Department of Applied Science and Technology (DISAT), Politecnico di Torino, Corso Duca degli Abruzzi 24, 10129 Torino (TO), Italy.
AGROINNOVA - Centre of Competence for the Innovation in the Agro-Environmental Sector, University of Torino, Largo Paolo Braccini 2, 10095 Grugliasco (TO), Italy; Department of Agricultural, Forest and Food Sciences (DISAFA), University of Torino, Largo Paolo Braccini 2, 10095 Grugliasco (TO), Italy.
Waste Manag. 2019 Nov;99:122-134. doi: 10.1016/j.wasman.2019.08.018. Epub 2019 Aug 30.
Sewage sludge production in European countries has widely raised in the last decade and its fate is currently landfilling, incinerators, composting or land application. To explore its agronomic potential, the main target of this work is to understand the effects of anaerobic digestates from sewage sludge (SSAD). To this aim, four different SSADs (two liquids and two dewatered) were characterized. On the liquid ones, Germination Index was evaluated through a plate bioassay with Lepidium sativum L. seeds; low concentrations of SSAD (2.5%) improved GI in one case, while at higher concentrations phytotoxic effects occurred in both. Then, pot experiments were set in climate chamber with Cucumis sativus L. grown for 30 days on two different substrates: a sandy, alkaline and poor soil, and peat substrate. All SSADs and a mineral fertilizer were used at three increasing dosages: 85, 170, 255 kg of nitrogen per hectare (kg N/ha). Results in terms of germination, dry biomass, chlorophyll content, net photosynthesis, stomatal conductance, CO concentration in substomatal cavity and root development were compared to a not treated control. All treatments gave results significantly higher or similar to control on all the parameters evaluated. Moreover, the intermediate nitrogen dosage (170 kg N/ha) generally showed the highest results compared to other dosages, especially for dewatered SSADs. All these results were much more evident for cucumber plants grown on an the alkaline, sandy and poor soil than on peat substrate, such demonstrating that SSADs have a fertilizing effect for plants growing on this kind of soil.
欧洲国家的污水污泥产量在过去十年中大幅增加，其命运目前是填埋、焚烧炉、堆肥或土地应用。为了探索其农业潜力，这项工作的主要目标是了解污水污泥（SSAD）的厌氧消化物的影响。为此，对四种不同的 SSAD（两种液体和两种脱水）进行了特性描述。在液体 SSAD 上，通过使用蕈菜种子的平板生物测定评估了发芽指数；低浓度的 SSAD（2.5%）在一种情况下提高了 GI，而在较高浓度下则会出现植物毒性。然后，在气候室内进行了盆栽实验，使用黄瓜（Cucumis sativus L.）在两种不同基质上生长 30 天：一种是沙质、碱性和贫瘠的土壤，另一种是泥炭基质。所有 SSAD 和一种矿物肥料以三种递增剂量（每公顷 85、170、255 公斤氮（kg N/ha））使用。发芽、干生物量、叶绿素含量、净光合作用、气孔导度、亚细胞腔中的 CO 浓度和根系发育等方面的结果与未处理的对照进行了比较。所有处理在所有评估参数上的结果都明显高于或与对照相当。此外，与其他剂量相比，中间氮剂量（170 kg N/ha）通常表现出最高的结果，尤其是对于脱水 SSAD。所有这些结果在碱性、沙质和贫瘠土壤上生长的黄瓜植物上比在泥炭基质上更为明显，表明 SSAD 对生长在这种土壤上的植物具有施肥作用。
