A high-tech approach to better-tasting water
Aqua Pennsylvania / Neshaminy, Pennsylvania
Drawing its source water from Neshaminy Creek, the Neshaminy Water Treatment Plant is a 15 million gallon per day (MGD) facility that serves the people of Bucks and Montgomery Counties in southeastern Pennsylvania.
The creek is subject to periodic blooms of algae, which can add unwanted tastes and odors to the water. The plant used a powdered activated carbon system to address the problem, but it was unable to remove enough MIB (2-Methylisoborneol) and geosmin, the compounds responsible for the taste and odor. Increasing the amount of carbon led to increased costs and a large increase in waste sludge.
Aqua Pennsylvania retained Mott MacDonald to evaluate the plant and develop an improvement plan, and later engaged us to provide services for the design and construction phase of the implementation.
Mott MacDonald used building information modeling (BIM) to engineer more efficient pretreatment and residuals treatment.
According to Margie Gray, a process engineer for Mott MacDonald, “Working from coordinated, data-rich models allows us to visualize every aspect of a water treatment process. It's a new, more integrated and intuitive way of designing but not a new way of thinking. Most importantly for our clients, our BIM workflow is more efficient because we can streamline nearly every design task.”
“We can design more efficiently because applying changes is so much more automatic,” Gray said. “Single changes made within the model are reflected in the respective views automatically. This is especially important when laying out complex systems of piping and process equipment.”
The upgrade to the Neshaminy plant included the following:
- Advanced oxidation treatment to address taste & odor issues, using UV light and hydrogen peroxide
- Chemical storage and feed systems including chlorine, lime, powdered activated carbon, polymer, and alum
- New raw pumping and screening systems
- Cleaning and lining of raw water intake and dual raw water transmission mains
- Replacement of coagulation/sedimentation basis with a new plate settler clarification system
- Residuals treatment including gravity thickening and mechanical dewatering
The use of BIM enabled us to deliver the entire project within 12 months.
“As our modeling proficiency grew, the Neshaminy project proved BIM to be a viable practice. The time spent developing and integrating a refined approach was offset by efficiency gains in the design process,” said Margie Gray.
The client agreed. “Working from a detail-rich, 3D model made it easy for our operational staff to visualize and enhance the design,” said Marc Lucca of Aqua Pennsylvania. “For example, our operational staff spotted a number of opportunities to suggest enhancements that would make maintenance easier for them. Being able to collaborate in real time was empowering.”
According to Gray, “Aqua Pennsylvania was so impressed that it tapped us to deliver a similar, fast-track project at its Crum Creek Water Treatment Plant. With Crum Creek, we built on our prior experience and realized efficiency gains that really illustrate why BIM will become a big part of the way multidisciplinary projects are executed.”
Implementing a UV oxidation system led to lower operating costs, a significantly reduced carbon footprint, and an improvement in water quality.
“Our Neshaminy WTP facility is space limited,” said Lucca. “The UV/Peroxide System affords us the ability to install a system that is easy to operate and fits in the space available while producing a superior water quality for our customers. It also provides positive environmental benefits by reducing our carbon footprint.”