Simerlink, Anthony S. 

The dairy industry is the main agriculture driver in Idaho. Dairy production produces large quantities of manure concentrated in the Magic Valley. The raw manure produces gas emissions and has the potential to leach nutrients into water sources posing an environmental concern. An adaptable pilot-scale composting system consisting of ten reactors was designed and evaluated to determine the feasibility of the composting system and to simulate on-farm composting. Data trends show that composting was achieved for several weeks without carbon correction. This system has the potential to implore many types of on-farm treatment effects at the pilot scale.

Budhathoki, Srijan

The consolidation of US dairy farming has led to concentrated manure production, resulting in manure management challenges and GHG emissions from unmanaged manure. Policies such as subsidizing compost production and implementing Strict Nutrient Application Standards incentivize composting of manure and mitigate these emissions while impacting compost demand and herd size. Our theoretical model indicates that both policies positively influence composting by lowering prices, increasing sales, reducing leftover manure, and cutting emissions. However, when considering the economic viability and size of the farm, subsidizing compost production and stringent Nutrient Application Standards have different impacts. Nutrient Application Standards, aimed at reducing runoff, increase the cost of managing excess manure, leading to smaller herd sizes.

de Haro Martí, Mario Emanuel ; Neibling, William Howard ; Chen, Lide ; Chahine, Mireille

A zeolite filter achieved 92% reduction in ammonia emissions from a dairy flushed manure pit. The reduction in odor concentration was 45% at a minimum filter residence time of 0.9 seconds. The on-farm filter and air collection structure over a manure pit demonstrated the applicability of the project. Abstract. The concentration of large numbers of animals in relatively small areas, high production output per animal unit, and concentration of animal excretions and air emissions are some of the characteristics of modern animal agriculture. Ammonia (NH3) and odors are among the most noticeable as well as locally and regionally problematic emissions generated by concentrated animal feeding operation (CAFO) dairy production systems. Zeolites are defined as aluminosilicates with open three-dimensional framework structures composed of corner-sharing TO4 tetrahedra, where T is Al or Si. Zeolites are able to lose or gain water reversibly and to exchange and retain cations, including NH3 and ammonium. This study demonstrated the design and performance of a zeolite filter treating the airstream from a flushed manure pit installed on-farm at a commercial dairy. Clinoptilolite zeolite mined in Idaho was used as the filter medium. The capacity of the filter to reduce NH3 emissions was tested at three, six, and 59 days of filter operation. Reduction of odor emissions was tested at six days of operation. NH3 emissions were reduced by 92% (p < 0.001) at three days of operation and by 42% (p = 0.13) at 59 days of operation. The ammonia concentration in the pre-treatment airstream from a dairy manure collection pit was relatively high at 5.287 ±0.04 mg NH3-N m-3 (p < 0.001). The odor concentration reduction was 45% (p = 0.001) at six days of operation with the minimum empty bed residence time of 0.9 s. Total trial running time was 59 days. The roof-like pit cover structure used for air collection and the zeolite filter were proven to be capable of operating in the harsh on-farm environment and to be adaptable to changing operating conditions within the dairy.

Ammar, Hajer ; Abidi, Sourour ; Ayed, Mediha ; Moujahed, Nizar ; deHaro Martí, Mario E. ; Chahine, Mireille ; Bouraoui, Rachid ; López, Secundino ; Cheikh M’hamed, Hatem ; Hechlef, Haikel

This study aimed to determine the emissions of methane (CH4) and nitrous oxide (N2O) from seven Tunisian livestock species and their evolution over eleven consecutive years (2008–2018). The species of animals used were cattle (dairy and others), sheep, goats, camelids, horses, donkeys and mules, and poultry. The estimations of CH4 and N2O emissions were based on the Intergovernmental Panel on Climate Change (IPCC) guidelines for national inventories, using Tier 1 and Tier 2 approaches, with its default emission factors (EFs). The Tier 2 approach was applied only for the calculation of EF to estimate CH4 emissions related to livestock manure management. CH4 emission represented more than 92% of the total greenhouse gas (GHG) from livestock emissions. Moreover, 53% of the total CH4 emissions from livestock were derived from cattle, followed by sheep, goats, other mammals (camelids, horses, mules, and donkeys), and poultry. During the period covered by the study (2008–2018), a slight and continuous decrease of both livestock population and total GHG emissions was observed, mainly in terms of CH4. In mammals, CH4 emissions were greater than N2O emissions, whereas in poultry, N2O emissions were up to 2.6 times greater than CH4 emissions. The aggressive drive of the government to increase cattle and sheep production might affect CH4 emissions in the future. Therefore, periodic estimations of GHG emissions from livestock are required to follow the time trends for more rational decision-making regarding livestock and GHG emissions policies.