Pall Water Treatment System Installation Saves Park and Protects Water Source for Residents of Pittsburgh, PA

For over a century, the Highland Park 1 Reservoir supplied the drinking water for the residents of Pittsburgh. Situated in a beautiful residential park, the 120 million-gallon reservoir came under mandate by the Safe Drinking Water Act (SDWA) of 1984 which required all open-air reservoirs to have protection from potential contamination. Disinfection goals were 3-log removal/inactivation of Giardia cysts and Cryptosporidium oocysts.

To achieve these goals, the reservoir would have to be covered to prevent microbial contamination, or treated to provide adequate disinfecting before the water could enter the distribution system. Although local people understood the importance of clean drinking water, they wanted a solution that would also preserve the beauty of the park. Citizens protested against covering or altering the appearance of the reservoir or infringing on the running track around it. Conventional filtration systems take up a lot of space and would require a large installation to be erected in the park.

In response to public opinion, the Pennsylvania Department of Environmental Protection (PADEP) and the Pittsburgh Water & Sewer Authority (PWSA) evaluated numerous types of covers and tanks from aesthetic, technical and economic considerations, but no solution met the criteria.

The PSWA then tested a variety of treatment technologies for the post-treatment of reservoir water prior to distribution, thereby eliminating the need to alter the appearance of the reservoir or its environs. Test results showed that membrane filtration provided the best solution at a competitive price. To be ideal, the new system had to incorporate primary membrane filtration, secondary backwash recovery, post-disinfecting and other control/monitoring components while being compact enough to leave the park intact.

After extensive evaluation, PSWA selected new 20-million gallon per day membrane Aria^TM microfiltration system from Pall. Pall’s engineering team designed the new treatment system with a very small footprint, thereby maximizing production while minimizing construction.

Pall’s revolutionary membrane systems help produce drinking water that exceeds standards set by the EPA Enhanced Surface Water Treatment Rule. In fact, Pall’s membrane filtration system is the first to be certified NSF International Standard 61 for drinking water. Pall microfiltration membranes remove bacteria and parasites to a higher level than required by EPA.

A Microbial challenge test was performed during the pilot study at the PWSA on a Microza* filtration module by an NSF / EPA-ETV qualified field testing organization (Gannett Fleming, Inc.). Testing was performed using Giardia cysts and Cryptosporidium oocysts as per procedure developed by the EPA. A total of 10,768,000 Giardia cysts and 104,548,000 Cryptosporidium oocysts were used to challenge the membrane system. The Pall system with Microza membrane modules demonstrated a 5.8 log10 removal of Giardia cysts and 6.8 log10 removal of Cryptosporidium oocysts, exceeding the stringent PWSA requirements.

“Results of our pilot testing showed that the Pall system was not only theoretically effective, but was able to exceed federally mandated standards under actual field conditions with water flowing through our distribution network. The system’s small footprint and low wastewater rate, coupled with first-rate design effort, allowed Pall to submit the most competitive prices. The citizens of Pittsburgh are really excited that we will be able to preserve the beauty of our park while providing drinking water filtered to the highest levels available.” Mike Hullihan, Director of Engineering, Pittsburgh State Water Authority.

A post-award project evaluation by PSWA and engineering consultancy firm, Gannet Fleming, showed that the new membrane filtration facility saved $5 million when compared to conventional technologies. Using its unique approach to problem-solving and advanced filtration technology, Pall helped Pittsburgh preserve the natural beauty of its park and save its citizens’ money. *Microza is a trademark of Asahi Kasei Corporation