FEASIBILITY OF INSTALLATION OF ANAEROBIC DIGESTERS AT CATTLE OPERATIONS AND DEMONSTRATION OF A DECISION SUPPORT TOOL April 4, 2013

Sybil SharvelleJeff Lasker

Catherine KeskeLucas Loetsher

Presentation Overview

Introduction to anaerobic digestion Feasibility problems in Colorado and arid West

region Online Decision Tool Developed by CSU

Anaerobic Digestion

High CarbonWaste

Organics Acids

Acids CH4

High NutrientLow OdorProduct

Anaerobic Environment

Cogeneration

Hot Water

CH4

Green Power

Near Complete Pathogen Removoal

Uses for Methane Biogas

Methane Gas

Cogeneration

Electricity Hot WaterPurification to Supply

Natural Gas Lines BoilerPurification

and Liquifaction

Benefits

Reduce greenhouse gas emissions Methane released from animal waste is captured Displacement of fossil fuels

Improved waste treatment Pathogen reduction Carbon removal

Odor control Renewable source of energy

Classic Lagoon Waste Management

Simple – Covered Lagoon

High Tech – Above Ground, Stainless Steel

AD Throughout US

Site Suitability

Digester temperature ideal at 35oC (98oF) Locations with cold winters are not ideal

Waste Quality Low solids content, < 17% solids Low inorganic content

Soil Rocks

Higher organic content, more energy content

Colorado – Cold Climate

Average Annual Minimum Temperature

Recommended Solids Content

Technology Recommended Waste

Solids Content

Covered Lagoon < 3%

Plug Flow 11 - 17%

Complete Mix 5 - 10%

Upflow Sludge Blanket 3 - 7%

Fixed Film

Dry Digestion

<3%

> 40%

Solids Content

Waste management practice impacts solids content Collection by flushing Concrete scrape Dry lot

Flush Collection

3-5% Solids

Scrape Collection on Concrete

Source: EPA AgSTAR

8-17% Solids

Dry Lot

Solids 20-90%

Colorado – Dry Climate

Average Annual Precipitation In Colorado

Need to Find Nearby Source of Wastewater or Add Groundwater to Waste

Problems with Dry Lot Collection

Dry scrape manure Contains rocks and sand Up to 80% TS in arid climate

Plug Flow

Slow, requires high retention time Typically loaded in batches on farm

Rocks and sand will Settle and Build Up

Complete Mix

Well mixed environment Slightly faster rate

of digestion than plug flow

High solids material can not be mixedSand/Rocks detrimental to moving parts

Technical Feasibility for AD

Technical Feasibility

Good

Technical Feasibility

Poor

Flush Dairy

Concrete Scrape Dry Lot

ADM Soybean Processing

Biodiesel Plant

Anaerobic Digester

Frito Lay

Hot Soybean Oil

Cold Soybean Oil

Hog Waste

Food Waste

BiodieselGreen Power

Codigestion: Planned Project in Indiana

Online Decision Tool Developed by CSU

http://www.erams.info/AD_feasibility/

Learn About AD

Determine Technical Feasibility

Determine Economic Feasibility

Select Appropriate Technology

Maintain AD System

1 2 3 4 5

Summary

AD can be a great waste management tool Care must be taken to ensure technical and

economic feasibility Online tool available for decision support

Acknowledgements

Colorado NRCS Colorado Agriculture Experiment Station Colorado Governors Energy Office

Questions???