DIGESTER UPGRADE, PHASES 1, 2, AND 3

EAST BAY MUNICIPAL UTILITY DISTRICT

DIGESTER UPGRADE, PHASE 1

During Phase 1 of the 14-year multi-phased Digester Upgrade project to rehabilitate digesters at the plant, Beyaz & Patel provided structural engineering services as a subconsultant to Brown and Caldwell, to improve the cogeneration system at the Main Wastewater Treatment Plant. We performed a feasibility study for converting digesters 6, 9, 10, and 11 steel floating covers to fixed steel roof covers. Additionally, we designed an 800-foot-long by 20-foot-high braced steel frame structure to support an elevated 36-inch-diameter pipe carrying sludge gases between the digesters and the power generation facility.

Our services included site investigation, review of background data, including structural calculations and drawings, establishing structural design criteria, structural evaluations, and preparation of calculations, drawings, and construction specifications. Phase 1 was completed in 2008.

Digester Upgrade Gas Pipeline
Digester Gas Pipeline Supports
Digester Upgrade Lid Replacement
During the Digester Upgrade, Phase 2, Beyaz & Patel analyzed and designed lid replacements for the digesters.
DIGESTER UPGRADE, PHASE 2

Phase 2 of the Digester Upgrade, completed in 2014, included cover replacement, coating installation, and mixing improvements for Digesters Nos. 5, 7, 8, and 12; the addition of a high strength waste (HSW) receiving station, blend tanks to mix the HSW with municipal sludge; and a new digester feed system.

Beyaz & Patel provided the structural design for the blend tanks, odor control area, pipe chase tunnel, MCC building, underground tanks, and miscellaneous foundations for small equipment items.

DIGESTER UPGRADE, PHASE 3
The scope of work for the Main Wastewater Treatment Plant Digester Upgrade Project, Phase 3, includes the following items:
  • Seismic retrofits for Digester Nos. 2, 3, and 4;
  • Removal of the floating covers on Digesters 3 and 4, and addition of new dual membrane covers;
  • Piping to allow for future mixing equipment for Digesters 2, 3, and 4.
  • Technical Memorandum (TM) with our recommended improvements to the HSW receiving station, including contamination and grit removal;
  • Drawings for Life/Safety modifications to the digesters to improve accessibility for digester cleaning;
  • Improvements to facilities and features constructed in Phase 2 that were either not completed and would improve the operation of the current systems.
Digester Upgrade, Phases 1, 2, and3