Latest News

GLSD featured in Wentworth Institute of Technology Magazine

GLSD featured in Wentworth Institute of Technology Magazine. To read the article, click here.

CSO Notification Subscription

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Greater Lawrence Sanitary District nears goal to produce enough power to meet its own electrical needs and become a Net-Zero or even Net-Positive energy user.  Read: GLSD Organics to Energy Press Release Dec 10 2019-1

Baker-Polito Administration Invests $2 Million in Emergency Power to Protect Water Quality in Merrimack River

Funding for Greater Lawrence Sanitary District Will Prevent Wastewater Spills

Regulatory support letters for GLSD’s Organics to Energy Project

Greater Lawrence Sanitary District received the following support letters for the Organics to Energy Project. MassDEP Cambridge City Council letter 10-5-18 EPA letter to Cambridge 10-5-18

Combined Sewer Overflows

Combined Sewer Systems (CSS) were designed to collect rainwater runoff, domestic sewage, and industrial wastewater in one pipe that, under normal or “dry” conditions, transports the water to a treatment facility. The volume of wastewater can sometimes exceed the system’s capacity, which most often occurs under “wet” conditions including heavy rainfall and snow melt. CSS were designed to deal with these large volumes through Combined Sewer Overflows, which discharge the excess wastewater directly into nearby streams, rivers, or lakes.

CSOs contain stormwater, untreated human and industrial waste, harmful materials such as oil and pesticides, and floating debris, making it a source of concern for many communities. In the Merrimack River, CSOs have been found to be a source of bacterial contamination, to contribute to the reduction of dissolved oxygen levels, and to increase nutrient levels to above normal ranges.

pdf-icon2020 CSO Reporting (download)

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Impacts of CSOs

Bacterial Contamination

One of the main concerns associated with CSOs is the discharge of untreated human excrement. Although diluted, these wastes may contain pathogenic bacteria and viruses. These organisms may cause illnesses such as dysentery and hepatitis when people swim in CSO affected waters or eat contaminated shell fish.

Dissolved Oxygen

When organisms break down biodegradable waste, they use the dissolved oxygen in water. An excess of biodegradable waste in a water body may therefore cause a reduction in the oxygen supply, resulting in fish kills, odor, and overall degradation of water quality.

Nutrient Enrichment

Overloads of nitrogen and phosphorous, which stimulate plant growth, may lead to rapid growth of algae and other plants, which also contribute to the depletion of oxygen levels in the water.


In accordance with the District’s NPDES permit, CSOs within the District are regulated and monitored to limit their occurrences and impacts. To learn more about these regulations, see pages 11-13 of the District’s permit.

Additionally, GLSD is currently working to upgrade the River Side Pump Station to allow for greater pumping capacity of sewerage and reduce the amount of CSOs.