Impact of sulphuric, hydrochloric, nitric, and lactic acids in the preparation of a blend of agro-industrial digestate and wood ash to produce a novel fertiliser
Impact of sulphuric, hydrochloric, nitric, and lactic acids in the preparation of a blend of agro-industrial digestate and wood ash to produce a novel fertiliser
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DOI：
10.1016/j.jece.2020.105021
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发表时间：
2021-01-12
影响因子：
7.7
通讯作者：
Aiouache, Farid
中科院分区：
文献类型：
--
作者：
Abelenda, Alejandro Moure;Semple, Kirk T.;Aiouache, Farid
厌氧沼气是一种大量产生的沼气废物，由于其含水率高，储存、运输和向陆地传播的费用很高。此外，土地应用需要特殊条件，以最大限度地减少养分的损失。这种材料主要用作土壤的有机物质来源，而农民则继续依赖NPK化肥，这些化肥是通过能源密集型工艺生产的。本工作评价了使用低污染的生物质底灰作为吸附剂来降低碳和养分的有效性和损失。试验了几种酸化条件，以增强有机废物的吸附和改善其脱水性能。最终的混合物旨在拥有更平衡的营养分布，并在作物生长方面提供比单独的沼泽地更好的表现。用硫酸、盐酸、硝酸和乳酸对废渣和灰渣进行严重酸化，使废渣-灰渣混合物中残留的氨量增加了两倍以上。研究发现，在灰渣与废渣混合之前，盐酸是制备灰渣作为吸附剂的最佳选择，并能促进混合物的脱水，以加强固液分离。这种酸并没有减少灰分中活性中心的数量，从而促进了酸化灰分的化学稳定；酸化灰分的加入使酸化灰分的pH值降低到低于豆渣的pH值，从而减少了混合物中NH3的挥发。
Anaerobic digestate is a waste product of biogas generation which is produced in large amounts and, because of its high water content, it is expensive to store, transport, and spread to land. Additionally, special conditions are required for land application to minimise the losses of nutrients. This material is primarily used as source of organic matter for soil while farmers continue to rely on NPK chemical fertilisers, which are produced using energy intensive processes. This work evaluated the use of low-pollutant biomass bottom ash as an adsorbent to decrease the availability and the losses of carbon and nutrients. A number of acidification conditions were tested to enhance the adsorption and to improve the dewaterability of the organic waste. The final blend was intended to have a more balanced nutrient profile and to offer better performance in terms of crop growth than the digestate alone. The severe acidifications of the digestate and ash using sulphuric, hydrochloric, nitric, and lactic acids increased more than twice the amount of ammonia which remained in the digestate-ash blend. Hydrochloric acid was found to be the best option for preparation of the ash as sorbent, before mixing with the digestate, and to promote dehydration of the blend to enhance solid-liquid separation. This acid did not reduce the number of active sites in the ash, to promote the chemical stabilisation of the digestate; the addition of the acidified ash reduced the pH below that of the digestate thereby reducing the volatilisation of NH3 from the blend.