Wastewater Treatment & Management

Industrial Pretreatment


Management of significant industrial users (SIUs) has been an important part of wastewater treatment plant operations since the 1980s, when new plants began experiencing process upsets due to industrial discharges. LRWWU has had an EPA-approved Industrial Pretreatment Program (IPP) since 1998. The purpose of the IPP is to prevent pass-through and interference caused by industrial discharges.

LRWWU's diligence with pretreatment activities can be credited for its success in avoiding process upsets and non-compliant discharges to the Merrimack River. Over the years, the number of SIUs has declined slightly, as domestic manufacturing has moved overseas. Recently, LRWWU began focusing on monitoring hauled waste discharges at the Duck Island WWTF, particularly industrial hauled waste. LRWWU plans to increase its monitoring of domestic and commercial septage once a new electronic billing system is implemented in 2015. This monitoring of hauled waste and management of its billing is crucial to prevent interference or pass-through of harmful pollutant loads.

Intermunicipal Management


Managing the wastewater discharged from four surrounding towns (Chelmsford, Dracut, Tewksbury, and Tyngsborough) that discharge to LRWWU's Duck Island WWTF is an important responsibility. Intermunicipal sewer billing generates revenue that funds both the capital improvements and operations/maintenance activities. Billing is based upon the measured monthly flows from the four surrounding towns. Sewer flows into the City of Lowell are measured either directly at sewer metering stations (which are located on town lines), or indirectly through water usage data. In aggregate, the towns contribute approximately 30% of the total system flow, while the City of Lowell contributes the remainder.

Stormwater Management (MS4 / MSGP)


Management of stormwater has become an increasingly important initiative over the past decade. There has been a recent emphasis on regulating the quality of stormwater discharges to surface water bodies.

The primary initiatives related to stormwater are identifying outfalls, eliminating illicit discharges, mapping the city's drainage system, and educating the public and municipal employees about stormwater issues. Stormwater is regulated by two permits:
  • Municipal Separate Storm Sewer System (MS4) - this program is aimed at regulating stormwater discharges to local waterways in urban areas. See the following EPA website.
  • Multi-Sector General Permit (MSGP) - this program regulates stormwater discharges to local waterways from certain industries, including wastewater treatment facilities. For more information on this program, refer to this EPA website.