Ak-Chin Indian Community,
Water and Wastewater Capital Improvements Project
- Wastewater collection system upgrades
- Reclaimed water system expansion
- New 0.6-mgd WRF designed to produce class A+ reclaimed water
- 3-D Design
- Treatment process options including MBR technology; influent pumping; fine rotary drum screens; zoned activated sludge basins; built-in flow equalization; and in-vessel, low pressure UV disinfection modules
The Ak-Chin Indian Community established long-range goals for economic growth and development. This proposed development would severely overload the Community’s existing water and wastewater infrastructure. Consequently, Community leaders commissioned a Water and Wastewater Feasibility Study that identified a series of critical infrastructure and facility upgrades necessary to accommodate the proposed growth initiatives.
Carollo was selected to provide planning, design, and construction-related services for the following project elements:
- new infrastructure including water production, storage, and transmission facilities, wastewater collection system upgrades, off-site lift stations, and expansion of the existing reclaimed water system;
- a new 0.9-mgd MBR Water Reclamation Facility (WRF), that can be expanded to 1.2-mgd capacity, and was designed to produce Class A+ reclaimed water for unrestricted use;
- a new 2.25-mgd Surface Water Treatment Plant (WTP) designed for membrane technology; and
- an 11,000 square foot Administration Building.
The water infrastructure components of the project included designing two new groundwater wells with associated storage reservoirs and booster pump stations, and approximately 10,500 feet of new water distribution piping. Wastewater system infrastructure improvements included design of over 8,000 feet of sewer system improvements to convey wastewater flow to the new WRF. New surface recharge basins and a new reclaimed water storage reservoir and booster pump station enable the community to reuse or recharge the reclaimed water at the WRF. Carollo also conducted hydraulic modeling to assess the performance improvements to the Community’s water and wastewater systems that were originally proposed as part of an earlier study.
For the WRF, Carollo initially evaluated a range of potential wastewater treatment process options including conventional activated sludge, SBR, MBR, and various package/proprietary facilities. Each process was evaluated based on capital and operations and maintenance costs, operational flexibility, and process reliability. Based on that evaluation, the Community selected MBR technology for the new WRF. Carollo assisted the Community in developing initial prequalification criteria and preliminary requirements for proposal packages for potential membrane manufacturers. Based on this process, GE (Zenon Environmental) was ultimately selected as the membrane supplier. As part of the design, Carollo built upon our existing relationships with Zenon to maximize the design efficiency, promote operational flexibility, minimize costs, and add overall value to the project and the Community. The ultimate treatment process for the new WRF was determined through a series of dedicated workshops with the Community and includes the following: influent pumping, fine rotary drum screens, zoned activated sludge basins, built-in flow equalization, membrane facilities, and in-vessel, low pressure ultraviolet disinfection modules.