Reduction of Bioaerosols Emitted from a Swine Confinement Building by a Percolating Biofilter During a 10-Month Period

Valérie Létourneau,Caroline Duchaine,Ariane Lévesque,Jonathan Vyskocil,Matthieu Girard

doi:10.3390/atmos10090525

Abstract

The release of pathogens into the air from swine confinement buildings are mitigated through preventative measures, such as outgoing air filtration, to reduce the risk of spread to nearby barns and communities. The present study aims to characterize the effectiveness of a percolating biofilter developed by the Research and Development Institute for the Agri-environment (IRDA) to capture airborne contaminants, such as bacteria and viruses emitted from a swine finishing room. Over a 10-month period (summer, fall, and winter), air was sampled upwind and downwind of the biofilter using two wet walled cyclonic samplers. Culture-dependent and molecular biology analyses were used to track changes in microbial concentrations and populations both captured and emitted by the percolating biofilter. Results revealed a minor reduction (median reduction efficiency 14.4%) in culturable bacteria. There was a decrease in total bacteria (qPCR) (75.0%) and other qPCR targeted organisms: archaea (42.1%), coliphages (25.6%), Enterococcus (76.1%), and Escherichia coli (40.9%). The community analyses showed similar bacterial diversity in the air upwind and downwind of the biofilter although more Proteobacteria were present downwind of the unit, likely attributable to the Proteobacteria-rich nutritive solution. Evidence is provided for bioaerosols reduction by a percolating biofilter treating air from a swine fattening-finishing room.

Highlights

The swine industry in Canada exported approximately $4 billion worth of pork products and $465 million in live pigs in 2017 [1], a financial portrait achieved by an industry continually moving away from small farms to large-scale operations [2]
The present study aims to evaluate the efficiency of bioaerosol removal by a commercial scale percolating biofilter, an air treatment unit (ATU) developed by the IRDA to treat emitted air from a finishing room
Upwind concentration for airborne culturable and total bacteria and archaea ranged from 333 CFU/m3 to 226,857 CFU/m3, 975 E. coli equivalent m−3 to 240,748 E. coli equivalent m−3, and 896 M. mazei equivalent m−3 to 5579 M. mazei equivalent m−3, respectively

Summary

Introduction

The swine industry in Canada exported approximately $4 billion worth of pork products and $465 million in live pigs in 2017 [1], a financial portrait achieved by an industry continually moving away from small farms to large-scale operations [2]. The increased number of pigs per building leads to larger amounts of air contaminants generated by swine confinement buildings (SCB) potentially posing a risk to surrounding farms and communities [3]. SCB emit contaminants such as dust particles, unpleasant odours, ammonia, hydrogen sulfide, various organic compounds and bioaerosols [4]. Bioaerosols are airborne particles containing whole or components of living organisms such as bacteria, archaea, fungi, and viruses. Workers may be exposed to and inhale pathogens [7,8]. These bioaerosols are capable of being emitted from SCB and travelling kilometers and, may pose serious concerns for neighboring farms, workers, and surrounding communities [9]. When examining air Atmosphere 2019, 10, 525; doi:10.3390/atmos10090525 www.mdpi.com/journal/atmosphere

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Conclusion