Aerosols in livestock production, including particulate matter, pathogens, microbes (i.e., endotoxins), and viruses are important to livestock health, disease transmission, worker health, and overall cost of production. As particulate matter is composed of organic substances it can absorb and contain gases, microorganisms (including viruses), and other agents that can enhance its biological activity and, therefore, increase the risk of health effects. A number of studies have shown high prevalence rates of respiratory illnesses in animal farmworkers due to particulate matter present in livestock production facility air. In addition, an outbreak within a herd can have devastating economic impacts on the farm and to the industry. According to the estimates made by the George Morris Centre, the Porcine Reproductive and Respiratory Syndrome (PRRS) is costing a minimum of 130 million dollars per year to the Canadian swine industry. Moreover, bacteria and viruses can be easily spread to other animals, as well as to human populations, during transport.

The reduction of particulate matter and microbes in livestock production are paramount to livestock health and productivity and to the health of those who work in these environments. A number of remedial techniques to control these contaminants in livestock barns have been reported. These techniques include oil spraying, modifying feeds, litter amendment, and exhaust air treatment. There are, however, few technologies currently available on the market for air quality control. Among these remedial technologies, the electrostatic precipitation (ESP) based technology has the potential to be a robust and economically viable technology to reduce airborne particulates and associated microbes and odour in animal buildings.

Electrostatic precipitators have been effectively used to remove fine particles in flue gases from industrial plants (e.g., power, cement, metal industries) for decades. Among the advantages of ESP are low-pressure drop, high gas capacity, low energy demand, and high collection efficiency for fine particles (> 99%). Despite its desirable characteristics, ESP application in removing particulate matter, odour, and microbes in livestock facilities, as well as its impacts on animal productivity, has not yet been fully explored and investigated. Preliminary laboratory and field studies, however, have demonstrated that ESP is capable of effectively reducing dust, gases, and bacteria in livestock barns. 

Although the efficacy of ESP technology has already been investigated in a number of studies, its application in livestock production is still limited to the research stage. ESP efficacy in removing microbes in poultry barns has not yet been fully investigated and needs additional studies. Detailed economic analyses such as those that look into energy savings from reduced power requirements during winter and productivity gains from improved air quality against both ESP installation and operating costs are still lacking. Moreover, a remedy to the generation of ozone, which is a by-product from the ionization process, has not been considered in other previous related studies. Thus, the proposed research aims to evaluate the strategies (e.g., material type and configuration of charging electrodes, voltage level) in minimizing ozone production in larger scales such as in commercial poultry houses. More importantly, from industry perspectives, the Chicken Farmers of Saskatchewan (CFS) are interested in applying new techniques, such as ESP, to reduce dust and associated odour and microbes in poultry barns.

In the context of microbial deactivation/elimination, the current methods used in livestock facilities, including animal transport trailers, are disinfection with oxidizing agents (e.g., chlorine, formaldehyde, hydrogen peroxide), fogging with an organic acid, ultraviolet irradiation, and air filtration systems. However, drawbacks of these techniques are cost, odour, residual contamination, and toxicity. More recently, a chemical-free nano-technology-based method has been reported for foodborne bacteria inactivation. In this technique, engineered water nanostructures (EWNS) are generated through electrospraying condensed water vapour recovered from room air and has been found to be effective in inactivating bacteria due to the high electric charge per surface area at the nanoscale of the generated EWNS. This technique appears promising as a non-chemical method for microbial deactivation in livestock barns as water spray is also commonly used in these facilities for cooling animals and mitigating dust levels.  However, this method has been tested only at lab-scales with foodborne bacteria and airborne transmitted pathogens. Thus, this project aims to evaluate the effectiveness of this method in deactivating microorganisms prevalent in livestock buildings and transport trailers.

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Aims of the Project

The aims of this project:

1. Reduce dust and microbes in livestock facilities, so as to reduce/eliminate risks and hazards and enhance health and safety in agricultural production.
2. Improving and/or adapting existing technological advances for application in dust and microbial reduction in livestock facilities.

To achieve this project, the following objectives will be completed:

1. Evaluate the efficiencies of  ESP based air-cleaning techniques in removing dust in poultry houses in small, medium, and full-scale studies.
2. Develop/adapt a nanospray-based technology in deactivating microbes in swine barns and investigate its potential application using a lab-scale electrospray.
3. Evaluate the performance of electrospray in deactivating microbes in small and medium scale swine barns.
4. Evaluate the performance of electrospray in deactivating microbes in swine transport trailers.
5. Compare the results of ESP and nanospray studies to the results attained from the previously tested dust reduction strategies (i.e., oil sprinkling, v-scraper, and air treatment unit) to determine the most efficient, cost-effective, and feasible dust and microbial reduction method.

2019 - 2020 Year 1 Update

Aerosols in livestock production include dusts or particulate matter, pathogens, microbes and viruses all of which pose risks to both human, animal and rural community health. This research aims to evaluate the effectiveness of two emerging green technologies, electrostatic precipitation-based air cleaning technique and electro nano-spray, in dust reduction and deactivating microorganisms prevalent in livestock buildings and transport trailers.

During Year 1 of Activity 2, a pilot-scale electrostatic precipitator (ESP) study was conducted at the Poultry Research and Teaching Unit at the University of Saskatchewan. For the pilot-tests, 2,195 one-day-old chicks were randomly placed in one of two identical rooms - control or treatment - and raised under a floor housing system for 113 days. In the treatment room, commercially available electrostatic particle ionizers were used to remove dust, gases, and bacteria. In the control room, pullets (young chickens) were raised under typical conditions without the ESP. The results of these tests showed that the ESP-room had a 69% reduction in total dust, a 48% reduction in PM10 and a 44% reduction in PM2.5 as compared to the control room. Total bacteria count was also evaluated and the results showed a 33% reduction in bacteria at the beginning of the trial, but the reduction in bacterial concentration became less apparent with time.

To study the effects of nanospray, a laboratory-scale nanospray apparatus was developed. Preliminary tests on poultry barn bacteria showed up to 95% deactivation efficiency with the use of nanospray. Subsequent trials will be carried out in swine barns.

• Reduction of Aerosol Risks and Hazards in Livestock Production

2020 - 2021 Year 2 Update

Year 2 was particularly busy for the research team with a multitude of experiments completed for both the ESP and Nanospray technologies.

ESP 

The ESP system was tested in a medium-scale facility at the Research and Development Institute for the Agri-Environment (IRDA, Québec) as well as in a large-scale study at the Poultry Centre of the University of Saskatchewan. The small-scale ESP study that was initially planned was abandoned as it was considered unnecessary with the preliminary trials conducted at the Poultry Centre prior to the official start of the project. The medium and large-scale studies evaluated the efficiency of the technology in reducing dust, bacteria, ammonia (NH3), and odour in broiler houses as well as its impact on animal health and productivity.

The experimental trials demonstrated that the ESP system could substantially reduce dust in broiler houses by up to 62%, bacteria by up to 63%, and odour by up to 50%. However, no considerable reduction was observed on the NH3 concentration and performance decreased over time, probably due to the high accumulation of dust on collection surfaces. No substantial impact was observed on animal mortality or on the feed conversion ratio.

EWNS (Nanospray)

The research team completed two lab-scale studies demonstrating the performance of the nanospray system for 1) decontaminating surfaces and 2) inactivating airborne bacteria. The EWNS were produced with a lab-scale nanospray system using a syringe pump to force a water-based solution through metallic needles connected to a high voltage power supply. Very high inactivation rates, up to a 4.0 log reduction (99.99 % efficiency), were obtained in the surface tests using small stainless-steel coupons inoculated with a solution of E. coli.

A 250 L acrylic chamber with a controlled airflow was then used for the tests with airborne bacteria. Good results were obtained for the deactivation efficiency, but the values were much lower than with the surface decontamination tests. Since the EWNS droplets fell through the contaminated air as it flowed across the acrylic chamber, contact between the microbes and EWNS was not as efficient as with the surface tests.

• Improving Air Quality in Broiler Houses
• How Can an ESP Reduce Dust?

2021 - 2022 Year 3 Update

ESP 

Experimental trials for the ESP system were completed in Year 2 for both the medium and large-scale facilities. Results demonstrated that this technology could substantially reduce dust, bacteria, and odour in broiler houses. Work in Year 3 consisted of analysing data and communicating results.

EWNS (Nanospray)

For the EWNS, the lab-scale tests were completed in Year 2, therefore Year 3 activities focused mainly on optimizing the pilot-scale electro-nanospray system for generating the EWNS during the tests in a real barn environment (small-scale pig rooms at the Prairie Swine Centre barn facility) that will be conducted in Year 4. Both the air flow rate through the treatment chamber housing the nanospray and the number of nanospray injector needles had to be optimized for the pilot-scale system. The optimization studies used Escherichia coli as the test pathogen. Airborne E. coli inside the treatment chamber was generated with a nebulizer and used to evaluate the inactivation efficiency of the EWNS injected with 4, 8, 16 or 32 needles at various chamber air flow rates. Using experimental data, data from the literature and mass balance equations, the highest E. coli reduction was obtained at a chamber air flow rate of 41 L/min (10 ACH) and a nanospray with 16 needles. The results obtained will be applied in the subsequent small-scale tests in the PSC barn facility.

Publications

Other than the experimental work in the lab, the research team was also prolific with regards to sharing their findings, a total of 4 scientific research papers were published in Year 3!

• Tiny Particles for Improving Air Quality
• Deactivating Microbes in Swine Barns

2022 - 2023 Year 4 Update

• Dust and Bacteria Removal in Large-Scale Poultry Houses
• Scaling-Up the Nanospray Air Treatment System

2023 -2024 Year 5 Update

• Testing the Nanospray Air Treatment System in a Swine Barn
• Barn Surface Decontamination Tests
• Decontaminating a Swine Transport Trailer
• Watch the Final Project Video