Testing an aerated static pile (ASP) compost system for efficiency of time and space

Project Overview

FNE16-855
Project Type: Farmer
Funds awarded in 2016: $14,953.00
Projected End Date: 11/30/2019
Grant Recipient: Tamarlane Farm
Region: Northeast
State: Vermont
Project Leader:
Eric Paris
Kingdom View Compost

Annual Reports

Commodities

  • Agronomic: corn, grass (misc. perennial), hay
  • Animals: bovine
  • Animal Products: dairy

Practices

  • Animal Production: grazing management, manure management, pasture fertility, grazing - rotational, feed/forage
  • Crop Production: food product quality/safety
  • Education and Training: technical assistance, decision support system, demonstration, display, extension, on-farm/ranch research, youth education
  • Energy: solar energy
  • Farm Business Management: farm-to-institution, agricultural finance, labor/employment
  • Production Systems: organic agriculture
  • Soil Management: composting, green manures, organic matter, soil analysis, soil quality/health
  • Sustainable Communities: community planning, infrastructure analysis, local and regional food systems, new business opportunities, public participation, community services, employment opportunities, sustainability measures

    Proposal summary:

    Kingdom View Compost was created in 2005. That same year the “Close the Loop” community composting program was created. In partnership with our solid waste district and a local non-profit, we began collecting food scraps from area food scrap generators such schools, restaurants, etc. These food scraps are mixed with wood chips and manure on our certified organic dairy farm to produce our valuable fertilizer. Over these ten years, the local program has grown from around 2-3 Tons/Week of scraps to around 12 Tons/Week. Our farm has worked to keep up, but the program is growing faster than we are, which has made the operation crowded for space and inefficient.

    Our goal it to able to efficiently process our permitted limit of 16 Tons/Week, without continuing to build compost pads on our valuable pasture. We looked at several options in depth and with limited funding, we believe that we have found a solution that fits. We wish to pilot a low cost aerated static pile (ASP) compost system can potentially decrease the time, costs, and footprint involved compared to the way we presently produce compost. If this new approach works well, it could serve as a model system for others to follow, as it might allow a larger volume of material to be processed using a smaller area than traditional composting methods allow. We will host an on-farm composting field day in the spring of 2017, after we have had enough time to trial and learn from the system.

    Project objectives from proposal:

    Farm business 

    I have lived all of my 54 years on the farm that I operate with my wife, son and son-in-law. We all work here full time. We produce certified organic milk, beef, and vegetables. I have worked full time on our farm since 1979. My wife and I took over management of the farm from my parents in 1988. We own 240 acres and rent an additional 300 to grow feed for our 150 head of milk and beef cattle. We market our milk to Organic Valley and our organic beef and vegetables through our natural food market / cafe in downtown Lyndonville, which our daughter manages. Compost is a small, but increasingly important part of our farming business. Compost and manure are the only fertilizers we use on our crops, and improving soil through the use of compost increases productivity of our feed crops, reducing the amount we need to buy in. The farm has worked with James McSweeney as a composting advisor for many years. He brings a great deal of technical experience that is required to develop a custom ASP system such as this. Other options that we have looked at have been too costly, both financially, and in terms of their land usage. This low cost ASP project could benefit the sustainability of our farm tremendously, especially if it proves to be able allow us to produce compost more quickly than we do now and with less costs, labor, and tractor operation.

    Background issue

    The Close the Loop program has grown tremendously in popularity and continues to do so. We need to grow in order to continue to be a model organics recycling system for other communities / municipalities / farms to follow. We have now reached the point of being challenged to continue to accept the volume of food waste generated by Close the Loop. As a small farm, land and time are extremely valuable to us and we work hard to reduce waste throughout our operations. Currently, we provide oxygen to our compost to keep it aerobic by turning it with a tractor, but this is a labor-intensive process, and only provides ideal oxygen for a brief window (20-60 minutes). Like many farms, turning the pile as frequently as we’d like not always possible, and at times, it is a challenge to meet the temperature and turning requirement set forth for windrow composting by solid waste permits or compost for use on organic farms. The Aerated Static Pile (ASP) composting system we would like to trial provides oxygen by pushing air through the compost with a timer controlled fan and aeration manifold beneath the compost (see attached drawings). Meeting the temperature requirements in our permits and for use on organic farms will only take 3 days at 131 F with ASP, which should be easily achievable. Most importantly, we think that this ASP system is affordable compared with other systems, and could allow us to process more material more efficiently, without increasing the footprint of our present composting facility. After comparing the speed and efficiency of the ASP to our conventional turned windrow methods, if it is found to be a significantly more efficient way to produce compost, we will save time and money. In light of Vermont’s universal recycling law, and increasing farm composting throughout the Northeast, future farm composters will benefit as well.

    Objectives

    The farm has looked at several ASP systems and found the costs to be prohibitive. Working with our technical advisor, we have identified a system design that could aerate just under 100 cubic yards, which is our weekly target at permitted capacity. The pilot system would cost approximately $1000, which is about 1/10th the cost of other systems we’ve looked at. The designs and budget are attached below.

    FNE16-855 Paris Design and budget

    We wish to measure the time it takes to produce finished compost using the ASP system to our conventional methods of composting. We also wish to measure the costs involved. With less pile rolling using the ASP, we believe that tractor time, fuel, wear and tear, and labor will be saved, but how much? We also wish to compare the finished compost itself produced using ASP compared to rolled pile in terms of nutrient values, density, moisture content, etc.

    How much money can be saved per cubic yard of compost produced in a year’s time?

    How much more compost can be produced in a year’s time, using ASP compared to traditional methods, on the same size facility?

    Is compost produced using ASP superior to conventional compost, inferior or comparable?

    Other efforts noted

    ASP composting has been around since the 70’s and a lot of research has been done focusing on using ASP for composting biosolids. Most of the examples are in warmer climates and use more expensive systems with concrete slabs and complex controls. While our research into these systems has led us to believe that it will likely be a net benefit to the farm, there are a lot of unanswered questions. Examples of on-farm composters using low cost ASPs at the small commercial scale really aren’t well documented that we could find. In searching the SARE report database I found that in 2014 Emma Jagoz of Cockeysville, MD received a SARE grant to measure the effectiveness of asp to windrow composting on small-scale farms. While there are similarities between the two projects, there are considerable differences as well. Emma’s project was of a much smaller scale than Kingdom View Compost. She produced about 25 cubic yards in a year, which is about 10% of what we have historically produced and only about 1% of the expected production long-term. Also, she turned her windrows by hand while we use a tractor loader. Her asp was covered by a roof while our system will not be covered and most importantly Emma’s system did not involve food waste as an ingredient. Additionally the climate in Maryland is quite different than northeastern Vermont. A very small scale operation such as that will contain many differences than a larger scale operation such as ours.

    Methods and measurements

    The main goal of this project is to compare our current turned windrow composting methods, to the low-cost ASP system, which will help us determine what the most beneficial route for our farm is over the long-term. The farm needs to expand its capacity, and we can either do that by making the compost pads bigger and continuing to use the turned windrow method, or we can make compost faster using less space, which is one of the potential benefits we hope to test with the ASP. We also care about the quality of the end product. It needs to be mature enough to sell to our customers and use on our farm and we’re not sure how long that will take. The compost also needs to meet temperature requirement as set out by our solid waste permit.

    We plan to use a low-cost continuous temperature logging system, under development by our advisor CTS, to show that both the ASP and windrow methods are hitting the target temperatures of 131 F. To make a fair comparison, we’ll make similar compost batches using both ASP and windrow methods and monitor their performance and the labor that goes into them. The compost will be made following our standard compost recipe of 20% food scraps, 40% wood chip, 20% cow manure and 20% horse manure, which has a Carbon : Nitrogen Ratio around 25-30:1. We may adapt it slightly due to the requirements of the ASP. We’ll also compare the footprint used to manage the system, and the materials and development costs of undertaking each method.

    For each compost “batch” monitored for the project, which equates to 1-1 ½ weeks worth of food scraps, carbon materials, and dairy manure, we’ll measure or record the following:

    • Pile start date

    • Compost recipe and total volume of inputs

    • Farm labor (Hours) in building the pile, monitoring the pile, and managing the pile

    • Temperature – Continuous monitoring of each pile with temp data logger provided by CTS – Temperature at 1’ and 3’ in 3 locations on each pile (so a total of 6 temp loggers). • Date temperature requirements are met (as shown by data loggers) • Moisture Content (weekly using squeeze test)

    • Management activities (such as turning) and general observations • Fan operating parameters & efficiency o Static pressure of ASP manifold (used to determine efficiency of fan operation) o Timing settings o Fan speed settings o Electric use & cost (Kill-A-Watt EZ electric cost/use meter)

    • Testing of finished compost o Solvita maturity tests – 2 tests per batch at 3, 6, and 9 months for the first 8 piles created in the the pilot (for a total of 24 Solvita tests) o Compost analysis – standard plus ammonium, phosphorus, and potasium We will document the process for 4-5 ASP batches and 4-5 windrow batches, for a total of 8-10 batches closely monitored, tested, and documented. This will give us a good window into how the ASP performs compared to the windrow system. Solvita maturity testing will be done on the first 2 ASP and windrow test piles we produce (as per above).

    We will compile the data we collect and write about it in both a final report and case study, to be shared at the field day and online (our advisor’s website, Compost Association of Vermont’s Website, etc).

    Timetable 

    I will oversee all aspects of our project. We would like to begin ASP construction as soon as conditions allow us to install an electric connection on the site, in the spring of 2016, hopefully close to May 1. We’ll pilot the first batches in June or July, forming 2 new piles (1 ASP and 1 Windrow) every 2-3 weeks. This will continue for 4-5 batches Many of the steps listed in the methods and measurement section will take place in 2nd year of the project, as we plan to test the finished compost at 3, 6 and 9 months after the piles are first created. Data will be collected by myself or a member of my family. Our technical advisor, James McSweeney, will also be involved in data collection, organization, and analysis. Some of the data from our testing will be available during 2016, as the compost is being produced, but all data including maturity testing should be complete no later than July 2017. We will do outreach for an on-farm composting field day in spring of 2017, and hold the field day in late spring (June most likely). James will take the lead on writing the project case study in spring of 2017, completing it before we host the field day, and I will take the lead on writing the final report.

    Outreach plan

    We now host many school class trips to our  facility and I’m sure that will continue. We will invite all agencies to visit at any time. 

    We plan to host one on-farm composting field day and site tour in the late spring of 2017. I will ask representatives from the VT Agency of Natural Resources, the VT Agency of Agriculture Food and Markets (AAFM), and the Northeast Kingdom Solid Waste Management District to be on hand. I will also ask our technical advisor, as well as our food waste hauler to be on hand. The general public will be invited, with targeted outreach to local farmers and on-farm composters in particular. We will also invite the Northeast Organic Farmers Association. Notice of this field day will be broadcast by taking advantage of the free advertising offered by local newspapers and radio stations under community events, Agriview (VT AAFM’s newsletter).

    We will also ask all agencies invited to help us spread the word. I will continue to speak at participating schools about Close the Loop. Along with the field day, we will write a case study about our experience building and using the ASP, that will be shared at the field day, and be posted to several websites including our advisor’s (CompostTechnicalServices.com) the Compost Association of Vermont’s (CompostingVermont.org), and SARE’s.

    Any opinions, findings, conclusions, or recommendations expressed in this publication are those of the author(s) and do not necessarily reflect the view of the U.S. Department of Agriculture or SARE.