always provide emissions testing data that directly corresponds to the language used on your plant’s air permit. Environmental/compliance engineers often have to interpolate available test data from OEMs to determine if the use of this particular product will enable the plant to achieve compliance. 

That leaves us asking....Why can’t there just be one standard method of calculating emissions data?

This is the first of two articles which will tackle that question and explain how to reconcile the two.

Rolling averages, pounds per hour vs. grains per standard dry cubic foot, PM 10 vs. PM 2.5…the complexities of emissions control, monitoring and compliance can make facility personnel feel overwhelmed at times. Trying to navigate the murky combination of environmental regulations from Federal, State and Local authorities while also striving to hit production targets can pose a challenge. At times, this is further complicated by the fact that many plants do not possess state of the art pollution control equipment and must rely on legacy systems in order to achieve compliance. 

Oldies....and not so goodies

Plume opacity emission standards and requirements have played a key role in enforcement of federal, state, and local air pollution regulations. Failure to take these regulations seriously can be costly, as violations of opacity limits for air permits can result in up to $25,000 per source per day!

For decades, the most common method used to monitor opacity levels has been the EPA method 9 and 22 visual observation tests. Consistent economical compliance relies on a better understanding of these tests, how they related to legacy air permits in the past ,and how they will relate going forward. 

What are Method 9 and Method 22?

Ignorance may not be bliss....

Environmental regulations have evolved over the decades becoming increasingly strict around emissions standards. As this occurs, many older industrial facilities find that it's not financially viable to invest in new pollution control technology. In some cases, exceptions have been granted to older facilities to facilitate the transition to stricter standards. This has meant that some facilities have received exemptions, often called “grandfather” exemptions from certain standards or specific requires of larger sets of emission standards. Often though, these exemptions are forfeited when any significant upgrades or modifications are made to the plant’s systems. 

For this reason, many plant decision-makers have developed the viewpoint that as long as they refuse to upgrade to newer systems they can continue to avoid compliance with new regulations.. This leads them to avoid at all costs any modification or upgrades to their emissions control systems in the mistaken belief that by doing so they will avoid difficulties (and costs) associated with complying with newer, stricter environmental standards.

This can be seen by some plants refusal to install a CEMS or BLDS for fear it will increase their risk of getting fined or sanctioned over emissions excursions. The reality however is the contrary...