规模猪场机械通风育肥舍氨气产生及排放研究

为了获取机械通风育肥猪舍内氨气产生和排放的基础数据,分春、夏、秋和冬四季对规模化种猪场育肥猪舍(试验期间猪的日龄在90～110 d)的氨气浓度进行测定,在猪舍设定3个采样点,每个季节连续采样5 d,每日采样4次,同时采用通风量现场测定系统对风机通风量进行测定。结果表明:育肥猪舍内春季、夏季、秋季和冬季的氨气平均浓度分别为(3.60±1.67)、(3.15±1.02)、(3.88±0.38)、(8.41±0.98)mg·m~(-3),夏季氨气平均浓度最低,其次是春季和秋季,冬季氨气浓度最高;育肥猪舍不同季节通风量为38.1～112.7 m~3·h~(-1)·头-1,夏季通风量分别是春季、秋季和冬季通风量的2.08、2.34、3.04倍,在此通风条件下育肥猪舍内氨气浓度为1.6～10.0 mg·m~(-3)(风机故障除外),均未超过GB/T 17824.3—2008的限值(25 mg·m~(-3));育肥猪舍不同季节白天管理活动时间内(7:00—17:00)氨气排放速率为0.17～0.24 g·h~(-1)·m~(-2),而全天平均氨气排放速率为0.13～0.23 g·h~(-1)·m~(-2),夏季和冬季猪舍氨气排放值较高、其次是春季,秋季排放相对最低。

Ammonia production and emissions from a mechanically ventilated fattening swine confinement building

Ammonia(NH₃)emissions from livestock operations have become a major concern owing to the potential environmental and health risks, but there is a lack of NH₃ emission factors for better understanding the contributions of livestock operations to environmental pollution, especially to smog. The purpose of this study was to quantify NH₃ concentrations and the emission factors from a mechanically ventilated fattening swine barn at a commercial breeding swine farm in a suburb of Beijing. The fattening pigs were 90 d to 110 d old during the experimental period. There were three sampling areas in the barn, and the gas samples at each location were collected four times per day for five consecutive days in each season. Meanwhile, the ventilation rates of the exhaust fans in the fattening swine barns were measured using a Fan Assessment Numeration System. The average NH₃ concentrations in the fattening swine barns were(3.60±1.67), (3.15±1.02),(3.88±0.38), and(8.41±0.98)mg·m^-3 in the spring, summer, autumn, and winter, respectively. Among them, the minimum average appeared in summer and the maximum average was observed in winter. The NH₃ concentrations were positively correlated with relative humidity, but negatively correlated with temperatures inside the fattening swine barn. The ventilation rates ranged from 38.1 m³·h^-1·pig^-1 to 112.7 m³·h^-1·pig^-1 year-round, and the ventilation rate in summer was 2.08, 2.34, and 3.04 times greater than those in spring, autumn, and winter, respectively. Under the current ventilation scenario, the NH₃ concentrations in the fattening barn ranged from 1.6 mg·m^-3 to 10.0 mg·m^-3(except for fan fault), and all the values were lower than the limit value of 25.0 mg·m^-3 of GB/T 17824.3-2008. The NH₃ emission fluxes of the fattening barn in different seasons during the daytime(from 7 am to 5 pm)were approximately 0.17~0.24 g·h^-1·m^-2, and the corresponding daily mean emission fluxes were approximately 0.13~0.23 g·h^-1·m^-2. The emission flux in summer was equal to that in winter, both were higher than those in autumn and spring, and the lowest value of emission flux was in autumn. The fundamental data on NH₃ production and NH₃ emission factors of a deep-pit confinement fattening swine house were achieved in this study.