Development of a Bench-Scale Air Sparged Continuous Flow Reactor for Struvite Precipitation from Two Different Liquid Swine Manure Storage Systems

Posted in: Environment by admin on August 20, 2010 | No Comments

Forced precipitation of struvite (MgNH ₄ PO ₄ ^. 6H ₂ O) can reduce dissolved reactive phosphorus (DRP) in swine manure slurries. Optimization of this process requires that the swine manure slurry pH be increased, that magnesium be added, and that sufficient reaction time be allowed for struvite precipitation. To gather data that could be used for a full-scale continuous-flow struvite precipitation reactor, a bench-scale (14-L) continuous flow reactor was designed, constructed, and tested. The bench-scale reactor used air sparging for both pH adjustment and mixing, used a peristaltic pump to continuously inject magnesium chloride (MgCl ₂ ^. 6H ₂ O), and was operated at a 10-min hydraulic retention time. The bench-scale system provided a 95% reduction of DRP in swine manure slurry collected from a concrete storage tank with a permeable cover, and a 78% reduction of DRP in swine manure slurry collected from a shallow under floor pit collection system. A bench-scale up-flow clarifier was designed, constructed, and tested for continuous flow separation of the precipitated struvite in order to provide total phosphorus (TP) removal. The up-flow clarifier was unable to continuously settle struvite particles formed in the bench-scale reactor and provided no significant TP removal through the system. The implication of this work for full-scale systems is discussed.

Comparison of the Effectiveness and Economic Costs of Two Production Scale Polyacrylamide Assisted Solid/Liquid Separation Systems for the Treatment of Liquid Swine Manure

Posted in: Environment by admin on July 30, 2010 | No Comments

This study evaluated and compared the effectiveness and economic costs of a polyacrylamide (PAM) assisted continuous gravity belt thickener and a PAM assisted inclined stationary gravity screen separator equipped with a backwash spraybar, each in tandem with an inclined stationary gravity screen-roll press separator to separate the solid and liquid components of liquid swine manure (raw slurry) under production scale operating conditions. The separation systems were operated from June through December processing 7,222,725 L (1,908,048 gal) of raw untreated slurry (RS1). Both treatments, gravity belt thickener and gravity screen, showed significant reductions of 84.9% and 97.8% for Settleable Solids, 93.2% and 93.7% for Total Suspended Solids, 63.7% and 69.5% for Chemical Oxygen Demand, 23.3% and 31.8% for total Nitrogen, and 52.3% and 60.5% for total Phosphorus, respectively, in the treated effluent. The cost for separation with the gravity belt thickener system was 0.474 per L (1.791 per gal) of raw slurry. The separation cost for the gravity screen system was 0.402 per L (1.518 per gal) of raw slurry. Application costs for irrigating the separated effluent generated from either system added another 0.061 per L (0.234  per gal) of raw slurry. Either of these solid liquid separation systems would be an effective and economically viable alternative to current disposal methods while providing additional operational and environmental benefits.

Characterization of an experimental water-cooled cover for sows

Posted in: Environment by admin on | No Comments

Heat stress relief for sows in hot and humid climates remains a challenge. This study investigates a cooling method that is intended to enhance heat dissipation from sows. The experimental device was an aluminium cover (1.5 m long by 0.65 m wide and either 0.8 m or 0.95 m high) fitted with water-cooled pipes (25 mm diameter, spaced at 100 mm, 150 mm or 200 mm) and attached to the frame of the gestation sow crate. Performance was evaluated for cooling water temperatures of 15 or 20 °C under ambient summer conditions. Results showed the black-globe temperature (BGT) in the simulated sow-occupied zone (SOZ) was reduced by the addition of the aluminium canopy by 3 °C at 200 mm tube spacing and 37 °C ambient temperatures. The narrower the tube spacing the greater the cooling potential, with the 100 mm tube spacing yielding a SOZ BGT reduction of 6.1 °C at 39 °C ambient temperatures. The results demonstrated that the larger temperature difference between ambient air and inlet water the greater the effect of the heat exchange, and that water of 20 °C or cooler could be used as the cooling water supply. The cooling potential with a 0.8 m high canopy was greater than that at 0.95 m. It was concluded that the cooling efficiency of the water-cooled cover was affected by the inlet water, the surrounding environment, and the structure and size of the canopy.

For more information the full article can be found at  http://www.sciencedirect.com/science/journal/15375110

Green Initiatives for the Swine Sector

Posted in: Environment, Pork Insight Articles by admin on April 1, 2010 | No Comments

Ontario’s Green Act has streamlined energy projects, and introduced the FIT program to the swine industry. Solar energy and biogas are two sources of energy the government is willing to purchase off of producers. The solar panels can be a micro-fit system, which can be placed on the roof or the ground. The ground panels will likely be better for rural areas where more space is available, and roof systems used in higher density areas. The roof’s integrity will have to be assessed before installing roof paneling. So far biogas projects are mainly run off of manure, as using high energy crops would not be profitable enough. Further use of biogas may take some re-evaluation of manure systems. Other green energy sources are wind, water, and biomass systems and new or renovated barns should consider their options before construction.

Evaluation of the Risk Factors for Shedding Salmonella with or without Antimicrobial Resistance in Swine Using Multinomial Regression Method

Posted in: Environment, Ontario Pork, Pork Insight Articles by admin on November 11, 2009 | No Comments

A multinomial logistic regression method was used to investigate the risk factors for antimicrobial resistance (AMR) in Salmonella isolated from faecal samples collected on 80 Ontario swine farms in Canada. The samples were classified into three groups including Salmonella-negative samples (S)), Salmonella-positive samples without AMR (S+AMR)) and Salmonella-positive samples with AMR (S+AMR+). The samples collected directly from pigs had a greater chance to be positive for Salmonella with AMR compared to those samples collected from the pen floor. The odds of culturing Salmonella with or without AMR was higher if pelleted feed was used compared with mash or liquid feed (P < 0.001). The faecal samples collected on farrow-to-finish farms had a significant lower chance of testing positive for Salmonella with multidrug resistance than the samples from grow-finisher farms (P = 0.004). The chance of culturing Salmonella without AMR on farms with a continuous system was higher than on farms with an all-in/all-out system (P = 0.009). However, there was no significant association between the flow system and recovery of Salmonella with AMR. The larger farms were more likely to be in S+AMR+ group than in S) group (P < 0.001) whereas herd size did not appear as a risk factor for being in S+AMR) group compared with S) group. These findings indicate that although on-farm antimicrobial use is one component of resistance, there might be other farm management factors that also affect the development of emerging resistant bacterial foodborne pathogens on swine farms. Finding different risk factors for shedding Salmonella with or without antimicrobial resistance would help to take the appropriate approach to each group if a control programme were to be implemented or an intervention applied.

Prevalence of Yersinia enterocolitica shedding and bioserotype distribution in Ontario finisher pig herds in 2001, 2002, and 2004

Posted in: Environment, Ontario Pork, Pork Insight Articles, Welfare by admin on October 10, 2009 | No Comments

We investigated characteristics of Yersinia enterocolitica infection in Ontario finisher pig herds. Our specific objectives were to estimate or test: prevalence of Y. enterocolitica shedding in finisher pigs, bioserotype distribution, agreement between the herd-level tests based on sampling pig and pooled fecal samples, whether bioserotypes cluster by farms, and whether Y. enterocolitica-positive herds cluster spatially. In total, 3747 fecal samples were collected from 100 farms over the years 2001, 2002, and 2004 (250 total herd visits). Fecal samples were tested by culture and positive isolates were biotyped and serotyped. Apparent pig-level prevalence of Y. enterocolitica was 1.8%, 3.2%, and 12.5% in 2001, 2002, and 2004, respectively. Estimated true pig-level prevalence of Y. enterocolitica was 5.1%, 9.1%, and 35.1% in 2001, 2002, and 2004, respectively. Herd-level prevalence was 16.3%, 17.9%, and 37.5% in 2001, 2002, and 2004, respectively. In all years, the most common bioserotype was 4, O:3, followed by bioserotype 2, O:5,27. Kappa between herdlevel status based on pig and pooled samples ranged between 0.51 and 0.68 for biotype 1A and bioserotype 4, O:3, respectively. For 4, O:3, a significant bias in discordant pairs was detected, indicating that pig samples were more sensitive than pooled samples in declaring a herd as positive. Farms tended to be repeatedly positive with the same bioserotype, but positive study farms did not cluster spatially (suggesting lack of between herd transmission and lack of a common geographic risk factor).

Intensive hog farming operations and self-reported health among nearby rural residents in Ottawa, Canada

Posted in: Environment by admin on September 10, 2009 | No Comments

Background: In 2004, hog farming operations were introduced in the village of Sarsfield in the
eastern part of Ottawa, Canada. This study evaluates the health-related quality of life (HRQOL),
and the prevalence of respiratory conditions among adults and children who lived in proximity to
this farm.
Methods: A cross-sectional survey was administered to a random sample of residents from seven
rural communities in the eastern part of Ottawa, Canada. We analyzed self-reported questionnaire
data obtained from 723 adults and 285 children/adolescents. HRQOL was assessed using the SF-
36 survey instrument, while data were also collected for sociodemographic characteristics, the
prevalence of selected health conditions, and lifestyle related behaviours (e.g., smoking) of
participants. Variations in self-reported health according to the residential distance to the hog farm
were evaluated using logistic regression and analysis of variance methods.
Results: For the most part, the prevalence of selected health conditions among adults and children
was not associated with how far they lived from the farm. No associations were observed with
migraines, respiratory conditions (asthma, rhinitis, sinusitis, and chronic bronchitis), and allergies.
However, a higher prevalence of depression was noted among those who lived within 3 km of the
farm relative to those who lived more than 9 km away (odds ratio = 2.01, 95% CI = 1.11, 3.65).
Furthermore, individuals who lived closer to the IHF were more likely to worry about
environmental issues such as water quality, outdoor and indoor smells, and air pollution. This level
of worry also contributed to lower HRQOL scores for individuals who lived closer to the farm. It
was also observed that the prevalence of depression was much higher among those who indicated
a concern about environmental issues (18.2%) when compared to those who did not (8.0%).
Conclusion: While our findings suggest that living in close proximity to an IHF may adversely
affect HRQOL these should be interpreted cautiously due to a lack of direct measures of
environmental exposures, and possible biases inherent in the use of self-reported health measures.

Dust concentration variation in relation to animal activity in a pig barn

Posted in: Environment by admin on September 2, 2009 | No Comments

The contribution of animal activity to dust concentration in a pig barn, was evaluated through the continuous monitoring of animal activity. PM₁₀ concentrations were measured during a three months observation period, from April to July, in a mechanically ventilated fattening room in Northern Italy. Pigs of 60 kg and with a mean age of 150 days were fed with liquid feed and were lodged on concrete fully slatted floor. PM₁₀ concentration was monitored continuously by a dust sampler. From April 12 at 13:42 until April 13 at 15:09, 33 pigs housed in two of the 16 pens of the barn were monitored using a video camera placed at the height of 5 m above the pen floor. A comparison of data related to dust measurement and to activity index was performed on the hours of recorded images. PM₁₀ concentration reached maximum values at feeding times, during feed release and with lights turned on. An increase in dust concentration took place within an hour after increased animal activity. PM₁₀ concentration decreased until it reached the nocturnal mean concentration (316 μg m⁻³) after 1 h from feeding time. As expected, correlation analysis showed that particulate matter concentration was associated with ventilation rate (70%, P < 0.001), with relative humidity (−93%, P < 0.001), with inside and outside temperatures which determine ventilation rate a priori, and finally with animal activity (99%, P < 0.001). These results confirmed the strong association that exists between animal activity and particulate matter concentration in animal houses. An increase in PM₁₀ concentration from 316 μg m⁻³ (the mean value of dust levels was observed at night when the recorded animal activity showed the lowest values) to 624 μg m⁻³ corresponded to the dust raised by 343 animals (with an increase in animal activity of 0.018 units), in a mechanically ventilated barn with fattening pigs fed with liquid feed, and lodged on a fully slatted concrete floor.

For the full text please subscribe to the Journal of Biosystems Engineering

Construction Resource Use of Two Different Types and Scales of Iowa Swine Production Facilities

Posted in: Environment by admin on July 30, 2009 | No Comments

As global populations and affluence rise, there is increasing demand for energy, animal protein, and construction materials. In many cases, available resource pools are insufficient to meet growing market demands, resulting in increased prices and competition for limited resources. This study evaluates key construction resources needed to build different types and scales of Iowa swine production facilities. Two types of facilities conventional confinement and hoop barn-based within farrow-to-finish pig production systems scaled to produce either 5,200 or 15,600 market pigs annually are examined. Conventional confinement facilities are typical of pork industry practice in the United States and are characterized by individual gestation stalls and 1,200 head grow-finish buildings with slatted concrete floors and liquid manure systems. The hoop barn-based alternative uses bedded group pens in hoop barns for gestation and finishing. Five building materials: concrete, steel, lumber, thermoplastics, insulation, as well as crushed rock and diesel fuel used for building site preparation are considered. Land surface area required for buildings and pig production infrastructure are also compared. Relative market costs of newly constructed swine facilities are compared under several material price scenarios. Using hoop barns for grow-finish and gestation results in lower construction costs. Increasing the scale of pig production results in lower construction costs per pig space, however the construction costs per pig space for a 5,200 head hoop barn-based complex is less than the construction costs per pig space for a 15,600 head conventional confinement system. In terms of construction resource use and cost, hoop barns for swine are a viable alternative that are less dependent on the scale of production than conventional confinement facilities.

Influence of source and concentrations of dietary fiber on in vivo nitrogen excretion pathways in pigs as reflected by in vitro fermentation and nitrogen incorporation by fecal bacteria

Posted in: Environment by admin on January 1, 2009 | No Comments

This study compared an in vitro method to measure bacterial protein synthesis during fermentation with an in vivo N excretion shift induced by diets differing in DF concentrations and solubility. It was found that, with the exception of final gas production, all in vitro kinetic characteristics and BNI were correlated with in vivo N excretion parameters, and regression equations for the prediction of N excretion pathways from in vitro data were identified. Even if the presence of resistant starch in the diet might alter the composition of the fibrous residue that is fermented, the in vitro method is a possible useful tool for the formulation of diets, reducing the effects of pig production on the environment.

For more information the full article can be found at http://jas.fass.org/