沼液中有機物濃度和營養成分較高，總固體含量1%～2%，pH值成微堿性，富含大量氮、磷、鉀和多種微量元素、水解酶、氨基酸、有機酸、腐殖酸、生長素、赤霉素、B族維生素、細胞分裂素及某些抗菌素等生物活性物質，對作物的生長、防治作物病害和改良土壤性狀等有多重功效，施用沼液對瓜、菜、茶、果等作物在產量和品質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.
沼液中的重金屬含量隨飼料、獸藥的使用不同而具有較大差異，畜禽養殖中使用的部分飼料和獸藥在生產過程中添加了含有重金屬的添加劑，如銅和鋅等重金屬元素，絕大部分通過糞便及尿液排出，造成部分養殖場沼液中重金屬超標。土壤中重金屬元素富集，導致蔬菜污染，再通過食物鏈進入人體，使人體產生慢性中毒，嚴重影響人們的身體健康。
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.
沼液在滿足施用條件的情況下，最好的處置方式為田間施肥。但多數養殖場沼氣工程周邊并沒有足夠的土地用于沼液消納，且養殖場沼液BOD5/COD低，可生化性差，C/N/P不合理，氨氮、TP濃度高，部分沼液重金屬超標等，加大了養殖場沼液的處理難度。因此，探究高效的沼液處理技術成為當務之急。
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.
