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Dr Praveen Kolar, assistant professor of biological and agricultural engineering at NC State, has developed an inexpensive treatment process that significantly mitigates odours from poultry rendering operations. Rendering facilities take animal by-products, e.g. skin, bones, feathers, and process them into useful products such as fertiliser. However, the rendering process produces extremely foul odours.

These emissions are not currently regulated by the government but the smell can be extremely disruptive to a facility's community. The industry currently uses chemical 'scrubbers' to remove odour-causing agents but this technique is not very effective, Dr Kolar says. Furthermore, some of the odour-causing compounds are aldehydes, which can combine with other atmospheric compounds to form ozone, triggering asthma attacks and causing other adverse respiratory health effects.

Dr Kolar, working with his co-author Dr James Kastner at the University of Georgia, has designed an effective filtration system that takes advantage of catalytic oxidation to remove these odour-causing pollutants. Specifically, the researchers use ozone and specially designed catalysts to break down the odour-causing compounds. This process takes place at room temperature so there are no energy costs and results in only two by-products: carbon dioxide and pure water.

The researchers developed the catalysts by coating structures made of activated carbon with a nanoscale film made of cobalt or nickel oxides, Dr Kolar says. "We used activated carbon because its porous structure gives it an extremely large surface area," Dr Kolar explains, "meaning that there is more area that can be exposed to the odourous agents."

The cobalt and nickel oxide nanofilms make excellent catalysts, Dr Kolar explains. "They increase the rate of the chemical reaction between the odour-causing compounds and the ozone, making the process more efficient. They are also metals that are both readily available and relatively inexpensive.”

Dr Kolar says his next goal is to apply this research to industrial hog farms. "This technology could be applied to swine operations to address odours and ammonia emissions," he sadi. "My next step is to try to pursue this research on a large scale."

Climate Change and Poultry Production

Poultry flocks are particularly vulnerable to climate change because birds can only tolerate narrow temperature ranges. Poultry farmers need to consider making adaptations now to help reduce cost, risk and concern in the future. 

Climate Changes Opportunities for Poultry Farmers

Savings may be possible: winter energy costs may reduce as warmer winters reduce the need to heat buildings and flocks can be acclimatised outside. Locally grown soya and maize would cut feed costs and poultry 'food miles'. Furthermore, meat products may increase in price and this – combined with feed prices possibly decreasing (due to the potential for soy yield to increase by 10 per cent as a result of rising carbon dioxide levels) – may make poultry farming more profitable. 

Climate Changes Challenges

The challenges posed by climate change fit broadly into one of two categories: loss of productivity or increasing costs.

Regarding productivity, housing systems need to be managed to maintain optimal seasonal temperatures and reduce the risk of heat stress, and increased investment will be required in ventilation and cooling.

Reproductive capacity may decrease. Studies by the Department for the Environment, Food and Rural Affairs (Defra) on broiler hens found that a poultry house put under a future climate change scenario exceeded critical temperature on 30 per cent more occasions despite a 10 per cent increase in ventilation.
Costs are likely to increase as the result of the need to cool buildings more in summer and reduce house humidity. Building infrastructure and maintenance will have to cope with more intense weather events and increased rainfall. This means that building plans need to consider more sustainable options, with greater investment in drainage systems to accommodate more extreme and frequent floods and frequent rainfall.

Stocking density in the house may need to be reduced in extreme temperatures, and actively controlled ventilation could become essential in transportation vehicles.

Adaptation Suggestions

Poultry farmers should reconsider building design in new builds to more effectively cope with new climate and weather extremes, including the installation of more/new equipment to cope with new climate extremes.

Mitigating Measures

These include the installation of renewable energy – such as solar or wind power – to power poultry sheds, and using biomass boilers or anaerobic digestion of poultry litter.

Although some of the impacts might happen to a greater or lesser extent in the short, medium or longer term, it is important to think ahead for the future, especially in relation to issues such as building design.

Creating a Healthier Environment for Poultry Workers

In their introduction, they explain that the Canadian poultry production industry contributes nearly $10 billion to the Canadian economy and employs nearly 50,000 workers. However, modern poultry facilities are highly contaminated with airborne dust.

They say that although there are many bioaerosols in the poultry barn environment, it is the endotoxin that is typically attributed with the negative respiratory symptoms observed in workers. They found that adverse respiratory symptoms are more prevalent in poultry workers than those working in other animal confinement buildings, and that those working in cage-housed operations facilities report a higher prevalence of some respiratory symptoms than those where the birds are kept on the floor.

In the paper, Just and her co-authors review the current state of knowledge on airborne dust in poultry barns and respiratory dysfunction in poultry workers while highlighting the areas that need further investigation. Their review focuses on the aerobiological pathway of poultry dust including the source and aerosolisation of dust and worker exposure and response.

Previous studies have found that dust levels are higher in floor system that houses with cages but that there was a tendency for the cage houses to have higher endotoxin levels, which has been linked to chronic phlegm in workers. However, the group points out that the two housing systems are not directly comparable because of differences in the age and type of birds kept in the house types, and the length of time workers spend in the houses.

There is evidence to support an adaptive response to endotoxin exposure in animal confinement workers.

The overwhelming evidence of the negative respiratory symptoms and immunological effects of poultry dust exposure suggests a need for remediation, say the researchers. They add, however, that many sources of dust, including some sources of endotoxin, are intrinsic to the poultry production industry and therefore, remediation is difficult. Measures that have been shown to be effective in controlling dust and ammonia levels include keeping poultry facilities clean, pelleted food, routine entry into buildings, use of lighting cycles, spraying water or oil and using respirators.