Industrial Pretreatment Part 2: Why We Need to Care About Pretreatment for Industrial Facilities

Technology is advancing, the world population is increasing and the industrial world must keep up with the new demands in every sector. These factors have led to the construction of more industrial facilities and warehouses throughout the country than ever before. Many industrial processes require water, whether it is for cooling materials or used in the process of making the product. The processes that occur at industrial facilities often produce polluted water that is discharged to a Publicly Owned Treatment Works (POTW), also referred to as wastewater treatment plants (WWTPs). These facilities receive wastewater from residences, businesses and industries in the community, direct the water through several treatment and disinfection processes and then discharge the treated water to a local receiving stream. If you live in a community that has a large industrial presence, it most likely upholds a pretreatment program that enforces local limits on pollutants.

Pretreatment is defined in the United States Environmental Protection Agency (USEPA) Pretreatment Guide as “The reduction of the amount of pollutants, the elimination of pollutants, or the alteration of the nature of pollutant properties in wastewater.” Essentially, industrial facilities using pollution control technologies remove pollutants from their wastewater before discharging it to the POTW. Industrial facilities often have a wastewater or pretreatment technology area in the facility that treats the industrial discharge before sending it to the POTW.

Pretreatment programs develop local limits for each of the pollutants that are received at the POTWs and those limits are enforced in municipalities’ sewer use ordinances. Pretreatment programs can enforce stricter limits than the national limits required by the EPA, but they cannot be less stringent than the national limits. Pretreatment programs require sampling to be conducted to ensure that the significant industrial user (SIU) is discharging within the local limits of the program. Pretreatment programs help protect water quality, natural ecosystems, wildlife habitat and human health. Enforcement actions are the tools that help motivate industrial facilities to comply with local pretreatment regulations. An enforcement action can be something as small as a verbal warning all the way up to judicial action in court depending on the severity of the violation.

Pretreatment is important because it helps protect not only the local environment, but also the POTW itself. POTWs are designed to treat certain levels of pollutants that enter with the water. However, if a pollutant enters the POTW at a higher concentration than what the POTW was designed for, it can potentially disrupt the operation of the facility. Disruptions at the POTW result in the microbiology being affected which can lead to decreased treatment of the wastewater. The microbiology has adapted to a certain level of influent concentration, so if one pollutant multiplies suddenly, the organisms may not adapt fast enough to the change to maintain the normal level of treatment. If this happens, the POTW may begin to violate the limits set in their National Pollutant Discharge Elimination System (NPDES) Permit because the plant is unable to remove the level of pollutants they usually would be able to remove.

Pretreatment regulations require each facility in the program to be inspected and pollutants monitored, which can involve a third party engineer being onsite to lead the inspections, staff from the city or town attending inspection meetings and providing insight into what they experience at the POTW. They can then learn how to correct any deficiencies that have been traced back to the facility. Depending on the city or town pretreatment program and number of staff available, assistance may be needed to help with enforcement for violations of the program. Each program should have an Enforcement Response Plan (ERP) that lists tiers of enforcement responses dependent on the type and scale of the violation.

Tim Gallagher, E.I.

Engineer

317.788.4551 | timg@wesslerengineering.com