Michael Jørgen Hansen

• Cand agro., PhD
• Senior Researcher at Aarhus University

Animal manure in livestock production facilities is a major source of methane (CH4) and ammonia (NH3) emissions from agriculture. In this study, we investigated different polyphenol-rich extracts and chemicals including commercial chestnut tannin (CT), shea meal extract (SME) and lignosulfonic acid (LSA) in combination with 1 mM of urease inhibitor...

Introduction A spreadsheet model for estimation of slurry methane emission has been developed based on feed input to the animals, their excretion of organic matter, information of the design and size of the pen and the slurry pits, hydraulic retention times in the barns and storages, and the Arrhenius model for description of temperature dependency...

In the development and implementation of housing systems for pigs, there has been a significant focus on pig welfare including loose housing of lactating sows either indoors or outdoors. However, it is equally important to consider the environmental and economic aspects of housing systems to ensure sustainability in livestock production. The aim of...

Manure management is a significant source of methane (CH4) and ammonia (NH3), and there is an urgent need for strategies to reduce these emissions. More frequent export of manure for outside storage can lower gaseous emissions from housing facilities, but the longer residence time may then increase emissions during outside storage. This study exami...

Reducing methane from livestock slurry is one of the quickest ways to counteract global warming. A straightforward strategy is to reduce slurry retention time inside pig houses by frequent transfer to outside storages, where temperature and therefore microbial activity are lower. We demonstrate three frequent slurry removal strategies in pig houses...

Anaerobic digestion of animal slurry to produce biogas is the dominated treatment approach and a storage period is normally applied prior to digestion. Pre-storage, however, contributes to CH4 emissions and results in loss of biogas potential. Manure management was found to be an efficient approach to reduce not only the on-site CH4 emission but ma...

Land spreading of liquid animal manure (slurry) is a major source of atmospheric emissions. Ammonia (NH3) emission is of concern, as it is one of the main contributors to ambient air pollution and nitrogen deposition. Storage and field acidification of the slurry prior to application is used to mitigate NH3 emission, but the effect of acidification...

Livestock manure emits reduced sulfur compounds and methane, which affect nature and the climate. These gases are efficiently mitigated by addition of a tannic acid-sodium fluoride combination inhibitor (TA-NaF), and to some extent by acidification. In this paper, TA-NaF treatment was performed on swine manure to study the treatment influence on me...

The verification of odor abatement technologies for livestock production based on chemical odorants requires a method for conversion into an odor value that reflects the significance of the individual odorants. The aim of the present study was to compare the SOAV method (Sum of Odor Activity Values) with the odor detection threshold measured by olf...

Measurements of ammonia with inexpensive and reliable sensors are necessary to obtain information about e.g., ammonia emissions. The concentration information is needed for mitigation technologies and documentation of existing technologies in agriculture. A flow-based fluorescence sensor to measure ammonia gas was developed. The automated sensor is...

In the report we have estimated the hydraulic retention times (HRT) of slurries in Danish pig slurry pits based on feed intake, feed conversion and excretion of feces and urine of the pigs. We have assumed that the height of the residual slurry after flushing always is 3 cm and the minimum height before flushing should be 10 cm. Based on an Arrheni...

Field application of animal manure is a source of volatile organic compounds (VOC) and hydrogen sulfide (H2S) emission that contribute to air pollution and odor nuisance in local surroundings. In this study the non-methane volatile organic compounds (NMVOC) and H2S emission and odor activity dynamics over time after field application of pig and cat...

Application of straw as bedding increases welfare of pigs, but requires a slurry system that can handle slurry with a straw content. A new slurry system has been developed for slurry with straw content, where U-shaped slurry trays were scraped mechanically or flushed. The aim of the present study was to investigate the effect of the slurry system o...

Gaseous emissions from livestock production are complex mixtures including ammonia, methane, volatile organic compounds (VOC) and H2S. These contribute to eutrophication, reduced air quality, global warming and odor nuisance. It is imperative that these gases are mitigated in an environmentally sustainable manner. We present the discovery of a micr...

Livestock waste is stored and used as soil fertilizer or directly as substrate for biogas production. Methane emissions from manure storages and ammonia inhibition of anaerobic digesters fed with manure, are well-known problems related to manure management. This study examines the effect of adding tannic acid with fluoride (TA-NaF) and lignosulfoni...

Partial pit ventilation is a strategy to concentrate a large part of the air pollutants from pig houses in a small part of the ventilation air that can be treated by an air cleaner. In this study, the effect of partial pit ventilation on odorant emissions from two experimental pig houses (32 pigs in each) with two different ventilation inlet system...

Performance of a New Two-step Chemical Air Cleaner for Livestock Pit Ventilation Air Anders Peter Stubkjær Adamsen1, Simon Wilhelm Yde Granath1, Michael Jørgen Hansen2, Anders Leegaard Riis1 1SEGES; 2Aarhus University, Department of Engineering A two-step chemical air cleaner with an acid step and an alkaline step was developed by Agrifarm as a par...

Analytical measurements of odorants in combination with odor threshold values is an alternative to sensory measurements that can be used to evaluate abatement technologies for pig production facilities. The purpose of the present study was to estimate odor threshold values for key odorants found in pig house air. A new method was applied where an o...

Biological air cleaners used for reducing emissions of odorants are often challenged by the low solubility of reduced sulphur compounds. In a recent study high removal of hydrogen sulphide (∼75%) from the exhaust air from a pig house was achieved using a biofilter. The aim of this study was to investigate if this high removal could be due to the pr...

Alteration of the chemical composition of odor samples during storage in polymer sample bags can significantly impair the accuracy of subsequent odor evaluations. To overcome or minimize this effect, the mechanisms determining compound loss must be more thoroughly understood. The present study examines the storage stability of a selection of key od...

Odor analysis by olfactometry relies on the use of n-butanol as a reference compound for standardizing the selection of human panelists. This requires that human sensitivity towards n-butanol is correlated to sensitivity towards other odorants as well as complex odor mixtures. However, there is limited evidence in the literature of such correlation...

Reduced sulfur compounds emitted from livestock production cause odor nuisance for local residents. The microbial processes responsible for this are not well described in swine manure and a method for monitoring the biological processes is necessary to develop strategic abatement technologies. In this study, Proton-Transfer-Reaction Mass Spectromet...

Hydrogen sulfide (H2S) from agricultural sources is generally not included in sulfur emission estimates even though H2S is the major sulfur compound emitted from livestock production. Here we show that in a country with intensive livestock production (Denmark), agriculture constitute the most important sulfur source category (~49% of all sources of...

The present study provides an elaborate assessment of the performance of olfactometers in terms of odorant recovery for a selection of odorants emitted from livestock houses. The study includes three different olfactometer dilution systems, which have been in use at accredited odor laboratories. They consist of: (i) a custom-built olfactometer made...

The aim of the present study was to estimate a prediction model for odor from pig production facilities based on measurements of odorants by Proton-Transfer-Reaction Mass spectrometry (PTR-MS). Odor measurements were performed at four different pig production facilities with and without odor abatement technologies using a newly developed mobile odo...

BackgroundH2S and methanethiol, which are important odorants from pig facilities, were unsatisfactorily removed in field biological air filters with short residence time. For a better understanding of the process, this study established a dynamic model for simulation of H2S and methanethiol removal in a 3-stage biological air filter (2 stages of bi...

Online monitoring of odorous compounds in the ventilation air was applied in an experimental pig house in Denmark. The measurements were executed by proton-transfer-reaction – mass spectrometry (PTR-MS) while grab samples are used to confirm the identity of the compounds. Sorbent tubes samples were analysed by gas chromatography – mass spectrome...

For 6 weeks, 256 female finisher pigs (initially 53.9 kg) were fed four dietary treatments of 136, 148, 159 and 168 g crude protein (CP)/kg diet. The latter diet was the 159 g CP/kg diet supplemented with dispensable amino acids, to study the effect of excess CP. Week 4 included use of metabolic cages. Feed intake, gain and feed utilisation were no...

The aim of the present study was to investigate the effect of reduced crude protein level in finisher diets on ammonia, methane, and chemical odorants emitted from pig houses. Over a period of 44 days, pigs in two similar houses with 32 pigs (55–100 kg) in each were fed either a low-protein or a standard protein diet containing 136 or 159 g crude p...

It has previous been demonstrated that a pit ventilation system could improve indoor air quality and reduce ammonia emission significantly from pig production if an air purification system was installed to treat the pit exhaust air. However, the knowledge about the influence of a partial pit exhaust unit treating a small part of the ventilation (10...

The performance of on-site measurements by dynamic olfactometry using a mobile laboratory with online measurements was compared with delayed olfactometric analysis carried out by two external laboratories using the same kind of olfactometer as the mobile laboratory. All sampling and analyses were performed according to CEN 13725:2003, and analyses...

The aim of the present study was to evaluate the effect of abatement technologies for pig houses on odour based on 1) on-site measurements of dynamic olfactometry and chemical odorants and 2) dynamic olfactometry with storage of air samples in sampling bags. The study was conducted at two facilities with growing-finishing pigs with either biologica...

Emissions of reduced organic sulfur compounds from livestock facilities can cause severe odour nuisance to residents living in the vicinity, and development of abatement technologies is necessary. The aim of the present study was to investigate the removal effect of dimethyl sulfide (DMS) by using the peroxone reactions (O3/H2O2), an advanced oxida...

The aim of the present study was to examine the recovery of odorants during the dilution in an olfactometer designed according to the European standard for dynamic olfactometry. Nine odorants in the ppmv-range were examined including hydrogen sulfide, methanethiol, dimethyl sulfide, acetic acid, propanoic acid, butanoic acid, trimethylamine, 3-meth...

Reduced sulfur compounds are considered to be important odorants from pig production due to their low odor threshold values and low solubility in slurry. The objective of the present study was to investigate the use of a portable method with a single silica gel column for trapping/separation coupled with chemiluminescence detection (SCTS-CL) for me...

Biofiltration is a cost-effective technology for removing air contaminants from animal facilities. Kinetic analysis can be helpful in understanding and designing the process but has not been performed on full-scale filters treating complex mixtures. In this study, kinetics was investigated in a full-scale biological filter treating air pollutants f...

Methanethiol (MT) is a potent odorant that can be difficult to measure due to its high volatility and reactivity; it easily reacts to form dimethyl disulphide (DMDS) during sampling and/or analysis. This paper focuses on finding an optimal method for sampling and measuring MT with minimum artefact formation using sorbent materials and a thermal des...

There is an urgent need to develop odor reduction technologies for animal production facilities, and this requires a reliable measurement technique for estimating the removal of odorants. The purpose of the present experiment was to investigate the application of proton-transfer-reaction mass spectrometry (PTR-MS) for continuous measurements at a b...

The present work was performed to investigate the use of odorant measurements for prediction of odor concentration in facilities with growing-finishing pigs and to analyze the odorant composition in facilities with different floor and ventilation systems. Air was sampled in Nalophan bags, odor concentrations were measured by dilution-to-threshold o...

The aim of the present study was to investigate the effect of pit ventilation on the emission of odorants from pig production facilities. The study was conducted in four experimental facilities with 32 growing-finishing pigs (32-107 kg) in each. Facility A had partly slatted floor and only room ventilation, facility B had fully slatted floor and on...

Odor from pig production facilities is typically measured with olfactometry, whereby odor samples are collected in sampling bags and assessed by human panelists within 30 h. In the present study, the storage stability of odorants in two types of sampling bags that are often used for olfactometry was investigated. The bags were made of Tedlar or Nal...

Emission of odorous compounds from intensive livestock production is a cause of nuisance in populated rural areas. Knowledge on the chemical composition of odor and temporal variations in emissions are needed in order to identify factors of importance for emission rates and select proper abatement technologies. In this work, a method based on proto...

The aim of the present experiment was to investigate the stability of volatile reduced sulphur compounds during dilution in an olfactometer. Two types of olfactometers were used. In the first olfactometer the parts in contact with the samples were made by glass and in the second olfactometer stainless steel and PTFE (polytetrafluoroethylene, Teflon...

In Denmark, two brand new systems for reducing odour from swine production units are being developed. One of these systems is based on air purification using membrane technology, and the other system is based on treatment of slurry using ozone. This paper will focus on the former. The membrane air purification system was composed of 3 modules. The...

The present study was carried out to investigate how three different fibre sources, sugar beet pulp, soya bean hulls and pectin residue, in diets for growing pigs influenced the concentration of short-chain fatty acids (SCFA) in faeces, pH-value in faeces and slurry, excretion of nitrogen in urine and faeces and ammonia emission from slurry under d...

The present study was undertaken to investigate how three different fibre sources, sugar beet pulp, soya bean hulls and pectin residue, constituting 15% of diets for growing pigs, influenced daily body gain, feed conversion, apparent faecal digestibility and nitrogen and energy balances. Eight castrated crossbreed pigs (30-80 kg live weight) were u...

Odour from pig production is one of the biggest barriers to expanding pig production units in Denmark. There is a great need to develop methods to reduce odour emission. However, it is very important that the solutions are economically feasible. During the last four years, the National Committee for Pig Production has carried out approximately 1000...