Lingua Guido, Copetta Andrea, Musso Davide, Aimo Stefania, Ranzenigo Angelo, Buico Alessandra, Gianotti Valentina, Osella Domenico, Berta Graziella
Dipartimento di Scienze e Innovazione Tecnologica, Università del Piemonte Orientale "Amedeo Avogadro", Viale Teresa Michel 11, 15121, Alessandria, Italy.
Mybasol S.r.l., via Gentilini 3, 15121, Alessandria, Italy.
Environ Sci Pollut Res Int. 2015 Dec;22(23):18616-25. doi: 10.1007/s11356-015-5502-7. Epub 2015 Oct 1.
High nitrogen concentration in wastewaters requires treatments to prevent the risks of eutrophication in rivers, lakes and coastal waters. The use of constructed wetlands is one of the possible approaches to lower nitrate concentration in wastewaters. Beyond supporting the growth of the bacteria operating denitrification, plants can directly take up nitrogen. Since plant roots interact with a number of soil microorganisms, in the present work we report the monitoring of nitrate concentration in macrocosms with four different levels of added nitrate (0, 30, 60 and 90 mg l(-1)), using Phragmites australis, inoculated with bacteria or arbuscular mycorrhizal fungi, to assess whether the use of such inocula could improve wastewater denitrification. Higher potassium nitrate concentration increased plant growth and inoculation with arbuscular mycorrhizal fungi or bacteria resulted in larger plants with more developed root systems. In the case of plants inoculated with arbuscular mycorrhizal fungi, a faster decrease of nitrate concentration was observed, while the N%/C% ratio of the plants of the different treatments remained similar. At 90 mg l(-1) of added nitrate, only mycorrhizal plants were able to decrease nitrate concentration to the limits prescribed by the Italian law. These data suggest that mycorrhizal and microbial inoculation can be an additional tool to improve the efficiency of denitrification in the treatment of wastewaters via constructed wetlands.
废水中的高氮浓度需要进行处理，以防止河流、湖泊和沿海水域出现富营养化风险。使用人工湿地是降低废水中硝酸盐浓度的一种可能方法。除了支持进行反硝化作用的细菌生长外，植物还可以直接吸收氮。由于植物根系与多种土壤微生物相互作用，在本研究中，我们报告了在添加了四种不同水平硝酸盐（0、30、60和90 mg l(-1)）的大型实验装置中对硝酸盐浓度的监测情况，使用接种了细菌或丛枝菌根真菌的芦苇来评估使用此类接种物是否可以提高废水的反硝化作用。较高的硝酸钾浓度促进了植物生长，接种丛枝菌根真菌或细菌使植物更大且根系更发达。在接种丛枝菌根真菌的植物中，观察到硝酸盐浓度下降更快，而不同处理的植物的N%/C%比率保持相似。在添加90 mg l(-1)硝酸盐的情况下，只有菌根植物能够将硝酸盐浓度降低到意大利法律规定的限值。这些数据表明，菌根和微生物接种可以作为一种额外的手段，通过人工湿地提高废水处理中反硝化作用的效率。
