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The Boston Harbor project is one of the largest wastewater programs in the United States. As program manager, Earth Tech was responsible for integration and oversight of 30 prime contractors and 300 subcontractors at project peak. Over the project duration, Earth Tech managed a total of 130 construction and professional services contracts.
Under its $311 million performance base, cost-plus contract Earth Tech provided engineering and construction management services in support of the $3.6 billion program -- the largest wastewater treatment plant construction project in the country. This project involved major logistical challenges due to the site location and congestion, multiple contractors, historic preservation and stakeholder sensitivity to the environmental impact of the project. The centerpiece of the project is a new primary and secondary wastewater treatment plant with the capacity to handle a peak flow of 1.3 billion gallons per day. The secondary treatment facilities were built on Deer Island, in a restricted 70-acre construction area.
Major project components included a $159 million, five-mile inter-island rock tunnel; a $482 million primary treatment facility capable of handling more than 1.2 billion gpd, a $506 million secondary treatment facility capable of handling 1,000 mgd, an $85 million power plant, $312 million sludge thickening and anaerobic digestion facility and a $260 million, 9.5-mile ocean outfall tunnel.
Earth Tech's day-to-day activities included resident engineering, project controls, labor relations, site-wide safety, facility testing and start-up and operator training. In addition, Earth Tech provided technical support for change orders, progress payments, and facility acceptance.
The Boston Harbor project was completed $500 million below the original cost projection of $4.1 billion.
