PALA CASINO, CA

The world-renowned MITA Pile Cloth Filter’s vertical shaft filter helps 1.15 MGD peak flows meet CA Title 22 reuse.

Project Background & Challenges

Located in the middle of the San Rey River, one hour northeast of San Diego, resides the Pala Casino Spa and Resort on California’s Pala Mission Band of Indians reservation. The Pala community itself is small, accommodating a population of 1,573 people, of whom around 44 percent solely identify as Native Americans of both Cupeño and Luiseño Indian heritage. However, when the resort opened in 2003, it boasted 500 rooms, a spa, large conference center, and nine restaurants, propelling Pala as a bustling tourist hub with resulting wastewater treatment needs.

Many municipalities across California are facing environmental concerns related to the treatment and usage of reclaimed water, also known as recycled water. This term refers to the process of treating wastewater to a standard suitable for beneficial reuse, such as irrigation, industrial processes, or environmental restoration, rather than simply discharging it into rivers or oceans. Given California’s persistent water challenges, including drought and water scarcity, recycled water has emerged as a crucial resource in the state’s water management strategy and provides ample opportunities to meet a wide variety of treatment needs throughout a variety of climates.

Out of this need, the state developed its Title 22 standards, which set out specific guidelines to which water must be treated in order to be reuseable. These standards involve water being treated to a turbidity level of <2 NTU.

At Pala Casino, where CA Title 22 reuse-quality water was the expectation, an existing inside-out disk filter system was failing to meet the turbidity standards and so an upgrade was sought, sized for a 0.576 MGD average flow with a 1.152 MGD peak flow.

The Nexom Answer

Given the casino’s need to meet CA Title 22 reuse quality standards, the MITA® Pile Cloth Disk Filter was identified as a great solution because it can cost-effectively achieve lower TSS and turbidity than most other options on the market.

The previous inside-out disk filter was removed, and the MITA outside-in cloth disk system was installed on the existing pad above ground. This system received the secondary effluent from the post-Sequencing Batch Reactor (SBR) equalization (EQ) tanks, which were then pumped to the MITA disk filter. Following filtration, the effluent from the MITA disk filter was routed to the chlorine contact tank.

Meeting California 22 Reuse

The MITA disk filter is an outside-in cloth media filter using depth filtration to capture solids. Headloss setpoints initiate an auto-cleaning cycle where disks rotate past fixed backwash shoes, cleaning the filter media. Automated desludging prevents accumulation or degradation to performance.

The MITA cloth disk filter includes multiple features that have allowed for great success in Pala. First, reuse-approved Scylla™ 500 filter media delivers the required water quality. Not only that, but Nexom provided multiple media options, ranging from 5-10 microns in nominal pore size. In addition, the MITA series of pile cloth filters offers a novel vertical-shaft orientation option that minimizes footprint by fitting the entire filter system within an easily-accessible round tank that is less than 9’ (3m) in diameter. Finally, the innovative MITA backwash vacuum shoes have enabled tighter disk spacing, which substantially reduces footprint in horizontal-shaft installations, but even in vertical-shaft orientations minimizes the required size of the tank and head profile of the filter.

Upgraded System Performance

The system has been working within California reuse targets since its start-up in October. This, combined with MITA’s simplicity of operation, means the wastewater operator has been very happy with its performance!

Project Information

Project Type: Municipal wastewater treatment
Completion Date: March 2023

Treatment Objectives

Design Flow:
• 0.576 MGD (Average)
• 1.152 MGD (Peak)
Effluent Objectives:
• California Title 22 Reuse

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