Oriënterend laboratoriumonderzoek naar ammoniakemissie uit bodempakketten voor vrijloopstallen = Laboratory study of ammonia emission from bedding materials of freestall dairy cattle houses

In the Netherlands there is growing interest amongst dairy farmers in new housing systems in which animal welfare and health are improved. A promising system in this area is a loose housing system (without cubicles) where cows have a large area with a soft bedding where they can both being active and rest, so called freestalls. Although these systems are already applied in the USA and Israel, little is known about the environmental impacts, and particularly the ammonia emission. The aim of this study was to get some first impressions of the suitability of different bedding materials, especially concerning ammonia emission. The ammonia emissions of simulated urinations were measured in a laboratory set up with several bedding materials. As non degradable materials, two types of sand with larger and smaller average particle size and one type of rubber shaving were tested. As degradable materials freshly produced press screwed manure (the solid fraction), without (1) and with (2) an added mixture of sawdust and wood chips, composted press screwed manure (3) and (4) mud (peat soil/clay) originating from the small channels in the grasslands in an area with a peat soil with a top soil layer of clay. One week before the laboratory experiment, each of the bedding materials was mixed with fresh dairy cattle feces, urine and press screwed manure to get a quick simulation of the excreta accumulation in beddings in freestalls. Into the non degradable materials less feces and less screw pressed manure were added to simulate an on farm partly removal of feces from the resulting beddings. After preparation the bedding-excreta mixtures were kept one week in boxes in a ventilated house, with similar conditions as in a cow house. After this week, the ammonia emission from a simulated urination was determined in a laboratory set up. The degradable variants were tested both after manually pressing (higher density) and without pressing (lower density) the bedding mixtures in the laboratory set up. Ammonia emissions were higher with the non degradable bedding materials than with the degradable materials. The emission of the mud bedding mixture was low after 4, 24 and 72 hours. The emission of the mixture of screw pressed manure, sawdust, and wood chips with added excreta was very low after 4 hours. However after 24 and 72 hours the higher density variant showed a remarkable increase of ammonia emission while the low density variant did not. Between the tested bedding variants substantial differences in ammonia emissions were measured. Only a quick and short simulation was done to get first impressions. In reality, longer term accumulation of excreta in the beddings may result in build up of layers, silting up and different conversion rates in the freestall beddings. This may result in higher or lower emissions. The ranking of bedding materials may change as a result of this. Further research, also on other gaseous emissions like greenhouse gasses, in real cow barns is recommended to study this time and conditions dependent phenomena in more detai

Ontwikkeling snelle meetmethode ter bepaling van ammoniakemissiereductie van vloergebonden maatregelen = Development of a fast measurement method for the determination of ammonia emission reduction from floor related measures

This report describes different methods for determination of the effect of different floor types on (ammonia) emission. One method, the box method, has been further evaluated

Gasvormige emissies en fijnstof uit konijnenstallen met mestopslag onder de welzijnshokken = Gasesous emissions and fine dust from rabbit housing systems

In this study emissions of ammonia and fine dust (PM2,5 and PM10) from rabbit housing systems were determined. In addition, emissions of greenhouse gases and odour were determined

Fijnstofemissie uit stallen: (groot)ouderdieren van vleeskuikens = Dust emission from animal houses: broiler breeders

In this study emissions of fine dust (PM10 and PM2.5) from houses for broiler breeders were determined. In addition, emissions of ammonia, greenhouse gases and odour were determine

Fijnstofemissie uit stallen: nertsen = Dust emission from animal houses: minks

In this study emissions of fine dust (PM10 and PM2.5) from houses for minks were determined. In addition, emissions of ammonia, greenhouse gases and odour were determined

Van heinde en verre

Voor u ligt een rapport waarin verslag wordt gedaan van twee studiereizen. De eerste studiereis vond plaats in juni 2000 naar het Verenigd Koninkrijk en in oktober 2000 heeft een tweede studiereis plaatsgevonden naar de Verenigde Staten. Het doel van de studiereizen was om inzicht te krijgen in de stand van zaken met betrekking tot de ontwikkelingen van afstandsonderwijs en het gebruik van ICT in het hoger (afstands)onderwijs. Tijdens de studiereizen hebben wij met een groot aantal vertegenwoordigers van verschillende hogeronderwijsinstellingen en overheidsinstellingen gesproken. Het rapport dat voor u ligt, is een gezamenlijk product van de deelnemers1 (zie bijlage 1 voor een uitgebreider overzicht van de deelnemers per studiereis) aan de studiereis en start met een\ud samenvattende beschouwing van de twee studiereizen, waarin ook een conclusie en aanbevelingen zijn opgenomen. Daarna volgen de twee beschrijvende verslagen van de door ons gevoerde gesprekken

Maatregelen ter vermindering van fijnstofemissie uit pluimveehouderij: validatie van een luchtwassysteem met water als wasvloeistof bij twee pluimveebedrijven = Measures to reduce fine dust emissions from poultry housings: validation of a scrubber system with water as scrubbing solution at two poultry farms

In this study the removal efficiency for fine dust (PM10 and PM2.5) has been determined at two scrubbers located at two different poultry houses in addition, inlet and outlet concentrations were measured for ammonia, greenhouse gases and odour

Monitoringsprogramma experimentele gecombineerde luchtwassers op veehouderijbedrijven = Measurement program on experimental multi-pollutant air scrubbers at animal houses

A measurement program was carried out in which the performance of 5 experimental scrubbers on animal farms was monitored for the removal of ammonia, odour and fine dust (PM10, PM2.5). This reports discusses and evaluates the realization of the program and its results

Pre-nucleation clusters as solute precursors in crystallisation

Crystallisation is at the heart of various scientific disciplines, but still the understanding of the molecular mechanisms underlying phase separation and the formation of the first solid particles in aqueous solution is rather limited. In this review, classical nucleation theory, as well as established concepts of spinodal decomposition and liquid–liquid demixing, is introduced together with a description of the recently proposed pre-nucleation cluster pathway. The features of pre-nucleation clusters are presented and discussed in relation to recent modifications of the classical and established models for phase separation, together with a review of experimental work and computer simulations on the characteristics of pre-nucleation clusters of calcium phosphate, calcium carbonate, iron(oxy)(hydr)oxide, silica, and also amino acids as an example of small organic molecules. The role of pre-nucleation clusters as solute precursors in the emergence of a new phase is summarized, and the link between the chemical speciation of homogeneous solutions and the process of phase separation via pre-nucleation clusters is highlighted