Improving biosolids stabilization with anaerobic digestion
The Trinity River Authority of Texas (TRA) embarked on an estimated $150 million construction phase at the 162 MGD Central Regional Wastewater System (CRWS) facility in Dallas. This project included the addition of thermal hydrolysis and anaerobic digestion to the solids process, which improved stabilization of biosolids, creating and increasing methane gas production and capture while reducing the quantity of biosolids disposed.
This began with the relocation and expansion of the CRWS waste-activated sludge thickening process via five three-meter gravity belt thickener (GBT) units, which centralizes its blending (primary and waste activated sludge) capability from two existing tanks to a single repurposed tank. This provided a blended sludge loop serving five new and one future pre-dewatering (pre-digestion) centrifuges. The waste activated sludge (WAS) thickening process, via the GBTs, and pre-dewatering process, via the centrifuges, are accompanied by separate polymer systems contained indoors in the repurposed inactive dewatering facility.