State Key Laboratory of Clean Energy Utilization, Institute for Thermal Power Engineering of Zhejiang University, Hangzhou 310027, China.
State Key Laboratory of Clean Energy Utilization, Institute for Thermal Power Engineering of Zhejiang University, Hangzhou 310027, China.
Waste Manag. 2018 Oct;80:349-358. doi: 10.1016/j.wasman.2018.09.034. Epub 2018 Sep 25.
The utilization of phosphorus from sewage sludge is an important method used to solve the shortage of phosphorus resources in the world. However, high levels of toxic compounds and low phosphorus bioavailability in sewage sludge are the main factors limiting its direct agricultural use. This paper proposes a low-temperature combustion method that can enrich the phosphorus in sludge ash. Low temperature-treated sewage sludge ash (LTSA) at different oxygen concentrations (20%, 60%, 100%) were obtained through a specific experimental device. Then, the species and leaching characteristics of phosphorus in LTSAs were analyzed and compared with pyrolysis sewage sludge char (PSSC) and incinerated sewage sludge ash (ISSA). Results show that low-temperature combustion of sludge increased the total phosphorus content in the bottom ash by 45.6%, and the bioavailable phosphorus content increased 2.9 times. Further, by increasing the concentration of oxygen while carrying out low-temperature combustion of sludge, part of the non-apatite inorganic P was converted to apatite P (AP), resulting in a 46.3% increase in AP in the sludge. Low-temperature combustion can also convert heavy metals (Cd, Cr, Cu, Pb, and Zn) in the sludge from an easily leachable form (acid extractable fraction and reducible fraction) to a stable form (reducible fraction) and decrease the leaching of heavy metals. Leaching of Cr and Cu decreased by 97.56% and 98.52%, respectively.
利用污水污泥中的磷是解决世界磷资源短缺的重要方法。然而，污水污泥中存在高浓度的有毒化合物和低生物有效性磷，这是限制其直接农业利用的主要因素。本文提出了一种低温燃烧方法，可以从污泥灰分中富集磷。通过特定的实验装置，在不同氧浓度（20%、60%、100%）下获得了低温处理的污水污泥灰分（LTSA）。然后，分析并比较了 LTSA 中磷的形态和浸出特性，并与热解污水污泥焦（PSSC）和焚烧污水污泥灰（ISSA）进行了比较。结果表明，污泥低温燃烧使底灰中的总磷含量增加了 45.6%，有效磷含量增加了 2.9 倍。此外，通过增加污泥低温燃烧过程中的氧浓度，部分非磷灰石无机磷被转化为磷灰石磷（AP），使污泥中的 AP 增加了 46.3%。低温燃烧还可以将污泥中的重金属（Cd、Cr、Cu、Pb 和 Zn）从易浸出的形态（酸可提取态和可还原态）转化为稳定的形态（可还原态），并减少重金属的浸出。Cr 和 Cu 的浸出率分别降低了 97.56%和 98.52%。
