Q: What are the regulations regarding airborne fryer and smoking emissions and how to handle them when venting to the outside? Do they need to be collected, and, if so, what are the best methods?
A: The governing law is the Clean Air Act of 1990. It sets standards for pollutants and determines areas of attainment (areas that meet the requirements) and non attainment. The EPA sets guidelines for each category in order to meet the agency’s requirements. In turn, each state sets its own requirements.
Smoking and frying pollutants likely are volatile organic compounds (VOCs) and particulate matter. Check with your state EPA for specifics. Each pollutant has an allowable yearly threshold tonnage. If your emissions exceed that, the state will not tell you how you need to control it, but they may require you to use either reasonably acceptable current technology (RACT) or best available current technology (BACT) to resolve your issue.
The best attainment method depends upon state requirements and the volume of emissions you produce. In cases where volumes are low, the solution to pollution can be dilution; and discharging the particulates and odor high into the atmosphere can be a low-cost solution provided you do not offend any neighbors. The most common method for particulate and VOC removal are water scrubbers. These can be as simple as running a water mist over the escaping vapor or as complicated as having media in a tower that forces more contact time. They are 50-70 percent efficient. HEPA filters can be used for smaller emission volumes, but they are more costly to maintain. Tougher requirements may cause you to use an electrostatic precipitator (ESP) or a catalytic oxidizer. Both of these solutions have higher capital and operating costs.
There is no requirement to consolidate these emission streams, but, economically, you will want as few emission sample points as possible. The most cost-effective way of consolidating emission streams is to use ducting and high-velocity updraft systems. These systems need to be carefully designed so they are compatible with your existing process.
The devil is always in the details when ensuring you are protecting your company by being compliant. The best approach is to develop a good working relationship with your regulators.