Weichao Zheng

Free chlorine loss during spraying of membraneless acidic electrolyzed water and its antimicrobial effect on airborne bacteria from poultry house

INTRODUCTIONnSpray-application of membraneless acidic electrolyzed water (MLAEW) is a novel technique for disinfection in livestock houses. This study investigated the loss of free chlorine (FC - the major germicidal component in MLAEW) over distance during spraying, as affected by air temperature and initial FC concentration. The anti-microbial effect of MLAEW on airborne bacteria from an aviary laying-hen house was examined.nnnMATERIALS AND METHODSnMLAEW was prepared at two FC concentrations: app. 15 and 60 mg L⁻¹, and sprayed at three air temperatures (18, 25, 32 °C). The original MLAEW solution and MLAEW aerosols collected at 0, 25, and 50 cm from the spray nozzle were analyzed for FC concentrations. Bacteria were immersed into these MLAEW samples and numerated for viable count after 0.5, 2 and 5-min treatments.nnnRESULTSnMLAEW aerosols collected at 0 cm lost 11.7-13.2% FC, compared with the original MLAEW solution. This initial loss was affected neither by the initial FC concentration (P = 0.13) nor by air temperature (P = 0.57). The rate of FC loss during travelling was 0.79-0.87 % per cm of aerosol travel distance (% cm⁻¹) at 18 °C, 1.08-1.15 % cm⁻¹ at 25 °C, and 1.35-1.49% cm⁻¹ at 32 °C. This travelling loss was affected by air temperature (P = 0.02), but not by initial FC concentration (P = 0.38). Bacteria were completely inactivated at 0.5 min when treated with MLAEW samples with FC > 16.8 mg L⁻¹, in 2 min when FC > 13.8 mg L⁻¹, and in 5 min when FC > 7.2 mg L⁻¹.nnnCONCLUSIONnAirborne bacteria from aviary hen house can be effectively inactivated by MLAEW with adequate FC concentration and contact time. During spraying, the anti-microbial efficacy of MLAEW aerosols decreased over distance due to FC loss which exacerbated at higher air temperatures.

Design and performance evaluation of the upgraded portable monitoring unit for air quality in animal housing

Upgraded Portable Monitoring Unit (PMU) to iPMU with online processing capability.Selected commercial electrochemical NH3 sensor to replace original obsolete sensor.Field measurements and subsequent laboratory reassessment show iPMU feasibility.iPMU provides economical and practical method for animal barn air quality studies. The Portable Monitoring Unit (PMU) was originally developed and used for measuring ammonia (NH3) and carbon dioxide (CO2) concentrations and emissions from poultry facilities. Its use entailed a substantial degree of manual setup and data processing, making field deployment of multiple PMUs a logistical challenge. The original commercial electro-chemical (EC) sensor for NH3 is no longer available. Thus, an effort to upgrade the PMU design was undertaken. A substantial redesign of the PMU system is reported in this paper, including the data acquisition and control system (DACS), and the circuit and tubing systems. A new NH3 EC sensor was selected by an evaluation of existing commercial sensors, followed by further tests to characterize its accuracy and limitations. The performance of the upgraded PMU (iPMU) was evaluated from field measurements taken in a commercial laying hen barn and subsequent laboratory reassessment. Results demonstrated the feasibility of iPMU, making multiple-point measurements for air quality in large-scale barns practical.

Design and Performance Evaluation of Upgraded Portable Monitoring Units for Barn Air Quality

Abstract. The Portable Monitoring Unit (PMU) was originally developed and used for measuring ammonia (NH 3 ) and carbon dioxide (CO 2 ) concentrations and emissions from poultry facilities. Its use entailed a substantial degree of manual setup and data processing, making deployment of multiple PMUs in field measurements a logistic challenge. The original commercial electrochemical (EC) sensor for NH 3 is obsolete and no longer available. Thus, an effort to upgrade the PMU design was undertaken. A substantial redesign of the PMU system is reported in this paper, and includes an upgraded data acquisition and control system (DACS), wireless data transfer capability, and a new commercial NH 3 EC sensor. An evaluation of existing EC sensors was performed, a sample of potential sensors was evaluated, and the selected sensor was further tested to characterize its accuracy and limitations. The performance of the upgraded PMU during field measurement in a commercial laying hen house and subsequent laboratory reassessment was evaluated and is reported here. Results demonstrate the feasibility of new system, termed the iPMU (Intelligent Portable Monitoring Unit).