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

Determination of ammonia concentrations in air from livestock housing systems : Reference method using gas washing as applied by Wageningen Livestock Research

This document is elaborated to give a description of the gas washing method as applied by Wageningen Livestock Research (WLR gas washing method). This measurement method is commonly used as the reference method for ammonia concentration measurements for the determination of ammonia emissions from agricultural activities (livestock housing, manure storage, field application of manure). The objective of this document is to specify the performance characteristics of the method, and the procedure for preparation and deployment of this method in practice to measure ammonia concentrations from livestock housing systems

Orthofosfaat gehalten in varkensmest en potentieel voor terugwinning

This report describes the results of the research into the orthophosphate content in (separated) pig manure and faeces. Manure from several different animal categories was collected and separated with a screw press or a centrifuge, and samples were collected of the manure and fractions and analyzed on the content of available orthophosphate and total phosphate. Furthermore, the orthophosphate was extracted from the liquid fractions of the centrifuge with calcium hydroxide. The orthophosphate contents were low with the exception of the faeces of piglets and finisher pigs fed dry feed which had a content of around 2459 mg/kg

Emissie van stikstofverbindingen uit luchtwassers met biologische wasstap

In de regel wordt aangenomen dat in luchtwassers met een biologische behandelingsstap ammoniak uit stallucht wordt omgezet in nitraat en nitriet, dat vervolgens met het spuiwater wordt afgevoerd. Er zijn echter aanwijzingen dat onder bepaalde condities (grote) hoeveelheden andere gasvormige stikstofverbindingen kunnen ontstaan en emitteren. Uit de steekproef die is uitgevoerd, blijkt dat bij biologische luchtwassers met een lage pH (<6,5) grote hoeveelheden stikstofoxyden (NOy) kunnen ontwijken naar de lucht. Voor dergelijk luchtwassers is de netto stikstofverwijdering veel lager dan de ammoniakverwijdering---In a biotrickling filter treating animal house exhaust air, ammonia is usually converted to dissolved nitrite and nitrate and subsequently removed with the discharge water. However, under certain operating conditions other types of gaseous nitrogen compounds may be emitted to the air. From the survey that was conducted it follows that at low pH values (<6.5) large amounts of gaseous nitrogen oxides (NOy) may be emitted from biotrickling filters. As a result, the net nitrogen removal of these scrubbers is much lower than the ammonia removal efficienc

Determination of carbon dioxide concentrations in air from livestock housing systems : reference method using the lung method as applied by Wageningen Livestock Research

This document provides a description of the lung method as applied by Wageningen Livestock Research (WLR lung method). This measurement method is commonly used as a reference method for carbon dioxide concentration measurements from agricultural activities (livestock housing, manure storage). The objective of this document is to specify the performance characteristics of the method, and the procedure for preparation and deployment of this method in practice to measure CO2 concentrations from livestock housing systems

Schuimvorming op mest : eindrapportage

This report deals with the chemistry behind foam formation on liquid manure and the abatement of this foam in practical farm operation