Department of Agricultural and Biosystems Engineering, North Dakota State University, Fargo, ND, USA.
Department of Civil and Environmental Engineering, North Dakota State University, Fargo, ND, USA.
Chemosphere. 2017 Nov;186:695-701. doi: 10.1016/j.chemosphere.2017.07.153. Epub 2017 Aug 1.
Dissolved organic nitrogen (DON) from animal wastes can contribute to pollution of surface waters. Bioavailable DON (ABDON) is a portion of DON utilized by algae with or without bacteria. This study determined DON and ABDON levels in animal wastewater collected from two different sources: an animal feedlot wastewater storage tank and a sheep wastewater storage lagoon. Inocula for the ABDON bioassays were comprised of individual species and several combinations involving two algae (Chlamydomonas reinhardtii and Chlorella vulgaris) and a mixed liquor suspended solids (MLSS) bacterial culture. The ratio of initial DON to initial total dissolved nitrogen was 18% in the feedlot wastewater samples and 70% in the lagoon wastewater samples. The results showed that between 1.6 and 4.5 mg-NL-1 DON (45-79% of initial DON) in the feedlot samples and between 3.4 and 7.5 mg-NL-1 DON (36%-79% of initial DON) in the lagoon samples were bioavailable with the inocula tested. These results suggest that when considering eutrophication potential of livestock wastewater, organic nitrogen should be included in addition to the obvious culprits, ammonia and nitrate.
动物废水中的溶解有机氮（DON）会导致地表水受到污染。可生物利用的 DON（ABDON）是藻类利用的 DON 部分，无论是否有细菌参与。本研究测定了从两个不同来源收集的动物废水中的 DON 和 ABDON 水平：一个动物饲料场废水储存罐和一个绵羊废水储存池。ABDON 生物测定的接种物由单独的物种和涉及两种藻类（莱茵衣藻和普通小球藻）和混合液悬浮固体（MLSS）细菌培养物的几种组合组成。饲料场废水中的初始 DON 与初始总溶解氮的比例为 18%，而在池塘废水中的比例为 70%。结果表明，在饲料场样品中，有 1.6 到 4.5 mg-NL-1 的 DON（占初始 DON 的 45%-79%）是可生物利用的，在池塘样品中，有 3.4 到 7.5 mg-NL-1 的 DON（占初始 DON 的 36%-79%）是可生物利用的，使用了测试的接种物。这些结果表明，在考虑牲畜废水中富营养化的潜力时，除了氨和硝酸盐这两个明显的罪魁祸首之外，还应考虑有机氮。
