Digester Case Study: New Horizons Dairy, LLC. by: Terry Feldmann, P.E. Agricultural Engineer Maurer Stutz, Inc. Peoria, IL

Transcription

1 Digester Case Study: New Horizons Dairy, LLC by: Terry Feldmann, P.E. Agricultural Engineer Maurer Stutz, Inc. Peoria, IL

2 General Facility Information Located south of Elmwood, IL ~1500 Cows (designed for 2000) Constructed 2002 Plug Flow Type Digester ( % TS) Ameren Cilco

3 Designers Terry Feldmann, PE Mark Moser, RCM Richard Mattocks, RCM

4 Waste Treatment Process

5 Scrape to Slotted Drop-24 Pipe

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7 Plug Flow Digester Scrape dairy manure only Manure is 11-13% solids Heated to 100+ degrees No Agitation Steady year-round gas output (if fed manure consistently) No climate limitations

8 New Horizons Dairy Example

9 New Horizons Dairy Example

10 Initial System Design Parameters 2000 Milking Cows Two concrete digesters sharing common center wall (28 x 136 x 14 each) Predicted Average Bio-gas flow = 154,700 cu ft/d for 2000 cows

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12 System Information Two CAT 3406 Engines Induction generators 2 X ~135 kw = ~270 kw potential capacity Electricity mostly used on site Excess sold to utility

13 Co-Gen Building

14 Dual Cat System (~135 kw each)

15 Co-Gen Building

16 Hot Water Supply/Return

17 Gas Uses

18 Fiber: Revenue Source?

19 Digested Solids for Cow Bedding? Sale?

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21 New Horizons Dairy Example

22 Screw Press Separator

23 Why a Digester at New Horizons Dairy Facility? A MANURE INVESTMENT WITH ECONOMIC RETURNS Usable and Saleable products Electricity Heat Digested Dairy Solids Environmental Benefits Reduced odor from storage AND field application Improved nutrient manageability (uniformity) accepted & encouraged by local EPA and AG enabled the Dairy to expand without a larger treatment lagoon and with less odor potential

24 Capital Costs Item % of Total Cost 1. Manure Collection & Transfer 22% +/- System (drop structures, alley scraper, 24 dia. gravity pipe, collection tank, pumps) 2. Digester, Bio-gas Utilization, 58% +/- Energy Conversion, & Permitting/Engineering 3. Solids Separation (67 x 130 x 12 20% +/- covered stack area, 3-separators, pumps, piping) Existing Effluent Storage 0%

25 Possible Revenue Sources Possible Revenue Source Replacement of Farm Electrical Purchases Sale of Excess Electricity Revenue ~54% or greater ~3% (~5.5% of electric revenue) LP/Gas Use Replacement ~3% Fiber Sales (raw?) ~32% Bedding replacement? Methane Credits ~8%

26 Projected Operating & Maintenance Costs Item % of Total Revenue % of Costs Operation and Maintenance ~16% 85% Fiber Recovery ~3% 15%

27 Illinois Design and Permitting Notice of Intent to Construct (NOITC = setbacks) Non-lagoon Application and Construction Plan (Design, Drawings and Specifications specific to the site) NPDES permit from EPA if a CAFO NPDES Permit to Discharge Storm Water from Construction Site Activities if 1 acre or more is disturbed during construction Livestock Waste Management Plan if required (1000 animal Units) IHPA and IDNR review/consultation (generally only for New sites)

28 Notice of Intent to Construct Maximum Feasible Location if existing Setback if facility meets the definition of New (1/4 to 1/2 mile to residence, 1/2 to 1 mile to populated area) unless approved as an innovative design Possible public information meeting for New facilities if over 1000 animal units Property owner notification if a New facility

29 Construction Plan Soils Investigation Shoot elevations & detail drainage Site Layout Plan (location of components and distances to wells, tiles, abandoned wells, streams, etc.) Drawings and design details for Digester and any other proposed livestock waste handling facilities/components (rebar, water stops, piping) Professional Engineer certifications as required (e.g., alternative designs)

30 Site Layout Plan

31 Soils Investigation

32 Soils Sampling

33 Soils Sampling Typical Typical Soils Soils Investigation Investigation (backhoe (backhoe or or borings) borings) Split Split spoon spoon sample sample Jar Jar samples samples and and take take to to a lab lab Lab Lab tests tests to to determine determine soil soil bearing bearing strength strength for for footing footing design design Log Log profiles profiles for for soil soil classification classification and and seasonal seasonal high high water water table table for for wall wall design, design, perimeter perimeter drainage drainage tile tile requirements requirements and and determining determining elevation elevation Two Two or or more more backhoe backhoe pits pits depending depending on on site site geology geology and and type/size type/size of of waste waste handling handling facility facility Use Use Dynamic Dynamic cone cone penetrometer penetrometer in in the the field field for for sandy/gravely sandy/gravely type type soils soils

34 Perimeter Drainage Tile Sump & Monitoring Port (shared)

35 Digester Excavation & Subgrade

36 Digester SYSTEM Success Success comes from design and operation experience including fitting the system to the site A digester should match the dairy rather than making the dairy to match the digester (e.g., plug flow, mixed/stirred, or covered ambient temperature lagoon) The digester is only 1/3 of the system. Reliability comes from proper design, equipment specification and good construction Well Designed Digesters are hard to kill Good systems have low O&M