沼液中有机物浓度和营养成分较高,总固体含量1%~2%,pH值成微碱性,富含大量氮、磷、钾和多种微量元素、水解酶、氨基酸、有机酸、腐殖酸、生长素、赤霉素、B族维生素、细胞分裂素及某些抗菌素等生物活性物质,对作物的生长、防治作物病害和改良土壤性状等有多重功效,施用沼液对瓜、菜、茶、果等作物在产量和品质上均有不同程度的提高。
Biogas slurry contains a high concentration of organic matter and nutrients, with a total solid content of 1%-2% and a slightly alkaline pH. It is rich in a large amount of nitrogen, phosphorus, potassium and many trace elements, hydrolytic enzymes, amino acids, organic acids, humic acids, auxins, gibberellins, B vitamins, cytokinins and some antibiotics, and other bioactive substances for crops. The application of biogas slurry can improve the yield and quality of melon, vegetable, tea and fruit.
沼液中的重金属含量随饲料、兽药的使用不同而具有较大差异,畜禽养殖中使用的部分饲料和兽药在生产过程中添加了含有重金属的添加剂,如铜和锌等重金属元素,绝大部分通过粪便及尿液排出,造成部分养殖场沼液中重金属超标。土壤中重金属元素富集,导致蔬菜污染,再通过食物链进入人体,使人体产生慢性中毒,严重影响人们的身体健康。
The contents of heavy metals in biogas are different with the use of feed and veterinary drugs. Some feedstuffs and veterinary drugs used in livestock and poultry farming add heavy metal additives, such as copper and zinc, and most of them are discharged through feces and urine, resulting in heavy metals in Biogas of some farms. It is beyond the standard. The enrichment of heavy metal elements in soil leads to vegetable pollution, and then enters the human body through the food chain, resulting in chronic poisoning, seriously affecting people's health.
沼液在满足施用条件的情况下,最好的处置方式为田间施肥。但多数养殖场沼气工程周边并没有足够的土地用于沼液消纳,且养殖场沼液BOD5/COD低,可生化性差,C/N/P不合理,氨氮、TP浓度高,部分沼液重金属超标等,加大了养殖场沼液的处理难度。因此,探究高效的沼液处理技术成为当务之急。
Under the condition of satisfying the application conditions, the best way to deal with biogas slurry is field fertilization. However, there is not enough land for biogas digestion around most farms, and the biogas slurry BOD5 / COD is low, the biodegradability is poor, C/N / P is unreasonable, the concentration of ammonia nitrogen and TP is high, and some of the heavy metals in the biogas slurry exceed the standard, which increases the difficulty of biogas treatment. Therefore, it is urgent to explore efficient technology for biogas slurry treatment.