PHOTO 1
Engineers view the process air and odor control piping for the new North and Central Battery aeration tanks.

PHOTO 2
To convey flow to the plant from Manhattan, a new control gate (inset photo) was constructed around operating piping, which was then "wet-tapped" using a unique 8-ft-dia core drill bit, engineered specifically for the job.

PHOTO 3
Malcolm Pirnie's hydraulic proflile model helped overcome flow splitting issues such as balancing loading and flow for new tanks started up with others taken off line. This is a CADD rendering of a complicated flow diversion changer for Brooklyn Queens flows to the new flow spliter box.

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PROJECT DESCRIPTION

Under a Consent Order to meet USEPA secondary treatment standards, the Newtown Creek facility, New York City's largest wastewater treatment plant, is undergoing a $3.5 billion upgrading and expansion - NYCDEP's single largest project ever.

Contract 35, a $660 million project, is a significant element of the overall effort - treatment and conveyance facilities for a new North Battery and reconstruction of the north half of the Central Battery, comprising the secondary treatment system. Completing Contract 35 on time to meet Consent Order deadlines while maintaining uninterrupted operations were the project's critical goals.

The joint venture design team of Greeley and Hansen, Hazen and Sawyer, and Malcolm Pirnie, with the construction management team of Hazen and Sawyer and Malcolm Pirnie, are responsible for Contract 35, along with significant teamwork from the client and contractors.

INTEGRATED APPROACH

This massive project required integrating hydraulic, odor control and safety concerns as well as wastewater treatment issues. As part of the Consent Order, all aspects of the plant's permit needed to be maintained during construction, requiring strict adherence to detailed planning and scheduling. This included not only hydraulic considerations to maintain flows which would give proper process ranges, but also the need to have subsystems like odor control available before any new process tankage was put on-line.

With phased construction, new construction was occurring adjacent to operating tankage -- requiring plant staff and construction staff to work closely to meet each others needs -- everything from health and safety to monitoring monthly permit averages to determine whether operating tankage could be removed on an expedited schedule. Since the project was built on a contaminated site in Brooklyn, part of the massive Greenpoint area Oil spill that is still being mitigated, many heath and safety protocols were followed.

Construction met all construction milestones while maintaining treatment. Fully meeting the client's needs, construction was completed and new Batteries placed into operation in less than 40 months to meet the Consent Order, while maintaining continuous operation and treatment performance of the existing Batteries.

Extensive teamwork was facilitated between the DEP and the project team. Accomplishing the project's daunting goals and completing critical construction milestones on schedule required the client and engineers to work together collaboratively. To provide DEP management and operations staff and the project staff with real-time access to the same critical project information, the engineers developed original internet-based construction services information systems.

Regulators approve additional work. Successful DEP Negotiations with the NYSDEC about Consent Order dates relied on the successful outcomes of Contract 35. An addition to the original contract, which will expedite overall project construction by two years, was allowed primarily because of timely completion and the project team's effectiveness.

ORIGINALITY/INNOVATION

Innovative hydraulic modeling techniques overcame extraordinary design issues. Malcolm Pirnie's Hydraulic Profile model enabled the team to develop, test and modify design to accomplish desired flow control and distribute plant flow proportionally among all Batteries. By simulating the complicated interactions between new and existing facilities, the model helped overcome flow splitting issues such as balancing loading and flow for new tanks started up with others taken off line. By demonstrating a need for bypass orifices during startup, impact on the existing Manhattan Pump Station was minimized while maintaining proper flow distribution to the North Battery.

New electronic information systems were developed to support team collaboration. An internet-based Construction Services Management System provided instantaneous access to all project documents. A Project Management Information System enabled users to quickly sort through vast amounts of data to focus on specific information, while capturing DEP business processes. Using a "paperless" Electronic Document Management system, the team scanned, filed and quickly routed the project's myriad documents, greatly increasing timeliness and efficiency.

On-site Design Services during Construction enhanced schedule. To facilitate prompt responses to RFIs and shop drawing reviews, design engineers were empowered to review drawings and submittals, make design changes, and coordinate with contractors and construction management to prioritize design responses to pending issues, minimizing referrals to the home offices.

Redesign was integrated throughout design and construction. All team members were empowered to develop innovative time-saving ideas. These included the use of stay forms and Poured-in-Place joints that allowed larger concrete pours, advancing the schedule and resulting in overall excellent concrete quality. In another successful redesign, the engineers maintained the Central Battery's final tank effluent channel structure intact and built new walls into it, saving costly/timely bulkhead work while maintaining effluent flows through the plant.

Timely startup confirms 'Track 3' Process Design. To confirm the effectiveness of an enhanced "Track 3" process, developed to produce secondary treatment without building new primary treatment tanks, the plant needed to meet permit requirements well before the Consent Order date, making timely startup of Contract 35 elements essential. Besides saving an additional $600 to 800 million in tankage not constructed, it left space for future storm water equalization tanks.

COMPLEXITY

Complex construction approaches meet schedule goal. Implementing a project of this magnitude with its rigorous schedule was an extraordinarily complex endeavor, requiring outside-the-box solutions. For example, to construct the only active conduit carrying Manhattan flow under the East River, a 45ft-high control gate was installed as a single structure around operating piping which was then "wet tapped" into the live conduit using a custom-designed eight-foot-diameter core drill bit.

SOCIAL/ECONOMIC ADVANCEMENT

Water quality improvement will result. Achieving secondary treatment standards - increasing removal of BOD and suspended solids from 60-70% to 85% -- will result in improved water quality in both Long Island Sound and New York Harbor -- on time to meet the Consent Order date.

Timely completion yielded benefits. Meeting the project timetable resulted in a $170 million addition to the contract including reconstruction of the South Central Battery, which will move project construction ahead by two years. A second $44 million addition, a complicated flow diversion chamber for Brooklyn Queens, will allow North and Central Batteries to receive the entire plant flow sooner, with important cost savings. Potential fines for not meeting the Consent Order could have been significant.


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