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In-house windrowing between flocks is an emerging sanitary management practice to partially disinfect the built-up litter in broiler houses. However, this practice may also increase ammonia (NH 3 ) emission from the litter due to the increase in litter temperature. The objectives of this study were to develop mathematical models to estimate NH 3 emission rates from broiler houses practicing in-house windrowing between flocks. Equations to estimate mass-transfer areas form different shapes windrowed litter (triangular, rectangular, and semi-cylindrical prisms) were developed. Using these equations, the heights of windrows yielding the smallest mass-transfer area were estimated. Smaller mass-transfer area is preferred as it reduces both emission rates and heat loss. The heights yielding the minimum mass-transfer area were 0.8 and 0.5 m for triangular and rectangular windrows, respectively. Only one height (0.6 m) was theoretically possible for semi-cylindrical windrows because the base and the height were not independent. Mass-transfer areas were integrated with published process-based mathematical models to estimate the total house NH 3 emission rates during in-house windrowing of poultry litter. The NH 3 emission rate change calculated from the integrated model compared well with the observed values except for the very high NH 3 initial emission rate from mechanically disturbing the litter to form the windrows. This approach can be used to conveniently estimate broiler house NH 3 emission rates during in-house windrowing between flocks by simply measuring litter temperatures.

An emerging poultry manure management practice is in-house windrowing to disinfect the litter. However, this practice is likely to increase emissions of ammonia (NH) and nitrous oxide (NO) from the windrowed litter. The objective of this study was to quantitatively compare NH and NO emissions from broiler houses with and without in-house windrowing. Two broiler houses at a commercial farm were used to compare the NH and NO emissions. Gas emission measurements were conducted continuously and simultaneously for both the control house (without windrowing) and the house with windrowing during the same production periods. The house emission rates were calculated by multiplying the hourly mean gas concentrations and the ventilation rates. The windrowed litter temperature was significantly higher than that of the control litter. The impact of downtime (the time lapse between flocks, during which the bird house is empty) windrowing litter on pathogen reduction was inconclusive because of very low or no recovery of both and spp. from control or windrowed litter samples, respectively. The windrowing house NH emissions were 26.2 and 16.6 kg d house, whereas for the control house, they were 14.6 and 12.8 kg d house in 2012 and 2013, respectively. The NO emissions from the windrowing house were also higher than those from the control house. The total NH and NO emissions from broiler houses practicing windrowing litter management were estimated to be 35.0 and 4.43 g bird, respectively, compared with 31.9 and 3.89 g bird for the control house, respectively., (Copyright © by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America, Inc.)

Gas-permeable membrane technology is useful to recover ammonia (NH 3 ) from liquid manures. In this study, phosphorus (P) recovery via MgCl 2 precipitation was enhanced by combining it with NH 3 recovery through gas-permeable membranes. Anaerobically digested swine wastewater containing approximately 2300 mg NH 4 + -N L -1 and 450 mg P L -1 was treated using submerged membranes plus low-rate aeration to recover the NH 3 from within the liquid and MgCl 2 to precipitate the P. The experiments included a first configuration where N and P were recovered sequentially and a second configuration with simultaneous recovery. The low-rate aeration reduced the natural carbonate, increased pH and accelerated NH 3 uptake by the gas-permeable membrane system, which in turn benefited P recovery. Phosphorus removal efficiency was >90% and P recovery efficiency was about 100%. With higher NH 3 capture, the recovered P contained higher P 2 O 5 content (37-46%, >98% available), similar to the composition of the biomineral newberyite (MgHPO 4 ·3H 2 O)., (Published by Elsevier Ltd.)

The gas-permeable membrane process can recover ammonia from manure, reducing pollution whilst converting ammonia into an ammonium salt fertilizer. The process involves manure pH control to increase ammonium (NH4(+)) recovery rate that is normally carried out using an alkali. In this study a new strategy to avoid the use of alkali was tested applying low-rate aeration and nitrification inhibition. The wastewater used was raw swine manure with 2390 mg NH4(+)-N/L. Results showed that aeration increased pH above 8.5 allowing quick transformation of NH4(+) into gaseous ammonia (NH3) and efficient recovery by permeation through the submerged membrane. The overall NH4(+) recovery obtained with aeration was 98% and ammonia emissions losses were less than 1.5%. The new approach can substitute large amounts of alkali chemicals needed to obtain high NH4(+) recovery with important economic and environmental savings., (Copyright © 2015 Elsevier Ltd. All rights reserved.)

While the oxidation of ammonia is an integral component of advanced aerobic livestock wastewater treatment, the rate of nitrification by ammonia-oxidizing bacteria is drastically reduced at colder temperatures. In this study we report an acclimated lagoon nitrifying sludge that is capable of high rates of nitrification at temperatures from 5 degrees C (11.2mg N/g MLVSS/h) to 20 degrees C (40.4 mg N/g MLVSS/h). The composition of the microbial community present in the nitrifying sludge was investigated by partial 16S rRNA gene sequencing. After DNA extraction and the creation of a plasmid library, 153 partial length 16S rRNA gene clones were sequenced and analyzed phylogenetically. Over 80% of these clones were affiliated with the Proteobacteria, and grouped with the beta- (114 clones), gamma- (7 clones), and alpha-classes (2 clones). The remaining clones were affiliated with the Acidobacteria (1 clone), Actinobacteria (8 clones), Bacteroidetes (16 clones), and Verrucomicrobia (5 clones). The majority of the clones belonged to the genus Nitrosomonas, while other clones affiliated with microorganisms previously identified as having floc forming or psychrotolerance characteristics.