RDP Project: The Journey to Exceptional Quality Biosolids

1. TRRWA RDP Project The Journey to Exceptional Quality Biosolids

2. THE INVESTIGATION • Studies began in 2003 for options to replace an obsolete heat treatment system coupled with composting • Options that were studied included • Mesophilic Anaerobic Digestion with Seasonal Composting • Thermophilic Anaerobic Digestion with Thermal Drying • Lime Pasteurization with Land Application and Marketing Sales Program

3. ECONOMIC EVALUATIONCost Analysis in 2004 Dollars

4. NON ECONOMIC FACTOR MATRIX

5. NON ECONOMIC FACTOR EXPLANATION • Reliability • Mesophilic Digestion well known and received top rating • Both other alternatives have more equipment and were considered less reliable • Operational Flexibility • Thermophilic Digestion with Thermal Drying had a positive rating as Class A and Class B can be achieved • Mesophilic Digestion with Seasonal Composting received a neutral rating because Class A was only considered as being achieved seasonally • Lime Pasteurization received a negative rating because there is no storage capacity for the incoming sludge and the system must be run daily • Ease of Operation • Lime Stabilization received best rating due to it being a physical process rather than biological • Mesophilic Digestion with Composting received a middle rating because of the composting operation • Thermophilic Digestion with Thermal Drying received lowest rating because of the complexity of the digestion process and the hours and attention required for the drying operation • Odor Potential • Mesophilic Digestion with Composting received a neutral score and odor control likely not required • Both remaining options received negative scores for odors and the required odor control systems • Product Acceptability • Thermophilic Digestion with Thermal Drying received the highest rating due to the dryness of the product • Lime Pasteurization received a neutral score due to product unfamiliarity in the marketplace, even though it is Class A • Mesophilic Digestion with Seasonal Composting received a neutral score due to the product being Class A only seasonally • Ease of Construction rated as similar for all three alternatives

6. The Dreaded Weighted Scoring(How Engineers listen to us)

7. Project Design Approach • Design Engineer Selected September 2003 • TRRWA Staff toured RDP Facilities 2003 and 2004 • Learned that feed sludge concentrations needed to be consistent • Learned that air handling design was critical • TRRWA Staff involved in design and approval of plans • All Staff invited to Design kick-off meeting • All Staff invited to 20% design review meeting • All Staff invited to 60% design review meeting • All staff invited to 90% design review meeting • Design review comments compiled and forwarded to Engineer by Plant Management • Systems Analyst expertise required for RDP system integration

8. Design Revisions By TRRWA Staff • Two RDP trains identified as being needed immediately to facilitate redundancy • Changes in building orientation • Changes in interior building layout • Retained some tanks which were scheduled for demolition • Increased attention to air quality • Increased emphasis on chemical handling

9. Construction Sequence • Design completed January 2006 • Project bid February 2006 at estimated cost of $14 M • Bids received and tabulated March 2006 • Project awarded April 2006 for about $12.4 M • Construction began May 2006 • Substantial completion January 2008 • Final building inspection done July 2008

10. Construction Issues • Blend tank • Concrete rock pockets • Blend tank membrane leaks • Computer system failures • DeviceNet failure which took entire RDP system down • UPS wiring issues • Acid delivery system issues • Air quality issues in chemical room • Acid manifold needed to be rebuilt by staff • Strain press problems • Training done too early, so operators not familiar with equipment when it was time to run it • Strain press wired backwards • Centrifuge gearboxes have each been replaced • Lime specification • Original product was too fine • Created dusting problems

11. First Year Revelations and Adventures • RDP System takes much more Operator oversight, cleaning, and more Maintenance staff involvement than expected  • Operational costs for chemicals were $300,000 less per year than forecasted  • Unexpected change for the end–use of the RDP Product created the need for agricultural beneficial reuse, resulting in a temporary cost increase of about $300,000 per year  • Unexpected problems with misinterpreting permitting delayed EQ status, which temporarily increased analytical requirements and resulted in a longer hauling distance at a combined cost of about $200,000 per year  • Capital projects developed by TRRWA Staff to resolve construction issues and improve RDP handling and building access, after the construction contract closed, cost an estimated $80,000 / • Stairways needed to provide better access • Overhead doors needed in storage bays to control dusting and product • Drive through truck bay not effective and was modified by staff • Containment needed outside of building where trucks are loaded

12. RDP Operations • Typical Operations day at RDP • Start up system, adjust lime dosage • Confirm air handling system running right • After RDP temperatures are achieved, take pH sample • Facilitate RDP loading with Contractor • Make hourly rounds to confirm everything is working within parameters • RDP system typically runs 2 shifts per day 7 days per week • Shut down and clean up system at end of the day, takes about two hours • Monitor RDP SCADA system from control room • Report all process issues to Supervisors

13. Maintenance Work • Calibrate and confirm temperature probes are reading accurately to meet DOE permit requirements • Calibrate and confirm pH probes for air handling system are reading accurately to meet SWCAA permit requirements • Confirm water is being properly circulated within scrubbers and biofilters to meet SWCAA permit requirements • Centrifuge, strainpress, and conveyor inspections and maintenance as required • One additional staff position was hired and probably one more will be needed.

14. RDP Operator Testing • Mandated DOE testing • Constant monitoring by SCADA to document temperatures 158ْ F or higher between inlet and outlet thermocouples • Monthly verification that time between the inlet and outlet thermocouples is at least 30 minutes • Daily pH testing • Time zero must be pH 12.0 or higher • 2 hour test at pH 12.0 or higher • 24 hour test at pH 11.5 or higher • Mandated SWCAA testing • Monthly ammonia emissions • Constant scrubber pH monitoring

15. Laboratory Testing • Mandated DOE Regulatory Testing • Metals every two months • Fecals every two months • Optional Testing • Nutrient sampling every two months • Organics sampling every quarter

16. DOE Permit Status • Began working on EQ Permit Application in August 2008 • Several revisions filed with DOE • Process and sampling plan • Contingency plan • Product fact sheet • Permit was Public Noticed on March 21, 2009 • Achieved EQ status late in April, 2009

17. Lessons Learnedand Confirmed • Visit other facilities when you design something, so you can make your own new exciting mistakes instead of the same old boring ones • If you involve your staff in planning, you will get better ideas, and more cooperation, when things go to heck in a hand basket as they inevitably will • Do homework up front with your regulator and follow-up as you go along; don’t assume that Conventional Wisdom or Historical Snapshots are going to carry more weight than what your Regulator is going to say