Rainwater harvesting system installed at early education center

By Michael L. Panco

The Hanby Elementary School & Bush Early Education Center, of the Brandywine School District in Wilmington, Del., was constructed in 2011 on the site of the former Hanby Middle School. The center opened its doors to students from the former Brandywood Elementary School and Charles W. Bush Preschool in January 2012.

Hanby & Bush School was designed to accommodate 750 to 800 students. The architect and the school district agreed that the design was to be innovative and efficient. The challenge for the plumbing design was to find a unique and low-maintenance rainwater harvesting system that would never cause the school to shut down for lack of water to flush toilets and urinals.

The company I formerly work with, Furlow Associates, of Claymont, Del., took on the project. During the preliminary sizing and design, we looked at several systems before selecting Highland Tank. Highland Tank manufactures water tanks for rainwater collection and harvesting, storing potable and waste water, and fire protection services.

Keep in mind, we only had about 10 days to finish the sizing and select the equipment. We knew that not only did the rainwater system need to fit in the mechanical room, but all other major equipment would need to be sized at the same time. We decided to have Highland Tank’s design team meet in our office to help in this arduous task.

On schedule, the Highland Tank team met our time restraints and completed the sizing of the filter system skid package with controls. They also selected the 30,000 gallon underground tank, 1,000 gallon day tank, and the Duplex pumping package.

Highland Tank’s schematic design was presented to the MEP engineering firm for review and approval. The filter system was placed before the day tank, which allowed the filtered and dyed chlorinated water to remain in the day tank during weekends. The day tank was designed to allow sufficient pressure head on the outlet to provide adequate pump suction pressure along with water level controls and automatic fill options.

We also included an indirect connected solenoid operated fill valve that would deliver domestic water to the day tank when and if there would not be enough rainwater. Finally, in that case that the booster pump package went out of service, we included a direct connected backflow preventer on the domestic water main that would tie in downstream of the pump discharge, with rising stem valves in the closed position. A total automated system that would keep the school open no matter what could occur.

When our firm realized that Highland Tank’s system exceeded the codes, we saw an opportunity to have the local county code officials review this system concept prior to the construction documents being released. The end result was we provided an excellent system and received the approval in record time. The county officials decided to use the Highland Tank system for their civil engineering model.

Michael L. Panco is a retired senior plumbing designer. He is also the vice president of Technical and Education at the Philadelphia Chapter of the American Society of Plumbing Engineers (ASPE). Panco can be reached at 610-497-4480. For more information on Highland Tank, visit www.highlandtank.com.

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