中国畜禽粪便污染现状及产沼气潜力

Pollution status and biogas-producing potential of livestock and poultry excrements in China

为弄清中国畜禽粪便排放总量、污染现状及其资源化潜力,通过查阅文献确定了主要估算参数,并结合畜牧业统计数据估算了2009年中国畜禽粪便排放量及其污染物含量、粪便农用地负荷并对畜禽粪便中氮、磷农用地负荷进行预警分级;同时估算了粪便资源沼气潜力。结果表明:2009年中国畜禽养殖业粪便排放总量为32.64亿t鲜重,其中BOD、COD含量分别为7273.95和8039.96万t。全国单位面积农用地畜禽粪便负荷为26.8t·hm-2,氮、磷素负荷分别为158.42和47.92kg·hm-2。预警分级显示:牧区畜禽养殖业对环境不构成威胁;农区除山西、黑龙江外,其他地区均出现不同程度的氮素污染,而磷素的影响在农区普遍存在。2009年畜禽粪便资源沼气潜力约1200亿m3,其中,大中型畜禽养殖场沼气潜力为240亿m3,约合天然气135亿m3。目前沼气工程已成为环境保护和能源结构调整的一种重要手段。

In order to make clear the discharged amount, pollution status, and biogas-producing potential of the livestock and poultry excrements in China, the main parameters for estimation were ascertained based on relevant references, and the discharged amount, pollutant contents, and farmland loading of the excrements in 2009 were estimated, according to the related statistic data. The farmland loading of the excrements nitrogen and phosphorus was assessed by alarming values and classification grades, and the biogas-producing potential of the excrements was predicted. In 2009, the discharged amount of the excrements in China was 330 million tons, with 72.7 million tons of BOD and 80.4 million tons of COD, and the average farmland loading of the excrements was 26.8 kg·hm-2, with the nitrogen and phosphorus loadings being 158.42 kg·hm-2 and 47.92 kg·hm-2, respectively. The alarming and classification grading showed that the livestock and poultry breeding industry in China had little effects on the environment in pastoral areas, but the manure nitrogen caused varying degrees of environmental pollution in rural areas except those in Shanxi and Heilongjiang provinces, and the manure phosphorus pollution existed in all rural areas. The biogas-producing potential of the excrements was 1.2×1011 m3, and that in large-and medium-sized livestock and poultry breeding farms was responsible for 2.4×1010 m3, corresponding to about 1.35×1010 m3 of natural gas. To fully use the excrements for biogas production would be an important way for environmental protection and energy source structural adjustment.