Evaluating the Future of Biosolids Drying: Louisville MSDs Decision. Robert Bates Louisville Metropolitan Sewer District

Transcription

1 Evaluating the Future of Biosolids Drying: Louisville MSDs Decision Robert Bates Louisville Metropolitan Sewer District March 3 rd, 2015

2 History MSD has been drying biosolids at the Morris Forman Water Quality Treatment Center since 2001, and actively marketing since 2004 All solids generated at five regional facilities in Louisville & Jefferson County are transported to MFWQTC by truck or force main MFWQTC processes approximately 25,000 dry tons per year of biosolids with the majority of final product historically being used by bulk agriculture

3 Morris Forman Solids Processing Additions / Improvements Digestion converted solids storage tanks to anaerobic digesters Dewatering 5 High Solids centrifuges Drying 4 Drum Drying Systems largest capacity in US at the time

4 From RAS/WAS Overflow to Primary Polymer Solids Receiving Tank Trucked Sludge From Primary TWAS DAFT (8) Digesters Flare Dewatering Wet Well HW N/C N/C DG Dewatering Centrifuges(5) Blend Tanks Dewatering Wet Well Wet Bin(4) Mixer(4) Process Water Main ID Fan(4) Condenser HW Overflow to Primary Exhaust to atmosphere Venturi Draft Fan(4) Venturi Scrubber RTO(4) Polymer N2 Recycle Bin(4) DG Furnace/ Drum(4) Preseparator/ Polycyclone (4) Shaker/sizing(4) Nitrogen Storage/Evaporation Solids Process Flow Diagram Natural Gas Recycle Solids Crusher(4) Pellet Cooler(4) Pneumatic Transporter(4) Storage Silo(2) N2

5 Jan-02 Jan-02 Jan-02 Feb-02 Feb-02 Mar-02 Mar-02 Apr-02 Apr-02 May-02 May-02 Tons per Day MSD first produced biosolids pellets in late 2001 Biosolids to Landfill $ $6000 / day Landfill costs $800 - $1000 / day Landfill costs Date Wet Tons Pellet Tons By April 2002, most solids were pelletized. Although solids were still going to the Landfill, the reduced volume meant an immediate cost savings for MSD.

6 Annual Biosolids Disposition by Form (by %) 100% 90% 80% 70% 60% 50% 40% 30% 20% 10% 0% Increased equipment wear and tear, and major maintenance, limited drying equipment availability Pellets to Beneficial Use Pellets to Landfill Wet Cake to Landfill

7 Complete Beneficial Use 100% Coordination with Marketer allowed for distribution of material previously disposed of in the landfill 0% 2013

8 But, And there s always a but. MSD had a decision to make regarding the future of biosolids drying.

9 Preseparator Replacement NEED MAINTENANCE vs IMPROVEMENTS Thermal Oxidizer Manifold WANT Courtesy of Cornerstone Engineering, Inc. Maintenance & Money Courtesy of BTM Engineering, Inc.

10 10/29/08 10/30/08 10/31/08 11/1/08 11/2/08 11/3/08 11/4/08 11/5/08 11/6/08 11/7/08 11/8/08 11/9/08 11/10/08 11/11/08 11/12/08 11/13/08 11/14/08 11/15/08 11/16/08 11/17/08 11/18/08 11/19/08 11/20/08 11/21/08 11/22/08 11/23/08 11/24/08 11/25/08 2/19/09 2/20/09 2/21/09 2/22/09 2/23/09 2/24/09 2/25/09 2/26/09 2/27/09 3/12/09 3/13/09 3/14/09 3/15/09 3/16/09 3/17/09 3/18/09 3/19/09 3/20/09 3/21/09 3/22/09 3/23/09 3/24/09 3/25/09 3/26/09 3/27/09 3/28/09 3/29/09 3/30/09 3/31/09 4/1/09 4/2/09 4/3/09 4/4/09 4/5/09 4/6/09 4/7/09 4/8/09 4/9/09 4/10/09 4/11/09 4/12/09 4/13/09 4/14/09 11/1/ /8/ /15/ /22/ /29/ /6/ /13/ /20/ /27/2008 1/3/2009 1/10/2009 1/17/2009 1/24/2009 1/31/2009 2/7/2009 2/14/2009 2/21/2009 2/28/2009 3/7/2009 3/14/2009 3/21/2009 3/28/2009 4/4/2009 4/11/2009 4/18/2009 4/25/2009 mg/kg Pounds per day Industrial Waste Department SIUs Trunk Line Monitoring Morris Forman Influent Nickel Data Louisville Green Nickel Data Product Analysis / 503s Nickel event

11 Rain Snow Frozen Ground Flooding August 4, Market Demands & Weather

12 Decision Point Dryers were just over 10 years old Largest Capital Project in MSD history at the time Land application of biosolids environmentally sound Avoided landfill costs Potentially save 8 10 employee positions Dryers were increasingly labor intensive Landfilling cake or pellets potentially cheaper Capital improvements needed to continue drying Utility costs harder to project / budget Potential write of ~$22 Million in assets

13 Decision Point Directions MSD Board requested a business case study of solids processing & disposal options with third party review Evaluate 3 Options: 1. Landfill dewatered biosolids (not pellets) 2. Landfill dried biosolids (low-grade pellets) 3. Continue marketing Louisville Green Options evaluation based on: Historical trends in natural gas and electricity costs Average LG revenue over past 5 years Labor costs specific for each alternative Maintenance costs based on historical costs plus annualized projections of major rebuild/replacement

14 Moving Forward MSD Staff Recommendations: Continue to produce and market Louisville Green Pursue high dollar markets Make needed repairs to reliably produce Louisville Green pellets Board Decision: Issue a Request for Proposals for Distribution and Marketing of Louisville Green but directed consideration of alternative approaches to LG marketing, to see if lower cost options existed

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16 Competing Interests? Green vs Green aka vs

17 MSD entered into a contract with a marketer and continues to distribute Class A, EQ biosolids

18 By The Numbers Today Total Processing Unit Cost 3.8 % more for pellets to landfill 1.2% more for pellets to market 3.8% 1.2% What it really cost to process solids by disposition method

19 Competing Interests? Green vs Green aka vs

20 AgNP Engineered silver nanoparticles (AgNPs) <20nm 20 15,000 silver atoms An emerging environmental contaminant of concern Antimicrobial properties Consumer products is increasing rapidly Enter terrestrial ecosystems through land-application of biosolids Microbial communities in organic matter and nutrient cycling in ecosystems Triclosan / Triclocarban Soaps, toothpaste, shampoo, kitchenware, pencils Lipophilic-readily available for absorption and bioaccumulation in fatty tissues Antimicrobial properties Photodegrades Public pressure causing manufacturers to remove from products Minnesota bans triclosan from consumer and PPCPs

21 Pharmaceuticals and Personal Care Products (PPCPs) PPCPs include: Prescription and over-the counter therapeutic drugs Veterinary drugs Fragrances Cosmetics Sun-screen products Diagnostic agents Nutraceuticals (e.g., vitamins) Sources of PPCPs: Human activity Residues from pharmaceutical manufacturing (well defined and controlled) Residues from hospitals Illicit drugs Veterinary drug use, especially antibiotics and steroids Agribusiness

22 What is the future of biosolids? Source Truly an A to Z approach: Digestion Conditioning Thickening Dewatering Minimization Resource Recovery Nutrients Heat Energy Disposition Compliance Purpose

23 Thank you! Robin Burch Joe Falleri Sharon Worley Alex Novak