Tuesday, April 17 — Track 4
|Tuesday, April 17, 2012 | | TRACK 4 || 11:00 AM — 12:15 PM|
Aqueous Extracts From Vermicomposts As Germination Stimulant
Norman Arancon and Jesse Potter, University of Hawaii at Hilo
Vermicomposting is the process by which earthworms and their associated microorganisms breakdown organic matter. The finished product, vermicompost, has many beneficial uses in agriculture, ranging from using it as an excellent media, suppression of a range of plant diseases and pests, and also as a growth stimulant for plants. Plant growth-regulating materials such as humic acid and plant growth regulators such as auxins, gibberellins, and cytokinins are found in vermicomposts and are the responsible agents for increased plant growth and yield of numerous crops.
Vermicompost aqueous extracts (VC tea) are produced by mixing the finished vermicompost in water and brewing it for some time, usually around 24 hours or longer. Aeration has been shown to be essential for the effectiveness of VC teas due to the need for oxygen by the aerobic microorganisms found in vermicomposts which are responsible for production of the beneficial plant growth regulators. This experiment was aimed at testing the effectiveness of VC tea as seed treatment of tomato seeds and to find the optimum concentration for such practices. Soaking tomato seeds in VC tea at a concentration, as low as 1 percent, could accelerate germination rates and seedling growth. Higher VC tea concentrations seem to suppress seedling growth. Mechanism of accelerated germination will be discussed.
Accelerated Composting Of Hardwood Bark
Hoda Bakhshizadeh, Mississippi State University
Forest products industry in Mississippi generates considerable amount of unutilized hardwood barks annually. This material can be turned into a useful value added products. In a 3-month accelerated composting study, hardwood barks were amended with (20% & 40%) poultry litter and (1% & 2%) ammonium nitrate. Fifteen 35-gallon plastic cans were held unamended and amended hardwood treatments. Moisture content (MC) was adjusted weekly to keep the moisture level at 50-65% range by rainfall or well water. Samples were collected at days 0, 45, and 90 for pH, MC, carbon-to-nitrogen (C/N) ratio, and compost maturity test. The compost cans were also weighted after taking samples to measure the weight loss. All treatments showed weight reduction, but the amendment containing 40% poultry litter showed significantly higher weight reduction than the others for days 45 and 90. The greenhouse study on collected samples of day 45 and 90 with transplanted Zinnia (Zinnia elegans) for a period of 4 weeks showed comparable vigor (height, bud, and flower) to commercial nursery container media for 40% poultry litter treatment. Dried above ground weight of Zinnias for 40% poultry litter treatments was also significantly higher than the other treatments at the end of the study. All amended treatments showed higher C/N ratio than controls but no significant differences were observed between amended treatments. Overall, results indicated that amendment of hardwood bark with poultry litter could produce comparable product to currently used commercial container media.
Microbial And Compost Dynamics In In-Vessel Systems
Amardeep Kaur Wander, Australian National University
Continuous in-vessel composting systems have been seen to be able to increase the speed of composting as compared to the traditionally used heap systems. The lack of knowledge about how these systems work has limited their use on a large scale. Hot Rot? continuous in-vessel composting system acquired and set up by ANU Green at the ANU campus in Canberra is one such system. The aim of my study is to establish the relationship between the changes in composition of the material being composted with the different microbial communities that inhabit this system using 16S rDNA-PCR followed by DGGE, 454 pyro- sequencing and standard chemical indicators such as the Carbon and Nitrogen content, pH, electrical conductivity and temperature. Variations in the general working of the system such as; varying the residence time of the material in the vessel, seeding the input with the finished product were trialed. Chemical results showed that it was almost impossible to produce a composted product with a consistent quality. High Throughput Sequencing using the 454 platform has provided deeper insights into the bacterial diversity present in the system and helped explore the reasons for the system's failure to produce good compost. It has resulted in significant improvements and an overhaul in the way compost was being made using Hot Rot. Not only have we been able to get high temperatures within the system, good quality compost was achieved in a very short time.
|Tuesday, April 17, 2012 | | TRACK 4 || 1:45 PM — 3:30 PM|
Institutional Food Waste Management
Developing A Successful Hospital Food Waste Composting Program
Nicole Chardoul, Resource Recycling Systems
Today's leading healthcare organizations increasingly recognize sustainability as an essential part of their business strategy. Hospital food waste generated from cafeterias and room service is rarely discussed, but accounts for 10% to 20% of a hospital's waste stream. The Beaumont Hospital in Royal Oak, Michigan, in an effort to increase their landfill diversion rates, looked to analyze the amount of food waste passing through their system and find solutions for beneficial reuse.
RRS's work at the Hospital involved a baseline waste assessment to gather critical information about the facility, its current dish washing and garbage disposal processes, collect food waste volumes (including both pre- and post-consumer food wastes), and identify current collection, transportation and disposal costs. This information provided a foundation for our team to conduct market and vendor research on all available local processing opportunities for the facility's food wastes. In addition, RRS investigated methods for reducing disposable take-out containers and options for compostable service ware items that the facility could consider as part of a food waste composting program. Our work provided a set of prioritized best practice recommendations including food service operations, purchasing and process changes, feasible haulers and facilities willing to take the food wastes and associated costs. This information allowed the Hospital to evaluate their waste reduction goals and provided the green team with a set of next steps in their decision making matrix.
Our case study presentation will provide a set of considerations for other healthcare facilities looking to divert their pre- and post-consumer food waste streams. RRS will provide an overview of our analysis and best practices recommendations that were generated from our work with the Beaumont Royal Oak Hospital.
On-Site Food Waste Reduction Technologies At Urban University
Joe Rasmussen, Loyola Marymount University
This presentation will discuss two research projects conducted at Loyola Marymount University on the effectiveness of on-site food waste reduction technologies. The first study analyzed a food waste dehydration system with a focus on the characteristics of the end product. The second study focused on a food waste reduction system that converts food waste into a liquid effluent that is processed through the local sewer system, with an emphasis on the make-up of the effluent and its potential to be reused. This presentation will discuss the role of each system in reducing food waste from a dining commons at the university, with an emphasis on the results of the studies as well as implications for these technologies in similar settings.
Nitrogen Management Applied To Campus-Scale Composting
Stacey Dorn, Lafayette College
Composting has become an increasingly popular practice in the past decades. Conventional industrial fertilizers have negative implications in the areas of water quality, waste management, and agriculture. They are also currently a main source of non-point nitrogen run-off because the form of nitrogen in conventional fertilizers, highly mobile nitrate. Compost, however, could be an environmentally friendly alternative because it tends to contain nitrogen in a less mobile organic form. But in order for compost to be competitive with conventional methods, it needs to be much higher in nitrogen content. The management and improved conservation of nitrogen in compost has been the focus of several recent studies, initially on the pilot scale and now on a large scale. This project concentrates on gaining a better understanding of the chemistry of compost in large-scale batches.
School District Food Waste Recycling
Kevin Barnes, City of Bakersfield (CA)
The City of Bakersfield spearheaded an exciting new food waste recycling program in local schools with a simple breakthrough in how compost contaminants, particularly plastic janitorial bags and food packaging, are handled. The program decreases roughly 50% of landfill waste generated from school cafeterias. This diversion offers significant savings to schools. The pilot went so well that all local school districts enthusiastically requested cafeteria composting service.
Our new composting process eliminates the historical need to remove plastic before composting begins. Compost contaminants, like plastic bags and food wrappers, are first ground up with desirable material, like food. The composting starts after the grinding. It isn't until composting is done, that contaminants are weeded out of the product, first through a half-inch trommel screen, then through a quarter-inch minus screen. Ground up plastic residue goes in the overs fraction, where air separators effectively remove it from finished compost. This new screening process produces a finer product that's in demand among compost customers.
The program is successful in Bakersfield because it allows custodians to continue to use plastic liners, and it is forgiving if chip bags and other wrappers are discarded with food. These elements make food recycling feasible within school budget and staffing constraints. The ease of implementation, budget savings, and a sense of environmental stewardship also encouraged schools districts to make the switch from using polystyrene lunch trays to compostable cardboard trays or reusable trays instead. Schools and composters in other cities can benefit from lessons learned in Bakersfield, CA.
|Tuesday, April 17, 2012 | | TRACK 4 || 4:15 PM — 6:00 PM|
Compost Use In Horticulture
Composts Improve Plant Establishment In Compacted Urban Soil
Dan Sullivan, Oregon State University
Multiyear trial evaluates use of municipal composts to improve landscape plant establishment in compacted urban soil. Presentation will discuss results of the landscape trials from 2008-2011.
Class A Biosolids Use In High-Value Potting Mixes
Rita Hummel, Washington State University
Greenhouse and nursery growers rely on peat and bark as the conventional substrates for growing plants in containers. But their price is increasing and availability decreasing. Biosolids and other organic wastes represent an important source of materials with potential to replace them. Container plant growers are an obvious choice for utilizing some of these recycled wastes because of their need for potting mixes. As plants are sold, the potting mix is sold with them, creating demand for more. Desirable characteristics of potting mixes and research results showing recycled organic materials used as peat substitutes will be presented.
Acidifying Compost For Acid-Loving Plants
Shannon Andrews, Oregon State University
Blueberries, rhododendrons, and other acid-loving plants are produced commercially in western Oregon. Growers are interested in substituting compost for other organic materials (bark, peat, sawdust) as amendments for acid-loving plant production. Composted manure (pH 7+) is a weak liming agent, increasing the pH of acid soils. In previous research, we determined that the acidification requirement of compost, or the amount of acid required to reach a target compost pH, varies 2 to 3 fold among composts. The objectives of the present study are to: 1) compare actual acidification of composts in a farm-scale windrow to laboratory predictions of compost acidification requirement, and 2) to evaluate two elemental S products for efficacy in compost acidification. Four dairy solids composts and 4 horse stable waste composts were collected from local facilities. Two S products, Lily Miller Sulfur Dust TM (LMD) and pelleted Keg River Nutrasul 90TM (N90), were mixed with each compost to acidify compost to a target pH of 5. Bags of each compost + S mix were placed inside a warm compost windrow. Compost pH was monitored for 10 wk. The laboratory test for acidification requirement underestimated the amount of S needed for compost acidification to pH 5. Compost acidified rapidly with S dust, but it was not acidified with pelleted S. With LMD, 95% of the pH reduction occurred in 2 wk. After 10-wk, the pH of composts treated with S dust dropped from 8.5 to 6.2, while pH was unchanged with pelleted S.
Compost Application To Tree Nursery Fields
Tamara Thomas, Terre-Source LLC
Horticultural tree farmers face a challenging environment when attempting to grow crops for market. The product must be visually appealing, usually large, fully leafed out, and healthy. Especially for horticultural products shipped over jurisdictional lines be they state or national borders, the tolerance for pathogens is zero. This pushes the farmer to use a number of synthetic pesticides and fertilizers that are expensive and may be environmentally harmful. Additionally, tree nursery stock requires multiple year tending prior to marketability making each individual plant very valuable and losses less tolerable. Compost has been shown to be beneficial for many types of crops and the additional material is needed to replace soil lost with the root balls of sold trees.
In an attempt to "dial in" benefits of compost application and to re-supply the field with a local biosolids compost, a field application trial was performed on two strips across two fields with heavy soils that were subsequently planted with 59 different tree varieties. Soil samples were taken before and, to-date, 3 times after application. Tree observations were made during the summer of each year following planting. Tree deaths were investigated and hypothesized. A third field is being prepared for the next phase of the study.