Recent heavy rains in parts of Minnesota emphasize the need to prepare for system overloads. Wastewater happens and continues to happen regardless of the status of its collection and treatment system. Unfortunately, spills, overflows, unauthorized discharges and bypasses also happen. The steps you take if your system experiences any of these situations will make a big difference in protecting human health, the environment, and your facility.

First, a vocabulary refresher:

• A bypass is the intentional diversion of a waste stream from any portion of your treatment facility. Examples of a bypass include diverting the flow of wastewater around a clarifier or dechlorination system. Bypass wastewater must enter waters of the state from outfalls specifically authorized by the facility’s permit and cannot, by law, cause an effluent limit exceedance. Bypasses are prohibited except in rare circumstances. State Rules and Federal Regulations provide some protection for permit holders in the event of a bypass. Additional information is available on the MPCA website’s Scheduled Maintenance Bypassing Review page.
• A release is any overflow or spill of wastewater or materials to the environment. A release is an unauthorized discharge and is prohibited. Examples include sanitary sewer overflows from a plugged collection system or pumping untreated wastewater out of a manhole to a nearby ditch. Unauthorized releases, such as sanitary sewer overflows, are the most common type of event when wastewater systems are inundated with rain/snow melt or from pump or electrical failures.

Regardless of the situation, MPCA does not approve any release or bypass. Your response to a release or bypass of any type of wastewater or its byproducts is outlined in your permit and summarized below:

• Take all reasonable steps to immediately end the release

• Immediately upon discovery of a release: notify the Minnesota Duty Officer: 1-800-422-0798; 651-649-5451 (metro area only)
• Recover, as quickly and thoroughly as possible, all substances released and/or take immediate action to minimize/abate pollution to waters of the state or potential impacts to human health
• Sample the release for parameters of concern, or those listed on your permit, immediately following discovery of the release; permit holders should consult with MPCA on additional sampling requirements
• Submit sampling results by electronically attaching to your eDMR the Release Sampling Report
• Plan ahead, keep clean water out of the system, and complete proper maintenance to reduce the likelihood of a bypass or release occurring within your system

For more specific information regarding bypasses and releases, consult your permit or contact your MPCA compliance and enforcement representative.

• Toolbox for local units of government recovering from a natural disaster on the MPCA website, including guidelines for wastewater treatment facilities during a flood
• MnWARN is a mutual aid program whereby water, wastewater and stormwater utilities sustaining physical damage from natural or human-caused disasters in the Minnesota can obtain emergency assistance, in the form of personnel, equipment, materials and other associated services necessary to protect the health and welfare of the utilities' customers. For more information on joining MnWARN, call 1--800-367-6792.