1. Sludge Dewatering Filter Press Controls Upgrade at SSWRF
Award Contract S04012C01
Sludge Dewatering Filter Press Controls Upgrade at SSWRF
Commission Agenda Item #4

2. Biosolids Processing & SSWRF Filter Presses
District must process biosolids each day
Biosolids composed of microorganisms and digested sludge
Normal operation: biosolids processed at JIWRF
During JIWRF biosolids processing outages, dewater biosolids using 4 operating filter presses at SSWRF

3. Sludge Dewatering Filter Press

4. Filter Press Dewatering
Uses pressure filtration to separate liquid from solids
Liquid filtrate returned to plant influent for treatment
Concentrated solids or dewatered sludge called sludge cake
Goal of process is to produce dry sludge cake while minimizing filtrate solids content

5. Filter Presses Installed early 1990s
Controlled by PLCs - specialized computers that automatically control pumps, valves, and equipment
Existing PLCs out of production for more than 15 years and no longer supported
Failure of PLC requires specialized parts only available from secondhand market

6. Filter Presses
Essential that filter presses be available for solids processing
To ensure reliability of sludge dewatering process, staff recommends replacing filter press control system
Proposed contract scope: replace PLCs, indicator lights, and operator interfaces

7. Filter Press Control Panel

8. Inside Filter Press Control Panel

9. Project Cost and Schedule
Project within budget
Contract duration 312 days

10. QUESTIONS?