Ammonia Emission Quantification from Pig Slurry Using Acid Wet Traps: Evaluation and Optimization of Measurement Frequency
2016
Antezana, W. | Ferrer, P. | Cambra-López, M. | Estellés, F. | Calvet, S.
Standardized measurement protocols are required to reduce ammonia (NH₃) emissions. In vitro measurement of NH₃ emissions consists in trapping the emission from an emitting source in an acidic solution under controlled conditions. The objective of this study was to assess the in vitro NH₃ measurement method from pig slurry with acid wet traps, as regards to the following: (i) the variation between replicates of NH₃ emissions measured in vitro, (ii) the relationships between partial and accumulated emissions, and (iii) the reduction of measurement frequency. For this study, a total of 60 pig slurry samples from different animal types (sows and growing animals) were collected from commercial farms. The coefficient of variation among replicates of accumulated NH₃ emission during 15 days was 6.73 %. Emissions tended to decrease with time, and an average reduction of NH₃ emissions about 16 % was found in the period 96–240 h with respect to the 0–96-h period. However, samples continued emitting considerable amounts of NH₃ after 360 h. Linear regression models allowed predicting emissions accumulated for 15 days using only the first 8 days (R ² > 0.90). Reducing NH₃ measurement frequency (from 24 to 48 h) did not significantly affect measured emissions (P > 0.05). The results of this study confirm that replication of measurements is required and a coefficient of variation of 10 % may be established as quality control requirement. The study also suggests that reducing the duration and frequency of measurements is a tangible option to simplify this methodology.
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