Particulate matter (PM) concentrations are high in cage-free aviary hen houses due to accumulation of litter on the floor and hen activities. The of a spraying agent such as acidic electrolyzed water (AEW) to mitigate PM levels and disinfect houses has been reported, and high spray dosages will reduce PM to a low level. However, spraying a high dose of AEW may generate high levels of ammonia (NH3) due to an increase in litter moisture content (LMC). Lab-scale experiments were conducted to assess the effect of AEW spray dosage and pH on PM and NH3 emissions from the litter of aviary hen houses. Four dynamic emission chambers (DECs) located in an environmentally controlled room were used for the evaluation. Three spray dosages of 25, 50, and 75 mL kg-1 dry litter d-1 (equivalent to area application rates of 125, 250, and 375 mL m-2, respectively) and three pH values of 3, 5, and 7 at a free-chlorine concentration of 200 mg L-1 were tested. Spraying occurred within 10 min once a day for five consecutive days. A no-spray regimen was used as the control. The results showed that higher spray dosages of AEW led to lower PM emissions. In particular, spraying dosages of 25, 50, and 75 mL kg-1 dry litter d-1 reduced PM levels by (mean SD) 71% 3%, 81% 1%, and 89% 1%, respectively, immediately after spraying. The PM reductions were still significant 24 h after spraying, averaging 57% 4%, 71% 5%, and 83% 1%, respectively. There was no significant difference (p = 0.30 to 0.43) in reduction efficiency among the PM sizes (i.e., PM1, PM2.5, PM4, PM10, and total suspended particulates). For NH3 emissions, spraying 75 mL kg-1 dry litter d-1 generated 5 to 6 times greater NH3 emissions when compared to 25 mL kg-1 dry litter d-1 due to the difference in LMC (22.6% vs. 13.0%). Meanwhile, spraying AEW of pH 7 yielded 2 to 3 times higher NH3 emissions than AEW of pH 3 at the same dosage. Ammonia emissions of all spray treatments were found to be higher than that of the control, albeit no significant difference between the control and the 25 mL kg-1 dry litter d-1 dosage at pH 3 or pH 5 (p = 0.81 and 0.47, respectively). Pearson correlation coefficients between NH3 and spray dosage (0.82) and pH value (0.46) indicated that spray dosage is more linearly correlated to NH3 emissions than pH value (p < 0.05). The results suggest that a 25 mL kg-1 dry litter d-1 dosage at pH 3 is a prudent combination to control PM levels without causing undesired elevation in NH3 emissions in litter-based cage-free aviary hen houses. This lab-based finding provides the basis for field verification testing.
Microbe(s): Total Microbial Count
Slightly acidic electrolyzed water (SAEW) spray has been considered as a novel approach for airborne bacteria reduction in animal housing. This study aimed to optimize the operating parameters of SAEW spray based on the size distribution of sprayed aerosols, the available chlorine travelling loss in sprayed aerosols, and the reduction efficiency of airborne culturable bacteria (CB). The optimized operating parameters were the nozzle orifice diameter and the spray pressure. The size distribution 50) 60-90 m) are recommended for SAEW spray in animal housing.
Microbe(s): Avian influenza
Hypochlorous acid (HOCl) solutions were evaluated for their virucidal ability against a low pathogenic avian influenza virus (AIV), H7N1. HOCl solutions containing 50, 100 and 200 ppm chlorine (pH 6) or their sprayed solutions (harvested in dishes placed at 1 or 30 cm distance between the spray nozzle and dish) were mixed with the virus with or without organic materials (5 fetal bovine serum: FBS). Under plain diluent conditions (without FBS), harvested solutions of HOCl after spraying could decrease the AIV titer by more than 1,000 times, to an undetectable level (< 2.5 log10TCID50/ml) within 5 sec, with the exception of the 50 ppm solution harvested after spraying at the distance of 30 cm. Under the dirty conditions (in the presence of 5 FBS), they lost their virucidal activity. When HOCl solutions were sprayed directly on the virus on rayon sheets for 10 sec, the solutions of 100 and 200 ppm could inactivate AIV immediately after spraying, while 50 ppm solution required at least 3 min of contact time. In the indirect spray form, after 10 sec of spraying, the lids of the dishes were opened to expose the virus on rayon sheets to HOCl. In this form, the 200 ppm solution inactivated AIV within 10 min of contact, while 50 and 100 ppm could not inactivate it. These data suggest that HOCl can be used in spray form to inactivate AIV at the farm level.
Microbe(s): Newcastle disease virus, Avian avulavirus
Existence of bioaerosol contaminants in farms and outbreaks of some infectious organisms with the ability of transmission by air increase the need for enhancement of biosecurity, especially for the application of aerosol disinfectants. Here we SAHW containing 50 ppm chlorine in the aqueous phase. These data suggest that SAHW containing 100 ppm chlorine can be used for aerosol disinfection of NDV in farms.
Ammonia (NH3) emissions from animal feeding operations (AFOs) are the source of a number of environmental issues. Wet spray scrubbers using non-acidic solutions might be a new approach for NH3 mitigation from AFOs. A lab-scale spray scrubber was built to clean 0.024 m3 s-1 of an NH3/air mixture with an average NH3 concentration of 20 ppmv. Three variables including contact time, nozzle type, and scrubbing solution were investigated to evaluate their effects on the ammonia removal efficiency of the scrubber. The contact times were to 0.3, 0.6, and 0.9 s, which were achieved by changing the elevation of the spray nozzle. Two types of spray nozzles were studied. The nozzles had full-cone spray patterns with different spray angles and different the scrubbing solution.
The safety of electrolyzed seawater was evaluated by measuring the production rate of organic halogen compounds and the occurrence of reverse mutations. Aquaculture feedwater and wastewater were collected from a fish-culturing facility, and available chlorine of approximately 1.0 mg/L was generated to ensure a disinfectant effect. More than 90% of the generated organic halogen compounds were bromoform. The amount of bromoform was far less than the reference values for drinking water standards in Japan and the U.S., provided that the electrolyzation was performed within the range of normal use. The reverse mutation assay of electrolyzed seawater showed no mutagenicity. Electrolyzed seawater with available chlorine at an adequate level for disinfection can be used safely and effectively in various aspects of aquaculture.
Microbe(s): Total Microbial Count
Reducing airborne dust is an essential process for improving hen housing environment. Dust reduction effects of neutral electrolyzed water (pH 8.2) spray were investigated in a commercial tunnel-ventilated layer breeding house during production in northern China. A multipoint sampler was used to measure airborne dust concentration to study the dust reduction effects and distribution in the house. Compared with the control treatment (without spray), airborne dust level was reduced 34% in the 3 hr after spraying 216 mL m 2 neutral electrolyzed water in the breeding house. The dust concentration was significantly higher during the periods of feed distribution (1.13 0.13 mg m 3) and artificial insemination (0.72 0.13 mg m 3) compared with after spray (0.47 0.09 mg m 3) and during lights-off period (0.29 0.08 mg m 3) in the three consecutive testing days (P < 0.05). The experimental cage area was divided into four zones along the length of the house, with zone 1 nearest to the evaporative cooling pad and zone 4 nearest to the fans. The air temperature, relative humidity, airflow rate, and dust concentration were measured at the sampling points of the four zones in 3 consecutive days and mortality of the birds for the duration of a month were investigated. The results showed that the air temperature, airflow rate, dust concentration, and number of dead birds increase from zone 1 to zone 4 in the tunnel-ventilated layer breeding house.