京郊畜禽粪污氮磷含量特征及影响因素分析

中国规模化养殖废弃物中养分资源数量可观,但缺乏循环利用技术,处置不当易引发环境污染问题。该文通过问卷调研和粪污样品检测,对京郊典型养殖场粪便和废水中的总氮、总磷含量特点进行分析,同时追踪典型规模化猪场废水中总氮、总磷含量变化的影响因素及其季节性变化特征。结果表明:所调研的养殖场中,猪粪、牛粪的总氮质量分数平均值分别为29.1,17.8 g/kg,总磷质量分数平均值分别为15.1,6.8 g/kg,猪粪便的总氮、总磷含量变异程度大于牛粪;猪场和牛场中废水总氮、总磷质量分数的平均值分别为892,540和82.4,53.3 mg/L,猪场废水总氮、总磷含量变异程度明显大于牛场。规模化猪场粪便总氮、总磷含量受到饲料配方的影响较大;受饲料和圈舍用水量的影响,现行饲养工艺及粪污处理方式下粪便对废水中总氮、总磷含量的影响较小;万头以上的规模化猪场废水中总氮、总磷含量存在季节性差异,且随着废水存储时间的推移其无机磷比例增加。这些变化特征可对畜禽粪便和养殖废水的资源化再利用提供了有用的参考。

Characteristics of nitrogen and phosphorus content and analysis of its influencing factors in feces and wastewater of livestock farms in Beijing suburb

Abstract: With the increasing demand of meat products, animal husbandry industry had been rapidly developed in China in the past decade, especially the intensive livestock farms, increased from 16% to 52% in the total amount, from the year 1999 to 2015. Large amount of animal manures have been produced at the same time, which would be serious pollutant sources to the soil and water if they were discharged without any appropriate treatment. However, there is no suitable technology to deal with these wastes to realize recycling of nutrients, e.g. nitrogen (N) and phosphorus (P) in feces livestock farms, which must lead to serious environmental pollution. Because of the increasing amount of feces and shortage of treatment methods, it is meaningful to assess their potential impacts and the influencing factors in the intensive livestock farms, together with the research of treatment methods. Based on the questionnaire inquiry and samples collection, this study collected 41 questionnaires and 218 examples from 19 scale pig farms and 22 scale cattle farms in different districts of Beijing suburb. Then the concentrations of N and P in 86 wastewater samples and 132 manure samples were analyzed. And taking one of the pig farms as an example, the main influencing factors that changed the nutrients content were analyzed. The results indicated that, in the livestock farms investigated in this study, the average contents of the total N (TN) in manures from pig livestock farms and cattle livestock farms were 29.1 and 17.8 g/kg, respectively; the total P (TP) were 15.1 and 6.8 g/kg, respectively. It also suggested that more variation of TN and TP contents were observed in pig manure than that in cattle manure. The average contents of TN in wastewater of pig livestock farms and cattle livestock farms were 892 and 540 mg/L, and the TP were 82.4 and 53.3 mg/L, respectively. That was similar with the manure nutrient content, more variation of TN and TP contents were observed in wastewater from pig livestock farm. The TN and TP contents in pig manure in the large-scale pig farm were mainly attributed to the feed formula. TN and TP contents of manures had less effect on TN and TP contents of wastewater under the current methods of feeding and disposal of manure due to the fodder and water usage. For the solid manure selected in pig farms, content of TN and TP were more influenced by their feed formulas, rather than other factors. While for the wastewater in pig farms, the content of TN and TP were more influenced by their manure management process and feed formulas rather than solid manure even though most of N and P in the wastewater come from solid manure. The seasonal variation of N and P in wastewater were observed in the large-scale pig farms with more than ten thousand pigs and the proportion of inorganic P was increased with the time of wastewater storage. Results of this study provide reference for not only land use of manures and wastewater, but also decision-making on regional gross control of animal feeding and distribution of livestock farming.