Management Plan for Food Scrap Feeding & Composting with Laying Hens
Version 1: November 2014
Management Plan for Food Scrap Feeding & Composting with Laying Hens Table of Contents Introduction 1. On-Farm Feeding and Composting System Components 2. Chicken-Feeding, Feedstock, & Compost Management A. Equipment B. Chicken Feeding C. Feedstock Management D. Pile Blending E. Windrow Composting F. Aerated Static Pile Composting G. Monitoring H. Pile Management I. Compost Curing and Storage J. Odor Control K. Vector Control L. Litter Control M. Conservation Measures N. Contamination Control Appendices A. Livestock Mortality Composting B. Invasive Species Composting C. Testing of Feedstocks D. Quality Controls for Sale of Finished Compost E. Working with Food Scrap Generators and Haulers to Minimize Vectors and Contamination F. Fire Prevention G. A Guide to Monitoring Compost Windrows Acknowledgments
2 2 6 6 6 7 8 9 10 11 12 14 14 16 17 18 22 22 23 25 25 27 28 29 39
1
Introduction This Management Plan Template has been written as a resource for egg farmers who will be feeding Source-Separated Organics (SSO), also referred to in this document as “food scraps,� to their laying flock as a primary feed source. As increasing tonnages of organic materials in Vermont are diverted from landfills in accordance with the 2012 Universal Recycling Law, recycling SSO as animal feed on farms is seen as a viable recycling strategy, although much is still not understood about this as a practice. The Management Plan describes the basic physical facilities and management protocols for operating a chicken-feeding and composting operation in accordance with Best Management Practices on farms. Farmers can use this plan as a reference for planning and managing an on-farm feeding/composting operation. Sections 1 & 2 describe general Best Management Practices central to feeding, handling, and composting SSO. Appendices A-G that follow contain specific information related to issues that may arise or be of interest to operators.
1. On-Farm Feeding and Composting System Components The physical site is divided into seven parts; (a) Carbon Materials and Feedstocks Storage Area, (b) Receiving and Mixing Bay, (c) Chicken Housing, (d) Chicken Feeding Area, [(e) Aerated Static Pile Composting System-where applicable] (f) Windrow Composting Area (g) Compost Curing and Storage Area, and (h) Vegetated Stormwater Treatment Areas. a) Carbon Materials and Feedstocks Storage Area – To ensure sufficient dry matter for chicken bedding and in the compost recipe, dry carbon materials will be stored under cover when possible. If cover is unavailable, dry feedstocks will be managed to shed water
2
and maintain low surface-to-volume ratio. Other feedstocks such as manure and yard waste will be managed in the same manner. b) Receiving/Mixing Bay – Receiving and blending of food scraps will generally take place in a designated, contained area which has an adequate working surface for tractor operation and which is, ideally, impermeable to liquids (e.g., leachate and storm water). Food scraps and any other high moisture, high nitrogen feedstocks, such as dairy manure, will generally be handled here; however, the operator may receive and blend materials directly on the Active Composting Area, or in the Feedstock Area, at their discretion. Food scraps will be combined with the dry carbon materials. Additionally, after the totes and trucks containing the food scraps are emptied in this area, they may also be cleaned here. After being fed to the laying flock, residual food scraps and blended materials will be moved to the Windrow Composting Area with the bucket-loader. Leachate capture is further detailed in Section D: Conservation Measures (p.19). The Receiving/Mixing Bay will be designed to either contain leachate where it can be absorbed with sawdust or another dry material, or shed to a vegetative treatment area. c) Chicken Housing – In the winter months, chickens will be housed in a stationary structure such as a high tunnel or wood-frame coop. The interior square footage of the coop will provide 2 sq. ft./bird, in accordance with 2011 NOSB recommendations. Access to an outdoor area equivalent to 2 sq. ft./bird will be provided. The housing will provide draft-free shelter to the flock in inclement weather. Chicken Housing will be adjacent to the Feeding Area in order to facilitate efficient feeding. Fencing surrounding the Chicken Housing will serve
3
to exclude the chickens from composting areas and neighboring properties. The Chicken Housing may house the laying flock year-round, at the operator’s discretion. If the laying flock is rotated on pasture during the growing season, alternative mobile shelter will be used during that time, and feeding practices will be adjusted accordingly (see 2-B: Chicken Feeding). d) Chicken Feeding Area – Food scraps blended with amendments will be fed to chickens daily in a designated Feeding Area. The area will be constructed of like material to the Receiving/Mixing Bay in order to provide an adequate working surface. At the operator’s discretion, the chickens may be fed directly in the Receiving/Mixing Bay, effectively consolidating the Receiving and Feeding Areas into one space. If this method is used, care will be taken to ensure that the flock is provided with access to adequate daily rations of food scraps equivalent to 2 lbs/day per bird. The Feeding Area will be sized in order to store a minimum of 1 week of blended food scraps and amendments at the determined feeding rate. Fencing surrounding the Chicken Feeding Area will serve to exclude the chickens from neighboring properties and actively managed compost areas. If the laying flock is housed in the Chicken Housing area year-round, the Feeding Area will also be used year-round. If the laying flock is rotated on pasture during the growing season, alternate feeding methods will be utilized accordingly (see 2-B: Chicken Feeding).
4
ASP Operator’s Note: e) Aerated Static Pile Composting System – After blended compost has been made available to the laying flock as feed, residual compost will primarily be composted in an Aerated Static Pile (ASP) System. The ASP system will be aerated with an in-floor aeration system. Aerated static piles may also be constructed with above-grade perforated pipes. Blowers will push air through the compost (positive aeration) to maintain aerobic conditions throughout the material.
f) Windrow Composting Area – Once a compost batch is blended and removed from, it will be formed in windrows in the Windrow Composting Area to undergo active composting. Windrows will be formed and managed with the bucket-loader. The working surface of the Windrow Composting Area will be constructed with a firmly packed aggregate product or other impermeable working surface. g) Compost Curing and Storage Area – Compost that is no longer actively heating will be cured in the Compost Curing Area. At this stage, piles may be consolidated and stacked higher in order to minimize wetting and freezing from inclement weather conditions. h) Vegetative Treatment Area – All non-contained composting areas are graded to allow any potential leachate, nutrients, or storm water to flow towards a vegetated treatment area. Any liquids that flow to the vegetative treatment area will be retained and treated there. Clean storm water will be diverted wherever possible from composting areas.
5
2. Chicken Feeding, Feedstock Management and Compost Management A. Equipment ! Wheeled loader or tractor-mounted bucket-loader ! Aerated Composting System ! Pressure Washer ! 36� Compost Thermometers ! Hand tools: shovels, hayforks, etc.
B. Chicken Feeding ! Food scraps will be capped with high-carbon feedstocks promptly after tipping to deter odors and scavengers. Following that, food scraps will be made accessible to the laying flock. ! Chickens will be given daily access to amounts of food scraps equivalent to 2 lbs food scraps/bird/day or greater. The operator will establish regular tipping of a generally specified amount of food scraps in order to ensure adequate supply of feed for the laying flock. Weekly loads will be procured in amounts sufficient to meet the flock’s daily requirements. ! Assuming the laying flock is housed in the Chicken Housing area, feeding will take generally place either in the Receiving/Mixing Bay or in a designated Feeding Area directly adjacent to the Receiving/Mixing Bay. ! If the flock is fed in the Receiving/Mixing Bay, the pile of blended feed will be managed with the bucket loader to expose fresh feed in
6
amounts equivalent to 2 lbs/bird/day. If the laying flock is fed using this practice, measure will still be taken to empty and prepare the Receiving/Mixing Bay in order to receive regular loads of food scraps. ! If the laying flock is rotated on pasture during the summer months, the food scraps will need to be brought to the flock, rather than the flock eating in the Feeding Area. This will be accomplished by loading daily rations in a wagon, manure spreader, or other mobile container. ! The Feed Pile will be capped with high-carbon amendments as necessary in order to control odors and vectors. Any pooling or flowing leachate in the feeding area will be absorbed with dry material such as sawdust. ! Care will be taken when operating the tractor around the flock to ensure that chickens are not injured. Extra care will be taken in the winter when chickens move more slowly due to cold temperatures.
C. Feedstock Management ! Incoming food scraps will be delivered to the Receiving/Mixing Bay; however at the operator’s discretion these materials may be received and blended directly in the Windrow Composting Area (or ASP Area) or in the Feedstock Storage Area. ! Food scraps will be capped with adequate carbon materials and manures to control odors and vectors. Refused food scraps will be incorporated to achieve a proper composting recipe. ! In winter months, blending biologically active feedstocks such as manures or actively decomposing woodchips and bark will assist in
7
thawing frozen food scraps and making them more available to the flock as a feed source. ! Dry high-carbon materials will be used as bedding in the Chicken Housing. Spent bedding will be utilized as a compost feedstock when cleaned out of the coop, either on a regular or seasonal basis. ! Dry carbon and bulking materials will be managed to protect them from moisture as much as possible. Large volumes of carbon and bulking materials may be stored and blended on the Windrow Composting Area at the operator’s discretion.
! If the farm is able to utilize delivered or on-farm-generated manures in the compost, handling and storage of livestock manures and other farm wastes will be contingent on the character and volume of the material, and the need for that material at the time of blending. These materials may be delivered to the Feedstock Storage Area, the Receiving/ Mixing Bay, or the Windrow Composting Area (or the ASP Area) at the operator’s discretion.
D. Pile Blending ! A compost recipe will be developed based on the aerobic management of food scraps and manure, which are both high nitrogen, high moisture feedstock. The mix will be achieved by blending the food scraps with dry high-carbon materials, based on analytically developed recipes, to achieve a Carbon to Nitrogen Ratio of between 25:1 and 40:1, a Moisture Content of between 50% and 65%, and a bulk density between 600 and 1200 lbs/cubic yard of blended material.
8
! Blending to achieve the compost recipe will take place in the Receiving/Mixing Bay either prior to or after feeding, at the operator’s discretion. If the recipe is achieved after feeding, sufficient amendments will still be added prior to feeding to control leachate, odors, and vectors. The combined feedstocks will be thoroughly mixed. ! Because the laying flock will consume a significant quantity of the received food scraps, the compost recipe will be based on the estimated amount of residual food scraps after feeding.
E. Windrow Composting ! Compost will be stacked in windrows on the Windrow Composting Area. Windrows will be built 5-7 ft High and 10-14 ft wide at the time of construction. At this time, other amendments may be blended in, as necessary to ensure active composting. Windrows will be actively managed and turned as needed to maintain aerobic internal conditions. ! Once stacked in windrow formation, fresh piles will be capped as necessary with well-bedded manure, finished compost, or other compostable material with good potential for odor absorption, to prevent odors and vectors. Compostex compost covers or a like product may also be used, if needed to mitigate vectors. ! Windrows will typically be constructed of batches over a 1-8 week period. After initial volume losses and temperature goals are met, piles of similar age (3-4 month range) may be combined to conserve space. Placement of piles in pairs will facilitate organized and effective pile consolidation and tracking.
9
ASP Operator’s Note:
F. Aerated Static Pile Composting ! After feeding and prior to windrow composting, residual blended materials will be stacked 5-8 ft high in the Aerated Static Pile Composting Bays (height depends on the system’s capacity). These materials will be retained in the aerated system, and then moved to the Windrow Composting Area to continue composting in windrows and finish the active composting phase. ! The Aerated Static Pile system contains aeration channels capable of pulling or pushing air through the composting materials at a rate adequate to maintain aerobic conditions. The operators will use their discretion to increase or decrease the frequency and duration of aeration in order to maintain optimal composting conditions. ! The contents of the Aerated Static Piles will ideally be turned after 2-4 weeks by rotating the material from one aeration zone to another, to ensure the compost has been re-homogenized during the mostly static process. This mixing process discourages preferential air channels and promotes even composting. After compost has completed the static process, it will be moved to the Windrow Composting Area, where it will be formed into windrows and managed. ! Aerated Static Piles will be managed to achieve 131 degrees Fahrenheit for 3 days throughout the pile, during which time even air distribution and pile activity will ensure all materials are exposed to thermophilic temperatures. ! ASP piles will be capped (covered) as necessary with well-bedded manure, finished compost, or other compostable material with good potential for odor absorption, to prevent odors and vectors. Compostex
10
compost covers or a like product may also be used, if needed to mitigate vectors.
G. Monitoring ! Monitoring of the active composting materials will inform the operator of the piles’ biological activity, as well as physical and chemical factors affecting the pile’s health and function. Monitoring will ideally occur at least twice per week. ! Temperature – Three-foot temperature probes will be used to monitor the compost piles. Temperature checks will be done in the middle of the pile (height) every ~10-15 feet on windrows, and distributed across the side and tops of ASP piles every ~10-15 feet. Temperature readings will be taken at depths of one and three feet. Temperatures will be recorded and used, in part to determine when to aerate. ! Squeeze Test – The operator will use a common field assessment for moisture known as the “squeeze test,” to monitor the moisture of the piles (Appendix G: Monitoring Compost Piles: Why & How). The squeeze test has been documented as a reliable field method for assessing pile moisture. The operator will manage the windrows to maintain 50-65% moisture. If significant moisture issues are noticed, the cause will be identified and the issue will be addressed promptly. ! Sniff Test - The operator will observe and monitor any odors generated by the site and/or individual piles. This can be done every time the site is visited. If significant odors are noticed, the cause will be identified and the issue will be addressed promptly. Generally most
11
odor problems can be addressed by correcting pile moisture and carbon-to-nitrogen ratios. ! A visual inspection of the site and the piles will be conducted whenever the operator enters the site. Such inspections will note if there is excessive moisture on the site and where it is coming from, the conformation of the piles, signs of vectors, visible food scraps, and any other signs of potential problems. If significant problems are noticed, the cause will be identified and the issue will be addressed promptly. ! Moisture issues deriving from excessive pile moisture will be addressed by correcting pile moisture with the addition of dry amendments. Leaching will be addressed by correcting pile moisture and by capturing leachate, by building berms of sawdust or wood chips around the pile to absorb the leachate. Saturated berm contents will eventually be incorporated back into the pile. ! Specific monitoring protocols are outlined in Appendix G: Monitoring Compost Piles: Why & How. Please refer to this guide for how to conduct monitoring and how to interpret monitoring results.
H. Pile Management ! Compost will be managed to maintain optimal microbial activity, aerobic conditions, and minimal trash contamination. ! Active compost piles will be tracked by pile name, recipe, starting date and finishing date. Recording monitoring data and management notes assist in assurance of temperature treatment and in tracking any potential management or contamination issues.
12
! Windrows will be aerated by turning. Turning of material will in large part be based on pile age and temperature as an indication of microbial activity, as well as other monitoring information gathered. When a windrow’s temperature peaks and starts to go down, or when there is a 20 degree difference between one foot and three foot temperature readings, the pile will be turned to restore the availability of oxygen, or in some cases, to release heat to cool the pile. ! Piles may also be turned to adjust moisture content, improve the homogeneity of the mix, integrate additional materials, or ensure efficient management of the composting area and process. ASP Operator’s Note: ! Aerated Static Piles will be managed to achieve 131 degrees Fahrenheit for 3 days throughout the pile, during which time even air distribution and pile activity will ensure all materials are exposed to these temperatures.
! Windrowed piles will be managed so that all of the material achieves 131 degrees for at least 3 days. This would involve sufficient turning to ensure all materials are adequately exposed to thermophilic temperatures. This is known as the Process to Further Reduce Pathogens, or PFRP. This practice should meet organic standards, but refer to your local organic regulations to ensure your practices meet their guidelines. ! Chickens will be excluded by means of fencing or other deterrent from all compost piles that have begun tracking temperatures to meet PFRP, in order to avoid contamination of compost with freshly
13
deposited manure. (This is especially important if the compost is used as “compost� on an organic farm vs applied as a manure.)
I. Compost Curing and Storage ! If cured compost is a goal for the farm, curing of compost will occur after the thermophilic composting process is complete and temperature has dropped below 90 degrees Fahrenheit. ! The curing pile can be 6-10 feet high by 14-20 feet wide at the base. Curing piles do not require workspace around them and may overlap at their bases. ! The compost will generally be allowed to cure 1 - 3 months. Cured compost will typically exhibit temperatures at or near ambient temperature, and not re-activate after aeration. After curing, compost will be stored on-site until it is used. If the compost will be sold, it can be screened, bagged and sold after curing. Cured and stable compost may be stockpiled in large piles up to 15 feet high and as wide and long as necessary, provided the moisture of the material is below 55%. Active aeration is not necessary at this time to maintain aerobic conditions in the compost, due to the low levels of biological oxygen demand.
J.
Odor Control ! Rapid, same-day incorporation of food scraps with high-carbon feedstocks, to achieve target recipe parameters when they are brought to the farm, will prevent putrefaction, stabilize odor-causing
14
compounds, and ensure rapid establishment of active aerobic composting. ! All piles containing food scraps will be “capped� as needed with an odor absorbent material such as well-bedded horse manure or finished compost. This practice is applicable from the point at which the food scraps are received in the Receiving/Mixing Bay to the point at which the compost pile has met PFRP. ! The operator will pay attention to odors when around active piles. ! The operator will utilize regular monitoring practices and review of monitoring results to effectively manage aerobic composting, thus preventing strong odors. ! The operator will take prevailing wind direction, atmospheric conditions, time of day, feedstocks, and pile conditions into account when making decisions regarding mechanical blending, moving, or aerating. ! The operator will maintain a clean composting area, ensuring all food scraps are incorporated into piles, and that organic materials are scraped from the compost pads with the tractor bucket regularly. ! If odors are present, the operator should refer to Appendix G: Monitoring Compost Piles: Why & How, and/or address the issue with the following basic strategies. Odors will be addressed through corrections in the compost recipe, aeration, and pile capping. For example:
15
o If fresh food scrap odors are strong, piles will be capped with a compostable material that has a high odor absorbency capacity, such as well-bedded horse manure. o If ammonia odors are an issue, the operator will incorporate more available carbon materials into the pile, such a hay, office paper, or sawdust. ! If odors persist after preliminary efforts to remediate the problem, or if experiencing odors not addressed here, the operator will seek technical assistance.
K. Vector Control ! Vector control will be addressed through preventative action, and begin at the place of generation. The operator will work with haulers to ensure that measures are taken to prevent fly access to the food scraps, generally through frequency of collection, or food scrap capping with sawdust between collections in the summer months. Applied at least four inches thick, sawdust will prevent the infiltration of flies, thus eliminating the presence of maggots in the food scraps when they are collected. ! Attention to proper recipe development, handling and mixing will reduce most concerns associated with vectors. ! Food scraps will be capped with dry, high-carbon feedstocks within the same day as receiving, if not immediately upon receiving, which will greatly reduce any odors that will initially attract vectors. ! After being fed to the laying flock and stacked, compost will be capped as necessary to minimize attraction of vectors. Capping
16
piles with a porous yet absorbent material, such as horse manure, will minimize pile odor and exposed raw materials. ! Proper mixing, pile making, and monitoring outlined in this Management Plan will rapidly achieve thermophilic conditions in the piles, and thus will alleviate odor and environmental conditions in the pile that might be attractive to animals, and will begin degrading the food scraps. ! Careful control of moisture both in the piles (through mixing, moisture balancing, and bulking) and on the site (through scraping, grading, and otherwise preventing ponding) will limit fly breeding potential. ! Pile covers will be used when possible or necessary on outdoor windrows containing fresh food materials, in order to prevent vector access to food material.
L. Litter Control ! Control of trash contamination starts in the businesses and schools separating their food waste for collection. Ensure that businesses and schools participating in the food scrap collection program will have effective employee and student trainings in proper source separation procedures, to prevent the contamination of food scraps with trash. Participant education and awareness have been shown to dramatically reduce the presence of trash in organic materials. ! Require haulers collecting and hauling food scraps to the facility to visually screen loads prior to accepting them. Contaminated loads may be rejected at the source of generation and the hauler can
17
provide feedback to the business and schools with contaminated loads. ! Should trash be identified, it will either be removed or the load will be rejected. Active communication with farmers, residents, landscapers, haulers and other partners will ensure that expectations regarding feedstock quality are clear. ! Any trash that makes it to the site will be handpicked, as it becomes apparent. A barrel with a lid will be kept on site for collecting trash on each pad, including the Receiving and Mixing Bay. ! All trash and recycling and other discarded materials will be managed in accordance with local municipal, state and federal laws.
M.
Conservation Measures Protection of surface and ground water will be generally achieved through effective site planning, materials management, windrow monitoring, and effective pile management. Test pits dug on the site to a depth of at least 72� should show no signs of seasonally high ground water or bedrock. The operation will not be sited in a flood plain, in a well protection area, or in a Class I, II or III wetland.
18
The following measures will be implemented to manage specific moisture concerns: Storm water ! Clean storm water will be diverted away from all composting areas wherever possible. ! The Active Composting Area will be graded at a 2-4% slope, which will drain storm water to a vegetated treatment area along the edge of the pad. No storm water should accumulate on the Composting Areas. The vegetated treatment area will absorb moisture, nutrients and sediment. ! Compost windrows will be oriented with the slope of the Composting Areas, in order to facilitate the movement of storm water off the pads, so it will have the least contact possible with the windrows, and therefore, the least contamination possible of the storm water. ! The operator will maintain all areas free of debris and organic matter, to minimize contact between these materials and storm water. ! Clean storm water will not comingle with storm water from the composting areas (leachate). The vegetative treatment areas will facilitate filtration to ensure treatment and sediment retention, prior to infiltration and recharge to localized groundwater.
Ponding ! Ponding will be avoided through good site maintenance. After turning active piles, the operator will scrape the site with the bucket blade or scraper/leveler in order to level any ruts and prevent potential ponding sites.
19
! Due to the slope of the compost pad and the low permeability of the packed aggregate material, little moisture is anticipated to accumulate on the site surface. If ponding does occur, the pad surface will be repaired to eliminate low spots.
Leachate ! Control of leachate will be largely achieved through prevention, via proper recipe development: sufficient amounts of dry, absorbent feedstocks will be used to create a compost blend with ideal moisture content (50-65%). During periods of excessive rain, recipes will reflect lower starting moisture content (MC), in order to increase pile capacity to take up precipitation without releasing leachate. ! Moisture content of the piles will be monitored regularly using the squeeze test method. High MC will be addressed before the piles reach saturation, to prevent the movement of free moisture from the piles. Pile moisture above 60% will be closely monitored and the operator will add dry matter to the pile if MC exceeds 65%. ! Careful and regular visual inspection of the piles will alert the operator to the presence of any leachate, and will further allow the operator to specifically identify the source of leachate in order to remediate it. ! If leaching does occur, the operator will construct a berm of sawdust or finished compost immediately downslope of the pile, or specific locations on the pile from which leachate is originating, to absorb the leachate. Saturated sawdust or compost will be incorporated into the windrow after the event, and composted.
20
! The use of windrow covers (Compostex or a similar product) will be considered to minimize additional precipitation onto the piles, if leachate does become an issue. ASP Operator’s Note: ! The Aerated Static Pile System will ideally be under cover and protected from influxes of precipitation into the pile, a circumstance that can lead to leaching. ! The Aerated Static Pile System may have an impermeable floor, which channels any pile leachate on slope through a sealed leachate collection system. The leachate collection system will deliver any leachate to a holding tank, where it will be retained, and reincorporated into a fresh blend of mixed compost to meet PFRP. ! Any Aerated Static Piles constructed outdoors and not drained into an operable leachate collection system will be sited on a grade which allows leachate to sheet-flow from the ASP pile towards a vegetated treatment area.
Livestock Exclusion ! Chickens will be excluded by means of fencing from any surface waters or seasonally high water tables to avoid nutrient runoff and groundwater pollution.
21
N.
Contamination Control ! Efforts will be made to source contaminant-free materials as feedstocks for composting. For control and prevention of trash as a contaminant, please refer to section L: Litter Control of this plan. ! Incoming agricultural manures and beddings (especially horse manure) will be sourced in a manner to avoid contaminating the compost with persistent herbicides. All efforts will be made to trace the manure back to the original feed source to ensure absence of pyralid-type persistent herbicides. ! Any trash that makes it to the site will be hand-picked, as it becomes apparent. A barrel with a lid will be kept on site for collecting trash on each pad, including the Receiving and Mixing Bay.
Appendices Appendix A Livestock Mortality Management ! If the farm needs to compost large animal carcasses, mortality piles will be built to Vermont Agency of Agriculture’s standards of 2’ of coverage with carbon-based feedstocks on all sides of the carcass. ! In the case of avian disease affecting the laying flock, several chicken carcasses may be composted in the same manner to a large farm animal, according to the management practices as follows. Individual chicken carcasses may be added to new active compost piles.
22
! Chicken mortalities will be inspected to assess the risk of disease within the laying flock, and appropriate remediation measures will be taken as necessary. ! Mortality piles will be managed as a static pile to reduce odors for the first 2-3 months (based on species and size of animal and pile monitoring) and aerated at 3 months. After three months the piles will be actively managed for aerobic conditions as needed, following the initial thermophilic stage. ! In the occurrence that there is detection of odor from the mortality piles, the operator will cap the pile as necessary with additional absorbent carbon material or bedded manure to suppress the odor. ! Mortality piles will be monitored for temperatures, odor and leachate weekly, and any problem with odor or leachate will be rectified by capping with wood chips or sawdust, if deemed necessary. Severe leaching will be remedied by reconstructing the pile with more adequate dry matter in the base, if necessary. ! Finished mortality compost will be blended with fresh active compost piles and will go through a secondary thermophylic process, where it will meet PFRP while being actively turned.
Appendix B Invasive Species Composting Management ! The farm may accept and compost invasive species such as Japanese knotweed and Eurasion Milfoil at the discretion of the Facility Operator.
23
! Class A and B Noxious Weeds on the State Quarantine List will only be accepted and composted with the approval of the VT Secretary of Agriculture. (Check VT AAFM for most Current List) ! The operator will make efforts to ensure that any accepted Invasive Species can be effectively managed through thermophilic composting conditions. ! If a significant volume of invasive species plant material is expected, feedstock analysis will be performed and a recipe will be developed to ensure active composting, as with any other new material. ! Invasive weeds will be received and blended in the Receiving/Mixing Bay. Material will be managed as with any other material, to ensure complete inactivation of potentially harmful plant parts, such as the rhizomitous roots of Japanese Knotweed. ! The facility operator will not accept any invasive plant materials that have gone to seed, if that seed may disperse from the plant’s seed heads. ! Compost piles containing invasive species as a feedstock will be tracked distinctly from other compost, and a germination/root growth test will be performed prior to distribution of the finished product. If any viable seed or plant parts remain, the material will be re-composted. ! The operator will require that haulers delivering these plants conform to Best Management Practices, including keeping vehicles hosed down and plant matter contained by a tarp. ! Equipment used for handling invasive plant materials will be visually inspected for seeds and plant matter after handling occurs, and cleaned accordingly.
24
Appendix C Testing of Feedstocks ! New feedstocks or existing feedstocks whose characteristics have changed significantly should be analyzed for %C, %N (total, organic and nitrate), C:N, % Dry Matter, Conductivity, pH, bulk density and other characteristics as needed to ensure effective recipe development. ! Feedstock sampling will be done according to industry standards for sampling protocol, ensuring a representative sample. ! On-going testing of feedstocks is not required once the basic recipe has been established (assuming feedstock streams are consistent); however periodic testing is recommended. ! Penn State, University of New Hampshire, University of Maine and Woods End Lab, as well as other university and private labs, all provide feedstock analyses that provide sufficient information for the purpose of recipe development.
Appendix D Quality Controls for Sale of Finished Compost ! Compost will be deemed finished when the temperature throughout the pile is less than 100 degrees Fahrenheit, at which point it may cure for 1-3 months.
25
! Monitoring records will be kept for the purpose of documenting sufficient heating for the purpose of pathogen and weed seed destruction. All monitoring will occur at least twice per week. Monitoring records will be stored in a safe, dry location for five years. ! Solvita Maturity Testing, Dewars Self Heating test, or other maturity tests will be conducted on a representative sample of finished compost at least 2 times per year. ! Finished compost will be analyzed at the operator’s discretion for the purpose of assessing product quality. ! Finished compost for sale may be analyzed periodically for the presence of the contaminants shown in the table below: Parameter
Maximum Total Concentration (mg/kg dry weight)
mercury
10
cadmium
10
nickel
200
lead
250
chromium
1000
copper
1000
zinc
2500
PCB, total
1
Fecal Coliform
1000 MPN/g total solids (dry weight)
Salmonella
3MPN/4g total solids (dry weight)
26
! Penn State, University of Maine, University of New Hampshire, and Woods End Lab all provide compost analyses that provide sufficient information for the purpose of assessing the presence and load of contaminants in the finished compost. ! Routine testing of finished compost should include % N – total nitrogen, % N - nitrate, % N – organic nitrogen, % P, % C, pH, conductivity, bulk density, and stability. Other nutrients of interest include Ca and Mg. ! Weed seed germination tests will also be conducted regularly to assess the efficacy of weed seed destruction.
Appendix E Working with Food Scrap Generators and Haulers to minimize Vectors and Contamination ! Efforts to achieve vector and odor control for food scraps begin at the source of generation ! In most instances, collection from commercial and institutional food scrap generators should be on a weekly or bi-weekly basis ! In warm weather, food scrap generators should be provided sawdust to cover full totes of food scraps to prevent odors. Generators are also encouraged to store their totes in shaded or cooled areas. ! After the generator’s totes have either been removed or emptied, the empty tote is lined with an absorbent material, such as sawdust, during the summer season and in some cases throughout the year. This material
27
absorbs free moisture, which tends to accumulate at the bottom of the tote and produce odors. ! Litter control will be focused in the businesses and schools separating their food waste for collection. All businesses and schools participating in the food scrap program will be trained in proper source separation procedures to prevent trash contamination of the compost. Participant education and awareness have been shown to dramatically reduce the presence of trash in organic materials. ! Require haulers collecting and hauling food scraps to the facility to visually screen loads prior to accepting them. Contaminated loads will be rejected at the source of generation and the hauler should provide feedback to the business and schools with contaminated loads. ! Incoming loads of other feedstocks, including manures and landscaping debris, will be inspected by the operator upon arrival. Should trash be identified, it will either be removed or the load will be rejected. Active communication with farmers, residents, landscapers, haulers and other partners will ensure expectations regarding feedstock quality are clear.
Appendix F Fire Prevention ! Careful and consistent monitoring of piles during their thermophilic stages will help the operator identify any concerns of potential combustion. The pile volumes and material characteristics of this operation are such that fire is very unlikely. Measures to minimize fire concerns include: ! Feedstocks and compost piles will not be piled higher than 12 ft.
28
! In the case of extreme heating and low MC in a pile, the operator will apply water to the pile and turn it to dissipate the heat and combustive conditions. ! If piles exhibit potentially combustive factors and the step above is either not possible or shows little effect, the pile will be knocked down until it has been adequately reduced in mass to eliminate the potential for combustion. ! The composting operation will be equipped with fire extinguishers.
Appendix G
Monitoring Compost Piles: Why and How Introduction Monitoring compost piles is done for several reasons. Primarily, monitoring is done to provide the composter with insight as to what is happening in the compost pile during composting, such as the microbial activity and other pile conditions that will impact microbial activity. This information can in turn impact the management choices you make in your composting operation, regarding the specific piles you are monitoring and/ or how you make and manage compost in general. Monitoring provides you with a feedback loop for maintaining optimal composting conditions and producing a quality product. For example, temperature monitoring can be very useful in determining when a pile should be turned to sustain optimum microbial activity. Additionally, monitoring also provides some information and documentation regarding the finished product and how it can be used. For compost used within 90 days of the planting of Certified Organic edible crops, documentation is required that demonstrates the compost reached specified time/temperature requirements. These
29
regulations are designed to ensure pathogen-free compost to protect consumer health. Meeting these criteria may be of interest to Certified Organic farmers wishing to apply compost within 90 days of planting edible crops or composters who sell to such growers. Either way, monitoring is a simple process that provides the composter with practical information that will help to improve and/or maintain a high quality of composting. When to monitor Monitoring is something that should be done to one extent or another every time you walk by your compost piles. To paraphrase an old Chinese proverb, “The best fertilizer is a farmer’s footsteps.” The composter’s attention is the best ingredient for making good compost. In fact, good compost will require a little more than attention, but attention will be a primary factor of ensuring good quality composting, as it will help you correct small issues before they become big problems, as well as helping you learn from your piles and refine your practices. Monitoring your piles, for specific feedback such as temperature, or informally by taking notice of them and being aware of changes, is a good management practice. Monitoring is most important during the first two to three months of pile activity, and should be done on farms at least weekly. Since monitoring should inform your management decisions, more regular monitoring is useful if it can be integrated into your farm system. How to monitor your compost In building and managing compost, you are primarily trying to ensure that you have created suitable habitat for the decomposer organisms that you want to decompose your feedstocks. Likewise, your pile monitoring is designed to assess the health of the pile habitat. There are four primary monitoring practices that you should employ to one degree or another. These are: pile temperature; pile moisture content; pile odor; and a visual inspection of the site and piles. These monitoring techniques are
30
listed below, with a short description as to why the specific monitoring practice is performed, the tools required, how the monitoring is performed, and general recommendations for the operator response. When monitoring, it is important to consistently monitor the pile in the same locations, to provide the operator with an accurate picture of the pile over time. While not discussed here, monitoring pile oxygen is also a useful practice to consider.
Pile Temperature: 1. Function – The pile temperature is primarily a product of the microbial body heat being generated in the pile from microbial activity. Pile temperatures can also be affected by the physical characteristics of an individual material (more versus less insulating) and the pile, as well as chemical reactions and external environmental variables. Pile temperatures are an imperfect but useful indication of microbial activity. Newly formed piles commonly reach or exceed 130 degrees within several days to several weeks of pile construction. Piles constructed during extremely cold weather or with frozen feedstocks will take longer. If you are trying to ensure weed seed and pathogen destruction, you will need to obtain 130+ degree temperatures for several days, and obtain these temperatures again following at least two turnings. 2. Field Tools – Compost temperature probe. We recommend using a 3’ probe with a 5/16” stem. In colder climates or on large sites, temperature probes with quick response stems can be useful. 3. How to measure – Pile temperatures should be taken roughly every 5 – 25 feet along the pile, depending on the total pile length. Additionally, temperatures
31
should be taken at depths of 12” and 36”. The probe should be left in place for at least one minute, or until the dial stops moving. 4. General Responses – Temperature will impact your decision to turn or not turn a pile, as well as whether factors in your pile recipe need to be adjusted. There may be a number of reasons for depressed temperatures, such as a C:N ratio that is too low or too high, high or low moisture content, compaction in the pile, or excessive pile density. Low temperatures that correlate with a high or low moisture content, determined through moisture monitoring, can be addressed generally by addressing the moisture issue. If you are experiencing low pile temperatures and moisture is not the issue, your C:N ratio or the pile density are the next issues to explore. If everything in your pile recipe seems fine, try turning the pile once to mix and aerate it. If your pile is heating, your temperature monitoring will help you determine when to turn the pile. Based on temperature, you will want to turn your pile after your pile’s initial heating has peaked and is beginning to decrease, or if your pile temperatures at 12” are consistently 20 degrees different than those at 36” throughout the pile. Additionally, if your pile is heating very well and your temperatures have gone above 150 degrees, you should consider turning your pile to cool it down and leverage the microbial activity most efficiently to prevent excessive loss of nitrogen and, potentially, spontaneous combustion if the mix is dry and high in carbon.
Pile Moisture: 1. Function – Moisture in the pile is a critical factor regarding the pile conditions for microbial activity. If you have too much or too little moisture, microbes cannot survive or function effectively. You are targeting a moisture content of roughly
32
60%. Pile moistures of 50-65% are okay; however moisture levels beyond these two parameters should be addressed. Moisture surrounding the pile can also adversely affect the composting process, as it will inhibit the oxygen intake of the pile through its sides. Standing water around the piles will result in the saturation of the pile base, creating undesirable, anaerobic conditions. Anaerobic conditions, in general, can cause odors, losses of nitrogen and carbon, the development of phytotoxins, and reduction of product quality (especially for seedling and transplant applications). 2. Field Tools – Hand, eyes. 3. How to measure – Take a handful of compost in one hand, remove excessively large particles and squeeze the material. Watch for water dripping freely from your hand, and observe the space between the fingers, looking for signs of excess moisture. If the contents in your hand begin to drip moisture from between your fingers, the moisture content is likely above 65%. If there is no dripping, but the moisture glistens between the fingers, the moisture content is roughly 60-65%. If no moisture is seen, open the hand palm up so that the contents remain on the palm. If the contents remain in a ball, depending on how tightly they remain in their form (as well as the pile ingredients and the age of the pile), your moisture content is 50-60%. If the contents fall apart, your moisture level is below 50%. A visual inspection of the pile and the surrounding site will also provide you with feedback regarding moisture. Site moisture and pile moisture may be connected or not, and therefore clarifying where the moisture is originating, from the pile or the site (including water coming onto the site from the surrounding environment), is important.
33
4. General Responses – If your moisture content (MC) is high (above 65%), you need to dry out your mix. If the mix is not significantly greater than 65%, simply turning the pile may achieve the desired drying effect. Turning, as well as general exposure to dry climatic conditions, can reduce pile moisture over time, and in dry climates, operators may mix to a higher than optimum moisture content to offset the drying effects of the air in the feedstock mixing and pile formation process. One further step along these lines that can be taken is to simply open the top of the pile up with the tractor bucket and allow the air to dry it for a couple of days before reforming it (this basically creates more surface area from which the air and wind can wick away moisture from your mix). If the mix is significantly more moist than 65%, the addition of dry matter is usually required (though in some cases, multiple turnings over several dry days may be sufficient, if the weather is dry). This can be done by opening the top of the pile with the bucket, forming a trough, adding some dry matter, and then rolling or otherwise turning the pile to incorporate the material. Windrow turners are particularly effective for drying the pile mechanically. If your pile moisture is below 50%, the addition of moisture is required. In some cases, impending rain may sufficiently wet the pile. When you are adjusting pile moisture up or down, you need to be careful not to adversely impact the pile recipe in other ways, such as C:N ratios. If you are bringing the MC down, the use of neutral C:N ingredients (those around 25-30:1) with low MC will help. Ingredients like dry, heavily-bedded horse manure, hay or small ruminant bedding often meet these criteria. If you are bringing up your pile moisture, water may be an effective way of increasing the moisture while not impacting the C:N (rain may easily suffice). This can be a good use for leachate or dirty storm water collected from the site, if the pile is still actively achieving thermophilic temperatures (to ensure pathogen destruction). If other indicators of pile health are good and your MC is on the low side, but within the acceptable range (50-
34
55%), minimizing pile agitation will help to retain as much moisture as possible until the pile is naturally moistened by rains. Site moisture resulting from the pile, or leachate, is indicative of excessive pile moisture, and the pile moisture requires significant adjusting. Site moisture from rain, runoff or flooding may also impact your pile management. Ponding on the site is problematic and can limit site access, turning capabilities and reduce the pile’s ability to passively respire. Addressing the reasons for site ponding is important to prevent on-going issues. Pile orientation should be roughly with the slope of the site to prevent ponding. Site management practices, such as scraping ruts on the site after working on the site, will reduce low spots where moisture will accumulate.
Pile Odor: 1. Function - Being aware of odor occurring in the pile will provide the operator with indicators of the internal dynamics of the pile and may direct management choices. Odors from compost piles and composting feedstocks are commonly associated with the release of nutrients or carbon in their gaseous form, Volatile Organic Acids (VOAs), or other chemical compounds. VOAs are a natural byproduct of microbial decomposition; however, they have a high odor potential and can accumulate in excess (becoming phytotoxic) under air-limited and/or low pH pile conditions. 2. Field Tools – Nose 3. How to Measure – Take note of the smell of the site and individual piles by consciously breathing in through your nose while working around the piles, including during monitoring and turning. You may be able to isolate the odor to a certain portion of a pile.
35
4. General Responses – A compost pile should generally smell earthy. Subtle odors from the pile may indicate potential problems or areas to improve upon in the next batch of compost, but may not be of specific concern. Additionally, some odors may be noticeable when raw feedstocks are combined, as well as when fresh compost piles are first turned. While these unsubstantial odors may not require an operator’s response, they should also not be ignored. When odors are distinct, strong, and/or present when the pile has not been agitated, they are commonly an indicator of a problem in the compost pile and should be responded to. Common odors from compost piles include ammonia, methane and sulfides (“rotting garbage” smell). Most odors are indicative of one of two things – either the pile is low in carbon (microorganisms therefore do not have enough carbon to consume in proper proportions with the available nitrogen, and nitrogen is released as a gas – nitrous oxide), or the pile is low in available oxygen/high in moisture. If the pile is low in carbon, steps should be taken to incorporate additional carbon material into the mix. If the pile is low in oxygen, it may be the result of one of two things: excessive moisture or a high bulk density/pile compaction. For suggestions to reduce pile moisture, see the “General Responses” recommendations in the “Moisture Content” section of this primer, above. If the pile is too dense, the best response is to incorporate a bulking material, something with a large enough particle size to allow more airflow in the pile. This can be done in a similar manner to adding carbon or dry matter. If such a material is not immediately available, several successive turnings may suffice to elevate pile oxygen sufficiently.
36
General Pile Conformation: 1. Function – The conformation of your pile is the result of how the pile was constructed, the ingredients, and what is occurring within it. Pile conformation impacts how well the pile will be able to passively aerate. Additionally, the size of the pile will determine if the operator is able to combine piles to consolidate materials and free up additional site space. 2. Field Tools – Eyes 3. How to Measure – There is no measurement for assessing pile conformation. Simply observing piles visually will give the operator an indication of the pile shape, size and overall appearance. The operator should also look for surface crusting on the piles. 4. General Responses – If a pile is slumping, it will result in increased pile density at the core of the pile, thereby diminishing the availability of oxygen to that part of the pile. Slumping piles should have more bulking material incorporated into them, and should be reformed. Additionally, if the piles were large to begin with (8+ feet tall), then the operator should consider reducing the pile size. All compost piles will reduce in size. This is not an indication of pile slumping, but rather volume reduction through moisture loss. Small piles of similar age can be combined to consolidate biomass and pile management tasks, as well as make space available on the pad for new materials. Crusting on pile surfaces will reduce air exchange in the pile. Efforts should be made when constructing and turning piles with a bucket to limit compaction. Additionally, if high moisture materials are being added to the pile, they should not be “dumped” onto the pile and left. This excessive surface moisture will cause surface crusting. High moisture feedstocks, such as dairy
37
manure, need to be thoroughly mixed with other ingredients to prevent these issues.
___________________________________________________________________ Responses to any problems encountered during monitoring can often be determined by crosschecking the indicators from the various monitoring practices. For instance, if a pile is generating an ammonia smell, the operator may be able to determine that it is a result of excessive pile moisture because their squeeze test showed similar results. While individual monitoring measurements can provide the operator with valuable information, the results of the combined monitoring techniques collectively portray the internal pile conditions and should be assessed in this way.
Monitoring Compost Piles: Why & How was created by the Highfields Center For Composting - Hardwick, VT.
Management Plan For Food Scrap Feeding & Composting With Laying Hens was based off of Composter Management Plans originally created by the Highfields Center for Composting and developed by:
www.CompostTechnicalServices.com
38
Acknowledgments This Management Plan for Food Scrap Feeding & Composting with Chickens was funded by a grant from the Vermont Agency of Agriculture, Food and Markets and the Working Lands Enterprise Board with the VSWDMA as grantee. Any opinions, findings, and conclusions or recommendations expressed in these materials are solely the responsibility of the authors and do not necessarily represent the official views of the Grantors.
39