At the turn of the century, Boston had one of the most advanced sewer systems in the country. Through decades of neglect and a failure to truly update the system until the 1980's, the pollution in Boston Harbor became so bad that the harbor became a national embarrassment. The two sewer treatment plants in Boston Harbor were only equipped for primary treatment when most plants in the country were providing secondary if not tertiary treatment for their waste water. The waste from these plants was being dumped into the shallow waters of the Harbor, at the end of a relatively short outfall pipe. Another eyesore for the Commonwealth were the eighty-one combined sewer overflows in the cities of Boston, Chelsea, Cambridge and Somerville. Combined Sewer Overflows occur when sewage flow in a combined sewer system backs up due to heavy rains or other precipitation. When the flow gets too heavy, these CSO's act as release valves spilling excess sewage directly into Boston Harbor (MWRA website).
Not even the passage of the 1972 Clean Water Act prompted Massachusetts to clean up its act, so to speak. It was not until the city of Quincy and the Conservation Law Foundation filed law suits against Massachusetts for violations of the Clean Water Act, that the state decided to make updates to its system (Aubrey, Connor 62). The result of these lawsuits was the creation of the Massachusetts Water Resources Authority (MWRA) in late 1984. Once the MWRA took control of the sewer system changes began to be made. The MWRA oversaw the construction of new primary and secondary treatment plants of Deer Island, which removed the mandatory 85% of pollutants in the wastewater required by the Clean Water Act (MWRA website). They built a new 9.5 mile outfall tunnel which would dump effluent into the deep open ocean currents of Boston Harbor.
Because of these achievements, Boston Harbor began to lose its reputation as one of the most polluted harbors in the country, until it rained. When it rained, the excess sewage still spilled through the release valves, into nearby bodies of water. It was obvious that the CSO problem had to be taken care of in some form or another for the Boston Harbor cleanup project to be a success.
A little history on the Boston area sewer system is needed before getting into how the problem was and should be handled. Since the problems with Boston's sewer system didn't begin with the MWRA, it is necessary to look at the history of Boston's sewer system. The system originated in 1876 when Massachusetts state legislators approved the construction of the Boston Main Drainage System (MWRA website). This drainage system was begun in 1877 and wasn't operational until 1884. The system piped sewage from 18 cities and towns in and around Boston to Moon Island in Boston Harbor. The sewage was held in giant vats and released into the outgoing tide where it would be carried out into deeper water where it was assumed it would cause no problems.
In 1889 the Metropolitan Sewerage District (MSD) was formed (MWRA website). The purpose of this group was to oversee the construction of a regional sewer system. The system was built and continually expanded upon for years. It was looked upon as one of the best in the country since the sewage was released into the outgoing tide as opposed to just being continually dumped into the harbor like most cities at the time.
The Boston system offered no form of treatment for the sewage and as a result, by 1919, many of the areas shellfish beds were closed due to sewage pollution. In an attempt to remedy this situation, the Metropolitan District Commission (MDC) took control of the MSD. The MDC couldn't stop the pollution and by 1933 all shellfish taken from Boston Harbor required some form of purification (MWRA website). It wasn't until 1940 that state legislators recommended the construction of treatment plants at the three raw sewage discharge points: Moon Island, Nut Island and Deer Island.
The Nut Island Primary Wastewater Treatment Plant was the first of the plants to be built in Boston Harbor. It was completed in 1952 and treated the sewage collected from the southern Boston collection system. It was not until 1968 that Deer Islands sewage treatment plant was completed. Deer Island treated the sewage from the northern Boston collection system. With both treatment plants operational, the old holding tanks on Moon Island were to be used only in emergency situations.
With the passage of the Clean Water Act of 1972, Massachusetts found their sewer treatment plants to be sub-standard. According to the Clean Water Act, all municipal sewer systems must have primary and secondary treatment of wastewater. Moon Island, when used, had no treatment. Nut and Deer Islands had only primary treatment. Primary treatment is a settling process and secondary treatment is a microorganism facilitated process which removes more impurities by further settling (U.S. Water News Online).
Initially nothing was done to bring the plants up to speed, but in the early 1980's when Boston Harbor was at its worst, all that changed. After the city of Quincy and the Conservation Law Foundation (CLF) both filed lawsuits against Massachusetts for violations in the Clean Water Act, the state decided to act (Aubrey, Connor 62). The Massachusetts Water Resources Authority (MWRA) was created in late 1984. The MWRA assumed control of the sewer system from the MDC in 1985.
With the creation of the MWRA came the new treatment plants and the new outfall pipe and a plan on how to deal with the CSO's. CSO's plague all cities with an old sewer system and Boston has one of the oldest. Parts of the sewer system in Boston, Chelsea, Cambridge and Somerville collect stormwater runoff in the same pipes that carry sewage, hence the name combined sewer. A combined sewer system is fine in dry weather when the flow can be handled by the sewer lines and sent to Deer Island for treatment. In times of unusually high rainfall, the excess water entering the sewer from storm drains can overload the system and necessitate its release through the CSO's into one of the following bodies of water: the Charles, Mystic, or Neponset Rivers or directly into Boston Harbor itself. As bad as these CSO's are, they are necessary because without them in times of unusually high rainfall the sewers would back up into homes and businesses.
CSO's are such a problem because they pollute the body of water into which they are released. CSO's also violate various federal and state water quality stardards. The most frequent reason why Boston area beaches are closed is because of CSO discharges. Boston is not the only area hampered by CSO problems, in all there are one thousand communities in the United States trying to figure out how to solve their CSO problems in a successful and cost effective manner.
After the more immediate task of solving Boston's main sewer treatment problems by building the new Deer Island plant, the MWRA could move on to solving the CSO dilemma. The MWRA met with the effected communities of Boston, Chelsea, Cambridge and Somerville to discuss possible solutions. In 1990 the MWRA came up with a possible solution. This solution called for the creation of huge underground storage tunnels in the bedrock under the city which would store the excess sewage until drier times when the overflow could be piped to Deer Island for treatment (CSO factsheet). This plan had worked for other communities, but the cost and complexity of such a project worried the MWRA and the citizens who would have to pay much higher rates for their sewer use to offset the estimated 1.3 billion dollar cost of the project (MWRA website).
The MWRA decided that 1.3 billion dollars was too much of a commitment to make so soon after the one billion dollars spent on the Boston Harbor plan already. In 1994 the MWRA and the four effected communities came up with another plan. This new plan would build upon present means of dealing with CSO's and cost only 370 million dollars, only one quarter of the cost of the original plan. The 370 million dollars would cover the cost of design, construction and operation.
Under this new plan 28 different projects would be undertaken which would focus on improving the water quality in five areas in and around Boston by reducing or treating the excess sewage released by the CSO's. The areas that would be cleaned up would be Dorchester Bay, the Neponset River, Constitution Beach in East Boston, the Charles River as well ...