You don't smell wastewater. You smell the air emissions from the wastewater.
There is thus a compelling logic to the multi-media regulations that address wastewater as a source of air emissions. These regulations took an interesting path to the fairly accepted status they now have. Among the earliest such regulations was NSPS Subpart QQQ, which sought to reduce air emissions from petroleum refinery oily wastewaters, focusing on sewer systems and phase separation. The Benzene Waste Operations NESHAP then also addressed air emissions from the treatment processes. The later-promulgated HON rule added a great deal of complexity to the topic by defining different types of wastewaters, constituent-specific removal targets, and so on, and this approach has carried over to the MON, Pharma MACT, and subsequent wastewater-related rules.
These rules strive to reduce air emissions by focusing on how to manage wastewaters, with less attention paid to calculating the air emissions themselves. The spotlight is on wastewater composition as a representation of potential-to-emit, and it is this potential the regulations address in their different ways.
To develop a good compliance program therefore requires a broad array of knowledge: the specific rule in question, as well as skill in both air and wastewater management, control, and treatment. Consider how Subpart QQQ, being an NSPS regulation, focuses on components: a captured drain is subject to controls regardless of whether the wastewater is oily to a large or small degree. The NESHAP/MACT regulations moderate the captured components by focusing on the amount of the target constituent - in terms of concentration or mass loading - with control provisions applying only to components managing wastewaters with higher constituent content. To learn constituent content, these NESHAP/MACT air regulations consistently require facilities to characterize the wastewaters where they first become regulated, which is to say at very upstream locations (the point of generation or the point of determination).
Experience has demonstrated that upstream characterizations often lead to under-quantified results, particularly in the amount of organic phase associated with wastewaters. So, while the air regulations stop at the upstream characterizations, wastewater professionals extend this effort by connecting the upstream results with downstream confirmation efforts. One needs a comprehensive grasp of how to conduct upstream- downstream balances for water, organic phase, and specific constituents. Balances rely not only on stream characterization, but also on an understanding of the industrial facility itself, its routine and nonstandard wastewater generation activities. Constituent balances must acknowledge compound volatility, a difficult quantification.
Once we know the universe of regulated material, the question becomes what we must do to control it. Can we do so with the existing equipment, retrofitting with covers and seals? Or do we need a new, separate controlled system? The best solutions spring from a full understanding of facility systems and company philosophy (will we require operators to change their wastewater generation and management behaviors or provide controls to accommodate traditional practices?). The treatment process design may need to address off-gas management to an extent not historically required by wastewater permit requirements. Wastewater treatment processes may be coupled with vapor control devices, or systems used that suppress vapor generation. Or can the facility access the treatment process option of controlling a wastewater without a cover (enhanced biodegradation)?
It is a complicated compliance landscape, the wastewater-related air regulations. Citations vary for different industries, wastewaters, compositions. A good compliance plan requires knowledge and experience with wastewaters, air emissions, the relevant rules, and process and facility knowledge. Each of these topics has many sub-themes, so this knowledge and experience does not happen overnight. But the fundamental objective is simple and always the same: reduce air emissions from wastewaters. And the reductions have occurred - our noses tell us so.
If you need assistance evaluating your wastewater-related air compliance, or have any questions regarding Trinity's compliance assistance capabilities, please contact Trinity's Chemical Sector Services at (713) 552-1371.