The City of Lancaster operates two water treatment plants (WTP). The Conestoga WTP is a 12-mgd conventional WTP that was constructed in 1933 and its source water is the Conestoga River.  The Susquehanna WTP is a 24-mgd conventional WTP that was constructed in 1955 and its source water is the Susquehanna River.  Both facilities have had minimal upgrades since the original construction.  Although both facilities treat water that meets all existing Safe Drinking Water Act  regulations, the outdated technology made it increasing difficult to do so in a way that was reliable.  The City also contemplated the existing technologies ability to meet the future drinking water regulations that may be promulgated in the not too distant future.  Concerns over microbial contaminants in our source waters such as Giardia and Cryptosporidium, independent of the regulations is another reason that the City selected membrane technology.  Other factors included the ease of operation, minimal staffing requirements, ability to handle fluctuations in source water quality and ability to expand the system.

To this end, the Conestoga WTP and Susguehanna WTP were among the nation’s first to competitively evaluate both direct- and clarified-feed water membrane systems for the City drinking water facilities.  Since then the City undertook an aggressive capital improvement plan, the largest in the City’s history, to upgrade these two drinking water plants to incorporate state-of-the-art low-pressure membranes for producing its drinking water.  While the City has produced water that has met all EPA drinking water requirements, these aging facilities made it increasing more difficult to do so.  Therefore, after significant study and engineering during the early 2000s, the City awarded a bid for the construction of the improvements at the City‘s two water treatment plants in 2007.

Recognizing this and the significant capital investment for any improvements at their water treatment facilities, the City had the vision to utilize the best technology available for water treatment at essentially the same cost of retrofitting the existing facilities with the existing, conventional technologies.

The City spent significant time and investment to determine the most cost effective and optimal treatment system for both of their facilities.  GE-Zenon low-pressure membranes have been installed at both facilities after significant testing and approvals with the Pennsylvania Department of Environmental Protection (PADEP).  In fact, this technology is the same type of technology used to produce bottled water that is sold in stores nearly 1,000 times more expensive than what it cost City customers at the tap.

See a related article: What is Microfiltration.

The membrane system at the Conestoga Water Treatment Plant recently completed all of its testing required to be operational and approved by the PA DEP and is currently producing water with the new technology.  Due to the size of the facility, the Susquehanna Water Treatment Facility is on a slightly longer construction schedule and is anticipated to be producing water for City customers by the summer of 2010. 

The City is proud of its new water treatment facilities and is looking forward to providing our customers with the cleanest water current technology can provide at extremely reasonable costs, especially compared to similar water purchased in stores across the region and other public water systems in surrounding communities.

Also see a related article: Identifying Future Drinking Water Contaminants (1999)
Commission on Geosciences, Environment and Resources; Excerpts from the National Academies Press

View pictures of Membrane