Covered Anaerobic Digester Developing an Environmental Management System

Covered Anaerobic Digester Developing an Environmental Management System (EMS) Approach for Agriculture and Agribusiness Dec. 18, 2000 Julian Barham Farms Zebulon, NC

Case Study - Barham Farm • Located - Johnston County, NC • modern swine farm • populated in 1994 • owned and managed by Julian and Elaine Barham

Background Information • • 4000 sow - farrow to wean 4 gestation barns 2 farrowing barns slatted floors (grates) shallow pit/recharge flush pit 4/8 day cycle waste gravity flow

Process Diagram

1994 - 1996 Effluent from barns to anaerobic lagoon 40, 000 gallons/day (total solids < 1. 0%) • lagoon surface = 6 + acres

Traditional Anaerobic Lagoon Design Evaporation Emissions Freeboard Rainfall/Storms Storage Treatment Sludge Field Application

Covered Anaerobic Digester ? 1 2 3 4 Odor Control Energy Resource Ammonia Emissions Rainfall Exclusion (*)

Anaerobic Digester and Storage pond Biogas Rainfall Digester effluent Treatment Sludge Anaerobic Digester Storage Pond

Lagoon Cover Design • partial cover ? lower cost (? ) rainwater into lagoon odor reduction high maintenance • bank to bank ? rain exclusion no emissions (sealed) biogas storage low maintenance

Partial Cover - Practical Application !

Bank to Bank Cover - Practical Application

Things Involved Biogas • Methane + CO 2 + H 2 S • Greenhouse gas Options • Flare • IC Engine • Micro Turbine • Burner/Boiler

Equipment Needed Boiler for hot water Engine for co-generation - 10, 000 gallon hot water storage - 120 KW for peak shaving - hot water for space heating and mats - engine heat recovery - hot water

Lagoon Performance

Covered Anaerobic Digester Effluent Organic Carbon - reduced 85% Ref: ASAE Proceedings TKN - reduced 30% 8 th Inter. Natl Symp. Total P - reduced 75% Oct 2000 K - reduced 20% Eval. of Alternat. Waste Sys.

Digester Effluent Use: Apply at agronomic rate to low value hayland!

Digester Effluent Use: Nutrient rich for high value produce in green house environment!

Benefits Seen Biofilter - low energy input process Reduce Ammonia Emissions (NH 4 to NO 3) Lower p. H

Greenhouse

Other Results and Conclusion It’s not “A Sows Ear to a Silk Purse” but Demonstrated Energy Resource Reduced Emissions Marketable Produce Manageable System ?