Abstract

This work investigates an innovative process to valorise agricultural digestate by the exploitation of solar energy. Digestate has been located in a lab-scale greenhouse to evaporate the liquid phase. Digestate vapours, rich in ammonia, are sent in a Drechsler trap, filled with 38% w/w sulfuric acid solution, through three solar air fans. A concentration of about 2 M of ammonium sulphate solution was recovered. The remaining dried solid phase, rich in phosphorous compounds, was evaluated as alternative to the commercial fertilizers (46% P₂O₅) in the growth of maize plants. Equal amount of P was applied to each pot (25 mg/kg soil). The plants were evaluated along the 8 weeks in a greenhouse monitoring the growth parameters and leaf SPAD index, micro-, macronutrients and non-essential heavy metals. The results evidenced that the dried solid phase of digestate can be used as an alternative source of P.

Graphic Abstract

中文翻译：

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用于硫酸铵回收和土壤改良剂生产的农业消化物的增值

摘要

这项工作研究了一种通过利用太阳能来提高农业消化物价值的创新过程。消化液位于实验室规模的温室中以蒸发液相。富含氨的消化蒸汽通过三个太阳能风扇送入充满 38% w/w硫酸溶液的 Drechsler 疏水阀。回收约2M浓度的硫酸铵溶液。剩余的富含磷化合物的干燥固相被评估为商业肥料（46% P ₂ O ₅) 在玉米植株的生长中。每盆施入等量的磷（25 mg/kg 土壤）。植物在温室中进行了 8 周的评估，监测生长参数和叶片 SPAD 指数、微量营养素、常量营养素和非必需重金属。结果表明，消化物的干燥固相可用作 P 的替代来源。

图形摘要