Central Regional Water System Wastewater Treatment Plant Phase III Solids Management Improvements


Trinity River Authority

The Phase III project has a design capacity for 174 dry tons per day through 2023. GAI provided the electrical distribution and controls design for the new THP, Boilers, Digestion, and related facilities. The design consists of routing primary power at 13.2KV to redundant 3000 KVA transformers. Power is distributed at 480V to main tie-tie main switchboard, which in turns distributes power to six MCCs and 30 free standing variable frequency drives. GAI performed extensive short circuit and arc flash study to mitigate the arc flash hazard at the MCC. Zone selective interlock scheme. In addition, GAI designed the power distribution, controls/ PLC interface, lighting, grounding system for the project. The PLCs are connected via fiber optic cable to the main control room.

The primary process components to be installed as part of this phase include the following:

  • Solids Storage, thickening and pre-dewatering including five new centrifuge systems, and major modifications to the Filter Press Building
  • Three Thermal Hydrolysis Process (THP) trains
  • New boilers inside a new building
  • Three new anaerobic digesters with a new Digester Building
  • Miscellaneous improvements including odor control, instrumentation and control systems, and electrical distribution improvements