For which category has the EPA established both concentration- and mass-based pretreatment standards?

The choice of pulp, paper, and paperboard manufacturing as the category for which the EPA has established both concentration- and mass-based pretreatment standards is grounded in the specific nature of wastewater generated by this industry. The EPA recognizes that the effluent from pulp and paper facilities can contain a variety of pollutants that could significantly impact water quality and the environment.

Concentration-based standards set limits on the maximum allowable concentrations of specific pollutants in wastewater, accounting for how much of a given pollutant can be present in a certain volume of water. Mass-based standards, on the other hand, limit the total amount of a pollutant that can be discharged over a specified time period, thus addressing the overall load of pollution entering water bodies.

In the case of the pulp, paper, and paperboard manufacturing industry, both types of standards are important because the characteristics of their wastewater can vary significantly due to the diverse processes involved in manufacturing. This dual approach allows for more comprehensive regulation, ensuring that both high concentrations of hazardous substances and total pollutant loads are managed effectively to protect public health and the environment.