Odor control in poultry farm
Definition: 1-The sensation that results when olfactory receptors in the nose are stimulated by particular chemicals in gaseous form.
2-The property or quality of a thing that affects, stimulates, or is perceived by the sense of smell.
3- A sensation, stimulation, or perception of the sense of smell.
Odour is measured according to 3 parameters: quality, strength and occurrence. Odour quality is a comparison with a known odour such as rotten eggs or roses. Strength is the amount of fresh air needed to dilute odorous air to the threshold odour level where it can just be detected. Occurrence is the frequency and length of time the odour persists.
Figure 1. If the right combination of organic matter, water and warm temperatures exist, there is the potential for foul odours to be created.
Spread Of Odours
Odours can either be broadcast through air as a gas or be absorbed and transported by dust particles.
Factors affecting odour generation in poultry farm
Process Affecting factors
Breath, flatus and faeces Bird number and diet
Degradation of waste Temperature, pH and water content in the litter
Volatilisation of odorous compounds
in the litter Ventilation rate, climate, litter pH and temperature
Good practice, design and management should
always be considered before other odour control
strategies are implemented.
• it is possible to eliminate odors completely from chicken broiler farms,
but it depends on several factors such as
the size of the farm,
the area of the farm,
odor causing factors in the farm.
• identifying the sources of the odor, factors that produce them and sources to
• Odor control technologies can be thought of in three different categories,
1-those that reduce the generation of odors,
2-those that decrease the emission of
3-and those that increase dilution of odors.
Practical Ways To Help Minimize Odour Complaints
Preventing the Production of Odour Through Management
There are several management steps that can reduce odour production on the farm such as good housekeeping:
• Clean up spilled feed and manure. Even small leaks in feeders can result in large accumulations of waste feed over time.
• Wash manure-caked spreading equipment shortly after use.
• Keep animals clean — their warm bodies accelerate anaerobic decay.
• Dispose of deadstock promptly and properly.
• Minimize dust levels to prevent odours attached to dust particles from escaping through the ventilation system.
• Keep organic matter such as feed or bedding dry. Anaerobic decay, the major process of odour generation, is inhibited if moisture content is kept below 40%.
• Grade the farmstead to avoid standing water. Direct clean water away from manure piles.
• Check regularly for leaks from drinking water supplies — especially in chicken and turkey broiler barns.
• Ensure the ventilation systems are in good working order. Good ventilation helps to keep barns dry.
• Divert clean water away from manure storages.
• Reduce water bowl spillage.
• Obtain drier manure by adding bedding to absorb water.
• Roof a solid manure storage to exclude precipitation.
Reducing the moisture content in the litter will
inhibit anaerobic bacterial activity, and reduce
the formation of other odorous gases.
Furthermore, low pH (< 7.5) causes anaerobic
conditions, which correspond to an increase in
odour emission rates. Jiang (2000) reports that
the control of pH and water content in the litter
can effectively reduce the odour emission from sheds.
• There are around 24
technologies, for odor control.
• Most common approaches taken for odor removal include, proper manure
management, chemical usage, moisture control, installation of aerated systems
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.Use of biofilters is cost effective way for odor removal by converting the odorous gases to carbon dioxide and water. One of the cost effective and easy to use biofilters is a bed of organic material,
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.
Chemical or biological products are added to the manure.
Odour control additives have been designed to mask, neutralize or alter, either chemically or biologically, odours or odour production. By strictly following the manufacturer's instructions, the correct additive under the proper conditions may reduce odour emissions. Research has generally been inconclusive on the effectiveness of additives. Cost and the duration of effective odour treatment are factors when considering the use of additives.
Fly ash has been tested as a stabilizing agent that can inhibit the production of odours. The ashes are rich in calcium which, when added to manure, will raise the pH to 12 where all microbial activity ceases and sulphur compounds are fixed. About 250 kg of fly ash per m3 (2.5 lbs./imp. gal) of manure is required. After an initial strong ammonia odour, the treatment lasts for approximately one month. Similar to fly ash, lime can also be used to raise the pH of manure to reduce odours.
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; its 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. CBPA is organic liquid chemical, which is widely used as odor abatement. It eliminate all the malodors from the poultry farms to satisfactory Level.
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.
Equipment used for odor control Rotary Odor which have adjustable flow rates and can be set automatically on timers. This equipment does not lead to litter wetting and is non-drip.
TrueFog is another simplest and most effective method of removing odors from poultry farms.
TrueFog odor control systems provide a safe and economical method of
eliminating a wide range of odor problems. It is easy to install within few
hours and can operate 24 hours a day.
• In chicken houses major odor-causing compound like ammonia, can be eliminated
using Effective Microorganism (EM) products like EM Probiotic and EM Waste
Treatment. Several experiments with EM Probiotic in broiler farm indicated
Reduction of ammonia up to 70% in chicken dung. Use of EM Waste Treatment can eliminate odors and insect pests within 48 hours.
If methods for containing odours within the boundary of the farm are insufficient, odour treatment methods may be necessary.
Manure and other organic matter can be treated biologically or chemically to reduce odour potential. Biological treatments include aerobic (with air) systems such as aeration, and anaerobic (without air) systems such as anaerobic digesters. Other methods include using additives designed to chemically or biologically alter, reduce or mask odours.
In aeration, air is introduced into the liquid manure storage by mechanical agitation, or under pressure with compressors or blowers. The resulting aerobic breakdown of manure is much less odorous, however, the process requires a lot of electrical power.
Digestion under controlled anaerobic conditions speeds up a natural biological decay process to create biogas and a low-odour, biologically stable manure. Under controlled conditions at elevated temperatures the anaerobic digestion is more complete, odorous compounds are created and are then converted to odourless biogas. While digesters are only beginning to become economically effective in gas production, they have been very effective in reducing odours.