The effect of protease and nonstarch polysaccharide enzymes on manure odor and ammonia emissions from finisher pigs.

A 2 × 2 factorial experiment was conducted to investigate the effect of dietary protease (0 and 200 mg/kg) and xylanase (0 and 200mg/kg) in reducing manure odor and NH(3) from finisher pigs. Sixteen pigs were assigned to 1 of 4 dietary treatments, (i) basal diet, (ii) basal diet + xylanase, (iii) basal diet + protease, or (iv) basal diet + xylanase + protease, for 24 d. The manure samples from pigs offered diets containing protease showed increased (P < 0.05) molar proportions of isobutyric acid, isovaleric acid, valeric acid, and branched-chain fatty acids in contrast to pigs offered diets without protease supplementation. The pigs offered diets with xylanase inclusion had reduced (P < 0.05) manure odor emissions compared to pigs offered diets without xylanase supplementation [598 vs. 1306 European odor units (OuE)/m(3)]. Pigs offered protease-supplemented diets alone had significantly higher NH(3) emissions compared to basal fed pigs. However, NH(3) emissions were reduced when protease was combined with xylanase. In summary, this study indicates that protease supplementation increased protein-derived VFA in manure and also increased manure NH(3) emissions when offered singularly. Consumption of diets containing xylanase reduced manure odor emissions.

Evaluation of the odour reduction potential of alternative cover materials at a commercial landfill.

The availability of virgin soils and traditional landfill covers are not only costly and increasingly becoming scarce, but they also reduce the storage capacity of landfill. The problem can be overcome by the utilisation of certain suitable waste streams as alternative landfill covers. The objective of this study was to assess the suitability of Construction & Demolition fines (C&D), Commercial & Industrial fines (C&I) and woodchip (WC) as potential landfill cover materials in terms of odour control. Background odour analysis was conducted to determine if any residual odour was emitted from the cover types. It was deemed negligible for the three materials. The odour reduction performance of each of the materials was also examined on an area of an active landfill site. A range of intermediate cover compositions were also studied to assess their performance. Odour emissions were sampled using a Jiang hood and analysed. Results indicate that the 200 mm deep combination layer of C&D and wood chip used on-site is adequate for odour abatement. The application of daily cover was found to result in effective reduction allowing for the background odour of woodchip.