The Portland Water District (PWD) owns and operates the 19.8 mgd East End Wastewater Treatment Facility (EEWWTF) in Portland, Maine. Faced with obsolete gaseous chlorination and dechlorination systems, compliance issues, safety concerns, and regulatory program requirements, PWD decided
to replace the disinfection and dechlorination systems. The new systems include properly sized pumps and storage facilities. The system includes residual trim control of chlorine dosing and feed-forward control of the dechlorination process. Chemical use is totalized in SCADA for record keeping
and reporting. The project embraced a new approach to project delivery. In addition to design and construction administration services, the engineer, Wright-Pierce, took on the responsibility of control logic programming of the new system. Through use of SCADA, PWD modified flow regulation
and the plant's transition to and from a wet weather mode. PWD has dramatically decreased the number of violations associated with its disinfection system as a result of this project.
Portland Water District, 225 Douglass Street, Box 3553; Portland, ME 04104 3:
Publication date: July 1, 2007
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Water Practice™ publishes peer-reviewed articles and reports focusing on applied water studies. Topics include monitoring, facility operations and maintenance, management, policy, and other issues of interest and concern to water practitioners. The Journal publishes on a monthly to bi-monthly basis and is available online only.