TRRWA RDP Project The Journey to Exceptional Quality Biosolids

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

ECONOMIC EVALUATION Cost Analysis in 2004 Dollars AlternativeCapital Cost Annual O&M Structure Salvage Total Present Worth Rank Lime Pasteurization with Marketing for Sales $13.5 M$1.1 M$ 0$26.1 M 1 Mesophilic Digestion with Seasonal Composting $22.9 M$1.1 M($2.4 M)$33.6 M 2 Thermophilic Digestion with Thermal Drying $28.0 M$0.8 M($2.6 M)$35.2 M 3 Lime Pasteurization with Land Application $13.5 M$1.9 M $ 0$35.5 M 4

NON ECONOMIC FACTOR MATRIX AlternativeReliabilityOperational Flexibility Ease of Operation Odor Potential Product Acceptability Ease of Construction Lime Pasteurization with Land Application NeutralLeast Flexibility BestHigh Potential Worst Acceptance Neutral Thermophilic Digestion with Thermal Drying NeutralMost Flexibility WorstHigh Potential Highest Acceptance Neutral Mesophilic Digestion with Seasonal Composting BestNeutralMiddleLow Potential Neutral Acceptance Neutral Lime Pasteurization with Marketing for Sales NeutralLeast Flexibility BestHigh Potential Worst Acceptance Neutral

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

The Dreaded Weighted Scoring (How Engineers listen to us) AlternativesScore (High Wins) Lime Pasteurization with Marketing for Sales 2.4 Mesophilic Digestion with Seasonal Composting 2.05 Lime Pasteurization with Land Application Program 2.0 Thermophilic Digestion with Thermal Drying 1.9

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

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

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

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

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

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

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.

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

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

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

Lessons Learned and 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