Evaluation of a Shaker Dust Collector for Use in a Recirculating Ventilation System

Abstract

General ventilation with recirculated air may be cost-effective to control the concentration of low-toxicity, contaminants in workplaces with diffuse, dusty operations, such as in agriculture. Such systems are, however, rarely adopted with little evidence showing improved air quality and ability to operate under harsh conditions. The goal of this work was to examine the initial and long-term performance of a fabric-filter shaker dust collector (SDC) in laboratory tests and as deployed within a recirculating ventilation system in an agricultural building. In laboratory tests, collection efficiency and pressure drop were tracked over several filter loading cycles, and the recovery of filter capacity (pressure drop) from filter shaking was examined. Collection efficiencies of particles larger than 5 μm was high (>95%) even when the filter was pristine, showing effective collection of large particles that dominate inhalable concentrations typical of agricultural dusts. For respirable-sized particles, collection efficiencies were low when the filter was pristine (e.g., 27% for 1 μm) but much higher when a dust cake developed on the filter (>99% for all size particles), even after shaking (e.g., 90% for 1 μm). The first shake of a filter was observed to recovery a substantial fraction of filter capacity, with subsequent shakes providing little benefit. In field tests, the SDC performed effectively over a period of three months in winter when incorporated in a recirculating ventilation system of a swine farrowing room. Trends in collection efficiency and pressure drop with loading were similar to those observed in the laboratory with overall collection efficiencies high (>80%) when pressure drop exceeded 230 Pa, or 23% of the maximum loading recommended by the manufacturer. This work shows that the SDC can function effectively over the harsh winter in swine rearing operations. Together with findings of improved air quality in the farrowing room reported in a companion manuscript, this article provides evidence that an SDC represents a cost-effective solution to improve air quality in agricultural settings.

Assessment of Interventions to Improve Air Quality in a Livestock Building

“…Prior to shutting the system down for the mid-winter background concentration measurements in week 6, the automated shaking feature was used, which reduced the pressure through the filter to 184 Pa. After the final four weeks of use, the pressure drop reached only 259 Pa. The filtration unit may have higher capital cost and maintenance than a cyclone, but the filter should provide effective control for several winters (Peters et al, 2015). However, care must be taken to secure the filter when not in use to prevent destruction by rodents.…”

Simulation of Air Quality and Operating Cost to Ventilate Swine Farrowing Facilities in the Midwest U.S. During Winter

“…The air cleaner exhausted barn air at the flowrate of 0.47 m 3 s −1 (1000 ft 3 min −1 ) with an internal fan, filtered the dust, and returned 100% of the treated air to the building. The air cleaner was operated with a standard fabric filter (14-pocket polyester sateen filter, United Air Specialists Inc., USA) used in Peters et al (2015).…”

Control technologies to prevent aerosol-based disease transmission in animal agriculture production settings: a review of established and emerging approaches

“…( 74 – 77 ) Natural products including Melaleuca alternifolia (tea tree oil) coated filters have also been shown to inactivate filter-collected bioaerosols ( 78 – 81 ). For efficient bioaerosol control using surface-coated filters, the use of pre-filters and regular maintenance [to remove collected aerosols and avoid dust-loading ( 82 )] and replacement would be required with a higher frequency, but this may prove prohibitively costly.…”