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
In the earliest days of air pollution control, regulators faced the simple yet challenging problem of how to measure the amount of contaminates emitted from sources. Seeking an expedient solution, regulators and industry borrowed from the process of making visual opacity measurements from the coal mining industry. (Coal mines had used this system for decades to monitor coal dust levels to control explosion hazards from clouds of coal dust).
The Ringelmann system used a chart showing approximations of what certain levels of dust concentration should look like to the naked eye when observed a certain way. In this way, a rough measurement could be taken that would show when large rises in emissions took place. Obviously this system was only useful for very rough measurements and depended greatly on the knowledge and skill of the observer and even light and weather conditions to take objective measurements.
Improved Stack Observation Methods
After some decades industry and regulators realized the need for improvement to the Ringelmann system. In 1974 the EPA began to formalize techniques and procedures to improve the accuracy and objectivity of the opacity observations. Observers had to receive training and be certified in these procedures in order to conduct the tests. These rules and procedures exist today as EPA Methods 9 and 22. With these improvements the reliability of relative opacity measurements increased.
However, the key shortcomings still remained. Even a properly conducted opacity observation can be skewed by weather or sun position relative to the stack/observer. Combined with the need for certified observers to be present on premises at all times, the time required for the actual test and the lack of automation in the process moved industry players to look for still better methods of monitoring emissions.*
Modern Days - Opacity Meters Come to the Fore
In time, two competing technologies emerged to finally bring direct particle concentration monitoring into use, opacity monitors and triboelectric dust detection systems. Both systems provided significant advantages over earlier methods. Foremost, they both provided for more direct and consistent measurement of particle concentrations coming from a process. Additionally, they allow for constant monitoring of a source and can more easily integrate with an automated record keeping system than visual observations.
During their initial introduction to the market in the early 1980s, early generations of triboelectric detectors were somewhat harder to implement across all applications compared to opacity meters. Also, air emissions standards were much less stringent then so the much lower detection sensitivity of opacity meters was adequate. For this reason opacity meters were often the preferred monitoring method in many applications.
Triboelectric Emerges as Best Solution with Tighter Standards
Triboelectric has evolved extensively, including the recent introduction of dual band DC/AC triboelectric technology by Auburn Systems. Changes to Particulate Matter regulations has shifted monitoring best practices to triboelectric detection systems. And plants that had managed to hang on to their old air permits with visual observations or differential pressure readings as the main monitoring metric in their CAM plans have seen these grandfather exemptions slowly replaced by newer direct monitoring requirements.
But in many plants compliance is now a byproduct of effective monitoring which has advanced to become a valuable operational capability. Triboelectric detectors incredible sensitivity provides added operational benefits not possible with opacity meters. These include rapid broken bag detection (within minutes of a leak forming), ability to accurately forecast when a set of filters will fail and easily automated record keeping for compliance purposes among other benefits. All of these contribute to vastly reducing unplanned and costly downtime, and simplifying the time-consuming reporting functions.
Compliance monitoring for particular matter emissions has come a long way from educated guesswork of early opacity observations to EPA method 9 and 22. Differential pressure readings and opacity meters are gradually being replaced with triboelectric systems as companies seek early, reliable, consistent compliance AND the operational benefits they bring.
As achieving compliance becomes harder and harder to achieve with older technologies, and more and more plants with grandfathered air permits are forced to meet the latest standards you can expect more and more facilities will move on from older technologies and embrace the many benefits of today’s best environmental compliance monitoring technology.
If you have an air permit renewal coming up and want to explore how implementing the latest generation can not only simplify your environmental compliance but deliver savings and efficiencies in operations, let's talk. Renewal a while off? We can remind you several months in advance so there's time to explore the full range of options.
*Due to the shortcomings of visual opacity tests, indirect methods of monitoring dust collector performance were introduced. The most widely used stand in for direct particle concentration measurements was dust collector differential pressure. Since dust collectors reach peak efficiency (99.99%+) within a given DP range this was used for years as a compliance monitoring method and is still in use on some grandfathered air permits.