J. Mosquera

Nitrous oxide (N2O) emissions from biotrickling filters used for ammonia removal at livestock facilities

Recently several manufacturers of nitrifying biotrickling filters for ammonia (NH3) removal at animal houses have started to add a denitrification step to the installation, aiming to reduce the amount of discharge water by conversion of NH3 to nitrogen gas (N2). The aim of this research was to quantify the possible formation of nitrous oxide (N2O), which is a potent greenhouse gas, in three of these farm-scale installations. Furthermore, the removal efficiency of NH3 and odor was determined. All installations were successful in reducing the amount of discharge water. The average NH3 removal efficiency for the three locations was 85, 71 and 86%, respectively. However, a significant part of the NH3 removed from the inlet air was not converted to N2 but to N2O, which is a potent greenhouse gas. The part of the inlet NH3-N that was converted to N2O-N amounted to 17, 66 and 24%, respectively. The high N2O production might have been caused by a too low scarcity of biodegradable carbon/N ratio for complete denitrification. The average odor removal efficiency was 21, 32 and 48%, respectively. Further research is necessary to explore how process conditions can be adjusted and controlled in order to reduce the production and emission of N2O from these types of systems.

NDIR Gas Sensor for Spatial Monitoring of Carbon Dioxide Concentrations in Naturally Ventilated Livestock Buildings.

The tracer gas ratio method, using CO2 as natural tracer, has been suggested as a pragmatic option to measure emissions from naturally ventilated (NV) barns without the need to directly estimate the ventilation rate. The aim of this research was to assess the performance of a low-cost Non-Dispersive Infra-Red (NDIR) sensor for intensive spatial field monitoring of CO2 concentrations in a NV dairy cow house. This was achieved by comparing NDIR sensors with two commonly applied methods, a Photo-Acoustic Spectroscope (PAS) Gas Monitor and an Open-Path laser (OP-laser). First, calibrations for the NDIR sensors were obtained in the laboratory. Then, the NDIR sensors were placed in a dairy cow barn for comparison with the PAS and OP-laser methods. The main conclusions were: (a) in order to represent the overall barn CO2 concentration of the dairy cow barn, the number of NDIR sensors to be accounted for average concentration calculation was dependent on barn length and on barn area occupation; and (b) the NDIR CO2 sensors are suitable for multi-point monitoring of CO2 concentrations in NV livestock barns, being a feasible alternative for the PAS and the OP-laser methods to monitor single-point or averaged spatial CO2 concentrations in livestock barns.

Long Term NH3 Flux Measurements above Grasslands in The Netherlands

Ammonia concentration gradients were measuredabove a grassland in an agricultural region fromJuly 1998 to July 2000 at the locationSchagerbrug in the Netherlands. They were used tocalculate the surface-atmosphere exchange ofammonia by means of the aerodynamic gradienttechnique. Measurements of the ammonia exchangewere also performed at a grass field that is partof a major wetland reserve in the centre of theNetherlands (Oostvaardersplassen), during theperiod June 1994–September 1995. At Schagerbrug,low net emissions or small depositions weremeasured during the winter months, and a netemission up to 5 kg NH3 ha-1 month-1 in summer. The net annual emission was 26 kgN ha-1, with manure application contributingabout 50% of this emission. AtOostvaardersplassen mainly deposition occurred,but large emissions were measured in autumn. Themeasured exchange fluxes are compared to modelevaluations that incorporate plant physiologicaldata, such as apoplastic NH4+concentrations and pH. Results show a goodagreement between field observations and modelsimulations, although some improvements arenecessary during nighttime periods. Themeasurements are conducted within the GRAMINAEproject, a second tranche project of EC TERI.

Two options to explain the ammonia gap in The Netherlands

Abstract This paper addresses two hypothesis that try to explain the difference observed between the estimated NH3 emission levels in The Netherlands and those indicated by atmospheric measurements, the so called ‘ammonia gap’: the role of SO2 emissions regulating ambient NH3 concentrations through co-deposition, and long-term NH3 emissions after slurry injection. It was found that throughfall measurements of NH4+ could not be used as indicator for changes in NH3 emissions. The throughfall deposition of NH4+ is in close equilibrium to SO42− and NO3− and is thus regulated by the equilibrium of ambient NH3 and NH4+ in wet deposition and canopy water layers. When SO2 emissions decrease, the amount of available SO42− decreases, which imposes a limit on the deposition of (NH4)2SO4. Long-term emissions of NH3 after application of manure were monitored using a new technique, which continuously measures the concentration of NH3 in a cross-section of the emission plume downwind of the source. The emissions could be registered for 3 weeks after application of manure. The results indicate that the long-term emissions only contribute 1–2% to the total emission level. Both the effect of SO2 on the NH3 deposition levels and the long-term emission fluxes are not enough to explain the observed ammonia gap. It seems that several counteracting effects, some of them emerging from the new emission reduction regulations, contribute to the ammonia gap. An integrated approach to abate ammonia emissions is, therefore, needed. The implementation and regulation of production ceilings for reactive nitrogen might be a good option.

Multi-Pollutant and One-Stage Scrubbers for Removal of Ammonia, Odor, and Particulate Matter from Animal House Exhaust Air

In several European countries, acid scrubbers and bio-scrubbers are off-the-shelf techniques for effective removal of ammonia from exhaust air from animal houses and, to a lesser extent, for odor. The number of operating air scrubbers at livestock operations in the Netherlands in 2008 is estimated to clean the air of approximately 10 percent of the pigs produced nationwide. Currently, a new generation of so-called multi-pollutant air scrubbers are developed for intensive livestock production that mitigates emissions of both ammonia, odor and PM10/2.5. A research and implementation program has been set up by the Dutch government that aims to stimulate the development and introduction of multi-pollutant air scrubbers The objectives of this paper are to give an overview of technical principles applied in the current generation of scrubbers for livestock operation, and present results from research on one-stage scrubbers applied in pig and poultry production and preliminary results of the Dutch research program with regard to removal efficiencies and operational parameters of multi-pollutant scrubbers. Results are presented from tests of an acid scrubber developed for pig and poultry facilities. Mean ammonia removal performance on two poultry and two pig locations were all higher than 90%, means of odor removal varied between 26 and 64%. The first preliminary results of multi-pollutant scrubbers are shown. Future measurements will be carried out in the coming two years in order to get reliable data on long-term performance of the multi-pollutant scrubber systems.

Removal Efficiency of a Wire-to-plate Electrostatic Precipitator for Abatement of Particulate Matter Emission from Poultry Houses

Fan emissions from animal houses may contribute to elevated ambient particulate matter (PM) concentrations and pose a public health hazard. In this study, we investigated whether a commercial prototype Electrostatic Precipitator (ESP) could effectively remove PM from the exhaust air flow of poultry houses. The ESP consisted of (inlet to outlet) a mesh filter with automatic scraper, a fan (max. 27,000 m3 h–1) and one ionization unit (3.0 x 0.8 x 0.8; length x width x height), consisting of two horizontal electrode wires (+30 kV DC) and a grounded mesh conveyor belt running above the bottom of the ESP. The ESP was tested at two non-cage laying hen houses. In total, 16 pairs of upstream and downstream 24-hour measurements of PM10 and PM2.5 were made, spread over the calendar year. Mean removal efficiencies were 57% for PM10 and 45% for PM2.5 at mean PM loadings of 2.78 mg m–3 PM10 and 0.179 mg m–3 PM2.5. Removal efficiencies were generally higher in winter than summer. From this study, we conclude that the ESP is an effective measure for PM abatement at poultry house ventilation exhausts.

Emissions and Concentrations of Dust and Pathogens from Goat Houses

The objective of this study was to determine the emissions of dust and pathogens, especially Coxiella burnetii (C. burnetii), from goat houses in the Netherlands. The study was conducted in two houses for milking goats. Furthermore, emissions of ammonia, odor, and greenhouse gases (methane and nitrous oxide) and the contribution of the different dust sources to airborne dust were determined.

StalSens-Oren: meetsystemen voor bedrijfs-monitoring van emissies in de veehouderij : deskstudie naar de mogelijkheden voor directe emissieregistratie

Regulations on emissions of ammonia, fine dust and odour from livestock barns are based on emission factors of specified housing systems derived from field testing programmes of prototypes. Compliance with emission regulations is verified by inspection on the presence of specified housing systems on farms. An alternative regulatory approach is to rely on a farm based monitoring system that allows farmers to comply with a specified emission target by mitigation measures of their own choice. To enable this approach the development of a reliable and cost affordable farm monitoring system is needed. This report provides an overview of current technical options and perspectives for development, as well as a list of requirements that farm monitoring systems for emissions would need to meet.

Effect of Bedding Material on Dust and Ammonia Emission from Broiler Houses

Fine dust and ammonia are main pollutants emitted from broiler houses. The type of bedding material could influence these emissions. Therefore, in this study the effect of different bedding materials on fine dust and ammonia emissions from broiler houses was determined. The study was carried out in a mechanically ventilated broiler house with eight identical rooms for 2260 broilers each and compromised two production cycles (rounds) of 35 days. The broilers were raised on four different bedding materials: 1) white wood shavings; 2) chopped wheat straw; 3) ground rapeseed straw; 4) silage maize. In each of the two production cycles the bedding materials were randomly assigned to two of the eight rooms. PM10, PM2.5 and ammonia concentrations and ventilation rates were measured. Ammonia and ventilation rate were measured continuously, whereas dust concentrations were measured during 24 h at 16, 23, 30 and 33 days of age. The main results of the study were: