UNH organic dairy farm agroecosystem study, phase III: A closed system, energy independent organic dairy farm for the Northeastern U.S.

UNH organic dairy farm agroecosystem study, phase III: A closed system, energy independent organic dairy farm for the Northeastern U.S.

Summary

This project focuses on reducing waste streams and closing nutrient and energy cycles on the commercial-scale Organic Dairy Research Farm operated by the University of New Hampshire. This part year has been dedicated primarily to acquiring final data sets in each of the areas of proposed research and beginning to draft papers and reports presenting those results. 

The analysis of economic viability of creating shavings for bedding using wood from an on-farm woodlot is complete and a manuscript has been prepared.  Processing of all on-farm manure/bedding wastes continues with different combinations of dairy and equine materials and carbon sources such as waste hay.  Detailed analysis of energy generation and capture by the aerated static pile composting system with heat capture has been completed for several composting cycles, and two manuscripts are in preparation describing and modeling this system.  Initial data on the concentrations of carbon dioxide, ammonia, methane and oxygen content of the exhaust air stream from the facility have been completed and a paper is in preparation using these data. 

Summary analyses and calculations, including compilation of the overall nitrogen and carbon budgets of this system and the development of management tools based on our extensive data sets were proposed for delivery in the third year of this award.  Work on these will be initiated in 2017.

Objectives/Performance Targets

The following Objectives/Performance Targets were included in the proposal:

Further Testing of the Process for Converting Low-Quality Wood to Shavings for Bedding

Complete analysis of data on production rates, costs, and value of product.  Complete existing Excel-based cost/decision tool for use by farmers and woodlot owners.

  Continue Composting Process and Experiments

As part of workflow on the farm, optimize management of composting facility including timing of initiation, material mixtures, air flow, irrigation, fertilization and other parameters.

  Assess the feasibility of Linking the Compost Facility to High Tunnel Production

Characterize exhaust air from the composting facility as a source for high tunnel production in terms of energy, moisture, CO₂, CH₄, O₂, NH₃, and total N. Test biofilters and other processes that can connect exhaust stream to a high tunnel system.

  Develop Concepts for Other Uses of Energy Produced Through Composting

These can include drying shavings, heating adjacent building, and others.

  Detailed Carbon, Nitrogen and Greenhouse Gas Budgets                                         

Develop detailed carbon, nitrogen and greenhouse gas budgets for the farm.  These budgets will include new information on bedding production and composting which will be added to previously available data from farm records and groundwater sampling.  Remeasure pasture productivity, including species composition (e.g. legumes for nitrogen fixation).

  Develop Decision Tools for Dairy Farmers, Woodlot Owners and Compost Operators

These tools will be built using data on costs, sales, yields, efficiencies and productivities developed during this study.  They will be designed to help practitioners optimize management decisions in terms of financial return as well as environmental footprints for nitrogen, carbon and greenhouse gases.  These tools will be relevant to dairy farmers, woodlot owners and compost operators, and will be the first to combine environmental and financial impacts for the alternative processes we have examined (e.g. heat recovery composting, bedding production).

  Outreach, Publications, Presentations

We present a detailed list of publications, presentations and management tools to be delivered that build on research completed and in progress, and that will make results accessible and useful for practitioners.  

Accomplishments/Milestones

 Further Testing of the Process for Converting Low-Quality Wood to Shavings for Bedding

We have completed testing of the use of a Tremzac wood shaving machine for the production of bedding for the Burley-Demeritt Farm.  Data have been collected on the capital and labor costs involved in this process.  A draft manuscript has been prepared based on these data and will be submitted in the 2-3 months.  Preliminary results suggest that this process is economically viable, but depends on the reliability of the shaving machine and the amount of down time for maintenance and repair required.

  Continue Composting Process and Experiments

In this year, an additional 4 batches of compostable bedding/manure/hay mixtures have been loaded in to the facility.  All wastes of this nature are processed continuously and timing is designed to be incorporated into the normal workflow of the farm.  Two batches also included bedding/manure material recovered from the UNH equine facility. 

Within this context, we have completed several studies on the rate of heat generation and capture by our aerated static composting facility.  These tests were run by refilling the hot water tank with well water and measuring the rate of temperature increase in that tank over time.  Preliminary results emphasize the importance of the temperature difference between the vapor generated by composting and the water in the storage tank in terms of amount of usable heat captured.

Two manuscripts are in draft form on this work and will be submitted early in the new year.  One presents basic data on heat generation and capture, the other describes a dynamic model that can be used to develop optimal operating conditions.

  Assess the feasibility of Linking the Compost Facility to High Tunnel Production

We now have nearly a year of measurements of carbon dioxide, methane, ammonia and oxygen concentrations in the exhaust gases leaving the composting facility.  After substantial testing of methods, standard procedures for timing and method of measurements have been developed.  Data on changes in concentrations with vapor temperature and age of material have been gathered over two complete 60 day cycles.  Preliminary results show very high initial concentrations of ammonia, and elevated carbon dioxide, but nearly undetectable amounts of methane, and near-ambient oxygen concentrations.  These last two results were expected given the aerated nature of this process.

  Develop Concepts for Other Uses of Energy Produced Through Composting

We have been concentrating on the requirements for converting the waste exhaust air stream from the facility into an energy and nutrient source for a greenhouse.

  Detailed Carbon, Nitrogen and Greenhouse Gas Budgets                                         

Work on this continues.  Two papers on the basic N budgets and on a comparison of methods for producing those budgets, will be produced by summer 2017.

  Develop Decision Tools for Dairy Farmers, Woodlot Owners and Compost Operators

This step was planned for year three of the funded work.  We continue to generate basic data that will be incorporated into these tools.

  Outreach, Publications, Presentations

Our most recent outreach outcome is the production of an informative video, produced by UNH communications, describing the composting work at the farm.  The video can be found here:

This video features the two graduate students and three undergraduate students working on the project.  It was recently featured on the first page of the website of AASHE – the American Association for Sustainability in Higher Education.

Other outreach efforts include:

PUBLICATION

Smith, M., J.D. Aber and R. Rynk. 2016. Heat recovery from composting – a comprehensive review of system design, recovery rate and utilization. Compost Science and Utilization. /10.1080/1065657X.2016.1233082

PROFESSIONAL PRESENTATIONS

Smith, M. 2016. Closing Loop: Nutrient and Energy Implications of Operating a Heat Recovery Composting Facility. Tin Mountain Conservation Center Ecological Forum. April 12. Conway, NH.

Smith, M. 2016. Recovering heat from composting for hot water heating and greenhouse gas mitigation. Food Waste-to-Low Carbon Energy Conference at Rutgers University. April 27-28. New Brunswick, NJ.

Smith, M. 2016. Composting and thermal energy system at the UNH Organic Research Dairy   Farm. Northeast Organic Farming Association (NOFA) Winter Conference. February 13,   2016. Burlington, VT.

GUIDED RESEARCH TOURS AT THE UNH COMPOSTING FACILITY

Jeanne Shaheen (US Senator for New Hampshire) July 2016

NOFA Vermont (Vermont Farmers and Extension Agents) October 2016

OUTREACH TO COMPOSTING CONSTITUENTS

Alternative Energy Associates, NJ May 2016

INTERNATIONAL OUTREACH TO COMPOSTING CONSTITUENTS

LM Tree Solutions, United Kingdom   February 2016

Impacts and Contributions/Outcomes

As this project moves into the final phase, we will be focusing on presentations, publications, and the development of management tools.  The proposal provides a list of the promised products.  We are currently drafting and submitting most of the papers listed and will have many submitted in 2017.  Tool development will begin in 2017.

Collaborators: