Acidic hydrothermal carbonization of sewage sludge for enhanced alkaline extraction of phosphorus and reduced co-extraction of trace elements

IF 11.2 1区环境科学与生态学 Q1 ENGINEERING, ENVIRONMENTAL

Resources Conservation and Recycling Pub Date : 2024-10-10 DOI:10.1016/j.resconrec.2024.107936

引用次数: 0

Abstract

This study presents a two-stage process to recover phosphorus (P) from sewage sludge (SS) hydrochar, aimed at reducing trace element (TE) contamination. SS, mixed with Al-rich alum sludge (AS), underwent acidic HTC to convert Ca-P to Al-P. Alkaline extraction of hydrochar produced a P-rich, TE-deficient extract, as Al-P dissolves at high pH (> 12), leaving TEs insoluble. Optimal conditions for maximum P recovery were high temperature (∼240 °C), Al/P molar ratio (APMR) of ∼4, and feedstock pH of ∼3 – 4. This design process achieved 82 % alkaline P recovery, 34 % higher than the reference process. Overall P recovery ranged from 59 – 75 % in the design process, compared to 30 – 37 % in the reference process. Solid-state NMR revealed the Al-P association in hydrochar through surface complexation. TEs were mainly concentrated in the hydrochar. Thus, this method offers co-treatment of two waste streams with simultaneous resource recovery.

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对污水污泥进行酸性水热碳化处理，以提高磷的碱性萃取率并减少微量元素的共萃取率

本研究介绍了一种从污水污泥（SS）水炭中回收磷（P）的两阶段工艺，旨在减少微量元素（TE）污染。污水污泥与富含铝的明矾污泥（AS）混合，经过酸性 HTC 将 Ca-P 转化为 Al-P。由于 Al-P 在高 pH 值（> 12）下溶解，导致 TE 无法溶解，因此碱性萃取水碳会产生富含 P 但缺乏 TE 的萃取物。实现最高钾回收率的最佳条件是高温（∼240 °C）、铝/钾摩尔比（APMR）∼4、原料 pH 值∼3 - 4。该设计工艺的碱性磷回收率达到 82%，比参考工艺高 34%。设计工艺的总磷回收率为 59 - 75%，而参考工艺为 30 - 37%。固态核磁共振显示，铝-磷通过表面络合作用在水碳中结合。TE 主要集中在水碳中。因此，该方法可对两种废物流进行协同处理，同时实现资源回收。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

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来源期刊

Resources Conservation and Recycling 环境科学-工程：环境

CiteScore

22.90

自引率

6.10%

发文量

625

审稿时长

23 days

期刊介绍： The journal Resources, Conservation & Recycling welcomes contributions from research, which consider sustainable management and conservation of resources. The journal prioritizes understanding the transformation processes crucial for transitioning toward more sustainable production and consumption systems. It highlights technological, economic, institutional, and policy aspects related to specific resource management practices such as conservation, recycling, and resource substitution, as well as broader strategies like improving resource productivity and restructuring production and consumption patterns. Contributions may address regional, national, or international scales and can range from individual resources or technologies to entire sectors or systems. Authors are encouraged to explore scientific and methodological issues alongside practical, environmental, and economic implications. However, manuscripts focusing solely on laboratory experiments without discussing their broader implications will not be considered for publication in the journal.