Water Campus Advanced Water Treatment Expansion,
City of Scottsdale, AZ
The 11.9 mgd Water Campus Advanced Water Treatment (AWT) system treats tertiary effluent for recharge and irrigation using microfiltration (MF) and reverse osmosis (RO) systems. The existing RO system uses 14 existing RO trains with two different types of RO membranes. The MF and RO systems include auxiliary systems (feed pump stations, chemical feed, clean in place, and flushing systems). The treated effluent is recharged using 27 vadose zone wells for a total capacity of 18.7 mgd. These wells were experiencing some failure; the cause was determined and the wells redeveloped under this project.
The City has been on the forefront of implementing innovative treatment systems to ensure water quality that surpasses the regulatory requirements. This was the approach when the Water Campus AWT concept was adopted by the City and is the driver for the City to investigate and implement Advanced Oxidation Processes (AOP). For the proposed Water Campus expansion, it is necessary to mitigate a broad spectrum of organic chemicals that include NDMA, pharmaceutical and personal care products (PPCPs), endocrine disruptors, and 1,4-dioxane that are being investigated, but are not yet regulated. The City commissioned the project to investigate the feasibility of AOP and to devise an implementation plan to incorporate the proposed AOP into the Water Campus WRF and AWT treatment train. The project will also upgrade and expand the MF system to 33 mgd and the RO system to 20 mgd.
Water Works Engineers and associated firms implemented the project in three consecutive phases – Conceptual, Preliminary and Detailed Design. The MF Conceptual Design included the evaluation of Pressure vs. Submerged systems, competitive piloting for 5 MF systems, pilot performance and cost evaluation, auxiliary systems analysis, demonstration testing needs assessment and membrane procurement. The RO system conceptual design included the development of a conceptual layout of the RO system using both 16-inch and 18-inch technology. This task also included the evaluation of full-scale threshold inhibitor testing in order to reduce acid feed and optimize the removal of NDMA in the RO system. For the AOP Conceptual Design, the Water Works team performed Data Collection and Data Gap Analysis. WWE also evaluated the Contaminant Source and developed Plant Profile, developed Contaminant Control and Treatment Strategies, Emerging Contaminants Treatment Goals and performed a treatment strategy selection. Conceptual designs were also performed for the recharge systems and RWDS feed system.
Existing Memcor 90M10-C Microfiltration Units Being Replaced
Water Campus Entrance