Delivering a Reclamation Facility SCADA Migration 

Challenge

The Encina Wastewater Authority (EWA) provides wastewater treatment services to almost 400,000 residents in northwestern San Diego County. Their facilities and services are essential in protecting the local ocean environment, preserving public health, and providing recycled water resources for the region. EWA operates the City of Carlsbad’s CWRF, which is adjacent to their jointly owned main treatment facility, and uses the plant effluent as a source of reclaimed water. In 2019 Tetra Tech completed a control system audit and determined with EWA and the City that the most comprehensive and cost-effective solution was to replace and upgrade the entire system instead of fixing problems individually.

Solution

For the upgrade, we had to take the CWRF offline, replace the entire electrical control infrastructure, upgrade networking, perform commissioning and testing, and validate the new software. The facility could not be offline for more than one month, with the upgrade occurring during wet weather winter timeframe. Startup activities were carefully planned and coordinated with the construction manager and electrical contractor to ensure deadlines were met.

We noticed that seven CWRF control panels were in various states of upkeep and required three different upgrade approaches. Two panels were completely rebuilt, one received all new hardware, and the remaining four received partial upgrades for outdated equipment. We selected the Schneider Electric programmable logic controller (PLC) equipment to streamline the hardware and reduce the number of spare parts needed on hand. To simplify the controls, three separate non-redundant PLCs were replaced by a single redundant Schneider Electric pair. The entire CWRF was redesigned as a single stratified network and connected to the new network we configured during the Authority’s network construction project.