|Odor Control Technologies for Buildings|
|Biofilters||Odorous gases are passed through a bed of compost and wood chips; bacteria and fungal activity help oxidize organic volatile compounds.|
|Biological and chemical wet scrubbers||Odorous gasses are passed through a column packed with different media types; water (and/or chemical) is sprayed over the top of the column to help optimize biological and chemical reactions.|
|Diet manipulation*||Enzymes added to diet to improve nutrient utilization; diets formulated to reduce crude protein content; or other changes in diets to enhance digestion.|
|Fat added to feed||Dust reduction and subsequent odor reduction by adding fat to the feed.|
|Manure additives*||Chemical or biological products are added to the manure.|
|More frequent manure removal*||Fresh manure (fewer than 5 days old) produces less odor than stored manure.|
|Nonthermal plasma||Odorous gases are oxidized when passed through plasma.|
|Oil sprinkling||Vegetable oil is sprinkled daily at low levels in the animal pens.|
|Ozone*||Ozone is added to the ventilation air to oxidize the odors.|
|Shelterbelts*||Rows of trees and other vegetation are planted around a building, thus creating a barrier for both dust and odorous compounds emitted from the building exhaust.|
|Windbreak walls*||A solid or porous wall constructed 10 to 15 feet from the exhaust fans will cause dust to settle out and will also help disperse the odor plume.|
|Odor Control Technologies for Manure Storages|
|Aerobic treatment||Biological process where organic matter is oxidized by aerobic bacteria; mechanical aeration is required in order to supply oxygen to the bacterial population.|
|Anaerobic digestion||Biological process where organic carbon is converted to methane by anaerobic bacteria under controlled conditions of temperature and pH.|
|Floating clay balls||Floating clay balls cover the manure surface.|
|Geotextile cover||Geotextile membranes are placed over the surface of the manure.|
|Manure additives*||Chemical or biological products are added to the manure to reduce gas formation.|
|Natural crust||Dairy and sometimes swine storage basins can form a natural crust. This crust will reduce odor emissions.|
|Solid cover||Non-porous cover floated on, or suspended over, the liquid surface. Covers trap gases before they escape. Gases must be drawn off and treated.|
|Solid composting||Biological process in which aerobic bacteria convert organic material into a soil-like manure called compost; it’s the same process that decays leaves and other organic debris in nature.|
|Solid separation*||Solids are separated from liquid slurry through sedimentation basins or mechanical separators.|
|Straw cover||An 8-12 inch blanket of dry wheat, barley, or other good quality straw floated on the manure surface reduces emissions.|
|Odor Control Options for Land Application of Manure|
|Manure incorporation or injection||Manure is incorporated immediately after land application or manure is injected under the soil surface.|
|Chemical addition||Chemicals added during agitation to reduce hydrogen sulfide or ammonia emissions.|
|Odor Control Options for Other Odor Sources|
|Mortality composting||Method to dispose of dead animals. Carcasses are buried in sawdust or some other organic composting material. Decomposition takes place very rapidly.|
*Effectiveness of these technologies has not been verified.
New or proposed facilities should be designed to minimize odor emissions. Currently, there are no standard criteria for “odor reducing designs.” However, any facility designed to reduce the surface area of manure exposed, control dust, capture and treat gaseous emissions, increase dilution of emissions, or treat manure could be considered as a design to reduce odor emissions. This may be as simple as building a deep pit manure storage versus having an outdoor manure storage structure, using a pull plug system with manure stored in an outside covered storage structure, or using a wet/dry feeder system to reduce dust. A new or proposed facility might also include plans for future odor control technologies should an odor problem ever arise. The design might include a designated space for a biofilter, liquid solid separation equipment, or plans for a windbreak. Solid manure systems also produce less odor per unit area than liquid systems and should also be noted on the odor management plan. Many new ideas and technologies are being developed to control odor. Those that prove successful should be integrated in future livestock and poultry facility designs.
One of the most important pieces of an odor management plan is the response protocol to address odor complaints. This is a critical issue from three perspectives. First, it is sometimes difficult to separate serious odor complaints resulting from excessive odor emissions from odor complaints registered by disgruntled neighbors during non-odor events. Second, it is difficult to determine how many valid complaints are needed to trigger the implementation of an odor control technology. And third, there must be some method for monitoring the effectiveness of the technology. The complaint response protocol will set up an odor monitoring plan and set guidelines for an acceptable number of odor events and some method to evaluate the effectiveness of an odor control technology. For this, it is critical to foster and maintain a good relationship with neighbors and other community members.
Avoid odor complaints by making an effort to control odor emissions, including peak odor events such as manure agitation or land application of manure. These efforts and their perceived effect on odors should be documented.
An effective complaint response protocol requires the input of neighbors and other community members such as environmental service specialists, county feedlot officers, and county and township officials. These individuals provide an honest evaluation of farm odor impacts. They could be listed on the odor management plan and help in the development of the complaint response protocol. A team approach fosters communication and flow of information which is critical to responding to complaints.
Monitoring odor events will help verify odor complaints and identify odor sources. Monitoring might include scheduled drives around the farm perimeter with a notebook recording the date, time, and location of the monitoring and the strength of any odors that were detected. Other monitoring might include record keeping of odor events by neighbors or community members. Strength of odors can be recorded on a three point odor intensity scale where 1=detectable odors, 2=recognizable odors, and 3=very distinct and annoying odors.
Since odors are a part of all livestock and poultry farming enterprises, it is impossible to expect 100% odor free air around the farm. However, frequent odor events of high intensity are unacceptable. Therefore, some reasonable frequency of odor events should be established. This frequency could include a given number of odor events per month or per year that are acceptable. Above this frequency, the odor management plan would be implemented. Establishing the acceptable frequency and intensity (how often and how strong) of odor events should be done with input from neighbors and community members so everyone is familiar with the goals of the farm.
After an odor control technology has been implemented, an honest evaluation of its effectiveness is needed. A complaint response protocol will outline evaluation methods and techniques. This evaluation will most likely be similar to Item 3—Monitoring Odor Events.
An outline for an odor management plan is given later. This plan should be reviewed and adjusted as needed on an annual basis. Changes in farm operation and management; additions or modifications of buildings or manure storages; changes in ownership of surrounding property; or changes in local, state, or federal regulations may all be reasons for altering the odor management plan. The success of any farm operation can be measured by the avoidance of community conflicts and nuisance complaints. This requires a planned approach to odor management and good communication between the farm management and the community.
Air Emissions Plan for Dust and Other Gases
An odor management plan is only one part of an air emissions plan. A complete air emissions plan would likely cover hydrogen sulfide, ammonia, and dust. Unfortunately, little information is available on the emissions of these gases from livestock and poultry facilities or on effective control technologies.
Creating a complete air emissions plan requires documentation similar to an odor management plan where emission sources and control strategies are identified. A key difference between odor management plans and management plans for other gases or particulates is in the goal of the plans. Odor management plans are written to reduce the impact of odors on the surrounding community. Hydrogen sulfide management plans are written to reduce the concentrations of hydrogen sulfide at the property line to levels below 30 ppb or 50 ppb according to the Minnesota Rules Chapter 7009.0080. The goal for ammonia and dust management plans is to reduce the total loading of these constituents to the atmosphere (e.g., tons of particulates emitted to the atmosphere per year). These differences in goals result in a plan that would be similar to odor management plans in source identification and possibly control technologies, but would be different in monitoring protocol and the response to measured exceedances of the standards.
Farm Name: _______________________________________________________
Developed by: _____________________________________________________
|Odor Source||Description||Nuisance Potential
high, med., low
|Odor Management Plan|
|e.g.||Manure Storage Basin||200 X 300 foot dairy earthen storage 100 feet from county road||high||A. Maintain crust by switching to straw bedding.
B. Blow straw cover on in spring and maintain crust or straw cover throughout the season
|Complaint Response Protocol
A complaint response protocol might include, but not be limited to, the following items:
|1. Steps taken to avoid nuisance odors.
|2. Steps to establish a working relationship between neighbors and community members.
|3. Odor event monitoring protocol.
|4. Defined frequency of acceptable odor events beyond which the odor management plan would be implemented.
|5. Criteria for monitoring the effectiveness of the odor control technology/management.
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