Towns and cities along the Merrimack River from New Hampshire to Massachusetts thrived in the 1800s and 1900s because of the river. Mills and factories used the river’s resources to produce goods that were shipped all over the country.
Unfortunately, the damage to the river from these booming industries was significant. Raw sewage, dyes, and other chemicals polluted the river and nearly destroyed the entire ecosystem. Because of the dyes used in the mills, it was common to see the river turn various colors.
A State Board of Health investigation in 1908 began water quality analysis along the river. The study determined that the untreated wastes of 270,000 people were being discharged directly to the river. The citizens, however, were more concerned with the appearance of floating grease due to wool scouring operations. A follow-up report recommended that communities contributing to the pollution build individual treatment plants but this was not acted upon.
A 1923 Department of Health study found that about 114 million gallons of raw sewage from Lawrence, Lowell and Haverhill were being discharged into the river daily. A summary called for construction of a trunk sewer to collect these wastes and discharge them into the ocean off Plum Island. By 1928, however, another Public Health Department investigation disclosed that industrial development had slowed and some industries were curtailing operations. The result was a decline in both discharges to the river and interest in the construction of wastewater collection and treatment facilities.
The Merrimack Valley Sewerage District and the Merrimack River Valley Sewage Board were established in 1935, but lacked federal funding, so the long-recommended trunk sewer remained only a recommendation.
Subsequent investigations included a joint study by the state Department of Public Health and the Federal Public Works Administration in 1937 and a study by Thomas R. Camp in 1947 which was updated in 1963 by Boston environmental engineers Camp Dresser & McKee (CDM). The 1963 report recommended cleaning up the Merrimack by building individual treatment facilities in certain areas and regional facilities elsewhere. The report called for one regional facility to serve Lawrence, Methuen, Andover and North Andover, the communities that would ultimately comprise the Greater Lawrence Sanitary District (GLSD).
The Greater Lawrence Sanitary District was established by Chapter 750 of the Massachusetts Acts of 1968 for the purpose of building, maintaining, and operating a system of sewage collection and disposal for the cities of Lawrence and Methuen, and the towns of Andover and North Andover. The District facilities have been operational since April 1977. The Town of Salem, New Hampshire joined the Greater Lawrence Sanitary District in the 1980s through enabling legislation, Chapter 387 Acts of 1982 and written agreement.
A Commission consisting of eight members (four from the City of Lawrence, two from the City of Methuen, one each from the towns of Andover and North Andover), and a ninth non-voting member from the Town of Salem, New Hampshire oversee the District. The Executive Director is appointed by the District Commission and implements decisions made by the Commission. The District employs approximately 40 people, of whom approximately 27 are represented by employee unions
The treatment facilities provide the District with the capability of processing up to 52 million gallons of wastewater per day. Major process components included in the treatment system are: primary sedimentation, biological oxidation, secondary clarification, and treated effluent chlorination.